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-   -   87 targa starting problem (https://www.germanautoforums.com/forum/general-tech-27/87-targa-starting-problem-3659/)

pfflyer 06-25-2007 07:16 PM

87 targa starting problem
 
My 87 targa(80K) was running great until recently. The engine would die while driving, would restart rather quickly. This happened several times, now will not start, the fuel pump seems to be working because I can smell the fuel after the engine turns over a few times. Any ideas?

PorscheDoc 06-25-2007 08:44 PM

RE: 87 targa starting problem
 
I would start by replacing your DME relay. It is located under the drivers seat.

oldskewel 12-09-2008 01:23 PM

RE: 87 targa starting problem
 
I may have a similar problem with my 85 cabriolet. Symptoms:
about 3 times in the last 1000 miles, the car won't start. Lights, etc. seem good, but the starter won't engage. When I turn the key, the only thing I hear is a humming, which I'm guessing is the fuel pump.
I have a fairly new (year or two old) Optima battery, and am very careful about having good battery terminal contacts.
Once this happened from a completely cold start (in my garage after several days). Once it happened after I had driven 45 minutes, parked for 20 minutes, and tried to drive again.
In all cases the car starts just fine after putting on jumper cables or charging the battery with a charger. Like instantly - within a minute of attaching the cables, the car starts perfectly, whereas prior to that, the starter would not move. It is as if there is some voltage threshold, below which the starter is held back, and then it is allowed to do its job.

Could this be due to the DME relay? By the way, when I got this great car 12 years ago, I read up on the DME relay failure, and have been carrying a spare in my car ever since. So I'm ready to go if needed. I'll probably just replace the relay anyway, but would feel better if I know this intermittent problem is solved.

PorscheDoc 12-09-2008 01:39 PM

RE: 87 targa starting problem
 

ORIGINAL: oldskewel

I may have a similar problem with my 85 cabriolet. Symptoms:
about 3 times in the last 1000 miles, the car won't start. Lights, etc. seem good, but the starter won't engage. When I turn the key, the only thing I hear is a humming, which I'm guessing is the fuel pump.
I have a fairly new (year or two old) Optima battery, and am very careful about having good battery terminal contacts.
Once this happened from a completely cold start (in my garage after several days). Once it happened after I had driven 45 minutes, parked for 20 minutes, and tried to drive again.
In all cases the car starts just fine after putting on jumper cables or charging the battery with a charger. Like instantly - within a minute of attaching the cables, the car starts perfectly, whereas prior to that, the starter would not move. It is as if there is some voltage threshold, below which the starter is held back, and then it is allowed to do its job.

Could this be due to the DME relay? By the way, when I got this great car 12 years ago, I read up on the DME relay failure, and have been carrying a spare in my car ever since. So I'm ready to go if needed. I'll probably just replace the relay anyway, but would feel better if I know this intermittent problem is solved.

That sounds to me like you have bad contacts at the starter or battery. The DME relay will not kill power to the starter, only to the ignition system.

oldskewel 12-09-2008 01:48 PM

RE: 87 targa starting problem
 
Thanks for the quick response. Good to know the DME relay will not fix this. I may replace it anyway.
I'll take another look at the battery contacts since that's easier. Then I'll look into the starter contacts. Ground strap too for good measure, I think I already have a spare one of those. Unfortunately, since this is a rare, intermittent problem, I probably won't know for sure if I fixed it for about a year after I find the problem.

oldskewel 05-31-2009 07:52 PM


Originally Posted by oldskewel (Post 21304)
Thanks for the quick response. Good to know the DME relay will not fix this. I may replace it anyway.
I'll take another look at the battery contacts since that's easier. Then I'll look into the starter contacts. Ground strap too for good measure, I think I already have a spare one of those. Unfortunately, since this is a rare, intermittent problem, I probably won't know for sure if I fixed it for about a year after I find the problem.

Update ...

I replaced the DME relay, cleaned contacts at battery and starter, replaced ground strap at transaxle. All good stuff, but none of these were problems. After the problems persisted, I finally did more careful testing on my Optima battery. My first Optima is still going strong after about 10 years in a different car, so I figured the one in the 911, being less than 3 years old should not be a problem. Turns out it was just a bad battery all along. Got a straight exchange on warranty, but I'd rather have them last 10 years+ like they used to.


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