# CIS-E 16v woes, maybe you can help?



## dacolino (Jun 1, 2002)

Hey guys i have a 89 GTI 16v that I recently bought. Its a late 88 US build car so has US wiring. I got the car in late december not running, had been sitting for 5 years. So I pulled the fuel tank, cleaned it all up, both fuel pumps were siezed so I replaced both, and got it running. I also just replaced the fuel injectors, and have a big issue going on. 

It starts and runs, but runs soso. Fuel delivery is great now. I have the test wire hooked up in line with the Differential pressure regulator and I have a inconsistent 0 reading. Sometimes it reads, and sometimes it just drops to zero and I have nothing. I went as far as tearing into the wiring harness cause ive been pinning out the ecm from the bentley manual and found I was missing ground, and repaired some wires. I have continuity from the o2 sensor wire to the ecm, I have now verified I have ground at all proper terminals on the ecm. I have verified good power to the ecm. Ive performed multiple tests according to the bentley and cant really make sense of any of it...just know that you start the car and get a reading, and then could be 30 seconds, could be a 3 minutes and then it goes to zero, and if you rev the engine a reading reappears? 

I also have a spare ecm that I tried and it does the same thing. According to the bentley test to check for proper ecm response with the engine off, I have as specified 10ma, then you ground the 02 sensor and the reading shoots up to like 40, then drops down and goes to zero. Im stumped currently, Im going to continue reading the bentley. I swapped out the DPR for another I had for the hell of it. I think its somewhere in the wiring, seems someone was messing around with the harness. 

Now that I have written a long novel, hopefully someone actually reads this and has some insight. Any help would be greatly appreciated!

Thanks,
Colin


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## WaterWheels (Aug 14, 2005)

You have provided a lot of information but at least one important factor is missing. Before I indicate what is missing I have to say that "zero" (0) *IS* a reading when doing the tests you are doing. The mA readings can go plus or minus and in the middle is zero which is valid. So one piece of information which might help is the readins you get other than the zero reading. A zero reading for your system at idle would indicate a rich mixture. But it is not easy to say why or if it is correct without knowing any other readings and when they are present.


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## dacolino (Jun 1, 2002)

WaterWheels said:


> You have provided a lot of information but at least one important factor is missing. Before I indicate what is missing I have to say that "zero" (0) *IS* a reading when doing the tests you are doing. The mA readings can go plus or minus and in the middle is zero which is valid. So one piece of information which might help is the readins you get other than the zero reading. A zero reading for your system at idle would indicate a rich mixture. But it is not easy to say why or if it is correct without knowing any other readings and when they are present.



Thanks for the response. Its hard to explain, I understand what you are saying though, The "0" reading I am seeing seems like a bogus number...it happens when the engine warms up, and when it drops down it dosent go past 0 into negatives...just hangs out there. The reading is very sporadic, but generally it hangs around 5, and fluctuates...now IIRC that is in spec...i can tell you the fuel distributor is definately not in spec, it idles like ****, runs so rich it burns your eyes after a while. Next time I play with it I will have to write down the readings to be sure, but I think my next move is try out a spare engine harness I have for this car. In my previous CIS-E experience what this car is reading it should not be doing what it is doing. I even tried a different 02 sensor that seemed pretty clean...not that im ruling that out as well. I cant rule anything out really, because I got the car in a non running state sitting for years, so I have no clue how it was running before it had been sitting. For those familiar, I also removed the pre-filter in the banjo bolt for the fuel supply line to the fuel dist...car wouldn't run until doing so. 

Does anyone know if there is a baseline setting for the sensor plate on CIS-E? I know on the earlier CIS cars you could start with a baseline and tune from there. I also built a wideband o2 sensor setup for tuning, and maybe I can probe that into the exhaust to see whats going on.


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## dacolino (Jun 1, 2002)

My issue is still unresolved. I have no clue where to even look anymore. 

Now I have...

Swapped ecus
swapped wiring harnesses
installed a brand new 02 sensor
swapped dpr's and cleaned both 
done a million tests, not kidding i have at least 20 hours into messing with this.

Currently what happens is you start the car, the reading is high, could be 20, could be 60 whatever it starts at it goes down and eventually goes to zero. INTERMITTENTLY I get an accurate fluctuating reading, but then it just goes to zero and no matter what adjustment you try to make it dosent change the reading, but may effect how the engine runs. I have pinned out the ecu as per the bentley manual and all my readings are good. I even went as far as putting a resistor in place of the cts, and same results. If I disconnect the cts and jump with a resistor or anything, the reading goes to 68? and stays there. For some reason, if you open the wiring (disconnecting the cts), and then reconnect the reading is there for a few seconds then drops to zero. Ive checked grounds, i have power where i should this makes no sense, and im sure reading this post makes little as well. Ive worked on many cars and I have NEVER seen anything like this, I have someone who is really familliar with cis/cis-e diagnostic (worked at vw when these were new) and he is also stumped. I think my wiring is good, being that i have a fixed reading when cts is disconnected, and that stays, dosent drop off. Even with the resistor in the cts plug (simulating a warm engine) it drops to zero and stays fixed there...so i dont think its the cts. Its not the 02 sensor. I did some pressure tests, and i have proper pressure in upper/lower chamber and proper differential readings.

Is the differential pressure regulator supposed to buzz? both of the ones I have do not (i thought they were supposed to?) but according to the pressure tests I performed the differential pressure regulator and regulator diaphragm are both in spec. 

Is there any way to check to verify I have a good ecu...I have two ecu's and the car does the same thing with either plugged in? 

Any ideas are welcomed, Ive checked grounds, fuses, im about to check every ground point on the car, and other things cause i seriously have no idea where to even look anymore. I have performed all tests in the bentley manual, and I also have a mitchell book from the late 80's with very in depth tests for various injection systems (cis-e section is like 40 pages) and have done a few tests from there.


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## WaterWheels (Aug 14, 2005)

> Is the differential pressure regulator supposed to buzz?


NO 


> Is there any way to check to verify I have a good ecu...


Yes and no. I have in the past found test equipment sold which is supposed to connect to Bosch ECU’s, not 100% sure CIS-e was listed, but the equipment was very expensive and more or less being sold to major electrical repair/rebuild shops. So as an end user I don’t know of any tests except for the old “if nothing else is wrong it must be . . .” 

All your testing is great and I guess you should be commended for doing that first before asking for help. There are two things that in my opinion are missing from the troubleshooting, exhaust gas testing and idle mixture adjusting. From what you indicate it does not run all that bad and if I recall, I don’t like stupid little “text gibberish” like IIRC, it was or is a little rich, correct? Having a zero mA reading would indicate a rich mixture at idle and again if I recall, at idle it will only go down as far as zero on the reading. During other duties the ECU performs the mA reading can go into the negative numbers but I do not believe it will at idle. So it is possible that the mixture is just too rich and hangs at 0. I suggest you do one or both of the following; take it to a shop with exhaust testing equipment and have it sniffed. It could be set correctly right then and there if it proves to be rich. OR With the multi-meter connected, adjust the mixture screw and watch the mA read-out. Go maybe a half turn, counterclockwise, first and see if things change. If not then try another half turn. Remember to write down how much you have adjusted it so if need be you can return. Either it will start to read in the positive numbers or it will stay at 0 and begin to run like crap. I am betting that it is too rich and just needs to be leaned out some, at least that is what I hope right now.


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## dacolino (Jun 1, 2002)

WaterWheels said:


> NO
> 
> Yes and no. I have in the past found test equipment sold which is supposed to connect to Bosch ECU’s, not 100% sure CIS-e was listed, but the equipment was very expensive and more or less being sold to major electrical repair/rebuild shops. So as an end user I don’t know of any tests except for the old “if nothing else is wrong it must be . . .”
> 
> All your testing is great and I guess you should be commended for doing that first before asking for help. There are two things that in my opinion are missing from the troubleshooting, exhaust gas testing and idle mixture adjusting. From what you indicate it does not run all that bad and if I recall, I don’t like stupid little “text gibberish” like IIRC, it was or is a little rich, correct? Having a zero mA reading would indicate a rich mixture at idle and again if I recall, at idle it will only go down as far as zero on the reading. During other duties the ECU performs the mA reading can go into the negative numbers but I do not believe it will at idle. So it is possible that the mixture is just too rich and hangs at 0. I suggest you do one or both of the following; take it to a shop with exhaust testing equipment and have it sniffed. It could be set correctly right then and there if it proves to be rich. OR With the multi-meter connected, adjust the mixture screw and watch the mA read-out. Go maybe a half turn, counterclockwise, first and see if things change. If not then try another half turn. Remember to write down how much you have adjusted it so if need be you can return. Either it will start to read in the positive numbers or it will stay at 0 and begin to run like crap. I am betting that it is too rich and just needs to be leaned out some, at least that is what I hope right now.


I think we are not on the same page. NO ONE is going to set this car up, its not a matter of reading exhaust gas and setting idle mixture. Let me clarify. I did not state ive been messing with the idle mixture, but all along I have been, I figured anyone who read this would figure I know enough that Id know how to adjust and properly set the fuel distributor if I went as far as hooking up the test harness to the DPR. I have posted here because I have a really obscure problem...not some common bs that has been overlooked. If you read the bentley manual and look through the tests, Ive done all of them. The only pinout test I didnt perform was output from the knock sensor control unit, because I do not have a LED test light. I have a mitchell book as well with a 32 page secton on even more tests and more specific answers and testing procedures that what the bentley has. 

I got this car not running, been sitting for 5 + years who really knows. I found both fuel pumps were siezed, so I dropped the fuel tank and cleaned it out. replaced both fuel pumps and filter. went to check if I had spray at the injectors, no spray still. Pulled the main supply banjo bolt, which had the pre filter still installed, removed that and injectors flow...but leak. Replaced injectors. Now the car runs. Go to adjust idle mixture, and find a zero reading after the car starts reading off the 02 sensor. Perform many tests, found faulty wiring, replaced one harness. Now have the other main harness installed in place of the one that was in the car to begin with and still have the same issue. change dpr's same issue. change ecu's same issue. bypass ect with resistor equivelent to a warmed engine while engine is warm, same issue. No matter what ive done so far I get the same thing. Intermittently, at complete RANDOM I get a reading other than zero. then it goes away...which is what made me start to think it was the wiring. 

I still question if I even have a good dpr or ecu. do i know...no. why? Because I bought the car not running and didnt see how it ran before it was parked, or even really know the true reason why the car was parked. For all I know, both ecus I have are bad, and same goes with the dpr's. I have no CIS-E car I can just pull known good parts off of to see if it makes a difference or helps.


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## WaterWheels (Aug 14, 2005)

"Any ideas are welcomed” Does not seem to really be the case now does it?

"I figured anyone who read this would figure I know enough that Id know how to adjust and properly set the fuel distributor. ." 
Pardon me but I am not in the habit of figuring or assuming if I can help it. I go by what is written and if something is not mentioned I ask about it or suggest it be done depending. In another thread where the person is having issues with the mA reading TO the DPR being much to high, you suggest to him to do testing of the cold start system and check the resistance of the DPR, why? The cold start system only comes into play when cranking the engine and even if it is leaking the mA reading at the DPR will be lower not higher. There is no connection between the cold start system and the fuel management ECU so where is he to check continuity? The DPR receives information from the ECU so if the resistance is bad it could have an effect on the reading being sent to it, but it will not hang the way his readings are doing and the ECU should still react to any mixture adjusting which it does not. He has also swapped the DPR with one from a running engine with the same results, so why the suggestion? You ask if the DPR is supposed to buzz as you thought they are supposed to. That did not come from any repair manual, unless you are working on an idle stabilizer valve or frequency valve. You ask if anyone knows of a base-line setting for the air sensor plate, which there is by the way and it’s explained in the Bentley repair manual and also, I would hope, in a Mitchell repair manual. 
NO ONE is going to set this car up, its not a matter of reading exhaust gas and setting idle mixture.
How do you know if you don’t know what’s wrong and don’t try? Plus you might just discover something if you do.
"I got this car not running, been sitting for 5 + years who really knows"
Could be issues here, but you’ll have to figure that out yourself.
"not some common bs that has been overlooked."
Really, most times it is but if you are to obsessed with yourself you may never see the forest for the trees as they say. 
"zero reading after the car starts reading off the 02 sensor"
Again that is an indicator, no?

You swapped ECUs and DPRs and cleaned them and still have the same results but question if they all might be bad? I think at this point I will let you continue chasing your tail or find another person with ideas more welcomed.


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## dacolino (Jun 1, 2002)

WaterWheels said:


> "Any ideas are welcomed” Does not seem to really be the case now does it?
> 
> "I figured anyone who read this would figure I know enough that Id know how to adjust and properly set the fuel distributor. ."
> Pardon me but I am not in the habit of figuring or assuming if I can help it. I go by what is written and if something is not mentioned I ask about it or suggest it be done depending. In another thread where the person is having issues with the mA reading TO the DPR being much to high, you suggest to him to do testing of the cold start system and check the resistance of the DPR, why? The cold start system only comes into play when cranking the engine and even if it is leaking the mA reading at the DPR will be lower not higher. There is no connection between the cold start system and the fuel management ECU so where is he to check continuity? The DPR receives information from the ECU so if the resistance is bad it could have an effect on the reading being sent to it, but it will not hang the way his readings are doing and the ECU should still react to any mixture adjusting which it does not. He has also swapped the DPR with one from a running engine with the same results, so why the suggestion? You ask if the DPR is supposed to buzz as you thought they are supposed to. That did not come from any repair manual, unless you are working on an idle stabilizer valve or frequency valve. You ask if anyone knows of a base-line setting for the air sensor plate, which there is by the way and it’s explained in the Bentley repair manual and also, I would hope, in a Mitchell repair manual.
> ...


Thanks. Maybe you should re-read what you have written, pretty much since your first input you have given me a hard time, or at least thats how I read it. I shouldent have to say this more than once but I dont normally ask for help because I rarely find myself having such un-resolvable issues. No I am not great like your trying to make me act like I have been making myself sound. Maybe if you believed what you read here in this post and didnt constantly question me you would realize something is not right. And if your talking about a basic adjustment of putting a nickel to measure the sensor plate height as a basic adjustment, Ive done it already. The reason I question If I even have good components is pretty obvious, I have spent a ton of time on this..about two months now in between other things going on to be exact, and when you pin out everything and it all checks out more than once, and it still isint right well then your going to begin second guessing your components again. I myself didnt think that the DPR is supposed to buzz, but someone else mentioned it should, thats why I asked. Both of mine do not. Yea you are correct, I gave wrong info on the other thread looking back at it with the cold start valve and thermotime wiring back to the ecu, but I suppose after a day of working on this issue and it racking my brain I slipped, again I am not perfect. Despite the fact that your giving me a hard time, Id like to say thanks for the input.


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## ziddey (Apr 16, 2006)

Let me apologize in advance-- I've skimmed through the posts, so I've probably missed something you've already done.

You said you've been playing with the mixture the entire way through? And you say it runs rich? When it is running rich, is that when you're seeing high dpr current? Or at 0ma? Cis-e will not go negative, and the most it can lean out is 0ma.

I'm assuming you've had all the injectors pulled, and verified that they're all spraying well and uniformly? Cold start valve doesn't leak/spray once the car is running?

I see that you're using a resistor in place of the CTS for testing. Do you have one you can use to simulate a warm engine?

Have you replaced the o2 sensor? I suppose you could unplug it, and tune it by feel for a while. You should be able to get the car into a pretty driveable state after a bunch of fine tuning. Then you'd be able to plug in the o2 sensor and see if it throws everything off again.

No vacuum leaks? Do you have a timing gun?

DPR doesn't buzz. That's the frequency valve in cis-l systems.


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## dacolino (Jun 1, 2002)

ziddey said:


> Let me apologize in advance-- I've skimmed through the posts, so I've probably missed something you've already done.
> 
> You said you've been playing with the mixture the entire way through? And you say it runs rich? When it is running rich, is that when you're seeing high dpr current? Or at 0ma? Cis-e will not go negative, and the most it can lean out is 0ma.
> 
> ...




Thank you for the input. 

Correct I have been messing with the mixture, both rich and lean. Let me explain, After I reinstalled the fuel tank and changed the pumps and filter I still had no fuel to the injectors. So we blew out the injectors with air to see if they did anything, and they cleared out so I put them back in. Still no fuel at the injectors, someone recommended that I check the banjo supply bolt for a screen as these were factory installed and sometimes never removed. I did, and it was there, removed the filter and I had great flow at the injectors, but they leaked a tiny bit when the sensor plate was at rest. Put then in, car fires up and runs great. I replaced the injectors anyway, so now they are brand new. To confuse things more, I was told by the previous owner of the car it was parked because the engine was losing oil pressure (and it is, I currently have a gauge hooked up for testing), so more or less I wanted to make sure that all the CIS-E components were good before I swap in a freshly built 2.0l that I have for this car. This is where the fun begins.

The car is definately running rich...not only does the dpr reading stay at zero most times with no flutcuation even leaning out, or richening dont change the reading one bit. We thought maybe it was so out of adjustment due to that screen being so clogged and such, but no dice. I have had the injectors out and sprayed them, being new they spray very good, I believe the cold start valve is ok...BUT I have not confirmed it to not be leaking, I will remove it and check that out to verify, thanks. 

The resistor I put in line specifically for the hell of it jumping the cts was 330ohm, which equates to around 175deg F, which I did while the engine was warmed up so it should have simulated a pretty warmed engine.

I have replaced the o2 sensor, have a brand new OE bosch unit in currently. I built a wideband o2 sensor setup to "tune" my 81 sciricco that is running on 16v cis basic, and it worked great for that car, but It is sitting on the header on that car still. I could run and get it...but my biggest problem is I have no spare bung to install it into and leave the factory sensor in. I was under the impression that unplugging the o2 sensor would essentially put the car into limp mode, as o2 sensor reading is most crucial, and if no reading would be present from it I would just get a fixed reading? 

Thanks for confirming the DPR not supposed to buzz, it was questioned by a friend, I know the frequency valve buzzes (at least it has on every cis-l car ive owned ha). This is my first 16v engine vw, and the last time I owned anything with cis-e was a 1989 fox back in 2002...so Im a little scratchy on it I suppose. 

I have someone local I found who has a dpr/fuel distributor setup and a ecu that came from his personal running car, so Im going to buy that stuff and give it a shot one piece at a time. hopefully it fixes or leads me into a direction where i can actually nail down this issue...once I do im ripping the car apart to swap in the new engine among other things.

Thanks,
Colin


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## ziddey (Apr 16, 2006)

With the o2 sensor disconnected, you should see whatever nominal dpr current, as dictated by the CTS. So, with a resistor to simulate a warm engine, and the o2 sensor unplugged, you should see a steady 10ma (I know it's 10ma on 8v's. it might be 5ma for 16v cis-e?). Indeed, if it's so rich, you'd see 0ma at the dpr, and that'd be that. How far have you tried leaning out the mixture? Give the throttle a blip between adjustments.

What's your ignition timing set at?

You could also try setting the mixture crudely, based on the o2 sensor. Unplug the o2 from the ecu harness. Use a resistor to simulate a warm engine / use cts if that works. You should see either 5ma or 10ma steady through the dpr. Then use a voltmeter between the o2 sensor and a ground of your choice (hold it on the intake manifold, or whatever). Adjust the mixture, blipping between adjustments, until you see about 0.7v.


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## dacolino (Jun 1, 2002)

I have been blipping and trying all sorts of that between. I am not sure what the ignition timing is set at, i havent looked into that because Im pretty sure with how it intermittently runs really good (rev's up nice and idles well) I cant see that being an issue bit I should verify it anyway. If I tune the car by how if sounds and revs I can get it to run ok, but this whole 0ma reading stays. 

My next plan, I am buying a known good fuel distributor with dpr, and a known good ecu both pulled from a fine running car. Im kinda banking on one of these items fixing the issue and getting a fluctuating "normal" reading. The last time I messed with the car on monday, I tried everything from little adjustments, to big adjustments, rich and lean...no matter the position the reading is 0ma once the car is warmed up. Im really thinking I have some kind of compnent failure...either a failed ecu or a dpr improperly regulating fuel. The dpr smells like varnished fuel whenever i pull it off. I have cleaned both units multiple times and whenever you actually mount them and remove them they smell like bad fuel...but if you crack a line on the fuel distributor the fuel smells new as it should cause the car has seen more than two hours of running time at this point, and the fuel tank is spotless because i cleaned it dry and have only been running super through it. Im hoping to have more answers soon, I should be picking up the parts this weekend sometime and will get to mess with the car again by monday im hoping.


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## dacolino (Jun 1, 2002)

Well I finally got it fixed. It was either one of two things...the fuel distributor or the differential pressure regulator. I put a known "good" one in, and it works. When I got a reading other than 0, i was able to tweak and tune a little and its right on range now. After doing so, I checked all the other ecu's I have and all work and give a good reading. I was going to try swapping dpr's to see what happens cause im just curious of the other two i have are no good. I swapped the wiring harness back, and its all good. Im kinda in a I have a verified proper system now and i wanted to verify my components are good/bad cause if stuff is bad im going to throw it out, if stuffs good ill mark it. 

Now that my cis-e is resolved, I am going to pull the engine out, and do some work :thumbup:


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