wigwampro

Hi Team,

I’ve done a lot of work to get my project in condition to start the engine. There was some rodent damage to the electrical and vacuum hoses that has been fixed and I’ve replaced fuel pump and other standard parts and purged all fluids. I hooked up a new battery and the dash gauges and lights work but when I try to start the car, all I get is a single click on the ignition relay. No crank/no start and no fuel pump operation upon ignition even after swapping relay with horn relay, which is operational. Ran some diagnostics and there is no signal to the starter. We jumped the fuel pump and it is operational but not with the relay plugged in, only when jumped. I’ve read that it may be an LH ECU failure but also that the 1986.5 model doesn’t fail often. Could it be the Python alarm intervention or maybe some wiring issues I can’t see? Any help is greatly appreciated!

Petza914

If you have the car in neutral or park and put 12v across the starter for a second, does it turn. If so, the starter is good and it's something else.

An alarm system with an ignition cutout relay is certainly a possibility. Do you know where that relay is installed and can you bypass it? Another could be a bad ignition switch. Seems like a bad LH would let the car crank but not start, however I know very little about the systems in the efi cars (mine is CIS) so don't know how those circuits work together.

davek9

A failed ECU on any year 928 will not prevent the engine from cranking.
The engine must crank for the Fuel Pump to start running, it won't pump with just the ignition switch on.
Disconnect the battery and clean the 14 Pin connector, you can also by-pass the starter relay and the key switch at the 14pin and crank the starter from the 14 pin (with the battery connected
I'd start at the 14 pin and work forward or back from there.

Dave K

Glen McCartney

In the words of Jim Bailey, relay, relay, relay

wigwampro

Good advice on powering the starter. We’ll give that a try. I’ve found some info about bypassing the alarm and will try that, as well. Also, good to know that the ECU failing wouldn’t give me current symptoms. That avoids some heavy expenses for the time being.

wigwampro

Thanks, Dave! My plan today is to clean all ground connections, clean the smaller positive battery wire, which has some corrosion, clean up the 14-pin connector, and continue to check and clean relays and fuses.

wigwampro

Yes, the easiest and least expensive possibility. Thank you!

wigwampro

So, I don't think it's a factory alarm issue as the alarm is a "Python" which leads me to believe it is after market. Would the F25 to B23 plug terminal connection I've been reading about the factory alarm still fix the potential issue? I've traced the red alarm light from the shifter to a series of loose wires and a shotty clear plastic control unit. Could this be the culprit? If so, how do I disengage? Also, I see that there is a white-ish wire that goes through the passenger floor under the car. This is also connected to some loose wires and a non-operational connector. What is this (yellow question mark in photo)?

"Python" Alarm System?

SeanR

Normally the alarm system will not cause a no crank issue, unless of course someone has butchered the wiring. None of the wires you have pictured will cause a no crank problem.

rjtw

See post #6 here about how to test the starter from the 14-pin connector. There’s more info there too about pulling out the wiring diagrams and troubleshooting a no crank condition. Although this link is in reference to the earlier cars, you can follow the exact same procedure (with the later wiring diagram) for your car. Hope this helps.

https://rennlist.com/forums/928-foru...r-dummies.html

Shark2626

Which relays did you “test?” There is a Starter relay. I assume that you have the CE panel (fuses and relays) diagram for your car and that it checks out.

https://www.928gt.com/t-8586fuse.aspx


I’ve read that some people test the Ignition Switch by turning the key to Start and then manipulating the key in various ways, but I don’t know their exact technique(s). If it gets to that as a potential suspect perhaps others can give you insight.

But corrosion is never a good thing, glad you found it and are addressing grounds as well.

Good luck!

wigwampro

Checked all relays and they all seem in reasonable shape except for some loose pins on the relays marked with yellow tape in the photo.

Relays marked with yellow tape have loose pins.

Shark2626

Are the batch of disconnected (brown) ground wires above / behind the CE panel just temporarily disconnected so that you can clean / refresh them?

Follow Davek's advice on the 14 pin first when you are ready.

I believe someone had already started to try to disable your Python Alarm so it may not even be functional and doing anything bad right now. That clear box seems to be a part of it and I assume that the other disconnected wires with connectors are as well. It would suck to try to get it all out of the car and button up the modifications but that may be in your future, I have no idea. But the Python does have a starter disable option. Here are the owners manual downloads in case you end up needing them:

https://www.pythoncarsecurity.com/Su...nersGuide.aspx

wigwampro

Yes, those disconnected ground wires are temporary while I clean the ground connections. Good eye! I found the Python alarm disable switch in the glove box but the wire was cut so I think you may be right that it doesn't operate. I also found that the yellow starter wire was loose from the 14 pin connector so I may have found the issue. I have a few other things to button up before I try but stay tuned.

Yellow starter wire loose on the 14-pin connector.

wigwampro

Team,

Successfully started the car this afternoon. The issue was the yellow wire into the 14-pin connector. It runs surprisingly well! Thank you all for the help and I appreciate all of your experience and expertise!

Best,

Erol