Lechto

Hello

I am new to the group and am in desperate need of some help. I am 19 and proudly own an 83 Porsche 944, that is when it starts. My problem is a hot starting problem. I have read about 30 pages worth of ideas and suggestions, but none of them seem to be my solution.
I will drive the car from 2 minutes to 2 hours and when I try to start it about 5 minutes after I shut it off, the majority of the time (almost always) it cranks and fires but never runs. Sometimes I can pop the hood and wait about 10 minutes for it to cool off and it will start up just fine, but sometimes it won't work for hours. This problem started when one night I was driving home, just cruising, when it just shut off. It completely died. I went through every step to figure it out and eventually found out the DME was bad. So I replaced that, but soon after the problem persisted. Here is a list of the parts I have replaced over the year:

Fuel Pressure Regulator
Fuel Pump
Re-built injectors
Mass Air Flow
Coil (twice, one after market the next factory)
Spark Plugs
DME
DME Relay
the 2 speed sensors on the bell housing (appropriately gapped by a Porsche dealership)
Starter

I initially checked for spark and fuel and all was good. Then, out of ideas, took it to two separate certified Porsche mechanics, and then finally to the expensive Porsche dealership. They all told me I was getting spark and I wasn't getting spark. Basically they didn't do ****.

I am out of ideas, mechanics, and soon to be money. I am on my last leg as a Porsche 944 owner and need help.

Oh and another thing. Last week at night I was about to get on the highway for a nice cruise when it just died on me at a light, just like the time the DME went out. Tried to start it and it could crank forever. But guess what, the next day it started just fine! Please help.

Thanks a lot, Craig

SoCal Driver

A few owners have found the shielded wires from the sensors to the DME plug to be damaged. The loss of sensor signals is one of the faults that will shut the car down without warning. Acts like a bad DME.

Another section of wire that can do this is the injector harness. Tends to have breaks at the crimps where the wires split.

Heard of the fuel pressure dampener having heat related lock ups. Most of the track racers don't run a fuel pressure dampener.

Another owner recently found the DME connector to be bad. A couple of the pins were making intermintent contact.

Could be bad battery conections.

Sometimes I think we 83 owners are luck to have the darn thing run at all!

Lechto

SoCal Driver

I really appreciate your response and I know this is a very delayed response to you, but I wanted to say thanks for your help. I had to go off to school after you responded to me so I didn't have any time at all to pursue my problem. I am back at it and very determined to find out what is wrong. I miss driving my 944 so badly I can't stand it! Thanks again for your help

Mr. Avionics

Try wiggling the wires that go to the connectors to the refrence sensors, as SoCal said they can give problems. I too have an occaisional intermittent start problem with my 83, I just give the wires a little wiggle and away we go. Havent looked into it any further yet but plan to when I get the time. Just an idea.
Good Luck,
Bill

Big E

Those symptoms sound exactly like the problems I was having on my 951. I found various things seemed like they would help a bit, but not solve the problem completely. What finally fixed it for me - and I did several of the things you've listed - is new plug wires. I've had them in about 6-9 months now, and it has started every time since then. While you're in there, you might want to do the cap and rotor, too. Might not be causing the problem, but will probably make it run better if they haven't been done in a while.

Good luck!

Lechto

Mr. Avionics I think I have the exact same 944 that you have, maybe a few more dings though, but same color and everything. I think I might have a break in the reference sensor plug wires going to the DME or something along those lines. I am just a little hesitant to cut into the main wiring harness.

Big E I have replaced the rotor and cap just because (wasn't in great shape) and to maybe solve my problem, didn't help. I haven't replaced the wires though, maybe it was something that simple all along. Wouldn't that be nice.

I'll try yall's suggestions and get back to you.

Thanks again, Craig

Lechto

Well, I pealed back the insulation on the DME side of the plugs and found each plug had a broken connection in it. I re-did all the connections and so far so good. It has started up great every time, but I'm not ready to say problem solved.

I am going to give it a week or so, but thanks for all of your help. I really appreciate it!

Lechto

It has been running great, until last night when I was pulling into a parking space and it just died on me. I coasted into the parking space and tried to start it up again, and all it did was crank crank crank. I came back a few hours later and jiggled the sensor wires and of course it started with no problems. Then today I tried to start it and nothing worked. I came back and re-checked my splices for the sensor plugs and everything was great. It started fine, but died when I was looking in the engine bay not touching anything. I have started it numerous times after that and it has ran great.

I think this will never end.

SoCal Driver

Use some string to tie up the sensor wires to the fire wall. Try different tension directions. If you had wire breaks at the DME plug then it's possible these are intermintent too.

Lechto

should I cut into the wire bundle going into the DME and see if there are any breaks there?