Anyone ever have hot restart issues w/ their SPB? I did at the UMC club race, had to push start after sitting waiting for the scales. Hot day, altitude, and engine temp after sitting/idling/heatsoak was pushing 250. Trying to decide if it's starter related or resistance in the starter wires from heat. I have a new starter (last winter), Bosch rebuilt in the car. Certainly could be a dud. I recall the 996's had problems w/ hot restart due to resistance in an aging starter-alternator cable, wasn't sure if that is an issue w/ 986s too. Cable is different P/N vs the 996.

When cooled and the following day races x2 it started fine at post-race hot engine temps around 210-215.

 

I fought that issue till I found that my negative ground from the starter to the chassis needed to be replaced. Once that was done, I have had no issues.

 

I have heard of this issue before and I learned the solution was to replace the failing 11lb BRAILE battery with a new one. Makes sense to me its electrical related (battery or bad ground).

 

That is what I was thinking. I had a similar issue on my 2003 996.

I have noticed the starter turning over a bit more slowly when the car is warm but it does start. That seems to support the wiring resistance.

 

Should have mentioned I am running an Odyssey PC680 battery, about 12-14 months old, showed 12-12.5V on my Motec dash at the time the car would not start. Starter tried to turn, sounded like it made it about 1/2 of a revolution then stopped.
That being said I have had these batteries die on other cars by 1 year. I always trickle charge it at home.

 

I'm digging into the same issue now, ran an enduro would start 3 of 4 times, then not at all, then 1x. Got so bad I actually hired a kid to 'crew' and basically push start me every session @ NJMP 2 weeks ago.
Tried charging, tried swapping (full size) battery. AIM shows 13.1v or better. I'm going to go after all the cables to-from the alternator and possibly the alternator itself over the next week or two.

 

Also forgot to say those red "on off" power kill switches fail often.

 

Another hot start issue is the crank position sensor. Symptom is it will crank but not fire.

 

Thanks. Crank sensor is new last winter, but doesn't mean it isn't a bad one.

 

Update:

Pelican says the cables are NLA from Porsche (ugh!).

986-607-029-00-OEM - Starter/Alternator Cable
986-607-030-00-OEM - Engine ground strap

Checking w/ Auto Atlanta to see if they can get them. They often have come thru for me in the past on NLA parts.

In the mean time once I get the original cables out I will measure cold resistance on them. Could stick them in the oven then measure again to compare when hot.
New/rebuilt warranty Bosch starter arrived yesterday.

 

I feel like it wouldn't be overly presumptuous to attempt make a set of those. Or use close cousin alternates. That's actually was I was considering myself.

 

Thanks good idea. I'll use that as a plan B.

 

Checking resistance is a difficult way to test a cable.

The best way to test a battery cable to pull a lot of current through it and see if the ends get hot. You will need a carbon pile (or similar) battery tester. Connect the cable and battery tester in series with a fully charged battery.

Be careful as a bad connection can get really hot.

Audi sold some nice 5 cylinder diesels in the late seventies and early 80s. Unfortunately, they would start poorly in a Minnesota winter. When I would get a non-starter the first thing I would do is hook up some jumper cables and crank the engine for 20 or 30 seconds without waiting for the glow plugs to cycle. I would then carefully feel the ground cable ends. (The ends on the ground cables were crimped without solder and the road salt would get in there and ruin the connection.) I would use a wire wheel to buff the copper shiny and then solder the connection.

After a while I quit testing and just looked to see if the ends had been soldered. It was a quick easy repair and I could bill an hour. Those diesels were pretty popular and I made a lot of money.

Good for the customer too as Audi was happy to cover this repair under warranty.

 

Had the same issue with my 9-month old Odyssey PC680 battery.
Replaced it with the Odyssey Extreme Series PC925 battery and the problem went away.

 

I'd throw a regular sized battery in there if you have one and see if the problems go away.