Bosch K-jetronic - Common Problems, Symptoms and Fixes

[@TruckerKingJM]

Thank you for all your very informative and educating videos of the K-Jet system! Unfortunatly there isn't many around these days that have any knowlegde about these old simply but yet so complicated systems! There is many of us out here in the world that are forever thankful to you sharing your knowlegde!😎😎😎

[@GreyGooseRestorations]

I was given zero help years back when i asked a well known company about kjetronic, so thought ok ill teach myself and show others, i hate people thinking they they hold all the magical information.

[@dionkollidi2498]

Thank you! My 1978 Porsche 928 had been sitting for 5 months, since I brought it home in non running condition. As soon as I replaced that o-ring in the FD fuel pressure valve, it fired and idled at the turn of the key. This resulted in my first drive 😊 - albeit up and down the driveway, but a first drive none the less. Thanks again for making and posting the video.

[@GreyGooseRestorations]

Wicked, love seeing comments like this 👍

[@amoredesign]

where did you buy the o-ring from?

[@GreyGooseRestorations]

@amoredesign any online supplier can supply the seals

[@janvodicka3057]

You just helped with my cold start issues, the filter was full of debris... now starts perfectly. Scirocco JH engine. Cheers!

[@GreyGooseRestorations]

Sweeet, this is the exact reason i make these videos 👍😁

[@smashmash2714]

bought an 8v scirocco k jet , really appreciate all the help man, top bloke, cheers

[@creativeenginechannel7182]

I will continue to see the videos that you put out, great expensive knowledge can share

[@GreyGooseRestorations]

Thanks

[@matto4253]

Interesting as ever mate. Just a small remark, where you say CO2, I think it should be CO.

[@GreyGooseRestorations]

@matto4253 noted 👍

[@charlesbradley7277]

thanks for your videos, i think your excellent could you sort this problem for me please, constantly running fuel pump, had new relay,still the same,would it cause an over fuel, how do i sort it ,could it be blocked filter next to the pump at the back of car, oh nearly forgot it is a mk2 golf gti 1.8 16 valve 1988, i suppose your too busy to acknowledge this but would be nice of you if you could.thanks again.

[@GreyGooseRestorations]

Thanks, if is it constantly running with ignition on?

[@amoredesign]

hey at 0:53 you say to put the 3mm allen key into somewhere. Is this the hole between fuel distributor and rubber air intake? I'm trying to diagnose a problem on my 924 so positioned differently in the engine bay. This is to adjust the air/fuel mix correct?

[@GreyGooseRestorations]

Yes thats correct, small hole on the air metering unit between the fuel distributor and intake boot, yup adjusts mixture at idle

[@fernandoalonso5970]

Hola, le escribo desde España. Enhorabuena por su canal, en estos días es dificil encontrar mecanicos entendidos en esta inyección K-jetronic y los mecánicos aficionados nos encontramos con grandes problemas para mantener vivos nuestros coches clásicos. Le expongo mi problema, soy propietario de un Mercedes W123 230E de 1982 y últimamente está dando problemas para arrancar en caliente después de haberlo dejado parado durante 45/60 minutos, arranca pero no mantiene el ralentí y se para. Hace poco lo cambié la bomba de gasolina, acumulador de presión, filtro de gasolina, inyectores, válvula de aire adicional y todos los tubos de caucho y el coche funcionaba perfectamente, pero hace un par de días empezó con este problema de arranque en caliente, aunque después de dar arranque varias veces y mantener el acelerador pisado a fondo al cabo de un par de minutos se estabiliza el ralentí y de nuevo funciona como si nada pasase. Usted me podría indicar alguna posible causa de este fallo ó como buscar el diagnóstico? Le estaría inmensamente agradecido, y le repito la enhorabuena. Saludos desde España. Fernando Alonso.

[@Phillologist]

Thank you. Very informative and spot on. As it relates to the pressure relief valve at the Centre of the 16mm is an Allen bolt if you should disassemble to will find a small O-ring that often deteriorates also. I have also from experience found that if the O-ring that sit at the base of the fuel distributor/metering head is bad it can run into issues. I found also that a spring sits behind the plunger in some application was missing from mine.

[@bigmike3443]

Thanks so much for all of these video's, very very helpful. I''ve just picked up a 1990 16V and it is tricky to start when cold but does eventually fire after 5 or so cycle's of the ignition. I've just ordered some O rings for the fuel pressure regulator so hopefully that cures it.

[@totte1015]

As of my knowledge there is a same kind of mini filter on the incoming fuel banjo into metering head from fuel filter in the back, that can clog up and cause issues

[@GreyGooseRestorations]

True, these should have been removed at the first service as it was there purely to catch any debris from factory assembly, obviously not all cars went to the dealer for servicing so many have this filter still

[@Mk2_Kizz]

Hoping this video helps me with the issues ive been having with my 1985 audi 90. Its been a nightmare trying to find someone to work on the k-jet system. Looks like ill have to give it ago myself.

[@leatherboot69]

I feel ya man

[@lilibethdoherty295]

My WUR Problem turned out to be the vacuum hose on top of WUR going to intake 3 way Tee on manifold was Kaputsa, I missed Three of the best Fall Months of Driving to find out this was the problem !

[@GreyGooseRestorations]

Sucks to miss out on good driving times but its good the problem is fixed

[@lilibethdoherty295]

I did replace the fuel dist. inline filter and was abut to buy a Digital electronic WUR for $549 Modern upgrade and watching the installation video I noticed I never checked all the Vacuum Connections on the WUR and that was all that was wrong !@@GreyGooseRestorations

[@wagonroller3019]

I'm a little puzzled , system pressure is held in front of small black o ring at far right inlet port in video. Return to tank is sent through middle port which is in between the two o rings. What does the far left port do which is behind the green o ring ? System pressure ? What are the holes for in the brass fitting ? Love your channel.

[@GreyGooseRestorations]

Thanks, the far left port is the WUR return line

[@lokvenc672]

Hi, where should I buy that mini banjo bolt filter? I cannot find anything similar on entire internet 😅

[@GreyGooseRestorations]

Have a look on Mr injector UK im sure they have something

[@mr.p6210]

Yet another amazingly infotmative video. Thank you so much.

[@GreyGooseRestorations]

Thanks 👍

[@mikeymak9512]

Great content and very helpful. I have a new issue with random low pressure to injectors at half psi. I found that if I manually play with the air flap back and forth they eventually get full power and car runs good. After a short drive they half pressure and car will die under load with gas. Any tips would be helpful. I had New injectors,New fuel pump and distributor. Thanks Mike - Dallas Texas

[@west-cam]

Videos are great - Keep them coming. You make it seem easy, but I've been struggling with my K Jet for over a year now. Car will not start. It's an 88 Lotus Esprit. System Pressure is sitting at 6.2 bar (cold) and control pressure is at 2.5 bar. both are within cold spec. both fuel distributor and WUR have been rebuild by SpecialTauto. had to add shims to pressure regulator to get up to the 6.2 bar system pressure. On crank, will not start. if I push down on the sensor plate and force fuel into the cylinders, it will start and immediately die, so I suspect it's something on the fuel delivery side. Both fuel pumps check out and filters are new. Aux air, cold start valve, and Thermal Time are okay as well. All I can think is it may be the mixture screw on the sensor plate arm, but I have not been able to find any info on how to set this from scratch. Any insight you have would be very appreciated!

[@GreyGooseRestorations]

Thanks, message me via WhatsApp or my Facebook page and I can help with the settings

[@MontyGriffsGarage]

I have watched this video a few times from end to end, and being a numpty in West Wiltshire, I am still a little confused as to my problem 🤨. 1.8 8v (Scirocco). New lift pump and relay as they went ping - Starts on the button, immediately dies. Keep foot on accelerator and hold at 2,000 for a minute or two, settles to idle and warm starts are easy. Tried with disconnect of 5th injector, never starts then. Just been watching the WUR from 17th December this year, drat that is for warm start problems - injector replacement time? Plunger free as a bird, no varnish - not looking for free advice, if you can point to another video would be useful! I'm back to my barn Saturday. Thank you. 😄

[@GreyGooseRestorations]

West Wiltshire you say 🤔 im North Wiltshire Check fuel system pressure to see what pressure is in the metering head, sounds like its trying to run on the 5th injector and also could be the CO adjustment needing adjustment

[@declanbroderick4453]

I am restoring a corrado with the same engine. It is doing everything it can to stay dead. It has been off the road for 15 years and I have spent a ton of money of it. It still runs like crap. What is the part number for the alternative injectors that will work with this engine? I have tried to clean mine, but maybe they just need to be binned. Thanks for all the content. I really appreciate it.

[@GreyGooseRestorations]

Injectors are generally a throw away item, they might be able to be cleaned but the pintle and wears which leads to poor spray pattern 0 437 502 023 are the steel ones. If yours has the air shrouded system then the nipple on the lower inlet between cylinder 1 and 2 needs to be blocked

[@declanbroderick4453]

@@GreyGooseRestorations Thank you.

[@terryraymond7984]

so on the Control pressure regulator can cause a lean mixture and run bad or not start

[@NassifBouMalham]

Hi, my mk2 16v won't start without priming but I do so the metering head starts to make winning noise. Please can you help?

[@GreyGooseRestorations]

Could be the pressure valve seal preventing system pressure building up

[@georgegeorgiadis8104]

Thank you for the video, can you please give me the part number for the Mercedes fuel injector?

[@GreyGooseRestorations]

Bosch number is 0437502047

[@tariqtayyan]

I have problem where my rpm or oil pressure keeps fluctuating during idle, what would be the cause of it

[@GreyGooseRestorations]

Check for air leaks on the rubber intake pipes and all the vacuum pipes first

[@tomaszkomorowski2500]

Great video, could You help me with advice : golf mk1 89’, 1.8 JH engine with ke-jetronic. Every now and then the engine starts like on two cylinders with poor idle and backfire and I have to drive through speedbump to make it work corectly. It doesn’t matter if the engine is cold or warm. It only happens when I start the car - never when its running. Would You help me where to look? The car drived like this for years but previous owned didn’t care - he drove it rarely.

[@iannixon8334]

I have a Audi WR Quattro that's been stood since 2007, I've rebuild the engine and replaced all the fuel lines/filter and fitted a new pump. It starts and runs for about 3-4 seconds and dies, can you advise what's most likely wrong? Thanks

[@GreyGooseRestorations]

Hi, it sounds like its starting on the cold start injector, try unplugging it and note any difference in starting, if it is that and the pump etc it all new then I'd test the fuel pressures at the metering head, after that it would be a metering head issue most likely

[@koosengelbrecht7138]

Thanks for the info, bought a 5 cylinder VW engine with k-tronic but no wiring, what does all the electrical plugs connect to?

[@GreyGooseRestorations]

There's a few to be honest Coolant sensors Idle valve Throttle switch Cold enrichment valve Deceleration Cut off Valve Thermostat sensor Oil temperature Oil pressure x2 5th injector Warm up regulator Ignition Distributor Think thats all the main engine ones

[@normabradley2544]

hi thanks for the info, could you let me know where you get the brass injectors from please. chas

[@GreyGooseRestorations]

I'd advise against using the brass injectors with any cast iron fuel metering head as I've recently worked out that they cause hot start issues as proven on my own car and 2 others

[@EWSSMAN]

I have a Porsche 928 each hole has a tiny tube like filter can I run without the filter ? Awesome video btw thank you !

[@GreyGooseRestorations]

Hi and thanks, its best to replace those filters but you can run without them

[@ronnie8752]

Another great vid. Thanks

[@GreyGooseRestorations]

No problems 👍

[@ToddMotto]

Great walkthrough. Wondered if you have any advice for a K Jet for a MK2 that’s flooding 3 cylinders with fuel? :-) thank you!

[@GreyGooseRestorations]

Thanks, i could be one of the internal seals failed with lets way to much fuel in so it could be in need to a rebuild, i do these if your interested, contact me via my Facebook page

[@kd23se4]

Thank you for the usefull advice!!!

[@323desi]

How about fuel flooding issue any tips, maybe this has been covered in another video?

[@GreyGooseRestorations]

That is another potential issue yes, most commonly when the 5th injector fails or the injectors leak, i think I've touched on those in other videos

[@ejmiller3109]

I have one of these, the fuel pin that come through the center and contacts a roller is stuck in and my father and I are trying to free the pin up, can you help??? Haven’t removed the pin for fear of damaging small fragile oe parts

[@GreyGooseRestorations]

The best way is to use WD40 or another penetrant fluid and spray it through the top centre connection (control pressure) and let it soak through Its hard to remove but can be done

[@RobertFlint-l4n]

Hi just seen you vidio very interesting.i have a 2.8i ford capri and I have a strange problem. Car starts from cold fine but when it's hot I do have a starting issue. When hot if I turn it off leave for 10 mins or so it starts fine but if I turn it off for 30 mins or more it starts but two or three cylinders flood but always starts. I have replaced the injectors as I thought they might be dripping ( no fix) replaced the temp sensor still the same. Just had the car MOT and it's running rich so not sure if this is the problem but any help would be appreciated. Many thanks Rob

[@GreyGooseRestorations]

Hi Rob, it could be a system pressure issue being either the metering head and/or WUR or an issue with the fuel pump/Accumulator. Contact me via my Facebook page if you need any more help

[@iWupo]

Great video, as always! Maybe you could help pinpoint the problem with my 16v scirocco, car starts great when cold although idles a bit high, but as it warms up and the WUR engages the engine just dies, won't start once it's warm and if it does won't react to throttle at all, sounds almost as it misfires and when the throttle is released it springs back again for a slight moment. I've also noted the metering plate has a lot of resistance once it warms up so i'm guessing the intake air just doesn't lift it. Everything on the car is new, FD rebuilt, only parts i haven't touched is the 5th injector and WUR.

[@GreyGooseRestorations]

Thanks, 99% thats the wur, most likely the filter gauze is partially blocked if not blocked so when the heating element comes away from the spring your getting system pressure for control pressure so you'll have 5bar or so pushing the control plunger (air plate) down

[@iWupo]

Thank you!

[@NWHITNEYJR]

Regarding the 7mm i.d. / 2mm cross o-ring on the FPR, would a Viton o-ring work?

[@GreyGooseRestorations]

Yes, viton has very high resistance to fuels and oils

[@educatedsloth]

Hiya hope you can help me. i have a 924 2.0 non turbo from 1980, I noticed a few times that i had fuel in my airbox. any ideas what could cause that?

[@GreyGooseRestorations]

It could be leaking from the fuel plunger meaning the body/plunger is worn as they are a matched pair machined with a clearance fit to move and also act as a seal, it could also be the body itself leaking via one or more of the housing bolts

[@prakashnarismulu3332]

Great job. K jet issues on a M110 280 E engine

[@flapbean]

Any advice for starting a vehicle that hasn’t run for 17years? 1980 924 Turbo. Wondering if it can be flushed somehow?

[@GreyGooseRestorations]

Best would be to fresh fuel and main filter, take the main feed off the metering head and prime/flush that with clean fuel Then put it back on and prime the metering head, it may work or it may be blocked, try and see if the air flap will raise and lower easily too

[@strm99]

Hi,do you know if there is a seal inside the pressure regulator also?i have problems with a k jet on a saab 900 ,i have fuel pressure coming out on the small line on the pressure regulator going up to the wur..(returnline from wur)..

[@GreyGooseRestorations]

Yes the fuel pressure regulator has 3 seals in total

[@strm99]

@@GreyGooseRestorations thank you 👍do you know the dimensions on the inside seal?took the regulator apart this morning and it dont look like a regular o-ring..

[@GreyGooseRestorations]

@strm99 the main one is 7x2 the others are a odd size that I can't remember currently

[@strm99]

@@GreyGooseRestorationsok,thanks!is there a k- jet dealer in uk or Europe you can recommend?

[@GreyGooseRestorations]

@strm99 only place I recommend is missingparts.de

[@vasya5579]

Do you know anything that would cause great engine running when cold but it gets so sluggish when warm

[@GreyGooseRestorations]

Most likely the WUR as that increases control pressure when warm and too high control pressure will cause poor running

[@mikemike-rf7qb]

Just found your channel, binging your videos.,new subscriber.that said. I just bought a 924 turbo. Iy starts ok but has brought idle that fluctuate in revs, but as soon as I give it gas, it almost dies and backfires. Any thoughts?? Thanks in advance from NZ

[@GreyGooseRestorations]

Hi and thanks Could be an air leak or fueling issues, first thing i would do is test the fuel pressures as that'll point you in the right direction

[@mikemike-rf7qb]

@@GreyGooseRestorations Thanks for that...just read my original post...auto correct is shocking..lol

[@Jim-Motorsport]

Hey mate, thanks for all the video you make about it. Been stuggling with the 86 GTi EV of a friend. No fuel to the injectors: injector disconnected bearly full coming out. Fuel pomp and filter brand new (had problem with the pump some miles ago), filter out the inlet of de banjo bolt on the K-jet. I disconnected the return pipe to te fuel filter, by-passing the pump relay and move the plate up from the kjet, no fuel going back to te reservoir. Could the plunger been blocked ? (red about the fuel accumulator, but if fuel is coming to the K-jet, i cannot be it). Could you gave me your opinion ? Thx

[@GreyGooseRestorations]

Hi, if you have some form of fuel into the metering head then most likely its an issue inside the metering head, could be gummed up ports or blocked fuel slits

[@Jim-Motorsport]

Thanks, going to investigate that further and take it appart, cheers@@GreyGooseRestorations

[@Roverturbo]

Hi mate, thanks for the videos, are you any good on the Ford 6 cylinder unit, like on the xr4is etc?

[@GreyGooseRestorations]

Hi, no worries, yes there all much the same as the Mercedes/Delorean ones

[@VitoSpillone]

Grey, I have a 1982 BMW e21 US version. The engine was professionally re-built and all fuel injection componets were replaced as well. The problem I am having is on start-up........the engine randomly surges rpms and will not idle. When I removed the #1 fuel injector, i noticed tha the fuel squirts out but not spraying out. Any advise would be greatly appreciated.

[@GreyGooseRestorations]

Hi, do you mean squirts as in poor spray pattern or as in not much fuel? Are the injectors brand new items and not 'cleaned' old ones?

[@VitoSpillone]

No spray pattern, it kind of just runs out and yes, injectors are all new.

[@GreyGooseRestorations]

@VitoSpillone if that's the case then it's looking at the fuel distributor to ensure it's got system pressure etc

[@flyboyfs]

nice work, do you know if the injectors are all the same ? because on, the same high, they have diferent codes...i like to you on turbo aplication... is ther an chart or something?cheers

[@GreyGooseRestorations]

All injectors flow the same as they are just a tap, the only difference is fitment some are long like ford and porsche etc Check out the injector testing video i did and you can see how much fuel the injectors will flow

[@flyboyfs]

Thank you, i will order ones for Ford Saab and Volvo, they are cheaper than the vw audi ones

[@RobStark-ot3ox]

Amazing thank you

[@andrebarbiaux2640]

Hello, does the low rpm missfire issue only comes from the injectors or can it be related to the metering head ?

[@GreyGooseRestorations]

Hi, 9 times out of 10 its the injectors but it is possible for the metering head to casue this fault too

[@andrebarbiaux2640]

Oh okay, think I'm screwed then, I have this issue + missfire on the 4th cylinder and the injectors have been recently replaced (+ spark plugs, rotor,...). I was thinking too of bad hydraulic lifter causing bad airflow into the 4th cylinder. Is that possible ? Anyways, thank you for your answer and videos ! @@GreyGooseRestorations

[@GreyGooseRestorations]

@andrebarbiaux2640 it possibly could be a lifter but more likely a fueling issue, i rebuild and test metering head as well as other K-jetronic parts, if you need contact me via my Facebook page 👍

[@ronalddean3630]

Thanks!

[@MK2GolfStories]

alright pal, my relay isnt cutting off and the fuel pump is running constantly .. any ideas ?!

[@GreyGooseRestorations]

So with the ignition on the fuel pump is running constantly

[@MK2GolfStories]

@@GreyGooseRestorations Thats right. donst just buzz for a couple of seconds, its buzzing constantly

[@MK2GolfStories]

@@GreyGooseRestorations i should mention i've already replaced the relay

[@GreyGooseRestorations]

@MK2GolfStories check the relay should be blue 67 relay far right lower row if later car

[@GreyGooseRestorations]

@MK2GolfStories so the fuel pump relay is an new 67 one but pump runs all the time By the ecu there is a small 2 pin plug, disconnect and see if it still runs (pump that is)

[@creativeenginechannel7182]

I have a new fuel pump under the seat, but when the engine is started, the sound it makes is roaring, is that an indication that the pressure is too high?

[@GreyGooseRestorations]

Not necessarily, there should be a nice strong buzz, high noise could be fuel starvation potentially

[@creativeenginechannel7182]

can you make a video about how the low fuel pressure system is on the jetronic?, and how the symptoms occur, thank you

[@GreyGooseRestorations]

@creativeenginechannel7182 ill see what i can do

[@creativeenginechannel7182]

@@GreyGooseRestorations I'm too confused because I don't have a pressure gauge for the metering head, can you explain the difference between the pressure that is too high on the metering head and the pressure that is too low on the metering head? maybe it can help me to adjust the regulator Thank You

[@GreyGooseRestorations]

@creativeenginechannel7182 to be honest thats very hard to do, if the system pressure is too low then the car will have starting issues, high system pressure won't effect much bar upping the outputs.

[@teme3232]

What would cause flooding?

[@GreyGooseRestorations]

Normally a seal failure meaning as soon as fuel pressure builds it goes straight out the injector, or the CO mixture being to far out

[@teme3232]

@@GreyGooseRestorations I have replaced every seal except in the wur and have the fuel adjustment screw fully lean and still floods the engine

[@GreyGooseRestorations]

@teme3232 I'm presuming the fuel plunger isn't stuck? What car is it on

[@teme3232]

@@GreyGooseRestorations no it's not stuck, ford escort mk4 xr3i 1989. I rebuilt the k jet because it was clogged and no fuel would come out and after that it started to flood. I have replaced all seals, fuel pump, injectors, fuel filter and cleaned everything. The only thing I have not touched is the fuel accumulator and the washer in the system pressure spring, there is one washer there

[@teme3232]

​@@GreyGooseRestorationswhat seal is it that would cause injectors to start to spray when pressure is on even when airplate flap is closed?

[@PabloGonzalez-zu9sz]

thank you !

[@Porsche928-h7y]

I have a question : my cold control pressure, warm control pressure, system pressure and residual pressure are all in range, as well as vacuum at idle, yet my engine runs rough first hour , it shakes heavily, stutters during acceleration…. When I let the car sit for half an hour till 1 hour, my problem is gone….. Any idea where to look for ? Also something strange : the plunger in my FD is slowly moved upwards after letting the car sit for a night…as if vacuum is occurring in the fuel line between FD and WUR…..any idea what can cause this ? When loosening the fuel connection on my WUR I can hear the plunger drop….so as if vacuum inside the fuel line is holding my plunger upwards.. I already put a spring above the plunger ( normally only used for older FD’s) but it doesn’t prevent my plunger to stay at the bottom. The plunger moves freely when I removed it from the car, so it doesn’t get stuck

[@GreyGooseRestorations]

Hmm that's an interesting one 🤔 have you tested if the fuel Accumulator is working correctly? Are your injectors new or old or been tested

[@Porsche928-h7y]

@ my fuel accumulator is new and is working. My injectors are MB injectors and are also new

[@Porsche928-h7y]

So main questions are : - what can cause plunger of FD sucked up in upper position - what can cause engine to stutter with heavy acceleration, although CO setting is OK

[@GreyGooseRestorations]

@Porsche928-h7y is the cap on your fuel tank functional 🤔

[@GreyGooseRestorations]

@Porsche928-h7y MB injectors i have recently found cause a few issues if used with any cast iron metering head

[@topfell8277]

Good Ole cis grew up working them

[@GreyGooseRestorations]

Fantastic system...once its all set and functional

[@richard21109]

Legend..great video thankyou

[@terryraymond7984]

a bad spray pattern can cause a rich mixture I had that happen on my Rabbit

[@topfell8277]

You can adjust the fuel dist clean out everything rebuild the fuel dist vws bms benzs had this

[@GreyGooseRestorations]

Yup, common misconceptions is that the metering heads dont flow enough fuel, but they can be adjusted, stock 16v for example to can flow 200+ ml/min

[@petnation4970]

What if control pressure is very high and car won’t start.

[@GreyGooseRestorations]

If the control pressure is too high and prevents starting, then i would pull out the small guaze filter in the WUR. Its in the inlet port then fit a new press in filter inside the banjo bolt. If its still high then it will be time to rebuild the WUR

[@petnation4970]

Thank you!

[@petnation4970]

I am working on 1981 380 sl Mercedes are they similar.

[@houseoffolly]

If the Germans could make it more complicated they would.

[@JosephBassettX]

Thank you!