Issue with 96 850R Starting Not Turning Over Topic is solved

wackenhut · Post by **wackenhut** » 05 Jul 2020, 10:55

Okay, I will check it.

wackenhut · Post by **wackenhut** » 05 Jul 2020, 11:27

I just initially opened the hood and both posts were somewhat hot. I drove for about 5 minutes and checked the posts again. The positive one seemed to be hotter. In this case, what should I do?

Thank you.

Post by **abscate** » 06 Jul 2020, 02:15

Take off both clamps and get every thing shiny clean with a wire brush

Reconnect, then look for voltage drops between the ends of the wires and the clamps with the car running and lights on, and report back

wackenhut · Post by **wackenhut** » 06 Jul 2020, 10:54

The voltmeter reads about 14 volts. I drove it today and it would not start again. Lifted the hood and waited about 5 minutes. Not sure if the lifting of the hood did anything. After about 5 minutes it started again. Very strange and not sure what else could be the problem. the positive lug is not heating up.

Post by **jreed** » 06 Jul 2020, 11:17

Would it be possible for you to measure the voltage during starting? You can test the battery and the starter terminals. That test might reveal the source of the problem.

wackenhut · Post by **wackenhut** » 06 Jul 2020, 11:49

What does the B cable do that runs from the battery to the fuse box? Does this have any purpose in starting the engine? Is there a way to test if the cable is good or bad?

Also, would a fuse cause this? Maybe the number 1 fuse or fuel pump relay?

Thank you.

Post by **scot850** » 06 Jul 2020, 12:01

I know the B+ cable in the 98-00 cars is a known issue and can be dangerous when they get really bad as they can short out. I can't unfortunately picture the 850 version as been way too long to know if it has a similar issue.

As to it's purpose it runs power up to the main fuse box. Having not actually had one fail completely I am not sure if this would cause your problem.

The fact that your issue would appear to be temperature related it would point to electrical wiring on contacts failing which gets worse when hot. This could point to many items, but you have replaced many items so as has been suggested it may be bad earthing/broken/missing earth wires, or bad positive feed wires to the starter.

Neil.

Post by **erikv11** » 06 Jul 2020, 12:26

For the record, B+ cable problems are basically nonexistent on 850s. Test it with a voltmeter.

I agree must be electrical.

Fuel pump relay - no. This gives a no-start, but the car would crank just fine.

Fuse, no. They are either working (intact) or not.

Post by **misha** » 06 Jul 2020, 16:17

I had bad b+ cable from battery to starter.
I had almost 1v voltage drop on it when everything is warmed up under the hood.
Cold test was always ok and without voltage drop.

Post by **erikv11** » 06 Jul 2020, 22:36

The cable from the battery to the starter is not the B+ cable, it's the starter cable. Agreed, basically every 850 the starter cable has gone bad by now or is going.

As posted above the B+ cable runs from battery to fuse box. The B+ is plagued on 99+ P80 cars but basically trouble free on 850s.