blitz951

Anyone know what it takes to rebuild the DME on our cars. I was told that when they are rebuilt only a certain part is changed so it sounds easy enough but whats the part or parts that go wrong in these things.

This is my second and last used DME before I go with a LINK stand alone but I would like to drive my car for the time being without getting stranded and dont want to spend the 250-300$ to do it.

DME failure on our cars is going to get more common as they are getting older so any info would be of great value to most on this list on the list.

Thanks in advance.

MHT

blitz, what were the symptoms when it failed, I often see a no spark condition, many times this is intermittant. The car will die and then restart, or not start and then after waiting for a while, start and run fine. This is caused by cracked solder joints between the ignition driver and the board.

blitz951

MHT,
The symptoms you described are exactly what my car was doing. So were is the ignition driver and is this something I can fix? I have the DME apart now and if you can give me an idea were to look maybe I can fix the problem.

threesticks1

There was someone here or on Pelican that posted an excellent article about how his car had lost spark, disassembled the DME found a bad transistor and what he did to replace it.

Try doing a search of the past posts and see what you can turn up.It was about a year and a half ago if my fuzzy brain remembers correctly.

Hope that this helps.

PorscheLars

Please let us other know if you find this thread/article. It would bee good to have in the tech library :-)

Joe Jackson

Send me an email and I can email you pictures of the most common cause of DME failure, at least in the later series cars. What happens is the solder joints crack around the main power transistor. It's a 30 minute fix if you know what you are doing and where to look. I've repaired a few DME's like this so if you don't feel comfortable doing it yourself, I can do the repair for a reasonalbe fee.

blitz951

Joejackson you have an email and thanks for the advice to all.

blitz951

Threesticks1,
I looked for that article on the Pelican tech. site and also did a search here on Rennlist and cant find anything so if you remember were to look let us know.

Joe Jackson

<a href="http://mywebpages.comcast.net/joejack951/pictures/porsche/DME01.JPG" target="_blank">cracked solder joint</a>

This is the back of the main power transistor on the DME. It's the big round, one attached to an aluminum heat sink. A quick touch is up is usually all it takes.

Russ Murphy

I know this isn't exactly what you're after, but if your repair doesn't go well, you can have my DME ('88 non-S) for $150 if you want.

blitz951

Hey Russ,
Nice to see you on the boards again. I dont know what I will do because I am considering a stand alone in the near future so I will try to fix my DME for now but if I have no luck and the car get real bad symptoms then I may take you up on that offer. By the way are you happy with that SDS system, sounds like Rage likes it alot.

Russ Murphy

Yes,
I've been very happy with it. If I could just get a Palm with the right OS system so I can use my Tech Edge wideband, I'd be really happy. It's been a comedy of errors. <img border="0" title="" alt="[Frown]" src="frown.gif" />

Lorenfb

Since you have a turbo, your problem
could be in the spark box (EZK). The
spark comes from the DME to the EZK
for retard based on the boost status.
The EZK then sends it back to the DME.

The resoldering in the local area might
solve the problem, but the whole board
should be resoldered as long as it's open.
You might check the DME relay, as it 's
problematic on DME cars. Also, if the
injectors are working and no spark, then
the DME or EZK is bad.

If ithe DME was previously rebuilt, they did a poor job.

Check out this website (systemsc.com)
for additional info.

Good luck
Lorenfb@aol.com

944turboracer

I found three cracked solder joints on the center power transistor of the DME ignition circuit. The joints heat cycle over time which causes them to get mechanically stressed causing cracks. If you are patient and have a magnifying glass you can save yourself some real money and fix those nagging intermittent no-starts.