Bosch K-jetronic - The Inside Truth
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- Опубликовано: 5 авг 2024
- #youtube #kjet #kjetronic
Here is part two of our Bosch K-jetronic CIS (constant injection system) how it works video's. I made a cut through of the Air metering flap and fuel distributor so you can see how the system works as one unit.
As mentioned in previous video's the K-jetronic system was fitted to the likes of Volkswagen, Audi, Porsche, lotus, Mercedes-Benz, Ford and Volvo to name a few.
The next video will be Specific to the 'WUR' Mod where we turn the fixed warm up regulator into an adjustable one, why? Your have to wait for the next instalment for that.
Thanks for watching and as always, Subscribe if you haven't already, Smash the notification bell and give the video a thumbs up.
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It's always great to see people still making such detailed video's about K-jet! As the knowledge of this system is slowly dying out, sadly :-(. I swapped my 1990 MK2 CL to a 1.8 KR. Had to learn a lot about K-jet as i've previously never heard of it before. It runs pretty decently, but still have some issues to sort (cold start doesn't work, also starts hard when cold, but once it's started it's fine, etc) I suspect the WUR is also not correct. The metering head and WUR are all really old lol and have never been serviced, so i'm very suprised it all runs so well for it's age! Next step is going to be measuring the system pressure :-) Wish me luck
K-jetronic is such a great system and rarely goes wrong but as you say, some parts may be original so 30 odd years old and would benefit from a rebuild but on the flip side if its still working well after all those years that just confirms how good the systems are
Subscribed off the back of this brilliant, fascinating video. I will now do a deep dive into the rest of your content.
Great channel. I cant wait see the rest!
Thanks 👌
I just found your channel.
That's treasure you are giving us!
Thanks, the more we all know then the better chance of our real cars lasting
Thank you for such a detailed video. This will be very helpful for me to trouble shoot, I let gas become too old and now understand the issues it can create.
Brilliant video thank you for taking the time to make it
No problems, it's helped a lot of people so thats a win for me
Great videos mate. I have had a 16v corrado for best part of 2 years, getting to know K-Jet has really been a journey. Awesome to see inside the metering head.
Thanks, I thought it would be good for people to see inside one
Your KJet videos are very good and im surprised you dont have more likes and followers on them. I've been down the road of KJet too, and its not as scary as people try to make out, you just need to be methodical in the testing. Its quite beautiful in its simplicity once you understand it.
Thanks, got a few more lined up too and unfortunately its shrouded by mythical danger but its very simple in its design and works perfectly
Thank you for going to such great lengths to explain this system. I’m considering buying an R107 SL and you’ve demystified this system for me.
No problems, glad its help so many across the globe
This airflow sensor model is the complete opposite of the model used on Mercedes Benz vehicles.
Yes, the Mercedes use CIS-E which im in the process of duplicating this video but for CIS-E
Subscribed from the US. Great video man
Much thanks 😊
Great video! This explains things things bettar than my haynes manual
Thanks 👌
I can finally see what that allen key was doing, while we were trying to improve the rough idle, power and fuel consumption on our terrible xr3i
Very informativ video,,,,I learned a lot ,,,,I which I had seen this ,,before,, I started dismantling and rebuilding my KE-jetronic ,,,,without any knowledge in advance,. Well I got it right after some" try and failure " and my Audi 80 cab with 2,3 L inline 5 pot,,(NG ) is running "smooth" today
Ace, glad it helped, KE-jetronic can be a nightmare so fair play 👍
Great video, thank you!
Thanks
I love to see all tips and tricks about K-Jetronics. Most information that i can find about tweaking this system is in russian...
Also i can't wait to see your 9A turbo build. Good luck!
Thanks, will have another k-jetronic video out this coming Friday 👍
Thank you so much for this demo video. I'm trying to adjust the the ratio on my 1982 911 SC with the Bosch K-jetronic and it's popping and smells lean with rough idle. Just by lifting the air plate a bit it instanly smooths out. I initally couldn't figure how deep the 3mm allen was but now I know where it is. Unfrutanly it feels frozen so I may try a small amount of penitrating oil over night. Subcribed.
The 3mm might be full of debris so hopefully some wd40 or the like will losen it all up
This is great!
Thanks
Thanks man
Man, great video!
I have Audi 80 2.3 with K-jet, and in Serbia we can't find mechanic who know to adjust K-jet. Now, when i understand how it work, i can start working on that. :)
Ace, any questions fire away always happy to help 💪
@@GreyGooseRestorations can you make video how to measure and how to perfect ajust k-jet? :)
Ill see what i can do
Brilliant video, i have just uploaded a video on adjusting the co2 on a 16v golf and have linked to this.
Thanks, nice one 👍
En las autoescuelas en España hace unos años tenían unos montajes parecidos para explicarlo todo.
Thank you very much I had problem with k jetronic because 8 bar is excesive.
I had 8 bar in filter of benzine and before fuel pressure regulator , and the car fail if push the throtle pedal at maximun.
The orange engine ligth sunrise and its a 1988 audi turbo.
Where are you getting 8bar
Great video mate. I'm really struggling with my RS turbo. After rebuilding the metering head I just can't get it to start. Pin nice and clean everything replaced as it should. Just a no go
Thanks, i could be something amiss internally if everything else is set up correctly, do all your injectors spray?
My jetta is over fuelling alway have been if I was to Touch any that k jet it never run agin …. I know my limitations ….. wish I had your knowledge …. Good k-jet video
That's all horror stores from people who want to keep all the secrets to themselves
Szkoda ze nie po polski,ale i tak bardzo dziekuje.
Golf Gti dx on k jet starts no problem ticks over no problem afr 14.7 after adjusting mixture screw if I rev it hard it misfires if I’m steady no problem afr drops to between 3 and 6 so overfuelling what could be wrong trying to work out how it works! Great videos but still can’t get my head around it all!
Great video…you also don’t get many people saying “orifice” these days 👏🏻
Its a great word haha
We have an 1986 sierra xr4x4 with the 2.8 v6 and k jetronic, after 17 years of standing we found that the rubber O ring on fuel pressure regulator had fallen apart this ment it wasnt quite making the correct fuel pressure to make it start, changed the rubber O ring...now runs superbly.
Glad to hear it, i do love an old ford, definitely not many xr4x4's still going 👍
@@GreyGooseRestorations we have the mk1, its going for its first mot since 2003 next week.....according to how many left, there's between 20 and 30 left...but there's discrepancies between how they are registered....some are registered as xr4x4 I and some just xr4x4....
That's one of the hard parts finding out the details like that as back then things weren't recorded or noted as good as they are now
Excellent demonstration and thank you definitely subscribed! I'm refurbishing an 87' 4000 CS quattro and starting with the fuel system. What is the best procedure to clean this pin so it moves freely?
Thanks, it uses the fuel to seal and lubricate itself so id try abit of fuel in the first instance
im just going to chuck on some good old carbs
Great vids, really appreciate you taking the time to do these.
I have 2.0 16v Corrado (9a) with fuelling problems, The main issue being fuel pump failures, Both the high pressure pump under the car and the in-tank lift pump!. Also on several occasions the car has refused to start and the high pressure pump leaks from the banjo...leave it for a few hours and it starts and runs, and does not leak!!
Have been advised it could be an issue with the K-jet system, sticking pin has been suggested, but would that cause pump failure/leaking?
The car also runs badly when warm (misfires and will not idle)
Any ideas really welcome! thanks
Thanks, firstly id focus on the pump, make sure its getting a good constant 12+ volts.
There is a inline check valve in the fuel pump output which can be removed and may need replacing, if its sticking it could be causing to much pressure in that area causing the leak, after while the fuel may seep past the check valve allowing the car to start.
If you want message me on my Facebook page - Grey Goose Restorations and we can go through the system and see if we can fix it 😁
@@GreyGooseRestorations thanks for the reply, will have a look on Facebook, I was not aware that there was an inline check valve, will have a look for that.
Appreciate your help!
Thanks for the video. Do you know if this is exactly the same on the early MK2 8v engines?
In principle yes its exactly the same
This was a wonderful explanation. If the needle is stuck due to setting. What is recommended? Is there a way to fix it or do you have to buy a new assembly?
Thanks, do you mean if the fuel pin/plunger is stuck?
If so it can be removed gently after spraying WD40 or similar in the top control pressure union and let it soak through
I have a 924 2.0 and I can't get it to run. I've removed all 4 injectors and when I crank the engine all 4 injectors spray huge amounts of fuel without the metering head even moving, I've checked the plunger in the metering head and it moves freely. The plunger looks very new and always seems to rest on the arm no matter how I turn the screw. Are there different lenght plungers?
Any ideas would be great
Hi, if its spraying fuel with the plate at its rest position then its either the fuel plunger is incorrect or not set right and you have control pressure being injected from the top of the fuel plunger due to it being to low or there is a seal or seals failed internally
Thank you for the great video. I have been wondering about one thing, where is the throttle body located in these systems? It looks like the air after passing the filter goes directly to the air flow metering arm thing in this video, does the throttle body come after this part? Or is this part also acting as the throttle body and there is no other seperate throttle body, in other words is the gas pedal that we push connected to this arm?
Hi, thanks
Nope there is a throttle body, after the air flap the air travels up and through the intake piping and then goes through the throttle body
@@GreyGooseRestorations i see, thanks a lot
Nice video! I have vw golf mk2 1.8 Cat from 1987 which wont start, but once you start it runs it does great. While engine is warm you can start with no problem. Once it starts cooling of, it gets harder and harder to start until you wont. Also, when you turn the car on and it is cold engine it fires but won't start. Any idea where to look?
Sounds like you may have an issue with the cold start injector, WUR or just a fuel pressure issue
Great and easy understandable video. But please tell me where is Part 1?
Thanks, there isn't a part one to this unfortunately
Our '88 Cabriolet had a tab holding the fuel control rod up. Does it need that tab? There isn't one in your video
It doesn't need it to be honest, it can't go anywhere, only helps when you are removing the metering head
How much voltage should the lower fuel pump receive to function properly? My friends car is getting around 9-10 volts, could that cause the fuel not to cone out of the shims? Thanks
The main fuel pump under the car needs to have 12.5 volts minimum. With around 10 volts, the pump won't be producing enough pressure
Something ro note is that on Mercedes the air venturi lowers rather than raises. This makes it more obvious to see if your fuel plunger is sticking.
Question. My Mercedes W123 spends a lot time standing and the fuel plunger does stick frequently. It's a pain to remove but does free up easily. I use a lead replacement additive and try to get low ethanol fuel. Would using a fuel additive or injector cleaner help?
Handy info thanks, potentially it would be worth adding something to provide some more lubricant in the fuel to help prevent the plunger from sticking.
A shot of E85 to clean it, then use some 2-cycle oil in the fuel at 500:1 or a little more the first time.
Good video, I have a 1982 Volvo with k jetronic and I need to repair or convert to electronic fuel injection if possible.
Easy enough to repair vs cost of efi conversion potentially
Sadly I had to sell my 16v PL KE Jetronic due to some unfamiliar fuel issue that caused jacky and uneven engine revving, it was getting severe, replaced every ignition part to fuel pump, only part that was original was the KE A/F meter... Guess it was that :/
This is one reason I want to make these videos so that the 'mystery' can be understood by the masses
Great video! In one of your other vuds you talk about honing the fuel pin to allow more fuel to the injectors. Now if the air-fuel mixture is balanced 14:1 based on the ratio between the fuel pin and the diameter of the air plunger, won't honing the fuel mess up the Mixture? i.e. how will you then add more air to the system? Is it now possible to adjust the air plunger to open more where it would have previously at that position given a lean mixture?
Agreed, i did attempt to opened out the the air flap with a larger plate with a % bigger than the % removed from the pin, however this didn't work, it may work if you could get the air plate cnc machined but vs the cost involved its not worth it
@@GreyGooseRestorations so you're saying that honing the fuel pin is not worth the trouble and that one should rather play with the WUR and system pressure?
Yes pretty much, took a lot of fiddling about but setting the pressures correctly and carrying out the WUR mod along with suitable timing advance make more difference (WUR mod video should be finished sunday 😉)
@@GreyGooseRestorations we appreciate your work. So many disregard the ingenuity and robustness of KJET and it has become a taboo topic. What would your view be in terms of performance between modifying the kjet system as discussed versus going EFI with the ABF manifold? I ask because I would first like to get some more ponies out of my kjet before moving over to ABF EFI.
@@colevincent8563 EFI will allow for more precise timing adjustments which is what the kjet doesn't have but i look at is as cost vs gain, the gain over and ABF on EFI vs KR on kjet could be 20bhp but would that 20bhp really make a difference in the real world plus the KR is very rev happy engine as it is.
That cut through model is a great idea!
Now I have red that for removing the plunger you need to measure the depth of the slotted nut at the bottom (somewhat around 0.6mm) to reset it to the exact same later on.
I understand that this nut defines the bottom position of the plunger but does it affect anything after the arm raises it up?
Greetings
Thanks, the slotted nut depth is only on the CIS-E / KE-Jetronic. On plain jane k-jetronic the nut is just for retaining purposes
@@GreyGooseRestorations Thanks for the reply. Do you know what exactly has been changed on KE for this to be a matter?
KE is a different kettle of fish (in the process of making a video specifically for KE) the metering head is upside-down and has a differential pressure regulator instead of a WUR and has a potentiometer for the air flap along with an o2 sensor
Just to make sure that my K-Jet and WUR are setup right...The top inlet part that you discuss at 3:10 should have fuel coming back from the WUR? Am I correct? Should it be connected to the WUR on the right side of WUR with the bigger banjo bolt and screen filter? It seems to me that the screen is to keep crap OUT of the WUR... Maybe previous geniuses screwed up the Meter-to-WUR-to-5th injector order...That might be why it only runs right when warm.
Potentially, the larger banjo with guaze filter is the fuel in. The other one is the control pressure that goes to the top of the metering head
@@GreyGooseRestorations Mine are hooked up backwards with regards to our conversation but when I look at the arrows that indicate flow direction and the curves in the hard line at the end of the hose and the size of the banjo bolts --- It can't be hooked up any other way. The larger banjo (with the guaze filter) is connected to the top of the metering head, it can't be hooked up any other way. I'm baffled.
Thats confusing 😕 send us a picture if you like via Facebook page Grey Goose Restorations
@@GreyGooseRestorations I will snap some pictures shortly just to add to the knowledge pool. I did solve my cold start issue: 5th injector was defective. I put it a used, working injector and I get normal cold starts now. Thank you for all of your help.
Ace, glad its starting better now
About to do some pressure testing on my mk2 tommorow. What would be some symptoms of a stuck pin?
A stuck pin would normally prevent starting but depending on where its stuck you may be getting to much fuel in and around idle position. The normally stick in the lowest position due to not being moved for a long time or they will stick or become very slow moving to come back down (closing the fuel off)
@@GreyGooseRestorations what’s a good way to free up that pin?
Take the fuel line off the middle centre of the metering head and spray some penetrative fluid in there such as WD40 and leave it to soak down, hopefully that'll free it up
So, in your explanation at abut 6:45 Mine has set for more than serval years, and when I manipulated the air flap manually it lifted. Even though the pin will not likely drop on its own weight, and each subsequent "plate lift' is not really pushing the pin anymore....it at least suggests that the pin is not "frozen". Correct assumption ?
If you can move the plate then potentially yes the pin isn't stuck just sticking so wont return under its own steam which is good
If you can move the plate then potentially yes the pin isn't stuck just sticking so wont return under its own steam which is good
Hi mate, been subscribed for a few months and loving your channel. Do you know how to set the CO screw for an engine thats not running due to the mix? Obviously you can see the pin gap on this model but how do I set it up without being able to see the pin? Ive found loads online for setting Mercedes one but this one operates the opposite way and i’m a little lost.
Any help would be greatly appreciated! Cheers
Simple way to get it in the ball park is pull injectors and stick in bottles
Swap relays so pumps continuously run
Turn ignition on and turn the 3mm allen clockwise untill the injectors just start to dribble/spray then back off half turn
@@GreyGooseRestorations thanks mate, ill give this a try tomorrow!
@@GreyGooseRestorations just a quick one from rewatching one of your other videos. Which position should the air intake flap be in for this test? Just the 1.5mm stock position? Or open slightly to mimic idle? Cheers
@ScouseSponge to test fuel flow?
@@GreyGooseRestorations yeah sorry realised later on its obviously not required! Cheers for the support and all the helpful videos!
Can’t get mine to idle , starts no problem but you have to keep it going with some throttle all the time otherwise it just cuts out, any thing I should check ?
It could need the hight of the arm adjusting to richen the mixture potentially, only a 1/8th of a turn at a time
@@GreyGooseRestorations thanks, sounds about right as the exhaust fumes stink on petrol when it’s running
mines the same i assume you turn the small.allen key clockwise? but if this doesn't work what do you try next please?
Clockwise = Rich
Anticlockwise = Lean
If all else is healthy then it should be case of adjusting clockwise a 1/8th turn at a time untill the engine will idle on its own, then adjust the idle screw on the throttle body to further smooth the idle, 1000rpm is where the 16v idles spot on
@@GreyGooseRestorations Hi, great thank you v much. When mine was in daily use it never missed a beat, but suddenly it started switching itself off when sat in traffic or when idling on the driveway.
It revved absolutely fine and drove spot on apart from this.
I have long suspected that i needed a new hall sender as it occasionally gave me the dancing rev needle when you went to start it (needle flew round to 4-5 rpm with engine off when you turned the key to first position) , ive got a brand new bosch dizzy sat here ready to go on, i just dont know how to fit it! 🙈🤣👍 many thanks again for your help
I have an XR3i, it starts fine from cold and if you switch off hot for about 5 minutes it will start. However if left longer than 5 minutes it won’t start. Eventually when it’s cold again it will start straight away. My theory is it’s loosing system pressure slowly and then vapour locks the injection lines from the heat? Any ideas? It’s had a new accumulator and non return and another fuel pump.
There is a seal in the metering head that holds pressure inside the metering head that are prone to wear and passing fuel back to tank, if this is at fault it could cause those symptoms, its the one on the end of the system pressure relief valve
@@GreyGooseRestorations Thanks for your help! That would make sense, the car is just shy of 40 years old now so it’s probably allowed to need a replacement! Anything else that you would recommend doing whilst it’s apart? Do you know if there is a service kit available?
You can get all the parts from missingparts.de thats who i use to supply the kits 👍
@@GreyGooseRestorations Thats great thanks. I’m surprised you can still get all the bits for the K jet considering how old it is now, other parts for the car are not the easiest of things to come by nowadays!
I know XR3I stuff is very hard to find, was trying to track my wifes old one down last year, its still on the road which is one thing 👍
I have a 2.2 Audi coupe b2 and i’ve managed to get it running on all cylinders now.
When i operate the throttle the engine stalls.
I have replaced the injector seals (plus 3 of the 5 injectors) and nearly every rubber hose for vacuum leaks. I can see the rubber intake boot deforming slightly as i open the throttle which to me means theres a good vacuum to operate the plate surely?
However there is little movement, if i operate the throttle and the plate manually it runs really well.
Could this be the pin sticking ? And if so is there a good way to unstick it ?
The car sat for 20-25years prior to me getting it and i did initially unstick it by operating it manually.
Any help is much appreciated thanks!
A good way to unstick the pin is to remove the metering head off the air metering unit
If there is a metal tab preventing the pin falling out the bend this out the way and remove the pin.
Spray some cleaner where the pin goes and clean the pin then use some fresh fuel for lubrication and refit the pin and bend retaing clip back
Also if one isn't fitted you can install a soft stainless steel spring in above the fuel pin which give a little aid to help the spring return to rest
@@GreyGooseRestorations i’ve managed to clean off the pin and it was pretty clean with a tiny bit of rust at the end which i cleaned and it moves freely. There was a spring above the pin already.
Still the same results where if i operate the distributor manually with the throttle it runs perfect, but if i just give it throttle it bogs and cuts out with an occasional backfire.
Any ideas ?
I’m stumped at this point.
Ah ok, at the rear of the air box there is s black and grey plastic valve with a vacuum connection and an electrical plug, un plug the electric connection and see itlf it revs ok
@@GreyGooseRestorations I will try that next and see what happens.
Thanks for the replies. Most of the system has been replaced due to it sitting for so long and every vacuum line etc except 2 which look okay.
@@GreyGooseRestorations I have given that a go, still exactly the same.
Becoming more of a nightmare than a project haha
Is it the same for Mercedes ?
In basic form yes
I have one of these with the fuel pin stuck up in the distributor, have it mostly apart but I can’t get the pin out from fear of damaging original parts, can you please help my father and I fix it?!?
Best way is lots of WD40 or similar, spray loads through the centre connection on the top of the metering unit, then all the other ports.
Take it slow and let the WD40 etc do its work, last one i had issues removing took a day or so of soaking over and over few houra apart etc
@@GreyGooseRestorations how’s brakeleen, with wd40 does it need any form of lubrication after?
@ejmiller3109 brake cleaner may cause damage to the rubber seals inside.
Just use the same WD40 or similar to lubricate the pin once its all free, its lubricated by the fuel in normal operating conditions
Compressed air
Wrecajac srube zwiekszam mirszanke paliwowa?
If you mean the CO screw then yes, turning it anticlockwise will make an improvement to fuel consumption.
Dalej czytam o tym k jetroik ,jest tyle niewiadomych....
Pewnie gdybym umiał angielski to bym już niemusial nic szukać i czytać.😊
You know what happens to the injection system if you installed a lpg systeem don't you.
I don't think k-jetronic would work with LPG