Motronic Nightmare

[PowerHaus944Turbo]

I have coughed up thousands at three Porsche garages for over six months attempting to solve this mystery...

I have a 1987 Porsche 944 Turbo with issues.

All sensors connected properly: the car stutters when accelerating (pushing the gas half-way or more) at mid to upper rpms. It feels as though it is running lean or is starving for gas.

Throttle postion switch disconnected: the car runs almost flawlessly (has fairly rough idle / sometimes stalls / runs rich / not acceptable).

Engine Upgrades: Autothority mass-airflow sensor, K-27 turbo, intercooler, oil cooler.

Motronic Upgrades: Authority DME and KLR chips.

Attempted Fixes: mixture adjustment on airflow sensor, wiring integrity check, replaced throttle position switch...

Known Anomolies: The speed sensor doesn't seem to be putting out spec voltage. (according to one garage)

PLEASE HELP ME!!! - Will

Email: butler.william@broadband.att.com
Phone: 720-280-1561
Fax: 303-766-5032

[This message has been edited by PowerHaus944Turbo (edited 09-26-2000).]

[porscheboi928s/c944t/n]

my best advise is... bring ur car to autothority maybe they will burn you a new chip..have them put it on their dyno make a new program..

[todd951]

Have you checked the fuel pressure regulator and damper? I had a similar problem with the car stuttering when trying to accelerate, and it turned out to the the FPR.

[cyclemike]

Just a shot in the dark... Maybe wastegate shim or cut-off. My 2 cents.

[Lawrence Coppari]

How do you know you have wire integrity? I have had trouble with my PowerHaus MAF unit right where the wires come together at the MAF unit. I use Wurth contact cleaner once a year. Mine ran rich when the problem occurred. It did not miss, however. Good luck.

BTW, I am thinking about buying some Stabilant 22a an putting it on all connectors.

[andrew4266]

I had a situation where the starter went out in my 87 944S. since it had only been 3 weeks since i bought it from a dealer it was covered by a 30 day waranty. they replaced the starter but could never get the engine to fire. after 3 months of replacing just about everything they took it to a specialist. and of course they determined the problem right away. the wrong starter had been installed and was turning the engine backwards. of course this seems to be a kick yourself in the ass situation. (at least for them). now they are confronted with a $1500 bill (alot of the work was fixing what they screwed up) and they will not pay. they are trying to tell me that i am supposed to pay half. i cannot get my car back because they will not pay the bill. any suggestions?

[944Driver]

I had a Nissan 300ZX a number of years ago with the same problem. It turned out to be a leaking injector. Just a thought.

[RAWXTC]

andrew, with the engine starting backwards im almost sure more damage was caused. the engine bearings will now wearout prematurely cause of the engine running backwards and who knows what else. as for the warrenty issue, they were in posession of the car within the warrenty period right. the problem was simple wrong starter. how they came to that conclusion is of no concern. i dont think you are responsible for the outrageous bill they handed you. good luck and if all else fails get a lawyer.

[waller71]

ANDREW----YES GET A LAWYER, OR ATLEAST LEAD THEM TO BELEIVE YOU ARE SEEKING OR HAVE ONE. SOME PEOPLE LIKE TO SEE HOW FAR THEY CAN PUSH. YOU'RE NOT OBLIGATED (UNLESS IN THE FINE PRINT). DON'T LET THEM PLAY YOU.

[RedS2]

Originally posted by PowerHaus944Turbo:
I have coughed up thousands at three Porsche garages for over six months attempting to solve this mystery...

I have a 1987 Porsche 944 Turbo with issues.

All sensors connected properly: the car stutters when accelerating (pushing the gas half-way or more) at mid to upper rpms. It feels as though it is running lean or is starving for gas.

Throttle postion switch disconnected: the car runs almost flawlessly (has fairly rough idle / sometimes stalls / runs rich / not acceptable).

Engine Upgrades: Autothority mass-airflow sensor, K-27 turbo, intercooler, oil cooler.

Motronic Upgrades: Authority DME and KLR chips.

Attempted Fixes: mixture adjustment on airflow sensor, wiring integrity check, replaced throttle position switch...

Known Anomolies: The speed sensor doesn't seem to be putting out spec voltage. (according to one garage)

PLEASE HELP ME!!! - Will

Email: butler.william@broadband.att.com
Phone: 720-280-1561
Fax: 303-766-5032

[This message has been edited by PowerHaus944Turbo (edited 09-26-2000).]

You may very well have a dirty MAF if your conversion does not include the burn out circuitry. With full flow, you should see 4.6 Volts and 0.2 Volts at idle. THese are the same voltages as the Flapper.

Try your own VOM and check. ALways check the connections because the MAF is a relatively high impedance device and dirty connections can casue a real problem.

[Lawrence Coppari]

How do you know when the car is in motion that the wiring integrety is there? The things might wiggle around a little.

[PowerHaus944Turbo]

The symptoms are too constant for it to be a intermittent wire. The problem wasn't prevalent when I purchased the car, but over a year, the performance slowly deteriorated. It misses when the car is not in motion and you depress the accelerator to rev it up. Could this possibly be a fuel delivery problem? I have a air-fuel guage installed and it seems to run too lean with everything connected.
** After testing the engine, it runs exactly the same if the TPS is disconnected and when a TPS is connected and set to full throttle ** I know that this is a special condition... perhaps by "tricking" the computer I am covering up the real problem...