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Addition to repair: On my early 1978 car, I have a ground stud from inside the spare tire well that goes under the car through a rubber grommet hole and back to the battery. Greg B. posted a wing nut ground that goes to the toolkit area, I will have to check but maybe this came on later model cars?
Addition to repair: On my early 1978 car, I have a ground stud from inside the spare tire well that goes under the car through a rubber grommet hole and back to the battery. Greg B. posted a wing nut ground that goes to the toolkit area, I will have to check but maybe this came on later model cars?
Correct - the 78 models are different from the later models. You do not have an easily accessible wing nut. Unfortunately, you need to pull everything apart to disconnect that ground cable (not a ground strap in the 78). I did sub a wing nut for the regular nut though, on mine.
Update on my 1978 928s progress:
It has been almost a year of troubleshooting this starting issue, I have done/tested the following in attempts to correct the problem:
1. Full ground points cleaning as outlines by Wally P.
2. Replaced battery ground and added a secondary ground(another 1gauge wire coming off negative terminal to another chassis point on frame under car)
3. New engine bay wiring harness
4. Rebuilt Bosch starter
5. Made new 1gauge positive battery cable from starter to battery.
6. Replaced CE panel with better one and cleaned very thoroughly with Dexit, scotchbrite, replaced ceramic fuses with new.
7. New battery
8. New ignition switch
I have traced voltage from the yellow wire entering the CE panel through the relay bar and found somewhat consistent voltage of anywhere from 11.2 to 11.8 during starting 'click'. I am able to jump start car at the 14pin connection to the hot post under the passenger hood.....indicates New starter and wiring are not the problem. I guess I have an issue either at the CE board somewhere...maybe an old relay in the yellow wire route that transverses from the plug number I to exit at the starter relay bar (manual car), and then forward to the 14 pin. I seems to sometimes get a positive start, and most times get a 'click' at the starter. I am nearing my wits end with this problem. I hope someone can help me before I ship out the car to a shop. I feel all the work I've done was needed at this point anyway. The car had a rebuilt engine and ran well until about a year ago when the starting problem occurred.
The relay is always the starting point (well, actually the fuse, if it's a fused circuit too). Cheap, quick and easy. It sounds like with all the stuff you did, you used old relays? I'd try that before going much farther down the rabbit hole, since you have already done lots. The 78's are a lot less complicated than the later models. No "brains" per se, all mechanical fuel injection.
The relay is always the starting point (well, actually the fuse, if it's a fused circuit too). Cheap, quick and easy. It sounds like with all the stuff you did, you used old relays? I'd try that before going much farther down the rabbit hole, since you have already done lots. The 78's are a lot less complicated than the later models. No "brains" per se, all mechanical fuel injection.
My thoughts are to clean and deoxit the CE Panel again, remove the CE Connector Plugs and deoxit and clean these again, and maybe start testing the older relays. Any advice on where to start with the relays? Could there be a relay that is somehow connected to the yellow starter solenoid trigger that runs through it where I am missing? Or could there be a stuck relay that is causing a whole panel voltage drop? Any techiniques on troubleshooting would be appreciated.
..... Any advice on where to start with the relays? ........
Yes, throw away the old ones and get new ones. Call Roger, Mark or Dave. Relay 15, and relay 17 just for good measure. Cleaning old relays is not the answer when you are having the issues you describe.
Any resolution to this problem? My'78 5 speed is experiencing the same.
I ended up chatting for a long time with a local starter/alternator repair shop and they had me wire a separate starter relay at the starter to trigger the starter from the yellow wire coming from the CE panel. They made a relay that took the poor voltage (drop) yellow wire and triggered a 12v positive feed directly to the starter when the ignition is switched.
I ended up chatting for a long time with a local starter/alternator repair shop and they had me wire a separate starter relay at the starter to trigger the starter from the yellow wire coming from the CE panel. They made a relay that took the poor voltage (drop) yellow wire and triggered a 12v positive feed directly to the starter when the ignition is switched.
12 volts at yellow ignition wire disconnected at starter when attempting to crank. 7.5 volts with yellow wire connected to starter when attempting to crank. Problem in starter or in yellow wire to starter?
Problem is in the yellow wire. You have a voltage drop somewhere. You should have 12v at the yellow wire when cranking. I chased this drop on my car for a year...changing the engine bay wiring harness, ignition switch, CE Panel replaced (cleaned new panel and applied Deoxit), replaced under hood resistors near the coil...etc. among all other things. I got my starting better, but not perfect. What solved my problem was all of the above, and then wiring a stand alone relay to energize this yellow wire. If you get a schematic, I dont have the details in my head of exact pathway, but you can trace the starting circuit. Other things like poor grounds, dirty engine bay wiring connectors, old batteries...can all add to the voltage drop. This was a very tough problem for me to finally settle. Good luck. I'm here if I can help at all.
AJC
On my 87, I had this problem over several years, the root cause - solenoid!
When it first started happening, I went ahead and replaced the original 30-year starter, and all was well - for 3 months.
It would start 100% of the time when cold, but when warm/hot, it was 50/50, and I started hating the car.
I bought another starter, and it worked - for 1 month! The car was hot, and would not turn over. Jean-Louis jumped me and it turned over. This happened several, several times.
Then I did an exhaustive investigation - cleaned all grounds, replaced relay several times, ignition switch, checked/cleaned 14-pin connector, checked voltages everywhere.
I then mistakenly learned that if it doesn't turn-over on the first try, on the third try it would, like clockwork - no need for a jump. Engine was always hot.
Then one day in the garage ice cold, it would not turn over on the 1st try - what the??
So I turned the key again, and because it was in the garage, I could clearly hear the solenoid clicking which confirmed all my earlier voltage readings which were good. One more try, and it turned over.
I immediately pulled the 1-month-old starter, then the solenoid, and the solenoid's contacts were burned on all 3 pieces. I must say it did appear that those pieces were replaced when whomever rebuilt starter.
Next I pulled apart my original starter and also the 2nd one I bought, and all had the same scarring on the solenoid's contact plates.
Did you know that there are no 928 solenoids for sale? I checked everywhere, you have to buy a starter to get one.
However, I found a NOS solenoid on eBay that closely resembled the original, but the part numbers were slightly different, but I bought it anyway for $35.
Guess what, the length was slightly different. So I decided to use the original 1987 solenoid, but used the new solenoid's cap, and fitted the new solenoid's plate onto the original, and it looked and felt good.
The result? Working perfectly for over a year now, and a big relief!
Hope that helps someone. I'll see if I can get pictures of all the solenoids.
Problem is in the yellow wire. You have a voltage drop somewhere. You should have 12v at the yellow wire when cranking. I chased this drop on my car for a year...changing the engine bay wiring harness, ignition switch, CE Panel replaced (cleaned new panel and applied Deoxit), replaced under hood resistors near the coil...etc. among all other things. I got my starting better, but not perfect. What solved my problem was all of the above, and then wiring a stand alone relay to energize this yellow wire. If you get a schematic, I dont have the details in my head of exact pathway, but you can trace the starting circuit. Other things like poor grounds, dirty engine bay wiring connectors, old batteries...can all add to the voltage drop. This was a very tough problem for me to finally settle. Good luck. I'm here if I can help at all.
AJC
Thanks again, I have done everything you have mentioned except the stand alone relay to yellow wire. Do you remember anything about type of relay, where it was installed under the car and it's wiring details?
Greg
After chasing down a similar starting problem in my Euro '85, I installed an ordinary relay (eg a "53" relay - any 30 amp 12 volt normally open relay would work), attaching it to a sump bolt right next to the starter. I wired it as follows: Disconnect the yellow trigger wire from the solenoid, connect this to terminal 86 of the relay instead, then relay terminal 85 goes to a ground point, terminal 30 is connected to the +12v battery wire at the solenoid, and terminal 87 goes to the solenoid trigger connection (where the yellow wire was previously). This gets full battery voltage at the starter solenoid instead of whatever weak voltage was previously available. Ideally the relay should be protected from weather/underbody impacts etc but I've had mine running for over a year with little protection without any problems - and no starting issues since installation.
David
82 Euro S manual Palisander
85 Euro S auto Prussian Blue
Greg
After chasing down a similar starting problem in my Euro '85, I installed an ordinary relay (eg a "53" relay - any 30 amp 12 volt normally open relay would work), attaching it to a sump bolt right next to the starter. I wired it as follows: Disconnect the yellow trigger wire from the solenoid, connect this to terminal 86 of the relay instead, then relay terminal 85 goes to a ground point, terminal 30 is connected to the +12v battery wire at the solenoid, and terminal 87 goes to the solenoid trigger connection (where the yellow wire was previously). This gets full battery voltage at the starter solenoid instead of whatever weak voltage was previously available. Ideally the relay should be protected from weather/underbody impacts etc but I've had mine running for over a year with little protection without any problems - and no starting issues since installation.
David
82 Euro S manual Palisander
85 Euro S auto Prussian Blue
Do you recall mfg part# and where you purchased? I have been looking at a sea of relays online. Will a five prong work if I just don't wire up uneede prong?
04-08-2020, 09:18 AM
