rough running 944
 

ok all you porsche nutz out there, please help a novice porsche nut out. i bought a 84 944 about 2 weeks ago and i didnt run well. my friend finally got my 944 running. we ran it for about 10 minutes before it started to run rough and died out. we replaced the airflow meter, tps and fuel regulator. checked all vacum hoses (all ok) fuel pressure is right on the money 33 to 38 psi. we are next going to replace the crank sensor, spark plug wires, cap and rotor. my friend is a mechanic by trade for 5 yrs and porsche is new to him ( his benz wasnt this tough ). is there something we overlooked? we are currently using the haynes manual until the porsche workshop manuals come in. if you need more info on what we did i'll be happy to tell you so that the problem will be narrowed down. any help will be greatly appreciated.

Check the 02 sensor as well since this is a key element in the DME, particularly if it is still running rough when warmed up. Also, make sure that you have the right plugs / heat range - go with Bosche, nothing else. Please post your results for the rest of us nuts.

motor mounts are fine and the car idles at 1000 rpm rough, as soon as we give it gas it bogs and wants to stall but doesnt, sometimes it does but rarely. the rpm sometimes goes as low as 600 and doesnt stall. the temp doesnt even reach the halfway mark. we replaced the tps w/throttle body and airflow meter from another 944 that was running fine. my friend has adjusted the throttle body screw and the airflow meter screw it didnt make much diffrence. when the parts were installed the car started right up and minor adjustments were made. it ran a little rough but was driveable. we went to the gas station about 10 minutes after getting the car started (92 octaine). we then drove the car arouned for about another 5 minutes before the car suddenly stalled. my friend then went under the hood and he began to do some minor adjustments again. we then finally got it started again but was running rough. we limped home at about 5 mph barely making it. has anyone ever experienced the same or similar problem, let me know.

o2 sensor was replaced and so were the sparkplugs ( both bosche ). we are going to give it another try today, i will keep everyone posted. thanx very much, Raul

Plugged fuel filter ??

What about your timing. This kind of has the symptoms of an engine that needs to be timed.

fuel filter is new also. im almost sure its not a fuel problem. how would you go about timing the car. isnt the timing controlled by the dme. let me know. thanx, Raul

Yes, the timing is controlled by the DME, and there's nothing to adjust there. Did you try the Timing sensors on the top of the bellhousing? What about a compression test?
My distributor cap got moisture under it once and acted just like you described, so that's another point to check.
And also check all of your engine, and DME grounds.
Hope it helps!

But the DME could be foobared point being.

But the DME could be foobared point being.

944 Mech. told me that its not too uncommon to see a screwed DME box that was damaged from working on the car and not removing the battery cable. 944's are supposedly picky about that.

i ordered the speed,refrence and tdc sensors distributor cap and rotor from my porsche dealer. i'll let you know how it turns out when my friend and i install them. thanx for all the replys

ok guys, i got the new parts today but was too late to install them, too dark. we messed with it agan yesterday and my friend found out that someone jumped the fuel pump wire. why could that be, my friend thinks that the dme may be bad or at least the output for the fuel pump. how do i know for sure. also can someone tell me where the tdc sensor goes i looked and coulnt find it, i think im blind. thanx, Raul

ok guys, i think my friend and i found out what the problem was. we removed the wire that someone else jumped to the fuel pump and the car started right up on cold start. after 10 minutes the car was bogging. the fuel pump relay was burning hot. we now think that the fuel pump is the problem. i am picking up a new fuel pump and relay tomorrow at the dealer. i'll keep everyone posted. btw, i still didnt find the tdc sensor. thanx

THE CAR IS ALIVE. its running great now with the new fuel pump and relay. we also checked the connection on the cold start valve and was not making good contact. thanx to everyone for there help. hope to see ya on the highway.