4B1

Chapter 4 Part B: Fuel and exhaust systems K-Jetronic fuel injection - 8 valve engines
Contents
Accelerator ca le - removal! refitting and adjustment " " " " " " " " " " " 8 Air cleaner element - rene#al " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " $ Airflo# meter - removal and refitting " " " " " " " " " " " " " " " " " " " " " " " " " 1% Airflo# sensor &late and control &lunger - testing " " " " " " " " " " " " " " " 14 Auxiliary air valve - testing " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " 1' (atalytic converters - general information and &recautions " " " " " " " ) (old acceleration enrichment system - testing " " " " " " " " " " " " " " " " " 1) (old start valve and thermotime s#itch - testing " " " " " " " " " " " " " " " * +xhaust manifold - removal and refitting " " " " " " " " " " " " " " " " " " " " " " )4 +xhaust system - ins&ection! removal and refitting " " " " " " " " " " " " " ), Fuel accumulator - removal and refitting " " " " " " " " " " " " " " " " " " " " " " )1 Fuel filter - removal and refitting " " " " " " " " " " " " " " " " " " " " " " " " " " " " )' Fuel injectors - removal! testing and refitting " " " " " " " " " " " " " " " " " " 1$ Fuel lift &um& - testing! removal and refitting " " " " " " " " " " " " " " " " " " 18 Fuel metering distri utor removal and refitting " " " " " " " " " " " " " " " " 1, Fuel &um& - removal and refitting " " " " " " " " " " " " " " " " " " " " " " " " " " " 1* Fuel tan- and associated com&onents - removal and refitting " " " " " )) .eneral information and &recautions " " " " " " " " " " " " " " " " " " " " " " " " 1 /dle mixture - adjustment " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " 0 /dle s&eed - adjustment " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " 4 /dle s&eed oost 1air conditioned models2 - testing and idle s&eed adjustment " " " " " " " " " " " " " " " " """"""""""""""""""""""""""" % /ncreased idling s&eed valve 1air conditioned models2 - testing " " " " , /nlet manifold - removal and refitting " " " " " " " " " " " " " " " " " " " " " " " " " )$ 3ressure relief valve removal! servicing and refitting " " " " " " " " " " " 10 4arm-u& valve testing " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " 11

Degrees of difficulty
Easy, suita le for novice #ith little ex&erience Fairly easy, suita le

" 1 * 8 % " " " " " " " " " " " 4 " 0 t o , " 4 a r F r o m = a r c h 1 * 8 % " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " 1 * 8 4 ; e & t " a r /dle s&eed7 3 r e , " * t o , " ) " " "

for eginner #ith " some ex&erience"

Specifications
Air cleaner
5y&e " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " Automatic air tem&erature control +lement ty&e " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " 6ene#a le &a&er element A&&lication7 1"8 litre .olf " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " (ham&ion 8,'% 1"8 litre Jetta " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " (ham&ion 8,') 1"8 litre .5i 1 engine code 632 " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " (ham&ion 8,0)

" " " "

" " " " " " " " " " " " " " " " " " " " " " "

Fuel filter
1"8 litre .5i 1 engine code 632 " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " (ham&ion 9)'% All other models " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " (ham&ion 9)'4 : : New copper washers must be used and these are not supplied with the filter

Injection syste
5y&e " " " " """""""" """""""" """""""" """""""" """""""" """""""" KJetronic! continuou s injection system 1(/;2 A&&licatio n""""""" """""""" """""""" """""""" """""""" """""""" 1"8 litre 1code +<2 engine ;ystem &ressure7 3 r e = a r c h

" " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " 1 * 8 4 " " " " " " " " " " " " " " " " " " " " " " " " 1 1 ' ' ' r & m A i r c o n d i t i o n e d m o d e l s " " " " " " " " " " " " " 8 , ' t o ; e & t " 1 ' ' ' r & m F r o m * ' ' t o " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " 8 ' ' t o " " "

' '

'

r &

m (> content ? " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " '", to 1",
1'81 <4 .olf @ Jetta

4B) Fuel and exhaust systems - K-Jetronic fuel injection - 8 valve engines

!or"ue #rench settings

/njector insert " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " /njector line to injector " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " /njector line to fuel metering distri utor " " " " " " " " " " " " " " " " " " " " " " " " " 5hermo-time s#itch " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " ;ystem &ressure relief valve " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " (old start valve " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " 5hrottle valve housing to manifold " " " " " " " " " " " " " " " " " " " " " " " " " " " " " /nlet manifold " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " Fuel filter clam& " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " 8nion olt at filter 1from fuel accumulator2 " " " " " " " " " " " " " " " " " " " " " " " 8nion nut at accumulator 1to filter2 " " " " " " " " " " " " " " " " " " " " " " " " " " " " " 8nion olt at filter 1to metering distri utor2 " " " " " " " " " " " " " " " " " " " " " " " Fuel &um& reservoir mounting " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " Fuel &um& non-return valve " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " Fuel &um& dam&er unit " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " /nlet manifold nutsA olts " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " +xhaust manifold " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " +xhaust heat shield " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " +xhaust &i&e clam& olts " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " " "

$ )' ), 1' $' )' 1' )' ), 1' ), )' )' 1' )' )' )' ), 1' 4'

l%f ft 1, 18 0 )) 1, 0 1, 18 0 18 1, 1, 0 1, 1, 1, 18 0 $'

& 'eneral infor ation and precautions

system and its various elements" 9ater ;ections descri e tests #hich can e carried out to ascertain #hether a &articular unit is functioning correctly" 6e&airs are not generally &ossi le"

Airflo#

eter

5he airflo# meter measures the volume of air entering the engine and com&rises an air funnel #ith a sensor &late mounted on a lever #hich is su&&orted at its fulcrum" 5he #eight of the airflo# sensor &late and its lever are alanced y a counter#eight and the u&#ard force on the sensor &late is o&&osed y a &lunger" 5he &lunger! #hich moves u& and do#n as a result of the variations in air flo#! is surrounded y a sleeve having vertical slots in it" 5he vertical movement of the &lunger uncovers a greater or lesser length of the slots! #hich meters fuel to the injection valves"

General information
5he &rinci&le of the K-Jetronic continuous injection system is very sim&le and there are no s&ecialised electronic com&onents" 5here is an electrically driven fuel &um& and electrical sensors and s#itches ut these are no different from those in general use on vehicles (see illustration)" 5he follo#ing &aragra&hs descri e the

5he system measures the amount of air entering the engine and determines the amount of fuel #hich needs to e mixed #ith the air to give the correct com ustion mixture for the &articular conditions of engine o&eration" Fuel is s&rayed continuously y an injection noBBle to the inlet &ort of each cylinder" 5his fuelAair mixture is dra#n into the cylinder #hen the inlet valves o&en"

&*+ ,-.etronic fuel injection syste

air inta/e co ponents - 01 engine

1'81 <4 .olf @ Jetta

Fuel and exhaust systems - K-Jetronic fuel injection - 8 valve engines 4B$
condenses on the cold #alls of the inlet manifold and cylinder #alls" /t also needs more fuel to com&ensate for &o#er lost ecause of increased friction losses and increased oil drag in a cold engine" 5he mixture is made richer during #arming u& y the #arm-u& regulator" 5his is a &ressure regulator #hich lo#ers the &ressure a&&lied to the control &lunger of the fuel regulator during #arm-u&" 5his reduced &ressure causes the airflo# &late to rise higher than it #ould do other#ise! thus uncovering a greater length of metering slot and ma-ing the mixture richer" 5he valve is o&erated y a imetallic stri& #hich is heated y an electric heater" 4hen the engine is cold! the imetallic stri& &resses against the delivery valve s&ring to reduce the &ressure on the dia&hragm and enlarge the discharge crosssection" 5his increase in cross-section results in a lo#ering of the &ressure fed to the control &lunger" y the normal o&ening of the throttle" 5he auxiliary air device y&asses the throttle #ith a channel having a varia le a&erture valve in it" 5he a&erture is varied y a &ivoted &late controlled y a s&ring and a imetallic stri&" Euring cold starting! the channel is o&en and increases the volume of air &assing to the engine" As the imetallic stri& ends! it allo#s a control s&ring to &ull the &late over the a&erture until at normal o&erating tem&erature the a&erture is closed"

Fuel supply
5he fuel &um& o&erates continuously #hile the engine is running! excess fuel eing returned to the fuel tan-" 5he &um& is o&erated #hen the ignition s#itch is in the ;5A65 &osition" >nce the starter is released! a s#itch #hich is connected to the air &late! &revents the &um& from o&erating unless the engine is running" 5he fuel line to the fuel su&&ly valve incor&orates a filter and also a fuel accumulator" 5he function of the accumulator is to maintain &ressure in the fuel system after the engine has een s#itched off and so give good hot restarting" Associated #ith the accumulator is a &ressure regulator #hich is an integral &art of the fuel metering device" 4hen the engine is s#itched off! the &ressure regulator lets the &ressure to the injection valves fall ra&idly to cut off the fuel flo# through them and so &revent the engine from CdieselingD or Crunning onD" 5he valve closes at just elo# the o&ening &ressure of the injector valves and this &ressure is then maintained y the accumulator"

Fuel distri%utor
5he fuel distri utor is mounted on the air metering device and is controlled y the vertical movement of the airflo# sensor &late" /t com&rises a s&ool valve #hich moves vertically in a sleeve! the sleeve having as many vertical slots around its circumference as there are cylinders on the engine" 5he s&ool valve is adjusted to hydraulic &ressure on the u&&er end and this alances the &ressure on the air &late #hich is a&&lied to the ottom of the valve y a &lunger" As the s&ool valve rises and falls! it uncovers a greater or lesser length of metering slot and so controls the volume of fuel fed to each injector" +ach metering slot has a differential &ressure valve! #hich ensures that the difference in &ressure et#een the t#o sides of the slot is al#ays the same" Because the dro& in &ressure across the metering slot is unaffected y the length of slot ex&osed! the amount of fuel flo#ing de&ends only on the ex&osed area of the slots"

Cold acceleration enrich ent

5his system is fitted to later models only" 4hen the engine is cold 1 elo# $,F(2! acceleration is im&roved y riefly enriching the fuel mixture for a &eriod of a&&roximately '"4 seconds" 5his cold acceleration enrichment #ill only o&erate if the thermotime s#itch! the dia&hragm &ressure s#itch and the throttle valve s#itch are shut off"

!e perature sensor
From =arch 1*8%! a tem&erature sensor is located et#een injectors 1 and )" After s#itching off the ignition! this s#itches on the cooling fan #hen the tem&erature of the cylinder head exceeds 11'F(" A time relay is incor&orated in the circuit" 5his s#itches off the function et#een ten and t#elve minutes after s#itching off the ignition"

Cold start 1al1e

5he cold start valve is mounted in the inlet manifold and s&rays additional fuel into the manifold during cold starting" 5he valve is solenoid o&erated and is controlled y a thermotime s#itch in the engine cooling system" 5he thermotime s#itch is actuated for a &eriod #hich de&ends u&on coolant tem&erature! the &eriod decreasing #ith rise in coolant tem&erature" /f the coolant tem&erature is high enough for the engine not to need additional fuel for starting! the s#itch does not o&erate"

Au3iliary air de1ice

(om&ensation for &o#er lost y greater friction is achieved y feeding a larger volume of fuelAair mixture to the engine than is su&&lied

2ar -up regulator (1al1e)

4hile #arming u&! the engine needs a richer mixture to com&ensate for fuel #hich

Precautions

dangerous and =any of the &rocedures in this (ha&ter volatile reGuire the removal of fuel lines and liGuid and connections #hich may result in some fuelthe s&illage" Before carrying out any o&eration&recaution on the fuel system! refer to the s &recautions given in ;afety firstH at the necessary eginning of this =anual and follo# them #hen im&licitly" 3etrol is a highly handling it cannot e overstress ed"

Fuel #arning

ed"

4nleaded petrol - usage

6efer to 3art A of this (ha&ter"

Catalytic con1erters
Before attem&tin g #or- on these items!

Fuel injection

relia le and sim&le device #hich needs no maintenance in itself! ut there are some facts of #hich an o#ner should e a#are if the converter is to function &ro&erly for

syste #arning
6esidua l &ressure #ill remain in the fuel lines long after the vehicle #as last used! therefore extra care must e ta-en #hen disconnect ing a fuel line" 9oosen any fuel line slo#ly to avoid a sudden release of &ressure #hich may cause fuel s&ray" As an added &recaution ! &lace a rag over each union as it is disconnect ed to catch any fuel #hich is forci ly ex&elled" 5a-e &articular care to ensure that no dirt is allo#ed to enter the system" 5he ignition must e off and the attery disconnect

carefully read the &recautio ns listed in the follo#ing ;ection"

its full service life"

1)DO
NOT use leaded petrol in a vehicle equipp ed with a catalyti c convert er - the lead will coat the preciou s metals, reducin g their convert ing efficien cy and

2 Cat
al yt ic c o n 1 er te rs g e n er al in fo r m at io n a n d &r e c a ut io n s
5he catalytic converter is a

b) lways !eep the ignition and fuel systems well-maintained in accordance with the manufacturer"s schedule. #nsure that the

will eventually destroy the converter.

4B

air cleaner element, fuel filter and spar! plugs are renewed at the correct intervals. $f the inlet air%fuel mi&ture is

allowed to become too rich due to neglect, the unburned surplus will enter and burn in the catalytic converter, overheating the element and eventually destroying the converter.

do es st ar t.

5)DO
NOT swit ch off the igniti on at high engi ne spe eds. $f

3)$f the engine develops a

misfire, do not drive the vehicle at all 'or at least as little as possible) until the fault is cured. The misfire will allow unburned fuel to enter the converter, which will result in its overheating.

4)DO NOT push or tow-start

the vehicle. This will soa! the catalytic converter in unburned fuel, causing it to overheat when the engine

the igni tion is swi tch ed off at any thin g abo ve idle spe ed, unb urn ed fuel

will enter the 'very hot) catalyti c convert er, with the possibl e ris! of its igniting on the elemen t and damagi ng the convert er.
1'81 <4 .olf @ Jetta

4B4 Fuel and exhaust systems - K-Jetronic fuel injection - 8 valve engines

1
6)DO NOT use fuel or engine oil
additives as these may contain substances harmful to the catalytic converter.

off during chec-ing and adjustment"

5 /f

the

injector

6efer to (ha&ter 1! ;ection $)

7)DO NOT continue to use the vehicle if

the engine burns oil to the e&tent of leaving a visible trail of blue smo!e. The unburned carbon deposits will clog the converter passages and reduce its efficiency. $n severe cases, the element will overheat.

4 Idle speed adjustment

& 6un the engine until the oil tem&erature is at least 8'F(" Eo not let the engine coolant tem&erature rise a ove normal as the electric

8)(emember that the catalytic converter

operates at very high temperatures, hence the heat shields on the vehicle"s underbody. The casing will become hot enough to ignite combustible materials which brush against it. DO NOT, therefore,

4*6 Idle speed adjust en t scre# location in throttle 1al1e housing (arro#ed)

&i&es have een reconnected just &rior to chec-ing the idle s&eed! run the engine u& to $''' r&m a fe# times and then let it idle for a minimum &eriod of t#o minutes efore chec-ing the idle s&eed"

6 /f adjustment to the idle s&eed is necessary! remove the loc-ing ca& from

par! the vehicle in dry undergrowth, over long grass or piles of dead leaves.

9)(emember that the catalytic converter is

)( *$+#. Do not stri!e it with tools during servicing wor!, ta!e great care when wor!ing on the e&haust system, ensure that the converter is well clear of any ,ac!s or other lifting gear used to raise the vehicle and do not drive the vehicle over rough ground, road humps etc. in such a

way as to -ground" the e&haust system.

10)

$n some cases, particularly when the vehicle is new and%or is used for stop%start driving, a sulphurous smell 'li!e that of rotten eggs) may be noticed from the e&haust. This is common to many catalytic converterequipped vehicles and seems to be due to the small amount of sulphur found in some petrols reacting with hydrogen in the e&haust to produce hydrogen sulphide './0) gas. 1hile this gas is to&ic, it is not produced in sufficient amounts to be a problem. Once the vehicle has covered a few thousand miles the problem should disappear. $n the meantime, a change of driving style or brand of petrol used may effect a solution. The catalytic converter used on a well-maintained and welldriven vehicle, should last for between 23 333 and 433 333 miles. )rom this point on, careful chec!s should be made at all specified service intervals of the 5O level to ensure that the converter is still operating efficiently. $f the converter is no longer effective, it must be renewed.

radiator fan #ill run and this should not e o&erating #hen chec-ing or adjusting idle s&eed" 7 (hecthe ignition timing and adjust if necessary"

11)

3 +xce&t on air conditioned models! the main headlights should e turned on" Eisconnect and &lug the cran-case reather hose from the valve cover"
air conditioning is fitted! the system must e s#itched

the adjustment scre# on the throttle assem ly and turn the scre# to achieve the s&ecified idle s&eed (see illustration)" Adjustment should e made only #hen the radiator fan is stationary"

7 /f an exhaust gas analyser is availa le! checthe (> reading and com&are it #ith the s&ecified figure" /f necessary adjust the idle mixture" 8 Air conditioned models #ill also e fitted #ith an increased idle s&eed valve and! in some

4 4here

5 Air cleaner ele ent - rene#al

instances! a second idle s&eed oost valve" 5o chec- these! refer to ;ections , or %! as a&&lica le"

Increased idling speed 1al1e

(air conditioned testing

odels) -

1 ;tart and run the engine at its normal idle s&eed" 2 4ith the air conditioner s#itched off! &inch the hose at the increased idle s&eed valve (see illustration)" 5he engine s&eed should not change" 3 ;#itch the air conditioning system on and then re&eat the test" 5his time the engine s&eed should dro&" /f these tests &rove the valve to e faulty then it must e rene#ed" 4 Eisconnect the hose! uncli& and detach the #iring connector then un olt and remove the valve from its su&&ort rac-et" 5 6efit in the reverse order of removal"

testing Valve 1 testing and and idle s&eed adjustment idle speed adjustment General
8*7 In c r e a s e d id li n g s p e e d 1 al 1 e (a ir c o n di ti o

2 <alve Io" 1 1in oard side2 increases the o engine s&eed d #hen it dro&s e elo# 0'' r&m! l #hilst valve Io" ) s 1out oard side2 ) increases the idle s&eed #hen the air conditioner is Idle speed %oost (air conditioned s#itched odels) on"

n e d

com&artment (see illustration)"

1 5he function of
this device is to sta ilise the engine s&eed #hen it dro&s elo# 0'' r&m under certain o&erating conditions" 5his is achieved y increasing the air su&&ly to the engine! #hich raises the idling s&eed to a&&roximately 1',' r&m" At this &oint! the air su&&ly valve is cut off and the idle s&eed then returns to normal" 5he t#o valves #hich control this system are attached to the right-hand front sus&ension mounting in the engine

5 6un the engine u& to its normal o&erating tem&erature! s#itch off the air conditioner and allo# the engine to idle" 4ith the exce&tion of the air conditioner! s#itch on all electrical consumers 1lights! etc"2! then adjust the idle s&eed to 0'' r&m" 4hen reaching idle s&eed! the valve should o&en and the idle s&eed increase" 8sing a &air of &liers! &inch the air hose from the valve then chec- that the s&eed dro&s"

chec/ 6*& Idle speed %oost 1al1e 4 6alve No 4 / 6alve No / 7 .ose 1'81 <4 .olf @ Jetta

Fuel and exhaust systems - K-Jetronic fuel injection - 8 valve engines 4B,

9*7 Idle C: adjust ent scre# location (arro#ed)

0*7 Accelerator ca%le connection to throttle 1al1e 6 5urn the adjusting ; 4hen reconnection of the 4 ;#itch off all electrical consumers! then &inch the air hose scre# cloc-#ise to cran-case again and adjust idle s&eed to that s&ecified" 4hen the correct raise idle s&eed is reached! unclam& the hose" 5he idle s&eed should the &ercentage of (> ventilation hose results in an then increase u& to a out 1',' r&m at #hich &oint the valve #ill and anti-cloc-#ise to increase in the lo#er it" /t is close and the s&eed dro& to the s&ecified idle s&eed setting" im&ortant that the (> content! the Valve 2 - checking adjustment is engine oil is diluted #ith fuel made #ithout 8 6un the engine at normal idle s&eed #ith &ressing do#n on the and should e the air conditioner s#itched off" 3inch the adjusting rene#ed" air Alternatively! if an oil scre#! ecause this hose and chec- that the engine s&eed change is not due! a long #ill move the airflo# fast drive #ill reduce remains the same" sensor &late and 6 Io# s#itch the air conditioning on and affect the adjustment" re&eat the test" 4hen the hose is &inched! 9 6emove the tool! the accelerate the engine engine s&eed should dro&" riefly and re-chec-" /f the air hose andAor valves Ios" 1 or ) /f the tool is not 9 are removed disconnected or removed for any reason! it is efore the engine is accelerated! there is a danger of the tool ecoming jammed and getting ent" 0 6echec- that the idle s&eed is correct and further adjust if necessary"

5 6elease the inner ca le from the control Guadrant and the outer ca le from the locationAadjustment rac-et on to& of the inlet manifold" 4 3rise free and remove the &lastic cover from the to& of the ul-head trough" 8 4or-ing inside the vehicle! remove the lo#er facia &anel on the driverJs side" 6 8ncli& the inner ca le from the accelerator &edal! then #ithdra# the com&lete ca le into the engine com&artment! together #ith the ru er grommets"

Refitting
9 6efitting is a reversal of removal! ut ensure that the ca le run is not -in-ed and is

correctly aligned! then adjust the ca le" im&ortant #hen refitting to note that condition three-#ay hose connector large s as hole must go those to valve Io" )" necessar y for adjusting the idling 9 Idle i3ture s&eed adjustment and that $ote: ccurate idle mi&ture the idling ad,ustment can only be made s&eed is using an e&haust gas analyser correct" the the amount of fuel in the oil" a t

Adjustme nt

4 B
a % n d a c

(see ca%le 0 Accelerator removal! illustrati on)" refitting and adjustment

Remo val

1 Eisco
nnect the atter y earth lead"

& 5he idle (> adjustment5 (onne scre# alters the height of thect an fuel metering distri utor &lunger exhaust relative to the air control &late gas of the air flo# meter" analyser 2 5he scre# is accessi le y to the removing the loc-ing &lug from tail&i&e! et#een the air duct scoo& and as the fuel metering distri utor on directed the the airflo# meter casing (see y eGui&me illustration)" nt 3 Although a s&ecial tool is manufact recommended for this urer! and adjustment! it can e made read the using a long! thin scre#driver" (> level"

2 3rise
free the inner ca le retainin g cli& from the throttle valve control on the throttle valve housing le a d j u s t e r a s u p p o r t % r / e t

0*; Acc eler ator ca% le clea ran ce

4 +nsure
running

that the engine is under the same

4B% Fuel and exhaust systems - K-Jetronic fuel injection - 8 valve engines

7 5o

;*5 Cold start 1al1e test la p connections

chec- the cold start valve! leave the thermotime s#itch 4 terminal earthed! remove the cold start valve and reattach its connector" 5a-e care not to reathe gas-et #hen #ithdra#ing the cold start valve from the inlet manifold"

4 inclusive" 5he coolant should e at $'F(" /f the s#itch needs to e cooled do#n to the tem&erature s&ecified! remove it and immerse its ase in

&+*5 Au3iliary air 1al1e (arro#ed) cold #ater" 4hen cooled! earth the s#itch to ma-e the test"

fuel line and electrical connections connected to the ; Cold start 1al1e and valve! hold the ther oti e s#itch valve over a glass testing jar and o&erate the starter for 1' seconds" 5he cold Cold start valve start valve should 1 5he thermotime s#itch energises the &roduce an even cold start valve for a short time on starting" cone of s&ray 5he time for #hich the valve is s#itched on during the time the thermotime de&ends u&on the engine tem&erature" 2 5his chec- must only e carried out s#itch is on" #hen the coolant tem&erature is elo#9 4i&e dry the cold start valve $'F(" #ith a 3 3ull the connector off the cold start valve noBBle clean non-fluffy and connect a test lam& across the cloth! then checcontacts of the connector (see that the valve illustration)" does not dri& or 4 3ull the high tension lead off the centre its ody ecome of the distri utor and connect the lead to dam& over a earth" &eriod of one 5 3ull the connector from the thermotime minute" /f &roved defective! rene# s#itch then connect an extension lead from the valve" earth to the thermotime s#itch 4 terminal 1greenA#hite #ire2" 5he redA lac- #ire must Thermotime not e earthed" s itch

8 4ith

11 >&erate the starter for 1' seconds" 5he test lam& should light immediately and stay on for three seconds" 12 6efit the high tension lead onto the distri utor and reconnect the lead to the cold start valve"
&+ Au3iliary air 1al1e testing

1 5o carry out this test! the engine coolant tem&erature must e elo# $'F(" 2 Eetach
distri utor lead" the K5

6 >&erate

the starter and chec- that the &+ 5o chec- the test lam& lights u&" /f it does not! then there thermotime is an o&en circuit #hich must e located s#itch! &roceed and re&aired" as descri ed in &aragra&hs $ and

3 Eetach the auxiliary air valve electrical &lug and ensure that the contacts in the &lug connector are in good condition (see

illustration)" u& a voltmeter across the contacts of the &lug connectors! start the engine and run at idle s&eed" 5he voltage reading must e a minimum of 11"% <" /f a voltmeter is not availa le! a test lam& #ill suffice to chec- the voltage su&&ly"

4 (onnect

1 Eetach

the distri utor K5 lead and earth it"

5 4ith the auxiliary air valve electrical &lug still detached! leave the engine running at idle s&eed and &inch the air inlet duct-toauxiliary valve hose" 5he engine s&eed should dro&"

2 4ith the engine cold! detach the #iring connector from the #arm-u& valve (see illustration)" 3 (onnect a voltmeter across the terminals of the #arm-u& valve connector and o&erate the starter" 5he voltage across the terminals should e a minimum of 11", volts" 4 ;#itch the ignition off and connect an ohmmeter across the terminals of the #arm-u& valve (see illustration)" /f the meter does not indicate a resistance of a out )' to
&&*7 2ar -up 1al1e
6 4hen the engine is #armed u& to normal o&erating tem&erature! reconnect the auxiliary valve &lug then &inch the hose again" 5his time the engine s&eed should remain unaltered"

the fuel mixture for a &eriod of a&&roximately '"4 seconds" 5his cold acceleration enrichment #ill only o&erate if the thermotime s#itch! the dia&hragm &ressure s#itch and the throttle valve s#itch are shut off"

2 5o chec- the system! first chec- that the cold start valve is o&erational" 3 Eetach the #iring connector from the cold start valve and connect u& a test lam& to its terminals" 4 Eetach the #iring connector from the thermotime s#itch and connect a length of #ire et#een an earth &oint and the connector Io") terminal 4 1greenA#hite #ire2" Eo not earth terminal . 1redA lac- #ire2" 5 6un
the engine

26 ohm! the heater coil is defective and a ne# valve must e fitted"

&&*4 2ar -up 1al1e heater coil resistance test

&& 2ar -up testing

and allo# it to idle! at #hich &oint the &7 Cold acceleration test lam& should enrich ent syste not light u&" 4hen testing the engine is Guic-ly & 4hen the accelerated! the engine is cold test lam& should 1 elo# $,F(2! light u& riefly 1'"4 acceleration is seconds2 (see 1al1e im&roved y illustration)" riefly enriching 1'81 <4 .olf @ Jetta

Fuel and exhaust systems - K-Jetronic fuel injection - 8 valve engines 4B0

&7*&+ !hrottle 1al1e s#itch chec/ &7*8 Cold acceleration enrich ent syste chec/ 5old start valve connector earth contact '/) 'green%white wire to 1 terminal) Do not earth contact 4 4 Throttle valve switch a 8 3./ to 3.9 mm

6 /f a fault is evident! checthe #iring connections! the throttle valve s#itch and the dia&hragm &ressure s#itch" 9 5he dia&hragm &ressure s#itch can e chec-ed using an ohmmeter" Eetach the #iring connector from the end of the dia&hragm &ressure s#itch! then start the engine and allo# it to idle" 8sing the ohmmeter! checthe resistance reading et#een the contacts" An infinity reading should e given"

&ositi &rise the oning connector a rac-et feeler a&art to

e n r

(see illustration)"

3 /ns&ect

&5*7 Air s h r o u d e d i n j e c t o r a s s e % l y (l a t e r o d e l s ) $n,ector (ubber rings 7 :

8 Accelerate

the engine riefly and chec- that the resistance dro&s riefly and then returns to infinity (see illustration)" chec- the throttle valve s#itch! detach the s#itch lead connector and measure the resistance et#een the s#itch contacts" An infinity reading should e given" slo#ly o&en the throttle valve to the &oint #here the s#itch is heard to o&erate #ith a clic-" 5he ohmmeter should give a ' ohm reading and the clearance et#een the throttle lever and the idle sto& must e et#een '") to '"% mm (see illustration)"
necessary! adjust the s#itch y loosening the s#itch 1underside of throttle 4 housing2 and /

9 5o

10 Io#

11 /f

lade release e the ru er of '"4 the seal" /f it s mm connector" sho#s signs t thicof crac-ing! a ness &5 Fuel injectors distortion or r et# &erishing! ti removal! een then it must n testing and g refitting e rene#ed" the lever /f found to and e defective! 3)T sto&" 1 An checthe h =ove injector other e the injector may give n s#itc seals as trou le for o; h they are one of the ;l to#ar li-ely to e follo#ing e ds in similar reasons7 filt the condition" er lever 1)The 4 ;&ecialise m spray until d tools are ay may the reGuired for b be s#itc an accurate e irregul h is test of ch ar in heard injector o! shape to &erformance e o&era 2)T " Ko#ever! a d, te! h asic checgi then e can e vi retigh n made as n ten o; follo#s" g the ;l le 5 Kold the s#itc e ss h and injector in a m th chec suita le ay at measuring n th adjus glass and ot e tment &lug u& the cl re " injector os q location e uir hole" ;tart w e the engine h d and let it idle e ra on three n tio cylinders th n and loo- at e of the sha&e of e fu the s&ray" /t n el should e of gi a 4)The n symmetrical seal e cone sha&e" may is /f it is not! be sh then the dam ut injector must aged d e changed , o ecause the allow w vi rator &in ing n, is damaged an ca or the s&ring air &7 /f us is ro-en" lea! the in ;hut off the throttl g 2 5o engine and e flo remove #ait for 1, valve o an seconds" s#itc di injector 5here must h is n for e no leaeing g ins&ectio or dri le remo w n! sim&ly from the ved! h &ull it free

noBBle" /f there is! the6 An injector injector must e rene#ed!cannot e as dri le #ill causedismantled flooding and difficultfor cleaning" starting" /f an injector is rene#ed! the line union must e tightened to the s&ecified torGue" 9 4hen inserting an injector! lu ricate the seal #ith fuel efore fitting"

centre! loosen

its centre lise scre# and carefull it! y run a '"1' the mm

4Bntra

ce

f e e l e r l a d e

n retigh ten the olt (se e illu str atio n)"

e fel t on th e do #n #a rd m ov e m en t" /f

ust e fitted"

&4 Airflo# sensor plate o u and control plunger - testing

n d t h e e d g e o f t h e & l a t e t o

36
ais e the airfl o# sen sor &lat e and the n Gui c-ly mo ve it to its rest &os itio n" Io resi sta nce sho uld

1 For

the

correct mixture to e su&&lied to the engine! it is essential that the sensor &late is central in the venturi and that its height is correct" First run the engine for a &eriod of a out one minute"

2 9oosen the hose cli&s at each end of the air scoo& and remove the scoo&" /f the sensor
&late a&&ears to e off-

th er e is re sis ta nc e! th e air flo # m et er is de fe cti ve an d a ne # on e m

&4*7 !op 1ie# of airflo# sensor plate

1'81 <4 .olf @ Jetta

4B8 Fuel and exhaust systems - K-Jetronic fuel injection - 8 valve engines
of the &late should e flush #ith the ottom edge of the air cone (see illustration)" /t is &ermissi le for the &late to e lo#er than the edge y not more than '", mm ut if higher! or lo#er than the &ermissi le limit! the &late must e &4*8 Sensor plate position re"uire ent adjusted" illustration)"

7 After
adjustment! tighten the #armu& valve union and chec- the idle s&eed and (> content"

&4*6 Airflo# sensor plate adjust ent clip (arro#ed)

<pper edge of plate 'arrowed) must be flush with bottom of air cone

6 Adjust

the

height of the &late 4 /f the sensor &late can e moved y lifting it and do#n#ards easily ut has a strong ending the #ire resistance to u&#ard movement! the cli&s attaching the control &lunger is stic-ing" 6emove the fuel &late to the distri utor and clean the control &lunger in alance arm" fuel" /f this does not cure the &ro lem! a 5a-e care not to ne# fuel distri utor must e fitted " scratch or 5 6elease the &ressure on the fuel damage the distri utor and then chec- the rest &osition surface of the air (see of the airflo# sensor &late" 5he u&&er edge cone

6 9ift off the distri utor! ta-ing care that the metering &lunger does not fall out" /f the &lunger does fall out accidentally! clean it in fuel and then reinsert it #ith its chamfered end do#n#ards"

refitting

Removal

1 6emove

the fuel lines from the distri utor"

Refitting

7 Before refitting the distri utor! ensure that the &lunger moves u& and do#n freely" /f the &lunger stic-s! the distri utor must e rene#ed"
&8 Fuel etering distri%utor removal and refitting

2 9oosen the clam&s at the air cleaner and throttle assem ly ends of the air scoo& and ta-e off the air scoo&"
the olts securing the airflo# meter to the air cleaner and lift off the airflo# meter and fuel metering distri utor (see illustration)"

3 6emove

5 6emove the loc-ing &lug from the (> adjusting then $ote: #nsure that the vehicle is in a well scre#! ventilated space and away from na!ed remove the three flames or other possible sources of ignition scre#s securing the distri utor Removal (see illustration)"
to &revent fuel from eing s&rayed out! loosen the control &ressure line from the #arm-u& valve" 5he control &ressure line is the one connected to the large union of the valve"

the &ressure control line to the distri utor"

8 6efit the distri utor! using a ne# sealing ring" After tightening the scre#s! locthem #ith &aint" 9 6efit the fuel lines and the ca& of the (> adjusting scre# then tighten the union on the #arm-u& valve"

4 5he &lunger should e &revented from falling out #hen the distri utor is removed from the airflo# meter"
Refitting
8 6efitting is the reverse of removing" /t is necessary to use

1 Eisconnect the attery terminals" 2 4hile holding a rag over the joint

3 =ar- each fuel line and its &ort on the distri utor" (arefully clean all dirt from around the fuel unions and distri utor &orts and then disconnect the lines" 4 8nscre#
and remove the connection of

&6 Airflo# and

eter

a ne# gas-et et#een the airflo# meter and air cleaner"

retaining scre#s (A)

&8*8 <ie# sho#ing fuel distri%utor

Do not remov e screw s '=)

&6*5 Airflo# eter and fuel distri%ut or unit (in1erte d) 1'81 @ <4 .olf Jetta

Fuel and exhaust systems - K-Jetronic fuel injection - 8 valve engines 4B*

the relay y first

6 /n

17 Pressure relief 1al1e removal! servicing and refitting

each case! attery voltage should sho#"

7 (hec-

1 6elease the &ressure in the fuel system" 2 8nscre# the non-return valve &lug and
remove the &lug and sealing #asher"

3 5a-e out the >-ring! &lunger and >-ring!

in that order (see illustration)"

4 4hen 5 5he

refitting the assem ly! use ne# >-rings and ensure that all the shims #hich #ere removed are refitted" num er of shims fitted determine the system o&erating &ressure" /f for any reason the system &ressure is sus&ect! it #ill e necessary to have a &ressure chec- made y your <4 dealer #ho should have the correct gauge needed to chec- the &ressure in the system" Ke #ill -no# the amount of shims reGuired to correct the &ressure should it e necessary"

&9*5 Pressure relief 1al1e co ponents 4 0hims rrows indicate Orings detaching the Kall sender connector from the ignition

that #hen the central connector #ire is earthed riefly! there is a voltage dro&" /f the voltage does not dro&! chec- the ignition 15(/AK s#itch2 unit" /f the voltage does dro&! rene# the fuel &um& relay" /f the &ro lem still &ersists! have the ignition Kall sender unit chec-ed"

Removal
0 /f after ma-ing the a ove chec-s the &um& still malfunctions! remove the sender unit as descri ed in 3art A of this (ha&ter! ;ection 8! then detach the &um& for rene#al"

Refitting
system distri utor" ; 6efitting is a reversal of the removal &rocedure"

&0 Fuel lift pu p - testing! removal and refitting

4 6emove

Testing

1 5he

fuel lift &um& is attached to the ase of the fuel gauge sender unit fitted to the fuel tan- (see illustration)" first chec- that the &um& #iring does not have an o&en circuit" 6emove the luggage com&artment floor covering and the circular cover in the floor for access to the sender unit and connections" Eetach the #iring connector and ma-e a continuity chec- et#een the centre #ires and the outer 1 ro#n2 #ire of the connector (see illustration)"

the fuse ox and relay &late cover then &ull free the &um& relay from &osition )" a voltmeter! s#itch on the ignition and chec- the voltage reading et#een the follo#ing7

5 8sing

2 /f the &um& is sus&ected of malfunction!

1)5ontact 2)5ontact

No. / and earth Nos. / and 4

3 /f the #iring &roves correct! then checthe &um& relay and &um& fuse 1Io" ,2" Assuming the fuse to e in order! chec-

3)5ontact
Nos. : and 4

4)5ontact
Nos. 2 and 4

&; Fuel pu p - removal and refitting

Removal

1 5he fuel &um& is located on the underside of the vehicle! for#ards of the fuel tan- on the right-hand side! the &um& eing housed in the &um& reservoir (see illustrations)" 2 Eisconnect the attery earth lead" 3 6aise the vehicle at the rear and
su&&ort it on axle stands 1see C>ac!ing and vehicle supportD2" free the retaining cli& and detach the &um& #iring connector (see illustration)"

6 8ndo the retaining nuts and #ashers and remove the ada&ter" 7 8ndo the three scre#s securing the &um& retaining ring and #ithdra# the ring! follo#ed y the &um& unit" 8 6emove
the >-ring and #ithdra# the

strainer"

Refitting
; 6efitting is a reversal of the removal &rocedur e" ;mear the >ring #ith fuel #hen fitting and checthat it does not ecome distorted"

#ith the slot in the retaining ring"

11 /f the &um& nonreturn valve #as removed from the rear end of the &um&! refit it using a

ne# seal #asher" Also use a ne# seal #asher each side of the 4B hose union" 5ighten the dam&er unit to the s&ecified torGue"

4 3rise

10 4hen
fitting the &um&! &osition it so that its lug engages

5 8nscre# the dam&er unit from the rear end of the &um& and detach the hose union! noting the #asher each side of the union"

&7 >n com&letion! start the engine and chec- for any signs of fuel lea-age from the &um& connections"

&0*& Fuel tan/ sender unit Tan! and other associated components are identical to those used for carburettor engines
1'81 <4 .olf @ Jetta

&0*7 Fuel tan/ sender unit an

4B1' Fuel and exhaust systems - K-Jetronic fuel injection - 8 valve engines

&;*&a Fuel pu p and associated co ponents

&;*&% Fuel pu p 1ie#ed

fro

rear

&;*4 D 4 Ei scand Fuel filter - removal on refitting ne ct th 6efer to (ha&ter 1! ;ection $$ e fu 7 Fuel accu ulator - el & removal &i and refitting &e s fro m Removal th & 5he fuel accumulator iseir mounted on the out oard sideco of the fuel &um& reservoir on nn the underside of the vehicle atec the rear! just for#ard of thetio fuel tan- (see illustration)" ns 2 Eisconnect the atteryat th earth lead" e 3 6aise the vehicle at the rearfro and su&&ort it on axle standsnt 1see C>ac!ing and vehicle en d supportD2" m (hec- that u the fuel line l connections a are clean t efore o refitting" >n rcom&letion! " checfor fuel lea-s R #ith the e engine running"

7 +

isconnecting #iring connector fro fuel pu p engine%gear 75 Inlet anifold bo& unit to and gain access refitting to certain items and allow clearance for manifold removal. =odificatio n: s from 0eptember

f i77 Fuel tan/ and tassociated t co ponents i and n refitting g 5he fuel
6 tanand associated 6 com&onent e s can e f removed i and refitted t in the same i manner as n descri ed for t car urettor h models in e 3art A of this r(ha&ter" test e 5o vthe e reather rvalve! lo# sthrough the hose e 1dotted arro# - see o rillustration 0"$ in 3art d A of this e r(ha&ter2 and &ush t the lever in to see if the o airflo# ro&ens then shuts off as e the lever is m released" /f o vdefective! rene# the a valve"

4?@:, component s associated with the inlet manifold were modified !see illustration ". ll wor! procedures remain as follows for engines manufactur ed before that date !see illustration "#

Removal
& Eisconnect the attery earth lead and decom&res s the fuel system"

of th e re gu lat or" 8 8n do th e cla m & o lt an d #it hd ra # th e ac cu

l "

Eisconnect the accelerator ca le from 7 the throttle valve and su&&ortAadjuster rac-et on the manifold" 5 Eisconnect the #iring connector and the vacuum hose from the auxiliary air valve" 4 Eisconnect the #iring and detach the #arm-u& valve" 8 8ndo the hose cli&s and detach the vacuum hose from the connection on the end of the manifold 1left side2 and the rear side of the throttle valve housing (see illustration)" 6 Eisconnect the vacuum hoses from the front of the throttle housing! noting their

connections" 9 Eisconnect the injectors and hoses from the cylinder head! release them from the location cli&s and fold them ac- out of the #ay" $ote: particular, is not good due 0to 8ncli& the close from ; disconnect the the 6emov su&&ort rac-et of the fastenings and and throttle e the from the fittings of the manifold, detach p r the bul!head side in the inlet olts housin accelerator ca le on ducting and g" su&&ortAadjuster 1'81 <4 .olf @ Jetta

rac-et and from the cam cover"

Fuel and exhaust systems - K-Jetronic fuel injection - 8 valve engines 4B11

75*+a Inlet anifold and injection co ponents (e3cept engine codes PB and PF) > fro Septe %er &;04

4 / 7 : 2

Two-way valve '$$) Two-way valve '$) T-piece 0crew Diaphragm pressure valve

? 4 3 4 4 4 / 4 7 4 : 4 2 4 9

Temperature control flap 'where applicable) 0crew $dle speed ad,ustment screw O-ring Throttle housing 6acuum booster =rac!et 0crew

4 A 4 @ 4 ? / 3 / 4 / / / 7 / : / 2

To multi-function indicator To valve cover u&iliary air valve 0crew Throttle valve switch To bra!e servo unit =rac!et To cylinder head To distributor

9 A

Blug Ci&ture '5O) ad,ustment screw

irflow meter

4B

75*+% Air cleaner, inlet anifold and associated co ponents > pre Septe %er &;04

1'81 <4 .olf @ Jetta

4B1) Fuel and exhaust systems - K-Jetronic fuel injection - 8 valve engines
Refitting
&5 6efitting is a reversal of the removal &rocedure" (hecthat all mating faces are clean and use ne# gas-ets" 5ighten the securing olts to the s&ecified the manifold, refer to Bart of this 5hapter, 0ection /3, paragraph 4, which concerns details on the special tool required to release and subsequently reconnect the

78 E3haust syste ins&ection! removal and refitting

$ithout catal%tic converter

e&haust manifold-todownpipe 14 4hen securing clips. 75*8 <acuu hose-to-cylinder connector reconnecting the <nless this tool is accelerator ca le! available, the ensure it is manifold is best &+ Eisconnect the cam cover-to-inlet correctly adjusted" removed and manifold reather hose" && 8ndo and remove the inlet manifold 15 (hec- that all refitted by your retaining olts then carefully lift the manifold! connections are 61 dealer together #ith the throttle housing! a#ay fromsecure and 6emove the inlet manifold" the cylinder head" Eisconnect any #iring or correctly made 6emoval and hose connections still attached as it is efore restarting #ithdra#n" refitting of the the vehicle" &7 5he throttle housing can e un olted from exhaust manifold is no# similar to the manifold and then #ithdra#n from it" 74 E3haust anifold that &rocedure removal descri ed in 3art and refitting A of this (ha&ter" $ote: =efore starting to remove

torGue settings"

& 6efer to ;ection )' in 3art A of this (ha&ter #hilst noting that all models manufactured after August 1*8, are fitted #ith a manifoldA do#n&i&e flange incor&orating a gas-et instead of s&ring cli&s"

$ith catal%tic converter

7 5he catalytic converter 1#here fitted2 is &ositioned at the for#ard end of the exhaust system and

com&rises a steel casing over a ceramic se&arating the ody" /t incor&orates a longitudinal multi-com&onents (see &assage honeycom unit! #hich is coatedillustration)" #ith a layer of &latinum or rhodium" 4 Iote that the 3 6emoval is sim&ly a matter of releasingcatalytic converter the flange or soc-et ty&e cou&lings andis fragile" Eo not

stri-e it #ith tools and ta-e care not to allo# it to contact jac-s or lifting gear"

ne# cou&ling seals and gas-ets during reassem ly"

5 Al#ays

use

78*5 !ypical e3haust syste catalyst

4 / 7

#ith $ntermediate @ pipe 5entre ? silencer 4 3 (ear silencer 1'81 <4 .olf @ Jetta

5ap 5O measuring pipe #&haust manifold

: 2 9 A

0pring clips #&haust front pipe .eat shield 5atalytic converter