Electrical Frustration: Mechanic cannot duplicate

[ae1969]

Originally posted by ae1969
When it fails.... tap the dme.

More than likely bad soldering point on the ignition driver....

TA-DAAAAAAAAAAAA .........



........ you are better off re-soldering the entire thing at this point........

[Eldorado]

was that an "i told ya so" ?

subtle, alex.. real subtle. :P

[NKN84944]

Good to hear that you possibly got it fixed. I am just South of you near Macalester but finished school a couple years back. I only drive the 944 a couple days a week, so if you see a guy in a black 944 or a new silver GTO wave its probably me.

[Pistol Pete]

I've been driving heavily for a few days now and now problems whatsoever. It also starts right off, where it would always chug for a few seconds before, even when it was starting properly. I don't want to jump to conclusions, but I'm hoping this is it. I'm finally enjoying my 944 with little anxiety. Thanks, everybody.

[Pistol Pete]

So I got the car back from the mechanic a while ago, over a week, and he had soldered in a new pin in the DME or relay or whatever in that assembly has the pins, because the pin that controls power to the coil was burned and it was arcing. As soon as I got the car back I noticed that it fired much quicker when I started it, especially after it had run recently. Over the last couple of days, starting time has increased to a couple of seconds and now the damn thing has gone back to not starting periodically. Of course, it has yet to fail when I actually have my tools and gauges with me. I'm thinking I should bring it back to the mechanic and find out if that same pin is burned once again. Am I right in thinking that a problem with the DME may be causing the pin to burn? (If indeed it is burned again)

[nynor]

too much power draw at the coil or something?

[NKN84944]

If I weren't leaving out of town on Monday and Grand Ole Days wasn't tomorrow, I would gladly lend you a hand figuring it out as I fought this same battle about a year ago. Hopefully your mechanic can get to the root of it as it sounds like the pin may not have been the culprit after all.

[Pistol Pete]

Originally posted by NKN84944
If I weren't leaving out of town on Monday and Grand Ole Days wasn't tomorrow, I would gladly lend you a hand figuring it out as I fought this same battle about a year ago. Hopefully your mechanic can get to the root of it as it sounds like the pin may not have been the culprit after all.

I'll be at Grand Ole Days too! Well, if Metric can't solve it, maybe i'll send you a pm and we can work on it.

[davec]

My track buddy had a similar problem: the harness had an ever-so-small bare spot that rubbed against the block in the rear of the engine, between it and the firewall. Cost him several thousands of dollars to find a 2 cent fix. His was cutting out whenever it touched.

[deekay911]

Why wouldn't you buy a new DME to fit? Must have cost you more than that by now. I keep a spare one in the glove box of the 964 and the 968.
DK

[Pistol Pete]

Originally posted by deekay911
Why wouldn't you buy a new DME to fit? Must have cost you more than that by now. I keep a spare one in the glove box of the 964 and the 968.
DK

Hasn't cost much more than my sanity so far. How much is a DME? I hear not cheap at all.

[Eldorado]

a dme wouldn't fit in our glove boxes. lol

[hpaulb]

Spend the time on following the harness. It's pretty small. If the pin is burned again, you have a problem internally or externally. Also mechanics are all thumbs with a soldering iron. Remove and take it to a electronic service shop. Have them go over it and resolder any suspicous solder joint. There use a large magnifying glass. Just tell them it's from somthing otherm than your Porsche or the price doubles?

[hpaulb]

O' take the schmatic in with it. There's lots of copies around.

[mlue]

Originally posted by Pistol Pete
So I got the car back from the mechanic a while ago, over a week, and he had soldered in a new pin in the DME or relay or whatever in that assembly has the pins, because the pin that controls power to the coil was burned and it was arcing. As soon as I got the car back I noticed that it fired much quicker when I started it, especially after it had run recently. Over the last couple of days, starting time has increased to a couple of seconds and now the damn thing has gone back to not starting periodically. Of course, it has yet to fail when I actually have my tools and gauges with me. I'm thinking I should bring it back to the mechanic and find out if that same pin is burned once again. Am I right in thinking that a problem with the DME may be causing the pin to burn? (If indeed it is burned again)

Sounds like you're on the right track if it worked flawless for a while.

Are your saying the mechanic soldered the DME or the DME Relay? If you're not sure you better find out. You can do the DME soldering yourself but if it was the DME Relay it's just better and cost effective to just get a new relay.

Here is a web tutorial that will point anyone that wants to solder the DME in the right direction. You can thank me later ;^)
http://www.rennspeedracing.com/DME_tutorial.html

[SoCal Driver]

Originally posted by hpaulb
Also mechanics are all thumbs with a soldering iron.

Really???

[Pistol Pete]

UPDATE: Mechanic pulled the DME out and checked the pin he re-soldered. It's still good, not burned like we thought it might be. So the problem persists. He has suggested replacing the DME. This, I can do myself. I'm picking the car up tomorrow and it's back to the drawing board. Does anyone have a corner on a re-manufactured DME? Thankfully I have a new motorcycle, so I can get around without the car, but the only way for me to solve it is to drive it regularly, which I can't do when i need to work. So...I'm leaning towards just replacing the DME. I've heard this isn't cheap, so let me know if you know where I can find a re-manufactured one. Thanks.

[nynor]

i'd try borrowing one, first, to see if it is the problem.

[74goldtarga]

Hello Pete,

I live in Bloomington, I don't know anything about the electrical system in these cars, or any car for that matter. Auto-Edge in Mahtomedi is the undisputed champ as far as expertise on these cars in this area. If you can't do it yourself, and your shop can't fix it, then let them help you. They aren't cheap but they are fair and honest and have an excellent reputation among PCA members who race/track their 944's. They have worked on my car briefly up at BIR and they do a nice job.

[olivar]

from my electronics expeirence,if that pin keeps burning out,that would indicate a short somewhere down the line,if you try another DME and it does the samething that would be the best bet.FYI