krahmlow

greenshoes: 100,000 miles on my car. Your friend was probably suggesting that you check for vacuum leaks. There are lots of threads on this, so you can do a search, but the basic idea is that you spray carb cleaner onto the various vacuum lines, hoses, and joints. If there is a leak, the carb cleaner will get into the intake and cause the engine to accelerate. If you spray a spot and you get acceleration, then you know you've found a trouble spot. Don't forget the seals around the oil/air separator and the intake system in general (between the AFM and the engine). If you haven't done the lines/hoses/seals yet, then you'll want to schedule that job. Just to eliminate possibilities.

gtroth

The final stage must be inside the DME for 4V engines.

Someone else here had a problem with the Huco (search here for ICM).

Here's a snippit of the schematic from FSM, and a rough indication of where the grounds are (they are ~ 25mm apart - I bet you found one of the two - use a mirror):

944bucky

gtrroth, thanks for uploading this diagram, it what I was trying to discribe.
I guess I might not be talking about the same part. Where is the ICU? THe final stage seems to match the initial discription on this post, a unit attached to a heat sink on the dirver side front fender, above the AC valve. This unit is a seven pin plug which is also inline. I got the name final stage on my 944S Technik, you can see a poor copy at my link in a previous thread.

I'm more interested in getting the facts straght than being right.

gtroth

What we have been calling "ICU" in this thread is more usually called the ICM (it is by the left head light as you say).

What I'm pointing to in the picture are ground locations krahmlow was asking about - not related really to the ICM, which might have caused some confusion.

944bucky

Thanks, nomenclature is a pain in the ***. As are those ground connections.
I wish I had a scanner, and I need to pay the cash to upload pics.

Gtroth, for a sanity check for my sake, can you check my registry link
http://registry.rennlist.com/registry/profiles/944bucky
if you scroll down there is a pic of the dme test manual. There is a pic of part I'm talking about. Does this look like the part you are talking about?

gtroth

Yeah, that's it.

greenshoes3

thank you for the help, but he said to spray some into my intake to unclog an idle valve or something of that nature, do you know what im talking about? I would greatly appreciate the help.

gtroth

The idle stabizer valve can gum up and stick. Some people have had good luck cleaning them. I don't know where you'd spray carb cleaner without removing the valve, and it's under the intake manifold. I replaced mine, but it was kind of pricey (~$170).

krahmlow

Thanks, gtroth. If the grounds are that close, then I probably found it and just don't remember. I'll look for it, though, to see if it jogs my memory. Also, I'm interested to hear that the Huco unit has given problems before. I'll check on that.

I'll post again when I get the Bosch unit installed.

krahmlow

Got the Bosch ICU in this morning. The car starts, but it hasn't solved the running problem. Back to the drawing board....

For future ref., though, I'd recommend that "S" owners drop the extra cash on the Bosh and avoid the Huco.

nickg

i would advise "s" owners to buy the $15 vw one.....like did for you, but you ignored that i see. Did you seriously diagnois the problem? rather than just poke and hope...fix it. you are gonna get really pissed when yuo buy electical "test" parts and find out that they are not returnable. BTW..when ignition modules go bad, the car does not run..or it cuts off when hot. Learn how the systems work and it will be much more of an open book. Most of the "Rennlist internet experts" have little real experience and guess....what you describe can only be caused by a number of things in a fuel or ignition system. Bottom line is that if you get a manual and do some basic tests, you will find the problem. Costs alot less that way too...but then again, most guys here are so f***ing cheap that they use universal oxygen sensers and crap to save a few bucks...only to wonder (like another one of todays posters) why their car runs like crap

krahmlow

Hey, thanks for the attitude, it's REALLY HELPFUL! Did I take the time to diagnose the problem? Did you take the time to read the post?! I've tested the injectors, the AFM, the fuel pressure, the fuel flow (volume), the spark at each plug, the injector signal at each injector. The sensors listed above were replaced to be on the safe side and since I had the engine apart. I'm running out of options. According to the manual, one tests an ICU using an oscilloscope, which I do not own and cannot borrow. If you can recommend a diagnostic procedure that I've left out, please chime in. If you're looking for someone to trash, I don't need that, but I can give YOU some advice on where to stick the attitude....

And you're slagging "cheap" people who use universal 02 sensors but you're trashing me for going for the OEM ICU? No contradiction there. As for this miraculous $15 VW part, it didn't show up as a recommended part in the searches that I did with any distributors. So I ain't puttin' it in my car.

nickg

that is because you don't know it's the same...there is a test called the wiggle test...try it. start the car snd jiggle the connecters at each part the car's vital system...if the problem is corrosion, this is the easy way to find it

nickg

along with the "tude, how about these? What you sdescribe is NOT gonna be ignition related. Unless the impulse senser is flaky. what you need to do is look and test each thing carefully. Rough running and stalling is normally a fuel related issue.
here is what I suggest you do:
1. check for and verify that there are no vacum leaks
2. check for proper operation of the throttle switchs...if someone thought they were adjusting the idle and turnd the screws...then the switch is not working right and you will need to reset the minimum throttle angle and then reset the switch.(this is most likely your problem as if this is not right it will do EXACTLY what you describe.) the function of this switch is to tell the ecm when to enrich the mixture and how much based on afm input vs throttle angle (i recall this is really eith on or off on these)
3 verify that the afm has NOT been tampered with...idiot will always enevitably start turning the trim screw "to get more power"...don't do that. EVER. also, pull the afm off and verify that the door swings cleanly and smoothly thru it's arc with no stiffness or binding. a sticking afm will also cause EXACTLY what you are experiencing.
4 verify fuel pump operation and pressure values.
5 lastly ohm the impulse sensers...
outside influences? cams out of time? build up on the back of the valves, blown headgasket
the fuel and ignition in a 944s is very simple by today's standards, with a bit of dilligence you will find that it is a simple problem or a combination of things.
How's that?

nickg

last thing...to verify and rule out stuff. start the car(preferably at night wityh no direct light on the motor) using a misting sprayer, spray the ignition componets....if they are bad...you see arcing...that would be your problem. Here's your sign...