elgy

I was preparing my 928 ('78 euro automatic) to attend the Camp 928 in upstate NY next week, driving around to build up confidence since the latest work I did on it (engine compartment rubber fuel hoses, new lower ball joints, changed transmission fluid).

The only problem was a couple of no starts due to slow cranking, that I put down to a weak battery, since it would start right up if I connected my backup battery. But it was intermittent and a bit... strange.

Then 2 days ago I stopped at a strip mall and when I got back in the car basically nothing happened, no cranking. Hooked up my backup battery and still nothing. CAA (that's like AAA but farther north) came and hooked up their battery, then the big rig in the back of their truck... nothing. So it came home on a platform.

Here is the strange part, once it was in my driveway I was able to observe more closely what was happening.

Normally with my car when I hit the starter the fuel pump starts up, and runs a couple of seconds. I hear this because it almost never starts on the first try unless I just touch the starter, let the pump run then cycle the starter properly.

What was is happening was now is:
1) When the key is a the accessory setting everything is normal (wipers, horn, lights etc).
2) When at the run setting usually nothing that runs through the ignition switch works and the the speedometer needle moves gracefully up to 80-100 kph (!) other than that nothing.
Sometimes at this setting it looks normal, specifically the battery light comes on and other systems stay active. This is very intermittently, sometimes I can repeat it several times, sometimes not.
3) If I am in the second condition above (battery light on) and I try to start, suddenly it returns to the inactive state and the speedometer climbs up to 80-100 again.

I have spent the last 2 days reading threads on how-tos and attempted to troubleshoot the electrics... but then I had a look at the CE panel and found this...



Hard to believe that almost all systems were functionning until this problem started. Actually the only system not functioning now is the starter. I can run the fuel pump by jumping the relay.

I have tried switching the starter relay with another.
I wanted to logically follow the current path from the ignition switch onward... but the CE panel has been "modified"... it seems that terminal one is not there, so I don't know where the wire coming from the ignition switch arrives in the panel, without pulling the panel. I don't see 12V on the starter relay.

I would like to try the starter, is it possible to short 2 contacts on the starter to see if it will turn?

Right now I would just like to get it running enough to allow me to get my 924S out from behind it and put it in the garage... with the intention of going through the CE panel as my new next project.

My thinking at the moment is it is one of three things:
1) the ignition switch.
2) starter
3) bad grounds

I will start with the grounds this weekend... and pull the panel if I have to... or just find some people to help me push it into the street to get my 924S out, then push back it into the garage.

As always... thanks in advance.

EC928NC

I'd go with No. 1. Cleaning the grounds doesn't cost anything but a little time though ... I think you're on the right track.

gazfish

Someone didn't like the old bullet fuses, as well as checking the grounds I'd pull every connector and relay one at a time out of the CE panel spray the pins/sockets with contact cleaner and push them back in again. The fact that the car has an intermittent problem rather than permanent would indicate the wiring hasn't been totally messed up.

drooman

The speedo climbing like that is typical of low voltage to the instrument...and probably indicating low voltage elsewhere as well. I would look at ignition switch intermittently (and maybe now permenantly) failing in the ignition on position.

This may get you going again, but the previous work to the wiring will make trouble shooting a bear for any further electrical issues...and there WILL be future issues because it's 78 928.

elgy

Start with the simple things, dammit! After much poking around I decided to have a look at the battery's positive connection, the cable is held on to the connector by a squeeze plate. Cleaned it out, ground the rust off the connector, reinstalled and... vroom!

Since, from the beginning, all boosting was on the positive connector at the battery it never got any juice beyond the bad connection.

If I had used the jump post up front all of this could have been avoided. I assume you can jump by connecting a spare battery via the jump post?

Mrmerlin

Grant its best to not be jumping the 928.
charge the battery with a 6 amp charger,
or replace it with a battery that will hold a charge.

Keep the ground disconnected till your ready to drive

SeanR

I think your best bet would be to start from scratch and put in a new CE panel.

Guy

seriously, the best 150 dollars you will spend. 928 electrics can be tricky enough without having to figure our some previous owners modifications. Return it to stock and go from there. Just be sure to match the part number exactly. Not close or similar but exact