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Adding credibility to Greg's percussive therapy concept, the car was flat bedded 7 miles to a Porsche dealership today and, once delivered, started right up -- without the 14 pin connector even being reassembled. Go figure! I may just need to add a hammer and about 4' of 2" dowel to my tool kit so I can thump the starter without getting under the car.
I personally used the car's factory tire iron. It works quite well, although I had to get a bit ingenious with some jump cables when I had to start my 81 on my own.
Clean all of the connections on the back of the starter and cover them in some dielectric grease to help keep dirt out from them. Don't forget to thoroughly clean all of the pins in the 14 pin connector as they may have some corrosion built up. DeoxIt helps here.
The rebuilt Bosch starters have been a nightmare, for me.
So many that I've installed have not worked properly, that I've given up and have been picking out used starters or using the lightweight starters, instead.
It's really frustrating to have a customer have a starter not work, only to install a "rebuilt" one, with the same problem.
This mystery continues. The Porsche dealer tech guy told me the starter was fine, but he was concerned with corroded wires to the 14 pin connector. I declined a totally new wiring harness and just had him clean up the connectors and individually wrap the wires so I could get it back to TX and Sean.
My car was driven hard today by the other 2014 widower in my family; highway and the twisty Kern River canyon road. He has now started shopping for his own 928!
Then I went to my son's for dinner. The car refused to start when I wanted to leave. I got a modest humming "grunt" from the starter this time, but no turn. We tried the hammer trick to no avail. Then we pushed the car, automatic in neutral, down his sloped driveway to park it where they could get their cars out the driveway. After parking it, it started up just fine!
Any ideas why rolling an automatic car in neutral for a very short distance would make the starter work again?? This issue is going to add a lot of suspense to my CA-TX drive starting 12/28!!
I had a bad yellow wire to the starter. had to rebuild the front engine harness. If you are really in a pinch, you can jump the posts on the starter, Battery cable to solenoid. Battery cable is huge wire, solenoid is smaller wire. (that is actually the keyed wire) This is the old screwdriver trick. If this is your problem, and you need to drive, get a remote starter switch from a place like advanced auto. It is just a push button with two wires. you can can attach it to the two hubs, run it into the cabin, and turn the starter like a key.
As was mentioned, you will have to be under the car, so be safe, and think what life will be like at least 10 seconds from now. We don't want you or anyone run over.
the screwdriver is a quick test of the starter functionality, and can rule out an electrical issue.
Also check and make sure you don;t have a bad battery. You will get aux stuff and not start with a weak battery. try a jump, that is the first thing I would do, then try the screw driver to see if the starter clicks.
This^^^^...
First thing done, would have been the screwdriver trick (the jumping of the solenoid posts, as mentioned above). This would eliminate the key switch and the wiring leading from there. Then if that didn't work, jump the vehicle. Sometimes just putting more amperage to the starter can get them spinning. Especially, if the vehicle has a bad ground(s) or minor corrosion issue inside the starter solenoid or a weak/malfunctioning battery.
Since moving the vehicle seems to make a difference, I'd clean all of my major grounds, check the connection at the battery terminals and make sure the battery is fully charged (between 12.4 and 12.7 volts). You may also have a bad/broken plate inside your battery that is making contact with another plate, weakening the battery, and possibly when you move the vehicle it jostles the battery around enough to make it move back into place.
First thing done, would have been the screwdriver trick (the jumping of the solenoid posts, as mentioned above). This would eliminate the key switch and the wiring leading from there. Then if that didn't work, jump the vehicle. Sometimes just putting more amperage to the starter can get them spinning. Especially, if the vehicle has a bad ground(s) or minor corrosion issue inside the starter solenoid or a weak/malfunctioning battery.
Since moving the vehicle seems to make a difference, I'd clean all of my major grounds, check the connection at the battery terminals and make sure the battery is fully charged (between 12.4 and 12.7 volts). You may also have a bad/broken plate inside your battery that is making contact with another plate, weakening the battery, and possibly when you move the vehicle it jostles the battery around enough to make it move back into place.
And thank your son for his service.
Good luck, with the rest of your journey.
Brian.
No disrespect intended, but your first suggestion is a very dangerous one for these cars. "Jumping the solenoid" may be possible on a 1970's American car but could be lethal to the very sensitive electronics on these advanced-for-their-day super cars. I'd work the new battery angle with cleaning all grounds. Search here will provide a ground location diagram for a 928. There is a very specific and safe process for jumping a shark (no correlation to the Fonz). There is a positive jump post on the passenger side fender in the engine bay. It should have a plastic cover over it. This is much easier than accessing the battery in the trunk.
I've been thinking about this. Both time putting it in neutral and rolling it made the starter work. I'm wondering if the problem might have something to do with having it in park when starting. If so, I might be able to avoid the problem by parking it in neutral with the hand brake on during the 3 day drive back home.
Are you saying you never moved the shifter back and forth when it did not start each time? I thought this was a "given" and you would have done this right off the bat. It's possible it is your neutral safety switch, which is normally located on the transmission.
After looking at this wiring diagraph...which looks pretty straight forward to me...I'd assume, since it really doesn't show me...that the neutral safety switch is used as the ground source for the starter relay. Normally, this is how they work, there is constant power to the relay, a supply power from the key (while held in crank position), a supply wire to the starter solenoid and a ground (which is supplied by the neutral safety switch...so the car will not start in gear).
I'd try to duplicate the situation by turning the car off and moving the shifter around and see if you can get it to fail. Or maybe do this once you are home. If you had a test light and someone to hold the key in the crank position, you should be able to touch the yellow wire on your starter and see what is happening (should be hot). Just be sure the car is in park while being under there.
A remote starter button from any auto parts supplier would be very helpful if this is your issue.
Your plight sounds a lot like an adventure my ex-brother-in-law was involved in years ago. He and a friend drove back from southern California, to Michigan, without shutting the car off. It had a bad starter also and after they got it going…they drove straight through. The car ran for three days straight. They slept in it, gassed it, ate in it...all while it was running.
You should get a test light, they can be very valuable asset to traveling.
No disrespect intended, but your first suggestion is a very dangerous one for these cars. "Jumping the solenoid" may be possible on a 1970's American car but could be lethal to the very sensitive electronics on these advanced-for-their-day super cars. I'd work the new battery angle with cleaning all grounds. Search here will provide a ground location diagram for a 928. There is a very specific and safe process for jumping a shark (no correlation to the Fonz). There is a positive jump post on the passenger side fender in the engine bay. It should have a plastic cover over it. This is much easier than accessing the battery in the trunk.
No disrespected here either, but the screwdriver trick if done right won't hurt anything on a 81 model. Of course, as with anything done right, it could be done wrong as well. The screwdriver takes the place of the keyswitch and any relay in place and will even eliminate a question of the neutral safety switch. So, I endorse it as the electronics in this car aren't that complex, and even if the worst happens, and the operator shorts the screwdriver to ground, this will not spike the electronics, it'll just go to ground and weld the metal to the starter case(ask me how I know this).
After the new info, it does sound like it could be related to the neutral(park) safety switch lockout. For the trip, one could simply wire a large gauge momentary contact button to pin 14 from the batt + at the jump terminal and use this as a starter until it is safely in Seans hand. Using a 10Ga wire, tie it to the jump start terminal at the right fender, through the momentary contact button, and then to pin 14, yellow wire of the 14 pin connector. If there is an issue with the start circuit, this would provide direct power to the solenoid to pick it and start the engine. If this fails, the only recourse is the hammer to the starter body trick. If this fails - replace car, and give the chiffon white one to me.
<edit; At NO time should any 928 be taken to a Porsche dealer. Take it to any euro car indie shop first.>
but he was concerned with corroded wires to the 14 pin connector.
Any ideas why rolling an automatic car in neutral for a very short distance would make the starter work again?? This issue is going to add a lot of suspense to my CA-TX drive starting 12/28!!
Originally Posted by oldfrat
I've been thinking about this. Both time putting it in neutral and rolling it made the starter work. I'm wondering if the problem might have something to do with having it in park when starting. If so, I might be able to avoid the problem by parking it in neutral with the hand brake on during the 3 day drive back home.
I was in the exact same situation with my 81 a few years ago.
Randomly it would not start, often at really annoying time like after getting gas. I remember one time I simply took the parking brake off, then it started up like nothing was ever wrong. Another time I turned the radio on / back off......stuff like that.
My initial "theory" was similar to yours: "My battery must be just on the edge.....having the parking brake light on...." I knew it was BS, but that's the thought that popped in my head.
The reality, which I've posted about in many threads of ill starting 928's.....the thick green or yellow wire that goes from the 14 pin connector to the starter is failing.
If you remove the front engine harness (not really that bad to do) and start to carefully peel back the shielding of that wire, chances are yours is corroded and / or damaged in some way.
Mine was so bad, when I removed all the shielding there were little only 4-5 strands of copper left, the rest were green & corroded. That was it, four tiny strands of copper starting my 928.
I simply replaced that one wire with a same color 10-gauge. Cleaned up all the pins and instead of the cheap plastic from the factory, covered it in 2,000F fire sleeve from DEI.
The first time I started my 81 after this fix, I thought my valves were bent it turned over so fast compared to before.
When I do the TB/WP on my recently acquired 87 I plan to completely disassemble this harness and rebuild it.
12-22-2014 | 05:10 PM
