scotts911e

My car has been running lean since I fixed a no start condition due to the reference sensor marker(pick-up) coming out of my flywheel, now the engine diesels after I shut the engine off for a few seconds. I was thinking maybe a hall sensor or something but not sure if I even have a hall sensor on the car! can someone help me out please!

89 n/a big p.i.t.a
87 944S
85 944 just sold

odonnell

Sounds like a DME problem, specifically DEE (digital engine electronics). Or very high engine temps

scotts911e

I had a dme from an 86 in it with a chip but I just switched it back to the stock dme this morning
I started it up and engine sputters with the stock one (thats why i've been using the other dme) when I rev it up goes away around 2500 rpm and it still diesled when I turned it off

89 n/a big p.i.t.a
87 944S
85 944 just sold

scotts911e

Ok I got rid of the lean condition I think, (well it's not pinging any more) by switching back to the stock DME, but it still sputters when cold from idle to about 2500 rpm and still hard to start half the time

89 n/a big p.i.t.a
87 944S
85 944 just sold

mel_t_vin

The reason your '89 944 would run lean with an '86 DME [designed for a 2.5L motor] is because the motor in your car displaces 2.7L.

There are countless, recent, threads on poorly running engines. You should probably start with the basics...fuel, spark, compression.

Sputtering...plugs, rotor, cap, wires, ISV, TPS, AFM. Are you saying the sputtering goes away after 2500 rpm? If so, that might point to a worn resistor track in the AFM. Does the sputtering go away [completely] when the engine is warm?

Hard start...fuel, spark, compression. Define "hard start". As the cars age, the intake system has become notorious for vacuum leaks...which affects AFR...which can affect starting/running.

If you're looking for additional suggestions, it would help [us] if you listed the things that have been verified, repaired, and/or replaced.

scotts911e

It's very hard to get it started when the engine is cold (mornings) it's got the fuel and spark but just doesn't want to fire-up, so after cranking for about a minute or so i let it sit for about 5 minutes and it fires right up but it takes about 30 seconds for it to smooth out and idle! It acts just as if it were out of gas every morning! I dont see or hear any vacuum leaks hoses all look good,the boot at the intake is secure and no visible cracks, the plugs and wires all look good, next I will check the cap and rotor but I'm pretty sure its a fuel problem!

V2Rocket

theres a screw on the AFM that adjusts the mixture, try playing with that?
or use the FQS on the DME?

http://members.rennlist.org/951_racerx/FQS-adjust.html

mel_t_vin

How long have you had your car? How long have you been having this cold start, rough running, issue?

After a few minutes of rough running, your car then settles down to a relatively normal idle and runs/drives fine?

This sounds to me like the pressure in your fuel rail is bleeding down, excessively, possibly caused by a bad fuel pump check valve. When is the last time the fuel filter and/or check valve was replaced?

This could also be FPR-related. While the engine is running, pull the vacuum lines from the FPR/FPD. You should not see any gasoline or smell any vapor from the vacuum lines. If you do, then the diaphram in that respective component has failed internally and needs to be replaced.

scotts911e

Iv'e had the car about a year I bought it for $700, with no service records except for a clutch replacement 8 mo. prior which came out to $700 and change! So I have no idea what has been replaced except for the wp,tb, hg and ref sensors and four exhaust valves that i did myself!
Iv'e noticed the colder it gets the harder it is to start this morning would not start at all until I
plugged in the DME from a 2.5 it started right up but still took a few seconds to smooth out and
it still diesel's when I shut it off half the time! I pulled the vac line on th fpr and no gas in the line!

89 n/a big p.i.t.a
87 944S

scotts911e

Thanks V2Rocket I totally forgot about the FQS it's not the reason for the hard start but sure is a quick solution for the lean condition! "You Rock rock"- Rocket!

89 n/a big p.i.t.a
87 944S

StickShift

How about the dme temp sensor? What happens if you unplug it? Blue sensor towards the front of the engine underneath the intake. I know if that is unplugged it will cause a surging at low idle and a hard start cold condition.