vette4lyfe

Wow my porsche is really giving me a problem. i have a 87 944 Na. IT WONT START! it turns over but will not start. and then bam! it turns on and im fine. Then 3 miles down the road it jus turns off again. 15 minutes of trying to turn it on and then finally turns on again. But recently, it wont even start. ive changed the distributor, DME RElay.. what else can be a problem? is it a fuel problem? any suggestions will be greatly appreciated. Or if anyone knows of a good shop in the los angeles area, that will be helpful too. thanx.

and sorry for the rudeness, im new on the site. name is alen and pleased to meet everyone. will post some pics of my car as soon as i get it working...

Matt O.

Sounds like the actual DME unit is going bad. Let other people chime in to either agree or disagree, but I had an 87 924S (basically 944) which did the same exact thing.

You should be able to pick up a used DME for that model year for three to four hundred bucks.

starr944

What a sucky username for a 944 forum.

vette4lyfe

sorry.. old habbits

Eyal 951

sounds engine managment related to me. Go mess with the DME.
~Eyal

Bri Bro

interesting logo. Edit:Removed comment

Skip

The place you really need to start is to determine if you have either spark or gas or neither. That will really help the diagnosis.

DME relay is the very first place to start - but, looks like you already went there. Just to be real sure, search here for discussion relating to jumpering/bypassing the relay - pin 30/87b.

There are a few other 944-isms that cause this:
- Reference sensors - search the archives, but they are at the back of the engine on top of the bell housing. Look for fraying of wires or at the connectors on the backside of the engine. Wihtou the ref sensor you get no spark.
- Fuel Pressure Regulator - near the end of life these things let pressure get too high which shuts down the injectors. If you are not familair with an injector test using a noid, try this: pull the electrical conection from one of the fuel injectors when it *won't* start. If it starts, reconnect the injector and try to start again - if it doesn not start, replace the FPR. If it does start, you may still have to replace it because this is the intermittent nature of FPR failure. The FPR is on the rear of the fuel rail.
- DME - the actual brain, DME, has injector driver within that have been know to fail or suffer from cold solder joints (broken joints). Any good TV/Radio repair shop can have a look at it and reflow anything suspect. There is much in the archives regarding this also - look in the email archives as well ("injector driver")

There are a good many shops in the LA Area that could be useful. Other than that, there is a step-by-step troubleshooting guide in the factory manual set.

Good Luck!

icat

Reference sensor. Had an 83 that did the same thing. As Skip said, the "plugs" for the reference sensor are in the back of the engine compartment, on top, attached to a small bracket, near the middle of the engine (someone else verify that Porsche didn't move these for me since 83). Anyway - as these plugs age they become somewhat brittle and they can begin to loose connection. If they become unplugged the engine will do exactly what you have described. Turns over, but will not fire. Then it starts, you drive down the road, and bam - you're dead again (usually when you hit a bump in the road that jars the connection - but then again engine vibration can do it as well). Once I found the problem on my 83, I would often unplug the connection if I was going to be away from my apartment for an extended period (like on vacation). Great anti-theft device!

BTW - I like Vettes too! Had 3 of them in the past. But I agree with the others - you really need to change that handle!

Chris_924s

beab- That's just wrong.

I had a '70 vette in 1980- loved it. [passed everything but a gas station]

I highly suggest you resolder all the connections on the ORIGINAL DME- If you cant or dont know how to do it let me know.

Travis - sflraver

Ya, you guys need to cut that **** out. If someone said that when I had just started coming here, I wouldn't have hung around to even see what it was all about.


And... back on topic.

The same thing happened to my 84 right before I sold it. Sometimes it would start, sometimes it wouldn't. It would never die once it was running but only after sitting parked for a while (as little as 5 min. once). It would only happen about once a month so I just figured it was a DME relay going or something like that.
Well, I sold the car. The man who purchased it test drove it, loved it , parked it, and was going to come back in two days to pay for it. After he parked it, that was the last time the DME started. My dumbass trying to turn it over so many times also burnt out the starter.
So I had to get a new starter and DME. Now thats some high dollar items for a car that is already sold.

Chris_924s

Bingo Travis. It pissed me off too.

Bri Bro

OK, my bad... It has been removed.

vette4lyfe

car started fine today but veryy rouch idle. i tried messing with the refrence sensor and it shut off.. then afew minutes later i turned it back on. if it is the refrense sensor, how do i replace or fix it? or how much would it cost for the pros to do it?

Travis - sflraver

A reference sensor is easy to install yourself if that is whats wrong. The only problem is there are 2 identical sensors right next to eachother. If that is the case it is likely only one is bad. New sensors can be pricey so make sure that is your problem.
How to make sure that is your problem:

The sensors plug in to the harness at the back of the engine by the firewall. There will be a metal bracket holding two identical plugs. Unplug one of them then try to start the car. See what happens then plug it back in and unplug the other one. See what happens. If the situation does not change during one of these tests that means that you have found the bad sensor.

83na944

Well, I guess if you mess with the sensor and the car stops, it's probably the senso. I had a similar problem with '83 that turned out to be the electrical part of the ignition switch. You might check that out, too.