1096369

Hey Guys,

Well.... My buddy picked up a smoke machine to check for vaccuum leaks..... We saw a little smoke under the intake manifold..... So we pulled it.....What do you think, would this constitute a leaky vacuum line???





Next step is to replace all vaccuum hoses and I guess the IACV while we are here..... Maybe, just maybe..... We made some progress!!! You can't even see this turkey, unless you pull the manifold!!!

1096369

Hey guys..

Just did the following work..... Car seems to run better/smoother, and it can be restarted but it still stalls when you step on the gas.....

Replaced....

IACV (used)
All vacuum lines great and small
Thermo Vacuum Valve
Coolent Temp. Sensor
Throttle Position sensor (used)

Rebuilt throttle body
Spark plug wires
Injectors rebuilt (Mr Injector)

Here is a video of it running:


http://vid497.photobucket.com/albums...449D01AC3A.mp4


Getting closer to the gremlin....made some improvements.... But not there yet....
Thanks!
Fred

mytrplseven

Did you check the gap on the speed/ref sensors when you replaced them? On my 951 the PO neglected to include the shim that needs to be used with the speed sensor so the sensor protruded so far in it was rubbing on the flywheel and it eventually tore it up. If your gap on the speed sensor is too wide, you'll get partial or no signal to the DME and the car runs like crap. You can verify this by checking pins 8/27 (speed sensor) and 25/26 (TDC ref) on the DME connector. 600 to 1100 ohms on each pair to verify the connection and condition of the sensor. Then using the same pins but using AC Volts on the voltmeter, you should see more than one volt on the speed pins and less than one volt on the TDC pins when turning the motor. I found the gap on my speed sensor was .8mm too far and only generated .6 volts on the speed pins. That's way to low and the DME doesn't like it.

1096369

Thanks mytrplseven,

I'll give it a try..... The fact that this car starts and runs is pretty frustrating! I am currently thinking it may be a vacuum / FPR / FPD
Issue....(even though they have all been replaced!). Now that I have all these pretty new vacuum lines..... Gonna go back and see if they are doing anything.....

Since changing out the vacuum lines it will now restart after a stall..... (All be it a hard start!), Something it wouldn't do before..... I hope that is a clue.....

Thanks !
Fred

Tiger03447

Dear Trplseven: Is that shim used on the early 944's too? Just wondering..I think you have one of these as well. Tks.

odonnell

Wonder what your manifold vacuum looks like... have a way to rent (or build) a vacuum gauge? You can tee it into the FPR/FPD line. My car sits around 40 kPa (absolute pressure) at idle and moves closer to atmospheric (103 kPa here usually) as load is increased.

mytrplseven

I found that two different thickness shims were available on the parts diagram. One was around .4mm thickness and the part number started with 944. The second one was 2mm thick and the part number started with 951. This information in mind I can only deduce that some vintage of 944 uses the thinner shim.

1096369

Hmmm..... There was no shim on the old sensors when I changed them out...... Bears looking into!!! (And it did the same crap with The old speed and Crank sensor....). Hmmmmmm!!!

I played with vacuum lines today.... Good vacuum all around, on the new lines..... even eliminated non essential items just to rule them out.

I hooked up a pressure gauge to the fuel rail and it held solid at 34 psi. Even held steady after the stall.



Here is a video of a stall.... It usually dies much quicker..... It kinda sputtered out this time..... It does run much smoother since the new Vac. Lines.....


http://vid497.photobucket.com/albums...EAE06D8E29.mp4




And here is the aftermath....




****NOTE: my buddies pressure gauge did not have the right adapter to fit my fuel rail.... I ran around all over town trying to cobble something up..... No joy..... Outta desperation I stopped in Zygmunt motors (BMW specialist). in Doylestown PA.... I talked to Chris Muzylowski...... Showed him my gauge.... He goes in back and comes back with the proper fitting, and says "bring it back in a couple of days when you are Done...". He didn't know me from Adam.... And never even asked my name..... Great guy!!!!

Thanks!
Fred

mytrplseven

I love it when "car guys" help out car guys.

Gofishracing

Fred- now I see your thread- When all else fails call Will DiGiovanni Works on 944 historically. 908 832 6572 precisionmotorsports438@gmail.com Long Valley, NJ Just imagine giving them your car and it's running in a few days. Will knows 944's.

1096369

Thanks Bob.... I will give him a shout!
I'm gonna beat this Gremlin if it kills me!
Thanks much!
Fred

Gofishracing

I use to throw parts at my car so I totally understand. Are you sure the cams are timed correctly and all? Something else doesn't sound correct to me.

mytrplseven

I'm still chasing the same issue on my 951. I've been through this thing from top to bottom but now I hope I'm on right track. I'm borrowing a DME/KLR to swap out. The AFM, fuel system, vacuum system, ignition system, wire connectors and ref sensors all check out. NEXT?

1096369

Hey Mytrplseven,

You are having the same starts, runs.... But stalls issue as me?


I have tried replacing DME, AFM, TPS, vacuum lines, rebuild throttle body, distributor, plug wires, various sensors.... Speed, crank, temp, rebuilt injectors, fuel pump, and filter, tested pressure at fuel rail, Noid test, Tightened and cleaned grounds, new DME relay and fuses....


All with no joy..... I am about to seek some professional help...... (I hear that a lot!) As Dirty Harry says..... "A man's GOT to know his limitations" my buddy wanted to put an oscilloscope on it..... But to me that is way over my rather pointed head!


I have done a ton of hunting online.... And have not been able to find an exact duplicate of this issue.... My car still starts runs, and can even be driven.... So long as you don't step on the gas...... It then stalls and will not (usually) restart for hours.....

odonnell

If you don't bury your foot in the pedal is it possible to rev it high? Like rising 100 rpm every second, so not a lot of pedal needed. Wondering if it could be determined to be RPM dependent, or load dependent.