LT Texan

A few years ago, I finished gassing up and I got in my 928, turned the key.....and nothing.

I was on a road trip, so I tried not to panic, and turned the key again, and she turned over and fired right up.

Then, in January, the same thing happened again. Finished gassing up, turned the key and nothing. Then gave it another try, and she fired right up.

So I bought an ignition switch (and of course let it sit on the shelf).

Then a few weeks ago, got in her, turned the key and nothing.

So I decided best to install the new ignition switch.

Now, my son borrows my 928 yesterday, calls me and says she won't start. I tell him to just try again. He does and she starts right up. (He said he tried numerous times before he called me to no avail.)

Then, that same day, he tells me she wouldn't start again. He was afraid to call me, so after trying numerous times, someone jumped the car and it started right up.

My son tells me that when he turned the key, all the warning lights came on, but no sound - starter did not click, nothing.

I can't recall if all the warning lights came on when this happened to me - but probably did.

I checked the battery this morning and it is at 12.8V. (Running I got 14.5V.)

And it started right up.

Any ideas?

Chris Hansen

I had this exact issue on my 1981 occasionally . . . once in a while when it was fully warm. Turned out to be a bad A/C fan relay (the aux cooling fan relay, not the blower).

LT Texan

Wow. That's odd. But I will check that.

The Forgotten On

I had a similar issue that would affect the car when it was fully warmed up =halfway up the temp gauge.

It turned out to be a voltage drop to the starter caused by some bad wiring by the PO after they removed an aftermarket alarm.

Check around the plugs of the CE panel to see if the wires have been messed with.

LT Texan

Got rid of all the bad wiring a few years back with a new engine harness.

The CE panel is clean, but I'll take a look there too.

gazfish

I also had the same thing happen to me for the second time yesterday when the engine was hot, I smacked the starter solenoid with a wrench and it fired right up. I've ordered a new starter motor, having checked the wiring first.

LT Texan

Well, my starter is coming up on 40 years old....

9two8

Just a thought, have you checked out the inner condition of the battery earth lead ?

davek9

Have you checked the condition and cleaned the 14 pin connector under the hood, it has the wire that feeds the Starter

auzivision

Check and clean all your grounds or as they say across the pond "earth".

auzivision

I like Dave's idea better.

dr bob

The starter circuit includes a few key things that fall into the relay-relay-relay and ground-ground-ground categories. Add in the ignition switch and the neutral-safety switch, plus the connection pass-through at the 14-pin connector under the hood.

The starter relay gets coil power from the ignition switch via terminal/circuit 50. The 50 designation is generally used for the starter trigger. The other side of the relay coil sees ground through the neutral-safety switch on the side if the gearbox on automatic cars. The ground for that switch is in the spare wheel well. The connector for that switch is in there too. So the order of diagnosis would have you swap a known-good (common recommendation: horn) 53b relay into the starter relay socket. Then clean the ground point in the spare wheel well area, and the connector to the neutral-safety switch. The connector for the speedo sensor on -'89 cars is in there too. DeOxit would be a good method, or at minimum disconnect and reconnect the connectors a few times.

On the power side of the relay: Do the cleaning and DeOxit on the 14-pin under the hood. The last connection to clean is the smaller wire that triggers the solenoid, the connection at the solenoid.



If you continue to have the problem, lift the carpet and cover over the CE panel, and cycle the key to the start position while listening for the starter relay to click. If no click then the problem is in the coil circuit described above, plus it can be the ignition switch. Diagnosis for the coil side includes using your DMM to confirm coil voltage from the ignition switch at the starter relay socket, and a good ground through the neutral-safety switch and the ground connection you cleaned in the spare-wheel well.

If the relay clicks and the starter doesn't crank, your DMM will help you find voltage at the white 50 wire in the 14-pin connector under the hood, and again at the small terminal at the starter solenoid. You can use the DMM from the relay socket to test the loop through the starter solenoid too, including the solenoid coil. With relay clicking but no response from the starter/solenoid, sometimes a firm whack on the solenoid will free it up if it's stuck.

Other things... The neutral-safety switch is configured to close when the gear selector lever is in Neutral or Park position. Immediately on having the no-start condition, try cycling the gear lever completely through all gears a new times, then stop in Neutral and try the key again. The switches fail very rarely, but sometimes a shift cable is worn-stretched to the point where the switch isn't pushed all the way to the end of its travel when Park is selected.

Tom in Austin

Are 928 alarms in any way connected into the starting circuit or do they only flash lights, honk the horn, etc.?

LT Texan

Brand new cable a couple years ago. Clean as a whistle.

LT Texan

Dr Bob, amazing advice as usual. And I will follow it all. Except, I just can't find that "park" thing.

😜