Bosch K-Jetronic (CIS) explained

[@JonBurr1]

Whoever made that deserves a medal, what a great explanation. Thank you

[@Corsa15DT]

excellent explanation of a terrible fuel injection system.

[@FirstOnRaceDayCapri2904]

K-Jetronic is an amazing system, light years ahead of its time. Dead reliable, very tuneable.

[@FRITZI999]

Actually the opposite. The worst ever inveted POS i´ve ever wrenched on. Tunable? nope. Reliable? Noooooo !!!

[@anthonidanowski9404]

@@FRITZI999 sounds like a technician problem

[@FRITZI999]

@@anthonidanowski9404 Shovel you shaming Comment up your Ass Buddy.... i studied this System over the Years, own all Technical Manuals and even Stuff from Bosch YOU would not even get your Hands on. Also Tools to fine tune that System. And even had Contact to a Guy who worked at BOSCH during the Invention of the System - his Comment: "the biggest POS we ever made...." Quote End. I learned plenty of Stuff from him. But in the End it´s an old, obsolete System full of Flaws. Yeah, mine runs perfect, but that does not make it more Lovable. Mine never had any Issue after i was done with my Cars fulll Restoration.... but that doesn´t make the System better. It´s just crap ! Yes, for it´s time it was "ahead", but pretty fast obsolete. That shows that it was just a kind of Learning Step in between to a better System.... KE and Digifant for Example. IF the K-Jet was so magificent, why don´t we still use it?

[@bikeman123]

Continous injection gives extremely poor fuel consumption and engine wear from the fuel continously washing the bores.

[@FirstOnRaceDayCapri2904]

@@bikeman123 Spoken like someone who knows nothing about K-Jet

[@bereal1807]

CIS is an engineering marvel of a time before EFI, don't forget that this was the best in the world injection solution at one point in time, my hat is off to BOSH for giving me such a magnificent system..

[@3rdGenGuy]

Ed Leclair it works well, except when it doesn't lol.

[@dgreatll]

+AllyourBaseArebelongToUs 👏 my 190e is a nightmare

[@3rdGenGuy]

Fresco L my brother has a 190e 2.6L 200,000 miles For some reason it hasn't broken yet. We are just gonna convert it to Mega squirt EFI when it goes.

[@timewa851]

+AllyourBaseArebelongToUs VW Golf, 460,000 mi.+, one h.p. pump & relay, I've been waiting for the "fail" too, not happening..

[@3rdGenGuy]

Tim Ewa maybe a diesel, not gas

[@lctv-pu7ch]

Older videos are the best, GREAT, thanks VILHUER

[@laynesamba]

This shit is why I can't sleep at night.

[@wbcars]

exactly -:)

[@yorrickwi]

now i gotta find out how L jetronic works i want my citroen cx gti on the road :')

[@chris425amp7]

LoL

[@friedchicken1]

And to prove it... it is... exactly... 2:50 am right now

[@crherniman]

Holy shit that was me last night watching all the k jetronic videos

[@prakashnarismulu3332]

Watching in 2021 trying to bring a 1977 Mercedes 280 e back into circulation

[@mightysprocket]

How'd you make out with the 280E?

[@DZGunner]

It's actually a really simple system. Testing the different components is easy. To anyone who has this on their car and wants to know exactly how to tune it and see whats going on, put a wideband O2 sensor in your car with an AFR gauge. Every time I do this, my cars run silky smooth.

[@nboy7]

Videos or guides anywhere?

[@DZGunner]

It's the same thing on any car with any fuel system. drill and weld an O2 sensor bung into the exhaust at an acceptable angle. Add the wideband sensor and route your wires to the interior. connect your wideband gauge and monitor your AFR under all driving conditions. Be sure not to adjust anything when the engine is still in its warm up phase, IE, get the car to normal operating temp.@@nboy7

[@MR-nz5pg]

I'm a lucky person. Had my '91 MB M103 CIS-E system adjusted by a good tech in 1997. That was the last time anyone has ever touched it. I do routine maint. often - use good gas and do sufficient highway driving in order to keep clean gas flowing thru the system. I have read 100s of stories about people having trouble with their CIS system. Many are DIY types who buy all of the special tools needed to adjust its various components. Its my belief that in some cases, these DIY types have no clue what they are doing when they start to tinker.

[@pilskadden]

This system is very reliable and I think you are right that people who have no idea what they are doing actually cause more harm when they start to tinker with the system. Rarely the fault is with the K-Jetronic itself. More like with vacuum leaks, leaking injectors etc.

[@ronalddean3630]

I have always thought this, about other car issues. With some things, you either know or you don't. If you don't you need call somebody who does.

[@ronalddean3630]

@@pilskadden Agreed, I think more problems are created by some DIYs.

[@OrionCrazyCarl]

love it !!!! loved my K jet for 10 years! the induction noise is to die for! GRRRRR!

[@donreid6399]

Had a problem in my Porsche 924 equipped with K-Jetronic years ago. It would start fine when cold, but crank and crank when warm. Turns out, I had a split in the air induction boot that was allowing air to bypass the plate so once it cooled down, the cold-start circuitry would kick-in and it would start fine. Replacing the boot made it all work wonderfully. This system is SO intuitive!

[@OmegaMale38]

Diagnosing my '77 924 at the moment, grateful for this insight!

[@donreid6399]

@@OmegaMale38 I hope it helps. As I said, the old Bosch F.I. systems were pretty straight-forward. Get hold of a basic layout diagram and you're halfway there. Good luck! 🙂

[@82accs]

I was given a '76 Audi Fox years ago. The car had been sitting unused for many years and needed some work to get it road worthy. I quickly had to learn this injection system. Once I had it all figured out, it was pretty reliable! And this was in the days before KZbin and Google. All I had was a Haynes manual, and fortunately a nearby foreign car parts store run by an old German gentleman who used to work on Audis, VWs, Porsches etc...

[@dekrev]

Well - just got a Delorian and this is a lifesaver - thanks for sharing!

[@Joe26383]

I just got an Audi 100 C3, great explanation! Man, lucky you with that car, good luck maintaining it and enjoying it!

[@zacharyp10]

@@Joe26383 I have an 87 audi coupe gt, cool system

[@danielbarton9291]

Big clue to lean running when they inform about gauze filter in tank. Caught me out with my 86 audi. The gauze clogs with rust and starves the pump. Look after your cars folks 😀

[@saqibnawaz5139]

Vry wonderful explaining of k-jetronic CIS fuel injection system vry Great invention by Bosch among many other inorder to serve humanity with clean burn guaranteeing Environmental security canb amassed

[@tahroo4262]

CIS in a nutshell: You put the gas in the car.. Witchcraft happens.. and you go faster.

[@pieterschaar5613]

What cool 1970's video, I remember these kind of video's a school This was very informative and clear on how the K-Jetronic system works, wll come in very hand on my 1982 982

[@Josh-py2in]

K-jet is a much simpler system than EFI. However, EFI is much easier to diagnose. People hate it because they don't know, or don't want to diagnose it. With EFI, just a simple computer scan will point you in the right direction. K-jet was from the time of real mechanics. Back when you had to adjust valves, adjust points, adjust fuel system pressures, etc. Unfortunately with modern technology, everyone either has a husband or dad that is a so called "mechanic" just because they have a scan tool and some sockets. My hat is off to Bosch for this great fuel system. When tuned correctly it can support good power, the acceleration and response is amazing, the sound is unique. And it blows people's mind when they see the mess of fuel lines an hoses under the hood.

[@chris425amp7]

Cracking system if you know what you doing😎

[@Kj16V]

If you think you can just fix every EFI problem with a scan tool, you obviously don't know EFI :D

[@rust_hunter7867]

Me watching it in 2023 to finally understand this black magic

[@tonyturner9146]

Worked on a lot of these in Volkswagen cars in the '70's and 80's and a few early '80s Volvos. Cold and warm start issues were the most common thing I remember working on. If you could get them to start they ran pretty well. Drippy start injectors, bad cold start times and leaky check valves made life... lets just say interesting lol. I much more prefer the LH-Jetronic systems used on the Volvo 240's. The LH 2.4 was bullet proof!! Thanks for the flashback!

[@turboenterprise790]

Hello Tony, Im having a problem with mu jetronic. It starts really bad when the engine is cold. Like really heavy. When it starts is stutters for like 10 secs and after that everything is fine. Do you have any ideas what might cause that problem. I have checked the spark plugs, injector leaks, changed the fuel-head (the one with airsensor hand), lambda, and fuel pump. Im out of ideas :( Have a good day!

[@hellofurend]

Lh is easy kjet is for men

[@jannis-joelfehl4855]

@@turboenterprise790 i hope you figured it out by know but after watching the video have you checked the injectors specifically for cold starts as shown in the video? As well as al components related to cold starts as shown in the video?

[@turboenterprise790]

@@jannis-joelfehl4855​​⁠Yes boss the issue was solved. It turned out to be a tiny crack in the fuel hose inside the tank. It was small enough for the pump to maintain the pressure needed for engine operation but big enough for the fuel fall back into the tank draining all the fuel systems hence the 20sec crank time(engine starting, pump filling the system with fuel before injection). I recommend for all having some issues they can not resolve: check the hoses for fuel pump inside the tank for leaks because the original systems are like 30 years old + there is a big chance some mechanic has already changed some stuff in there and not used the correct hoses for fuel therefore they will wear our much sooner causing random problems. If anybody wants to see a video about checking the fuel system for pressure holding up after the engine is shut off, without a gauge or special tools. (needs to hold some bars for some time)

[@jannis-joelfehl4855]

@@turboenterprise790 Ah well thats great and really interesting but if there was a leak there also must have been fuel under the car? Which you would notice right?

[@19553129]

simple and efficient, I love this system.

[@Corsa15DT]

this is not simple, this is all analog signal transmission, extremly unreliable and innefficient.

[@peepoop6630]

Thanks, I'll have to pick that up. I don't know if you have read this book, "Bosch Automotive Electric-Electronic Systems" but it really helped me understand FI as seen from Bosch's viewpoint. Obviously, K-Jetronic is completely outdated, but studying it really helped me understand. EFI systems have such a low part count that a beginner is left in doubt as to how it does what. With the old mechanical, every function has a part that corresponds to it. That book explains better than this vid.

[@ganessanesandjivy7021]

Really I impressed this animation , it has a great explanation of the fuel distributor system . I honestly proud of your efforts ...........

[@bikeman123]

It's a Bosch video, the guy only posted it on youtube.

[@danielbarton9291]

Brilliant explanation video. Well done for posting. Anyone with running issues should take notes - this vid could save you money and time. Check the basics first.

[@lewdards1127]

"always consult the parts microfiche" yep, ill just crack out my microfiche reader........

[@Cheepshooter14]

lew dards You can borrow my dad's. Just pay shipping both ways!

[@jiixybaloba9592]

Grateful for the video.. almost got into a fight with my senior colleague cause too stingy to explain.. thanx again

[@ssarkees]

This is a great video! It was a revelation to me!

[@peepoop6630]

Yes, this is a really good point. I had a Chevy OBD0 TBI that I bought cheap. It ran okay at some points but crazy elsewhere in the range. The light was on. All the older mechanics that knew more about a short block than I will ever dream of were scared of it. I jumpered it and it flashed out some codes. It was getting false air and maybe a bad TPS or IAC. Something else, too, but can't remember. It only took $75 and a few hours to make it purr. So, yes, self-diagnostic can't be beat.

[@robertp404]

It's a great video. Now I know mine is broken, I think. Now if I don't commit suicide trying to rebuild the thing we'll be getting somewhere.

[@budrobadre]

Did you ever fix it?

[@Koskelo98]

@@budrobadre Silent moment for Robert P

[@budrobadre]

@@Koskelo98 lmfao

[@xQuandaleDinglex]

@@Koskelo98 😔 sad times indeed.

[@chengreg252]

very very good tuition.Cant wait to see the diagnostic for fuel pressure testing ,control and system pressure hookup.

[@tombutchen6552]

You can tell that it is a heinously complicated system by the fact that it takes a 20 minute video just to explain all the components.

[@AppleJack1997]

I have this system in my Mercedes 380SE. It's so complicated that I'm scared to mess with anything on it. I always have to give it gas when I start it in the morning because of the stupid warm-up valve. Plus my exaust smells like pure gasoline.

[@bereal1807]

Tom Butchen OK then how long would it take you to explain all the components and function of an EFI system in comparison? If you don't understand k-jet do you understand efi? CIS is more intuitivly understood than EFI IMO..

[@AppleJack1997]

Ed Leclair I agree with you now. When I first commented, I didn't even know what a camshaft was. I did some work on my EuroVan with a VR6 and with so many sensors and computers for the EFI alone, it makes K-jet seem so simple. You can actually see every part working, instead of messing around with digital components. Yeah, it's less efficient than EFI, but would you give up simplicity for efficency? I sure wouldn't. My K-jet is still going hard, so much so that I blew my head gasket and I'm pulling the system apart now. K-jet only seems overly-complex for narrow-minded people who are too lazy to figure out the problem.

[@FukU2222]

Or just new technology. Hardly that complex, merely new concepts that need explanation to the masses.

[@jellert1233]

Lol I have this on my Saab 900 because it was the easiest to install.

[@Hoffie92]

hope this will help me repair my porsche 924

[@JMc.D]

Well did it?

[@donaljamescaddye3805]

Yeah I want to know as well !

[@Hoffie92]

It didn't haha. Had to scrap the 924 unfortunately. Car has been gone for cose to 7.5 years now

[@timevscars]

Finally I can use this and understand how to tune and fix the m103 engine and know how it works

[@Baba-yz3kp]

Watching in 2022 trying to bring a 1986 Volvo 740 back into circulation

[@binagarten4667]

Great upload, many thanks.

[@CreRay]

Very useful, thanks for sharing.

[@petermccarthy4332]

Love the to refer to the manufacturers microfiche!! Or "brisk" acceleration!

[@letakis01]

Finally i found good explaining about k-jetronic

[@skiwhh]

My 911 1982 SC CIS works perfectly starts on first turn for the last 10 years.

[@TheEpmedia]

My 1978 bmw cis still works good too

[@ladislavleitner1729]

Hi, the video mentioned a self study book. Does anyone have any info on it?

[@businesswolle666official]

Could you upload the next part of the video?

[@rice8041]

Thanks for posting!!

[@DavidParker-cf2km]

No computer, absolute air density sensing! At the mechanical tolerances we can machine to these days, I would like to see a non-computerized mechanically analog car built that the CIA can't screw with and use your own car to kill you.

[@lprater11]

Excellent video.

[@ozelot250]

Thank you, very informative.

[@SaGalv]

The Bronco I had with the speed-density type fuel injection never left me stranded...and what did go wrong with it was never a result of EFI failure...not saying it cant happen, or hasn't..but it never was for me. I wouldn't go to an audi if i was looking for reliability though. Mine had so many electrical issues that its a good thing the fuel injection was mechanical, or else it wouldnt have even drove.

[@EvanJ-g8n]

every time i close my eyes i see fuel pissing out the seam...

[@SanojMendis]

Very useful video. Thank you for sharing this.

[@tarounterburger3032]

20 people must have broken K-Jet systems lol

[@Kj16V]

You mean 1000 people had broken k-Jet systems and came here to find out how the hell these things work :D

[@sparkie5571]

mine is...

[@tarounterburger3032]

64 people now hate KJet. I do too. LH for LIFE

[@dakotamonroe9746]

This was super helpful

[@azmike3572]

"Consult the part's microfiche". Quaint.

[@jeremys924]

trying to figure out why the injectors are spraying too much fuel into the cylinders. i think its because the plunger, thats controlled by the air flow meter, is stuck open causing it to send too much pressure to the injectors. im not sure if it is attached to the meter arm or if its pressed down with a spring, the video didnt mension either.

[@top6ear]

thank you for posting this

[@angelicazepedaorozco9283]

QUE BUEN VIDEO COMO NOS A SERVIDO MUCHAS GRACIAS

[@pastorboy0]

I don't know if I would go so far as to say that TBI>CIS... especially since around '91, you would have had CIS-E, which would have had O2 sensor feedback, and also CIS is port injection.

[@ratscoot]

i had a 1986 VW Golf 2 GTI 16V back in the time. The K jetronic of my GTI went regulary out of calibration, needing a readjustment by a VW dealer.

[@80fordmustang6]

Had a 86 5000s with this system was pretty neat

[@bikeman123]

Next video 'diagnosis and testing procedures'?

[@TheVillee]

Great video!

[@saadalghamdi3203]

Wher is the black vaul regloto rinjector .

[@SaGalv]

I would honestly hate to work on a broken Jetronic ...I think all I would be able to do is take it apart, clean it, and put it back together and hope it works. EFI always seemed to make things easy (Even OBD-1, which you can also pull codes on just like the current OBD-II, even on the vehicles without the check engine light)....Most of the time its, pull codes, okay this sensor went bad, replace sensor, car runs like new. If not, you are at-least pointed in the right direction

[@issamalmousa76]

Why the translate not active in the video

[@dragonvlv]

How CNG (Compressed Natural Gas) is working with K - Jetronic ?

[@takemebacktothen]

It doesn't. lpg systems are always standalone

[@AB-rr6iq]

Is the Bosch K-Jetronic mechanical fuel injector in 1989 car compatible or incompatible with E10 petrol?

[@Danger_mouse]

If you have a choice to avoid E10 petrol, do so. It is the devil for all older fuel systems that are not specifically set up for it. I don't imagine K-jet being any happier with E10

[@a-aron5691]

Consult your owner's manual

[@Foozer1337]

V B as long as you keep driving it. Try to avoid if you can, check pure-gas.org try using some fuel treatments like Startron.

[@XvS6-Lemaza]

Is there anything similar on KE Jetronic?

[@bethells86]

Love my 1990 Audi Coupe except for CIS system. Would love to convert it to Carb.

[@orionz168]

very very nice video .. much appreciated :) where did u get this lol

[@homeistheearth]

very nice video..

[@billybobjoe198]

Why does my 87 have K jet but my 82 has L Jet? I'm almost certain my WUR is bad, it rattles. Makes me think I've got low pressure and it's just flowing back to the tank.

[@JohnSmith-ug3qk]

Does anybody have the transcript of this video?

[@alexandercella7990]

Hi Vilhuer, do you know a skill mechanic who knows to service the KJ tronic of my Volvo 740 turbo ? B19ET is the engine and the car has been made in Sweden in 1984

[@peepoop6630]

Jerking your chain a little there, man. I just have to take up for Bosch. I shade-treed on old Mercedes when I was a teen and love all things Bosch. Never had any trouble with Ford EFI, but it always worried me, whereas with the MB, I knew I had carburetor-style reliability with FI precision.

[@michaelhilber8284]

Many bmw's have this, such as the '77 to '83 320i's.

[@SaGalv]

My old audi had this bullcrap. It is literally mechanical fuel injection. Crazy concept for a petrol powered car...especially since my audi was a 1991 and had mechanical fuel injection, yet my other vehicle, and 1987ford bronco II had electronic fuel injection. Which is obviously better and more sophisticated

[@patikbasyir7228]

It helped me alot..!!thank you!!

[@nt4755]

the video says' all injectors spray fuel at the same time continuously'. what happen to the fuel sprayed into cylinders that are not at its compression cycle (or ignition)

[@aeroe2144]

Its port or manifold injection (so the intake valves will essentially block the fuel, SORT Of similar to a carbed setup)

[@Corsa15DT]

We were all victims of this terrible, mechanicle, unrealiable, fuel gazzling bosch shittronic system. Looking back at it now, it brings back memories though.

[@SaGalv]

Nah, my bronco ii had muiltport fuelinjection, 100% electronic. The only thing was that it ran from a MAP sensor instead of a mass air flow like vehicles that shortly followed it. Hell, in 1991, the Ford 4.0 had the mass airflow sensor and already has distributor less ignition. Im surprised audi was still using this ancient setup in 1991.

[@KM-bj4ju]

نظام معقد جدا رغم أنه يمثل عبقرية الإنسان الألماني إلا أن نظام الحقن الكهربائي اثبت انه أفضل منه بكثير واسهل وأقل تعقيدا وأقل صيانة ....

[@niklashenne9340]

deine video sind geil Xd

[@paulleslie9110]

Brilliant

[@nicholasagnew2792]

One must always consult the microfiche.

[@turboenterprise790]

Mine is fucked. The car doesn’t start normal when its cold. Have tried soo many things to repair it but its still fucked

[@oldsccaguyyah9901]

And people back in the '90s wondered why I didn't hate my Digifant. Just joking, vilhuer! Great video!

[@Mark-vi7ef]

Thank YOU !!

[@fabricioagustinonboard4844]

i am changing my bosch k-jetronic fuel injection of my passat variant cl to carburator Webber, anybody know if the admision is the same of audi AP1.6? thanks

[@keithhoughton4308]

I have a Merc 123 estate quietly rotting away in the yard. Every six months or so I amaze my friends by putting a battery on the car and it fires first time every time. If it wasn't so rusty I'd trust it to take me anywhere. Mot testers have no soul.

[@Aaronhouston33]

I horrible moment in automobile history I hate this system the price for a fuel distrbutor can cost 1,000$ PLUS for new and rebuilt ones are disaster waiting to hapen

[@alexanderx3554]

Stay away from ethanol fuel, stick to as pure gas as possible add an additional filter to the fuel distributor inlet down to a few microns I think 5 or 6. Your system will be worry free. Ethanol eats the seals up and particulate matters clogs the micron size slots where fuel goes through. Never let vanish build up in your system, store your vehicle with fuel tanks of pure gas. Long term Headaches solved.

[@ShinyRedGrapple]

Um does anyone have an extra Self-Starting book I can borrow

[@ronalddean3630]

😵‍💫Well, I think I need to watch it a few more times, maybe with some actual images of the system next to it. Seems terribly complex as opposed to a 5-cylider diesel engine.

[@MrMaze.]

om603 swap here i come:DD

[@georgessafi9302]

Air plates go down most of the time

[@Jr05ful]

can you translate that in spanish...??

[@rezpectz]

Bmw e30 1983 !!

[@gtautomotive22]

this is old lol. But good info thanks.

[@tymac3306]

Falling asleep....

[@kermitoz7734]

for my w116 mercedes a change the original part accumulator bischoff 1164700516 for this new part 1264700116 for a good start when the engine is hot ! bye !

[@lumbrs]

Thanks this shitty BOSCH invention i have problems with cold start. I have been to lots of electricans, mechanics, even audi center. Anyone doesnt know whats the problem. Nice job BOSCH

[@fairyheli2]

replace it with a carb

[@superluvver3]

most likely your fuel filter is clogged -if you struggle to blow though it its clogged . If the car has been left for a few years the warm up regulator (the boxy thing with two fuel hoses and electric connection) is clogged up .Take it out when cold, clean with carby cleaner and blow it out . It must be cold or you won't be able to blow through it .It's basically a choke system - cuts off when hot . The K-jet system is pressure sensitive so anything that stops the pressure getting up to spec can cause problems. The injectors are really sprayers! very little moving parts . Hope this helps.

[@frankinhistank]

There is nothing wrong with this system. At the time it was a major advancement over carburetors. Even now I consider it superior to carbs. The system is shitty though if its not maintained properly, and taking it to skilled mechanics/VAG specialists who aren't 100% skilled and confident in CIS is just throwing money away. In most cases VW/Porsche enthusiasts who toil endlessly on these systems are a better bet than current VAG mechanics, as they know the troubleshooting better, and also how to deal with the scarcity of spare parts.

[@groupbmotors]

Most techs these days will have no idea how to work on or diagnose CIS, they are not trained in old systems like this. You need to take it to an old timer who worked on these cars when they were new.

[@Phenom98]

lumbrs Well it's always like this for new tech. You have to expect to have failures if you do something revolutionary or cutting-edge

[@sukeshford2013]

ferrari testarosa i repaire jetronic

[@peepoop6630]

Both of Ford's systems (speed-density and mass-air) from the 80s and 90s are inferior to Bosch, which had Motronic and coil packs out back in the 70s. Even the mass-air Ford system squirts fuel on one bank of the V8 then the other. This approach is virtually a continuous squirt. Furthermore, if anything screws up, you are on the side of the road with your thumb up your butt. K-Jetronic is deliberately mechanical for those of us who have owned F-series Fords and want D8-dozer type reliability

[@Kj16V]

Bosch Woe-Betide-you-if-it-Goes-Wrong System

[@abdulaiabdurahmani2913]

Japanese were smart. They made the best vehicles without using this SHIT made by Bosch. Sorry but at that time Japanese were using a good old reliable carburetor.

[@beechcoma]

Not for long.