It Just Died

[prairiedawgshoo]

So there I was, finishing up my 60 mile Sunday drive in my '87 930, cruising at 75 mph on the interstate and the power just dropped off, RPMs steadily decreased, I put it in neutral and coasted to the shoulder, before the engine died, it backfired

while I was trying to find the number of a tow truck I tried to start it again and it did, so I limped the 7 miles back home, as I turned into my neighborhood, it did it again, power dropped off and the engine died...I waited another 5 min and it started again so I was able to get it home

any Ideas?

thanks!

[chrisbruck]

Out of gas or clogged fuel filter? Or the fuel pump may have gone kaput.

[prairiedawgshoo]

Full tank...new filter...fuel pump-don't know...sounds like a cheap fix

thanks for the input

[tmadden2]

Sounds like something similar that happened to my 1986 911. I replaced the DME relay under the driver's seat and the problem hasn't returned.

[T77911S]

most likely coil, could also be the CD unit. you need to check for spark as soon as it dies and when it will not start. also check for fuel pumps running by turning key to on. you should them run for about a second.

other things to consider:
fuel pump
fuel pump relay
speed relay under seat.

[ischmitz]

Here is a quick test: Drive the car around the neighborhood until it dies. Once it does, do not turn the ignition key. Open the engine lid and listen carefully to the whine of the CDI box. Remember the sound (pitch and volume). Then turn the ignition OFF, wait 5 seconds and then turn the key back to the RUN position but do not attempt start the car. Listen again to the whine.

If the note is now lower and the volume of the whine is noticeable louder you have identified a bad CDI unit that latches up when hot.

Ingo

[prairiedawgshoo]

tmadden...how did you determine it was a bad DME?

thanks for all the good inputs...I'll start your diagnostic suggestions shortly

I appreciate your help

[Bob Kontak]

Mentioning only because I recently was in a garage queen 89 930 with my pal. Pretty as a picture.

Did an ugly face plant like nobody's business in Asheville, NC traffic.

One fuel pump fuse blown. There is (are) an issue with the amp draw on the fuel pumps. Don't fully understand why the 930's do this but there are robust fixes documented.

I told my pal years ago to get another red relay as a spare. Once he said "What about that relay thing" , we looked at the fuses and sure enough, one was blown.

[ischmitz]

A DME and DME relay are for Motronic cars. The 930 has no such thing

[bugstrider]

Originally Posted by prairiedawgshoo

So there I was, finishing up my 60 mile Sunday drive in my '87 930, cruising at 75 mph on the interstate and the power just dropped off, RPMs steadily decreased, I put it in neutral and coasted to the shoulder, before the engine died, it backfired



while I was trying to find the number of a tow truck I tried to start it again and it did, so I limped the 7 miles back home, as I turned into my neighborhood, it did it again, power dropped off and the engine died...I waited another 5 min and it started again so I was able to get it home



any Ideas?



thanks!

Check the internals of your distributor.............. Excessive shaft play or wobble. If it fails while running, it will/could grenade internally. Mine did and I was able to drive it home the last little bit. Upon opening up what was left of the dizzy, it defied the laws of physics. In every sence of the word fail, it should not of even started, but it did.

[timmy2]

Green wire to distributor all brown and cracked?
Test the CDI as Ingo indicated.
Red fuel pump relay in the back fuse panel or the 2 up front working loose.(spread the contacts a bit)
Coil.
One of your fuel pumps dying a slow death perhaps.

[prairiedawgshoo]

Thanks...I hope to get in there this week...I really appreciate the advice, but am getting worried by the possibilities, but I guess worry never helps anything

[timmy2]

Simple process of elimination for everything listed. Hopefully something simple to repair or replace. May even just be a loose or bad fuse.
Good luck and post what you find as you go through them.

[prairiedawgshoo]

I'm up and running...thanks to all who gave me their 2 cents...they were worth more than that to me...

and the gold star goes to Ingo!

while the car was dying...the CDI box was making different noises, right before it died for good...Luckily for me Ingo had rebuilt a 'spare' box for me...once I got the rebuilt box I was up and running in about 8 minutes

thanks again to everyone and lots of appreciation to Ingo for the internet diagnosis and the great work on a new CDI Box...the current dead one will be heading Ingo's way shortly

cheers!

[timmy2]

Always good to have a good extra CDI on the shelf, I do.


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