944 keeps randomly dieing

[jacobhogan1]

I think its the crank sensor. ill be driving down the road, most commonly after shifting but it has done it just sitting at a light, and it just dies. It wont start for a min or 2 but then it just starts right up. It happend 4 times within 3 miles of driving. Its not the dme relay because i have a spare and that did not fix the problem. Any other ideas before i go and change the crank sensor?

[John_AZ]

The sensor plugs, check to make sure they are not brittle and losing the connection.

Check the battery POS wires--especially the 3 small for a tight fit.

Clean the main ground by the bell housing---put tape over the TDC hole so no bolt falls in!!

Wiggle the main DME computer wire--gently.

Tap the DME computer--gently.

Use a 3 wire DME jumper---your spare DME might be faulty.

What year car?

GL
J_AZ

[Gawernator]

Could it be a fuel pressure issue?

[jacobhogan1]

Its an 87'. I dont think its a fuel pressure issue. It runs very strong and normal until it decides it wants to die. I put the dme in my buddys 944 and it ran fine. so its not that. its not the vain air sensor either. I dont think it has anything to do with the battery because the only thing i loose is the engine. radio, lights, and everything on my dash works fine. On the sensor connectors, the plastic is very brittle as i think they are the origional sensors. is there any way to check if the wires are still connected inside?

[AKCJ]

AFM - Air Flow Meter.

I had those exact symptom (different vehicle but same AFM). You can probably fix it by working on the AFM. I haven't done it but I've seen the instructions on moving the wiper arm to get out of the old grooves in the wiper track. Check FR Wilks site. Also, there's a U-Tube video on how to do it. Another thing to do is make sure you've got a good clean connection at the plug to the AFM.

Good Luck

[John_AZ]

Originally Posted by jacobhogan1

Its an 87'. I dont think its a fuel pressure issue. It runs very strong and normal until it decides it wants to die. I put the dme in my buddys 944 and it ran fine. so its not that. its not the vain air sensor either. I dont think it has anything to do with the battery because the only thing i loose is the engine. radio, lights, and everything on my dash works fine. On the sensor connectors, the plastic is very brittle as i think they are the origional sensors. is there any way to check if the wires are still connected inside?

jacob,

If you think the sensors are OEM just replace with the less expensive sensors for the BMW. Same sensor with a longer wire. I prefer the silver capped sensors over the black plastic.

Make sure you can remove your old sensors carefully before ordering.

BMW Reference sensor question - Rennlist Discussion Forums

Cover the TDC hole to prevent droping a bolt in the clutch.

J_AZ

[gtroth]

I believe the tach will bounce when you crank it so next time it dies check that. That should
tell us the speed sensor is at least alive. You can I look at its signal and the ref signal at the dme connector on an oscilloscope. Tough measurement to make for the uninitiated, but if you are so inclined, that's a real good test.

Sudden stall sounds electrical to me. If it were mine, I'd want to rule out the ignition switch, dme relay socket connections, and any harnesses that might be shorting or loose connections (and grounds) thet might be resetting the dme.

[spaguy007]

so i am going to jump in here as i have the same issue. i have a 1987 944 n/a and i was driving it and it just died then after it sat for 5 mins it would start back up and then die again in 20 secs i brought it home and the next day it started and ran for 2 mins then died and repeated the short run and die again then it just died and would not start again so now i have removed checked and replaced most any issue it could be so now i know the dme is good and all relays ect so i have power to the 30 pion but when jumped the fuel pump will not run this is a fuel supply issue. is there anything else that will keep the fuel pump from running when the car is turned on ? is there a power wire to the pump that typically breaks or does some one have a electrical scamatic they can email me ? please let me know.
Michael

[John_AZ]

Originally Posted by spaguy007

so i am going to jump in here as i have the same issue. i have a 1987 944 n/a and i was driving it and it just died then after it sat for 5 mins it would start back up and then die again in 20 secs i brought it home and the next day it started and ran for 2 mins then died and repeated the short run and die again then it just died and would not start again.........


......so now i have removed checked and replaced most any issue it could be so now i know the dme is good and all relays ect so i have power to the 30 pion but when jumped the fuel pump will not run this is a fuel supply issue.....

....is there anything else that will keep the fuel pump from running when the car is turned on ? is there a power wire to the pump that typically breaks or does some one have a electrical scamatic they can email me ? please let me know.
Michael

Michael,

If I understand, you have tried the Clarks-Garage 3 wire jumper in place of the DME fuel pump relay.
http://www.clarks-garage.com/pdf-manual/fuel-05.pdf

You can follow Clarks advice and run a 12V wire to the fuel pump:
Troubleshooting Fuel Supply Problems

If the fuel pump does run with 12V wire from the battery attached but does not run with the 3 wire jumper you might have a bad ignition switch:
Ignition Switch Replacement

or a bad DME computer---bad solder joints or burned out transistor.

Basic wiring schematics are available in the Haynes manual- Porsche 944 or the WSM.

Clarks does have more troubleshooting pages.

GL
J_AZ

[spaguy007]

quick reply
1 new dme.
2. new pump 6 months ago and removed to test out of car and also tested plug at pump no power.

[mytrplseven]

In older cars that I have driven there was a thing called vapor lock. It was a bubble of vapor that interfered with the flow of fuel from the fuel pump. Where am I going with this? I'm wondering if the fuel filter might be restricting the fuel flow. It's a cheap and easy replacement and I always do the easy stuff first.