1987 Porsche 930 with no spark

[mtm100]

Hello everyone. I am 40 and finally bought a 930 after wanting one since I was a teenager. The car has 122,000 miles on the chassis and about 6500 on the engine, tranny and turbo rebuild. The rebuild was a little over 2 years ago.

So here is my problem. I went to pick her up in another state. About half way through my 7 hour drive home the car just stalled on the highway. Before the stalling issue I was in some stop and go traffic and smelled a burning smell. The temp gauge was a little more than halfway up on the gauge and not close the the red so I don't believe the burning smell was heat related but not sure. It restarted right away but would stall again as soon as I would try to accelerate After parking along the highway for about an hour to let traffic thin out I restarted it and was on my way again. When I restarted it idled rough for a minute or two but then leveled out and ran fine the rest of the way home. The only issue I noticed was the boost gauge was bouncing up and down for the first 15 minutes or so even though my tach was only around 2300 rpms. I stopped two more times after this issue to eat and get gas and each time it fired right up and ran fine.

When I got home I parked the car in the garage and all seemed fine. The next morning the car would not start. I checked spark and she does not have any.

The only thing I notice when I crank her is the tach jumps to around 4000 rpms but instantly falls back down. Is this normal, I don't know.

Any ideas on what to test and where my problem may be? I have checked for loose relays in the front and the back. Is the boost gauge related to the no spark issue or are these two separate issues?

Thanks for any help, Mike

[turbobrat930]

My guess it is probably the CD Permatune box... I cant really tell you how to troubleshoot them, as I have not had one on my car for over 12 years... (crank fire and now full EFI)....

[A930Rocket]

Did I miss he had a Permatune? Either way, it might be the ignition (stock CDI or Permatune). when running, wiggle the wire going to it and around it. Might be a bad/loose wire. Or it might be going bad. It happens

Check your voltage at the battery as well. Might be alternator related.

Side note: we should have a sticky of what to check when our cars don't run/start. It seems to be common problem and the most asked question.

[9dreizig]

Ok couple things.. 1) it's tradition to post a pic of your car when you start posting here
2) Where are you ? it's easier sometimes if you're near other Pelicans
3) I'm thinking it might be regulator related. The guages going crazy are a sign.
The first thing I'd do is start checking voltages #1 with your battery.. If it was a bad regulator it would cook the battery

[mark houghton]

Originally Posted by A930Rocket

Did I miss he had a Permatune? Either way, it might be the ignition (stock CDI or Permatune). when running, wiggle the wire going to it and around it. Might be a bad/loose wire. Or it might be going bad. It happens

Check your voltage at the battery as well. Might be alternator related.

Side note: we should have a sticky of what to check when our cars don't run/start. It seems to be common problem and the most asked question.

I would bet a bag of doughnuts that's your issue. Alternator and/or regulator going bad on you.

[Greyhound - 930]

Hi Mike - Just had a similar problem myself and finally found that it was the coil. In the process I learned a few diagnostic tips. My tach had been jumping around prior to failure and from what I had read I suspected the voltage regulator. This unit was an external on my car ('79) and had completely cooked itself (it sits next to the CDI unit in the left rear of the engine bay - not sure if your car may be internal as part of the alternator). I replaced with a unit from our host but still the car had no spark. Removed alternator and had it bench tested - tested fine and also had been upgraded to an internal regulator so now I'm running 2. next step was to check the distributor signal to the CDI. Two wires coming from the bottom of your distributor by the fan strap. There should be a plug inline. Disconnect this and with a multi metre that reads AC voltage measure accross the two wires coming from the distributor as you crank the engine over. You should see 0.1V - 0.3V. Now circuit check from here to the Plug at the base of the CDI for a broken wire (also check from the CDI back to the coil while you're here). If your CDI is still stock when its plugged in properly you should hear a high pitched squeal coming from it with the ignition on. If not this may be your problem. I have a workshop manual which lists an early diagnostic faulty ignition system check as removing the tach (easily done - just pull it gently out of the dash) and remove all connections from the back of it as it is part of the ignition circuit to isolate wether it's faulty or not. I had done all of the above and ended up suspecting the coil. For safe measure I took both the coil and CDI unit to my mechanic who checked them on another car and found the coil to be at fault. Pelican to the rescue and we're going again. As an aside a couple of years ago I had similar problem of cutting out which got progressively worse which turned out to be a faulty overboost switch. This is easily checked by earthing the wire that connects to it. If the car starts your switch could be the problem. Sorry if this is a bit long winded but hopefully there's something in here that may help. Good luck and enjoy getting to know your car - Konrad

[mtm100]

Thanks everyone for the ideas and suggestions on what to check, I truly appreciate the help.

I won't get a chance to do any testing until this weekend but will keep everyone updated on my progress finding the issue. If anyone has more ideas on things to check feel free to suggest them.

I will get a picture of her up as soon as I can. I am located in Lebanon PA. If anyone one knows of a good Porsche tech in this area I would appreciate it.

Thanks Mike

[MikeD930]

Mike,
Welcome to the 930 club! Several suggestion (none of which will help trouble shoot your car). Try to do the diagnostic yourself and replace simple parts yourself (such as a coil). These cars can be expensive to own if you have the shop to do everything everytime. Relays can go bad so it's best to have spare(s).

Do post pics when you get a chance. How long was your drive home? I hope you enjoyed it in spite of your troubles.

[mtm100]

Wanted to update everyone and thank you for all the great suggestions on things to check.

It turns out it was something real simple. The wire from the coil to the distributor was loose on the coil side. I pushed it into the coil until it snapped into place. No problems since!

She is running great now except I am not getting boost beyond .4. I can hear the turbo spool but I do not feel very much power so I think the gauge is correct. Any suggestions on what to check for on this issue. Should I start a new thread?

Thanks again,

Mike M

[mark houghton]

Originally Posted by mtm100

Wanted to update everyone and thank you for all the great suggestions on things to check.

It turns out it was something real simple. The wire from the coil to the distributor was loose on the coil side. I pushed it into the coil until it snapped into place. No problems since!

She is running great now except I am not getting boost beyond .4. I can hear the turbo spool but I do not feel very much power so I think the gauge is correct. Any suggestions on what to check for on this issue. Should I start a new thread?

Thanks again,

Mike M

If she's running fine and smooth otherwise with no other weird symptoms, but just not getting boost beyond .4 bar, then my guess is your wastegate is stuck partially open. Can you feel/hear exhaust coming out the WG exhaust pipe when sitting in the driveway and revving the engine? Could be corroded valve stem and/or guide hanging the valve up from closing completely, or a badly worn guide letting exhaust gas escape. Pretty simple job to pull the WG off and take a look inside, apply some air pressure (around 15 pounds) to see if the valve is opening (and then closing) completely.

If the WG checks out ok, then the turbo might be showing some problems not spinning up all the way....but I'm still thinking WG is more apt to be the problem. You could of course have an air leak post-turbo compressor, but you would see that in poor running symptoms as your mixture would go pig rich.