Randy V

Looks like you are not reading along. I replaced the CPS for no improvement.

Thanks, Alan.

Rob Edwards

Brains mailed yesterday, USPS priority mail, should be there tomorrow.

SwayBar

Doh!

Schocki

Sorry but he is wrong. The DME for "Digitale Motorelektronik" is an upgraded Version of a L-Jetronic.
The 944 uses DME but not the 928. DME in a 928 woould combine the two boxes LH (Luftmassenmessung Heissdraht or air mass metering by hot wire) und EZK (Elektronische Zündkontrolle or electronic ignition control) in one housing. But that´s not the case.

Randy V

Thanks for the clarification Schocki - I believe tech lore coming from a man from der faderlund such as yourself.

ralphr1780

Randy,
Did you check the FPRs? The symptoms you describe point also to a likely failing FPR.
-----------
Ralph
S2 '84 manual

Randy V

Qu'est-ce que c'est - FPRs?

All signs seem to be pointing to the LH ECU.

AO

WHat's with the Frechy crap? Are you missing the Sault?

James Bailey

The ONLY good thing about intermittent failures is...usually they become permanent Then you can easily find them !

ralphr1780

Bonjour Randy,
FPR = fuel pressure regulator. You have 3 on your car, in fact one damper at the front of the engine and 2 regulators at the back under the air filter on each cylinder bank side.
I faced the same symptoms that you have now, and searched for weeks.
Had ruled out the FPRs since they had been changed a year ago, and went through the complete check list and of course through all electrics/ignition/fuel pump/filters/... But then finally discovered that the front FPR was nevertheless acting wrong (light smell of gas in the vacuum line). Ordered a new one and fitted, like magic no more ANY cut!
Worthwhile having a close look.
-----------------
Ralph
S2 '84 manual

Randy V

Resolved.

I sent my LH to Louis Ott.

He was able to replicate the condition by installing my unit into his GT and driving for about 1.5 hours. There was no problem in that configuration.

He then tried idling the car and blowing a heat gun onto the LH. After about 15 minutes the engine died. The LH showed an exterior temp of 40*C.

When it cooled down it ran normally again.

So I then bought a rebuilt LH from Louis. No problems since then.

Tom in Austin

Great news, isn't it great when you finally fix something for good on a 928?

andy-gts

so was the lh getting hot and malfct or just discovered the problem and heating brought the problem to the surface quicker?

Randy V

If you read through this thread from the beginning all the answers are in there.

Fabio421

I believe I have the same issue. The only difference is that this car is a 5 speed so when it stalls while driving it immediately re-starts so it feels more like a big miss. Sometimes it won't re-start and I have to pull off to the side of the road and wait a second before it will restart.

Things that have been checked or replaced so far are knock sensors (new), crank position sensor (new), injectors (new), intake gaskets (new), all hoses on top of the engine (new), hall sensor, cleaned the grounds in the back of the "v", checked the connections at the battery. The problem doesn't really appear until the temperature is warm. These days in FL, every day and most nights are above that temp threshold and this problem is a real PITA.

Does anyone have a loaner LH and/or EZK that I can borrow for testing purposes? If so, I will be forever grateful. I'd rather not buy a rebuilt unit until I know for sure I need it.

1988 S4 5 speed

Thanks