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Been wanting to do a CIS fuel injection thread for a while, and now have all the parts to do it for one of my cars, so let's talk CIS! What is it? Before the heady days of EFI, Bosch produced a system called CIS Continuous Injection System AKA a carburetor on steroids:  It came in several flavors, but the main differences come down to the method used to meter the fuel: Downdraft or Updraft (Updraft shown above) Downdraft CIS fuel metering:  The downdraft models were more common on Mercedes Benz and some Porsche/Lamborghini setups The Basics CIS is pretty simple really: intake air pulls on a balanced metering plate, as the throttle valve opens, the metering plate rises or falls and allows a fuel regulator pin to open, allowing higher fuel flow to each injector. There were additional components that helped with boost and warm up: Warm Up Regulator (WUR)   The WUR is mounted to the side of the engine block where electrical signals OR the engine heat allowed it to regulate the control head pressure for the CIS distributor block in order to adjust for cold starts. It was also used to regulate fuel enrichment for boost for turbocharging Cold Start Injector  A precursor to EFI injectors, the cold start injector injects extra fuel during cranking to start them motor, its commonly also hacked to help with fuel enrichment for boost in the VW/Volvo crowd Port Injector  The individual injector for the system Frequency Valve  The frequency valve is mounted next to the distributor head for the CIS system, and is controlled by the ECU Lambda system which changes the 'duty' of the valve based on O2 sensor readings to keep its emissions in check. CIS Distributor Head and Fuel Pressure Regulator  The heart of the system. Meters and distributes fuel. 1500quidporsche posted:My favorite obsolete automotive technology... https://en.wikipedia.org/wiki/Jetronic EDIT: I had a thread tag chosen. But rather ironic...MOD please change to 'Classical' CommieGIR fucked around with this message at 04:26 on Jan 20, 2017 |
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Jan 20, 2017 04:04
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I love K-Jetronic and I won't hear a bad word said against it.
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Jan 20, 2017 04:07
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1500quidporsche posted:I love K-Jetronic and I won't hear a bad word said against it. Its not a bad system. Its really not. I rebuild CIS stuff, and plan on turbocharging the black Audi 4000 Quattro with the CIS alone, with some modifications for a WUR and boost controlled fueling.
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Jan 20, 2017 04:08
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when it works, its great. When it doesnt work, get out the multimeter and O-scope. I cut my cis-teeth on a 308. Both Italian and German manuals. hnggggggg
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Jan 20, 2017 04:10
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cursedshitbox posted:when it works, its great. When it doesnt work, get out the multimeter. I cut my cis-teeth on a 308. Both Italian and German manuals. hnggggggg I was feeling nostalgic because a guy called me today asking if I wanted to pick up his spare Audi 4000 motor and CIS system. How could I say no?
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Jan 20, 2017 04:11
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Goodman. Now give it blowies. cis loooooves boosts
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Jan 20, 2017 04:11
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Dug up my old post in the PYF obsolete tech thread:1500quidporsche posted:My favorite obsolete automotive technology...
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Jan 20, 2017 04:12
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cursedshitbox posted:Goodman. Now give it blowies. cis loooooves boosts That's the plan. Dug out a bunch of Audi 5000 Turbo CIS parts from my storage shelving, and already planning to boost a JT block. 1500quidporsche posted:Dug up my old post in the PYF obsolete tech thread: ...and now its quoted in the OP! CommieGIR fucked around with this message at 04:19 on Jan 20, 2017 |
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Jan 20, 2017 04:12
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Is there a list of cars that use it? I know early Volvo 240s did.
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Jan 20, 2017 04:21
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CharlesM posted:Is there a list of cars that use it? A lot of them. Nearly ever European manufacturer used it at one time or another. From my side of the house: Audi 4000 CS Quattro Audi 5000 Quattro Audi Coupe GT Audi Ur Quattro Audi 80 Quattro Volkswagen Rabbit Volkswagen Jetta Volkswagen Scirocco Volkswagen Golf Porsche 911 The list keeps going. BMW used it, Mercedes used it, Ferrari used it https://en.wikipedia.org/wiki/Jetronic
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Jan 20, 2017 04:24
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CharlesM posted:Is there a list of cars that use it? Anything with a variant of K Jetronic. CIS is a bit of a misnomer, it was VW's terminology for Bosch's K Jetronic branch of fuel injection, I know some Volvo people refer to it as CIS as I think that's really just down to parts commonality and VWs being a bit more popular.   
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Jan 20, 2017 04:27
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1500quidporsche posted:Anything with a variant of K Jetronic. CIS is a bit of a misnomer, it was VW's terminology for Bosch's K Jetronic branch of fuel injection, I know some Volvo people refer to it as CIS as I think that's really just down to parts commonality and VWs being a bit more popular. I think everyone just adopted the CIS moniker because it was short and easier to say than 'Jetronic', but yeah, it was VW/Audi/Porsche that pushed the CIS name.
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Jan 20, 2017 04:30
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My introduction to CIS is getting hosed by a CIS-E Audi 5000 which had a melted ECU wiring harness and a system-pressure screw turned to maximum to compensate for a dying fuel pump/clogged filter. It ran great for years, even in the coldest weather. My buddy got it from a junkyard for $600 because the fuel tank had been drilled through by a Future Shop stereo-install tech. When the fuel pump finally died and was replaced, the hosed up adjustment (unknown to us) must have blown out some internal seal in the fuel dizzy because no amount of system-pressure adjustment would ever get stable pressure to the injectors. We blew probably a year worth of weekends doing various shade-tree advice on forums (measuring injector flow using a coke bottle, making sure the fuel distributor machining wasn't galled, checking the mixture adjustment lever for stickiness, thermo-time-switch multimetering, new Viton seals for the injectors, warm-up regulator testing and cleaning, cold start injector testing, double-checking lambda-sensor functionality, adjusting with a fuel pressure gauge) and could never get it back to where it once was. Meanwhile, we were getting pretty good at parallel parking the car on the owner's busy street by pushing it with the steering lock disabled every 72 hours lest the city tow it. After a few months, we managed to get it to cold start and idle (eye-wateringly rich) so at least it would drive, but there was no way to get it to warm start, it would just instantly die when it came off the starter. Any parts were impossible to get (the only source for new fuel distributor parts was the Ferrari dealer, and they don't even have a parts desk) at the time, and aftermarket upgrade stuff was primarily focused on turbos. We also didn't have room for a parts car which was probably the right way to go. In the end, we threw it at a local vintage-VW mechanic who diagnosed the burned-up lambda sensor wiring immediately (even though the sensor multi'd out as well as the CIS-E diagnostic website we found said it would) and then got into some kind of conflict about back-pay for my buddy's other car. I will always be curious what he saw and didn't tell us (and also what else is on that harness that could have died too). Since it was an FWD 3-speed auto non-turbo Audi 5000, we just let it go to a dealership who was offering a ridiculous trade-in offer and had very trusting salesmen for nearly quadruple its original purchase price. It is one of my biggest automotive regrets that I did not try harder to save it. Seat Safety Switch fucked around with this message at 05:04 on Jan 20, 2017 |
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Jan 20, 2017 04:39
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CIS parts for an Audi 4000 CS Quattro, minus the injector lines: CIS Parts for an Audi 5000 Quattro Turbo, with injector lines: 
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Jan 20, 2017 04:52
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Jetronic can suck a dick. Sourcing replacement parts for a shop restoring a 412 is slowly driving me up a wall because I'm our resident "aircooled stuff is neat/euro cars are neat" person. 
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Jan 20, 2017 06:50
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I remember the CIS setup on my parents 280SE. It worked well, the only things we needed to do was put in new injectors (which is about as easy as replacing spark plugs) and get a new cold start injector.
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Jan 20, 2017 10:53
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One thing that cannot be argued is that the Vanagon-only "Digijet" system is dogshit that never, ever works right. Ever. Speaking from personal experience here. It's one of those early, lovely injection systems that is so bad that when it gets ripped off and replaced with carbs (Often) the carbs deliver better performance and mpg.
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Jan 20, 2017 12:12
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This seems like carbs but worse, why?? edit: This thread is neat and I learned quite a bit! thanks for posting it KYOON GRIFFEY JR fucked around with this message at 14:57 on Jan 20, 2017 |
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Jan 20, 2017 14:04
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KYOON GRIFFEY JR posted:This seems like carbs but worse, why?? It wasn't worse, it was incredibly reliable for the most part, but the advantages it offered was mostly emissions related due to the ability to take in Lambda feedback from an O2 sensor and adjust accordingly, as well as adjust for boost, it was much more friendly to turbocharging applications than carbs, and was probably a cheaper system than early EFI that was just coming out at the time.
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Jan 20, 2017 15:51
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Yeah the K-Jet on the DeLorean was my only exposure to the system. When I bought my car, it had been sitting in a garage for 15 years. The fuel distributor was full of goop. I ended up getting lucky and finding a dizzy and set of injectors from an 82 Volvo 760 in a pick n pull which were identical. I managed to get the car running extremely well without even using a fuel pressure gauge. I never had hunting idle problem and never had a problem with it passing California emissions. The secret seemed to be making sure there were zero air leaks and putting in a brand new o2 sensor and fuel accumulator. It did have one annoying sporadic problem. If I drove around and let the car sit for about a half hour it wouldn't want to start. Parking and then starting it up within 5 or 10 minutes it was fine. Letting it sit for an hour or more it would start just fine but let it sit for a half hour after being fully warm and it would just crank and crank and crank. I ended up figuring out a trick which was to pull the cables off of the WUR and the cold start injector and plug the WUR cable into the injector. This would get the car to catch and barely idle. Quickly swapping the cables back allowed the car to settle back to normal idle and normal drivability. Very strange.
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Jan 20, 2017 19:46
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That's a fairly common problem, my Scirocco had that before switching over to CIS-E, atleast yours would hold an idle in that condition. The cold start injector in most these systems is just wired to the starter so you probably didn't have to mess around with the WUR connection and could've just kept cranking it. I'm pretty sure its mainly down to vapor lock but I know a lot of guys blame the issue on the WUR being out of whack. Some guys have had luck taking the WUR apart and reshaping the diaphram but I never really did that since it seemed like there was a potential for it running way worse.KYOON GRIFFEY JR posted:This seems like carbs but worse, why?? It really wasn't but there's probably some merit to the argument that to the end user the advantages of K Jetronic over a carb aren't immediately apparent and the complexity of the system made it appear like a step backwards. K-Jetronic is far better at metering air and can inject fuel in high pressure conditions and closer to the valves, which is all stuff carbs really suck at. Once they added lambda feedback so the system could self correct they really had a decent system and CIS-E fixed almost all the leftover issues and turned it into a nice little package. It probably would've stayed around a lot longer if the price for microchips didn't drop so rapidly, that's what really killed it off.
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Jan 21, 2017 00:55
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I think the porsche 912E had it too the one I looked at had replaced it with a carb and I stupidly did not pay $7,000 for the car cause it was brown. Poor jetronic was in a box on the floor.
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Jan 21, 2017 01:25
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Aha! My 190e has k-jet too. It seems like a clever system. Mine's got a very low idle at all times (~600 even on cold start). It *always* requires two goes at starting cold unless you're VERY lucky with the gas pedal. From the look of the plugs i'd say it is running a little bit rich.
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Jan 21, 2017 02:39
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Good to finally see this thread, my Merc 200E has KE-Jetronic aka CIS-E and I'm suspecting there's some gremlins in there. Last inspection failed because of emissions and I'm trying to find out whether the O2 sensor is hosed or if there's some other cheaper way of fixing it. Emission test (if my memory serves me right, the papers are all in the car, 20 km away) showed too high CO, HC and CO2 levels. Lambda value was off, but might be due to exhaust leaks. The car has a strange misfire at 2500+ RPM, especially when cold where it has a pretty major hesitation and acceleration problem. Anyone here who knows some good tests I can run to find fucky components? edit: Could it be the ignition system that's jacked? I know I should take some stuff apart next time I'm in the shop but just tell me what things to check so I have some bearing. Cached Money fucked around with this message at 04:43 on Jan 21, 2017 |
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Jan 21, 2017 04:35
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I love mechanical fuel injection in general - the Bendix Stromberg injection carburetor, the Bosch MFI and Kugelfischer (ok, they bought Kugelfischer, whatever) systems, the Lucas petrol injection setups... mmm. And yes, even CIS. There might be something wrong with me.
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Jan 21, 2017 04:53
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Cached Money posted:Good to finally see this thread, my Merc 200E has KE-Jetronic aka CIS-E and I'm suspecting there's some gremlins in there. Last inspection failed because of emissions and I'm trying to find out whether the O2 sensor is hosed or if there's some other cheaper way of fixing it. KE Jetronic has diagnostic codes: http://mbworld.org/forums/e-class-w124/400937-ke-jetronic-diagnosis.html I'd replace the O2 sensor just to be safe.
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Jan 21, 2017 04:56
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Cached Money posted:Good to finally see this thread, my Merc 200E has KE-Jetronic aka CIS-E and I'm suspecting there's some gremlins in there. Last inspection failed because of emissions and I'm trying to find out whether the O2 sensor is hosed or if there's some other cheaper way of fixing it. High HC is generally ignition issues so I'd start there with a new set of plugs, wires and distributor cap and rotor. HC can also be affected by contaminated oil so changing that before an emissions test will help. This can directly relate to high CO which is caused by incomplete combustion or an overly rich mixture. Test or change your O2 sensor for this condition. High NOx is generally based on too high combustion temperatures which could be caused by a lean mixture but more often than not by a bad catalytic converter assuming your base mixture and ignition are in spec. Same goes for high CO2.
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Jan 21, 2017 07:07
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I could of sworn my old 280ZX had K-Jetronic, but a quick search shows it was L. Was there much of a difference?
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Jan 21, 2017 23:07
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L was Bosch's pulsed injection system and isn't all too different from modern fuel injection systems. It was a lot more sophisticated from the start and I think you'd have a hard time arguing that K was a better system on anything other than cost.
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Jan 21, 2017 23:26
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mekilljoydammit posted:I love mechanical fuel injection in general - the Bendix Stromberg injection carburetor, the Bosch MFI and Kugelfischer (ok, they bought Kugelfischer, whatever) systems, the Lucas petrol injection setups... mmm. And yes, even CIS. Bow down before the ridiculousness that is SPICA
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Jan 22, 2017 00:25
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KYOON GRIFFEY JR posted:Bow down before the ridiculousness that is SPICA AFAICT SPICA is basically an Italian implementation of the same principle the Kugelfischer pump uses. Which is amazing. Hell, boost compensated Kugelfischer pumps were used into the early 80s in F1. I like the Lucas injection in that it used the tank fuel pump to provide injection pressure, in an indirect way.
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Jan 22, 2017 00:56
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CommieGIR posted:KE Jetronic has diagnostic codes: Thanks for this great writeup on the duty cycle diagnosis, I've been looking for something like this. Panaflex posted:High HC is generally ignition issues so I'd start there with a new set of plugs, wires and distributor cap and rotor. HC can also be affected by contaminated oil so changing that before an emissions test will help. This can directly relate to high CO which is caused by incomplete combustion or an overly rich mixture. Test or change your O2 sensor for this condition. High NOx is generally based on too high combustion temperatures which could be caused by a lean mixture but more often than not by a bad catalytic converter assuming your base mixture and ignition are in spec. Same goes for high CO2. Plugs are pretty fresh, changed them due to this issue and did not help. Rotor and cap is probably the next step, previous owner changed the ignition cables to silicone ones.
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Jan 22, 2017 01:38
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Kugelfischer looks pretty cool, its basically the same VE pump design as the Bosch Diesel Injection Pumps 
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Jan 22, 2017 01:47
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CommieGIR posted:Kugelfischer looks pretty cool, its basically the same VE pump design as the Bosch Diesel Injection Pumps Similar - the trick is the compensation cam is basically a 3d rpm vs throttle position fuel map determining fuel delivery, whereas the diesel ones are just linear throttle doing it.
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Jan 22, 2017 02:07
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I remember my dad disliking the Lucas fuel injection used on some 1970s British cars, like the Triumph 2500PI. The "spit and dribble system" is what he called it. I think his man issue with it was that it could flood the cylinder with fuel, as metering of it was pretty rudimentary
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Jan 22, 2017 02:44
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A 1982 UK-market Porsche 924 would be K-Jetronic, yes?
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Feb 1, 2017 01:11
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InitialDave posted:A 1982 UK-market Porsche 924 would be K-Jetronic, yes? According to "How to Understand, Service and Modify Bosch Fuel Injection & Management"*, a USDM '82 924 is K-jet with Lambda. *(hereafter referred to as "The Useful Blue Book with the Absurdly Long Name") meltie fucked around with this message at 23:55 on Feb 1, 2017 |
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Feb 1, 2017 02:05
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Anyone got a lead on someone who can rebuild my '82 BMW 320i fuel distributor? I have replaced almost whole fuel system, relined the tank, new warm up regulator, cold start valve, both pumps and new accumulator, injectors etc. Car runs much better than when I started but still takes two cranks to start each morning and catch and a minute or two to warm up before it wants to go anywhere. I am up for rebuilding myself if there is a kit for it as well.
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Mar 26, 2017 04:30
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EvellSnoats posted:Anyone got a lead on someone who can rebuild my '82 BMW 320i fuel distributor? I have replaced almost whole fuel system, relined the tank, new warm up regulator, cold start valve, both pumps and new accumulator, injectors etc. Sounds like a bad cold start injector. In other news: Someone sent me the CIS setup from a Ur Quattro, wiring harness and all. 
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May 2, 2017 03:29
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EvellSnoats posted:a minute or two to warm up before it wants to go anywhere. I am up for rebuilding myself if there is a kit for it as well. Really dumb question, but have you checked your dizzy cap and rotor for any sooty arcing? My merc was being a poo poo to me for the first few minutes until I cleaned (and ultimately replaced) these.
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May 3, 2017 21:58
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