I have a '84 AT 928s euro. Got a bit of a strange problem. When I turn the key everything looks and acts normal, but the engine won't start. It is completely silent, the starter engine does nothing.
Everything looks okay. All warning lights come on, all other electric stuff works, but when I completely turn the key nothing. I can turn the key only once, after that some lock activates. Then I have to turn back completely to try again.

Anyway, it did this when the battery was real low because of some other repair work of mine on the automatic window switches. So I let the battery load overnight and it's nicely 12 volt again, according to the cars meter and according to my own meter.

It is quite wet and cold lately. About -2 celcius at night and 5 degrees during the day. I was working on a leak in the hatch window and there was some water there in the back.

I fixed about 10 little problems lately, but this one is a mystery to me. Please help!

 

Did you try replacing the starter relay? (Relay XIV) https://www.928gt.com/default1.htm

 

Could be that the starter relay/solenoid isn't getting a full 12 volts plus enough current to turn the starter, or it could be the nuetral safety switch if there isn't *any* voltage at the starter.

The quick easy test is to put your charger on your battery while turning your ignition key, but lots of folks don't like to take voltage spike chances with their engine computers, so you may not want to try that easy trick.

The right way to test is to measure the voltage with your voltmeter at the starter connection while the key is being turned. Obviously that requires more effort.

What you are trying to identify is if the voltage loss is before the starter (e.g. low battery, bad ignition switch, etc.) and thereby not triggering an otherwise good relay/solenoid, or if you have good voltage to the starter is the solenoid bad or is the starter itself bad.

 

Fixed it!

It was the neutral safety. When I put the gear in N it started right away. Tried a couple times more and it sometimes does not start in P, but always in N. A bit strange, but good to know in the future.

Thanks soontoberred84! I removed the starter relay, cleaned it up and also replaced it with the horn relay.

And thank you 'no doubt'. I didn't know that starting with the charger on is bad for the computer. Now I know I let the battery load overnight before trying.

I also cleaned the ground attachment where the minus pole of the battery is connected to the chassis in the back. That was pretty dirty, problably because of the leakage. I found that tip in this thread: https://rennlist.com/forums/showthre...hlight=starter

Awesome load of information on this forum by the way. A real treasure for the 928! I was worried about finding info when I got this car in here in Holland but this forum is much bigger than the 944 dutch community I was with first. This forum rules! Thank you experts!! You helped me out many times already! About 10 times actually

 

your N eutral SS may need to be adjusted you will need to get the back of the car up possibly use ramps then in the WSM there is a procedure for adjusting the switch with the shifter in neutral. If adjustment doesnt work then a new switch will probably be needed. Also when you have a car that has had a lot of starts made without starting the starter relay will get hot hot enough to melt and this can cause the starter relay to fail usually at the base of the relay where the solder joints are. You can remove the relay and open it and check its condition, Disconnect the battery B4 working on the elex system

 

I had similar results on a batt that would show 12.5 on the Fluke, but it was weak in CA. Could still be some corrosion adding to the problem. Then with your history, I would take the batt to a shop for a load test before replacing anything else.

 

starter relay or ign switch. Im betting switch, its common

 

Do you even read threads that you open? The solution was posted 7 hours ago...

 

Concor, glad you figured it out. Good Luck.