Champagne

We will check the crank position sensor first thing tomorrow.

I need to get in touch with John Speake so he can tell me how to plug my '88 spanner into Hans '89
That should tell us something if any of the sensors entered a code.

In any event, thanks to all for the input

Paul

FlyingDog

ABS is chassis grounded at the pump. It does have a very large 12V supply connector next to the power steering that could potentially cause a power draw problem, but I don't think that would effect the computers.

Champagne

It is definitely not a battery or alternator problem. The car cranks with a lot of power and no weird noises while doing so. It just does not have any fuel or spark.

Paul

John Speake

Hello Paul,
I don't think a diagnostic tester will help in the first instance, to get the engine running. It could help later, when trying to analyse the ABS issue.

It is very significant that there is no power on the fuel pump relay pin 87. It is fed with permanent battery volts from fuse 42. So there should always be power on there.

When you say that Han's car has a "special electrical system" what does that mean ?

hans14914

Hi, all.

Thanks for all the replies. It certainly is an interesting set of circumnstances. I have moved the electrical panel to the rear of the car, and it is now mounted near the battery. While at this point, everyone will jump to the conclusion that the modification is the problem, i highly doubt it. The car has driven to SITM and back twice with this electrical system, and it made the 1300+ mile journey down to corpus without a hitch. Each wire was soldered and heat-shrunk one at a time, and the quality of the materials far exceeded that of porsche from the factory.

The car stopped in such a hurry, that i just cant get my head around the concept that it was just brakes. *IN THEORY* if something happened inside the transmission that would have caused either the parking or reverse gearing to be engaged, what would happen at a speed of approximately 50 mph? Are there any internal safe-guards in the trans to prevent this? All 4 wheels definitely locked, but i have never seen a car stop like this, i really think it was beyond the ability of the brakes alone. The car had to be traveling at least 50 mph, and the skid marks the tires left were thick, and only about 15ft long. I know all 4 locked up, because there was a small pebble in my front left tread, and it drew a white line in the rubber patch.

Thanks,
Hans

Leon Speed

Hi Hans,

Can't imagine what would lock up the front wheels other than the brakes. I thought about transmission failure too, but that doesn't add up for the front wheels.

As to your non start, maybe this will help? http://www.jdsporsche.com/fault%20find.html (John is already on this thread) and http://www.electronikrepair.com/wst_page6.html

Good luck.

Mrmerlin

Check the transmission shifter cable connection both at the trans and the shifter handle. Check the wires under the hood at the hot post and the ABS connector just in front of the power steering resivour. Check for free play between the brake pedal and push rod, Check the drive axles to see if the CV joint may have come off, check the brake resivour for quanity, check battery connections , Check hot post connections with the battery disconnected

cold_beer839

If the car slid straight, you may be seeing just the rear tire impressions. If all 4 wheels locked up you would see 2 distinct starting points for the rear tires and front tires, then as the rear tire impression reached were the front tire impression started the marks would merge and become noticably darker. If you don't have that darkness transition of the tire impressions, then only one set of wheels locked up (either the front or the back).

I am a Porsche newbie, but I have looked at a 'blue million' tire impressions at accident scenes. I agree with most here that nothing on the car except the brake pedal at your foot as input on the front wheels.

Champagne

Here is an update:

we did a more thorough check this morning and we did in fact have power at pin 87 of the fuel pump relay.
As a matter of fact, we now know that the fuel pump does get energize.

The car started this morning and idled for a good 20 minutes to 1/2 hour.

The only thing we did actually was clean the poles of the fuel pump relay and wiggle the lead of the crank position sensor.

The car ran well. At one point it died on it's own, but re-started right away and idled fine. Then, after about 30 minutes, the idle started to fluctuate for a few seconds and the car dyed. We can't start it anymore.

While it was running, the tranny shifted fine and the brakes worked as they should. No weird noise to be noticed anywhere. I think that the whole "wheel locking" thing is a completely separate issue that seems to have solved itself.

We would have to assume that either a sensor or other component shorts out or just stops working when it gets hot.
Further trials to start it probably just floods it at this point, adding to the problem.

Any ideas on how to pin point the problem?

Paul

dr bob

Paul--

Ugly theory to follow, but...

Check the crankshaft endplay. Thrust bearing failure (TBF) symptoms include a lot of what you describe, including the 'surging' as the CC tries to maintain a set speed, and the perception of wheels locking up as the engine slows faster than the car does. If the car is on a lift, it's relatively short work to pull the undertrays and check.

Champagne

We will Bob, thanks

But I doubt it is, since we just got it started again, and just like earlier this morning, once it starts, it idles fine, rock solid, with no strange noises at all.

But if TBF is something that can come and go in the earlier stages, then gloom and despair might be in Hans future. I certainly hope not.

This time around, we were able to reach both ends of the crank sensor connector. The part that goes to the sensor itself as a crack in the boot, but the prongs themselves looked good. We cleaned as best we could and put the thing back together in a way that we can reach it with the car running.

We also unplugged all the connectors of both the LH and the EZQ

We had one plug lead unplugged checking for spark and the car started. Hans put the lead back on and the car runs fine.
Wiggling the crank sensor connector does nothing.

We will check for crankshaft endplay, but I still think that an electronic component get too hot and cuts out. No idea how to find it though.

Paul

Paul

michael j wright

Coils tend to go south when hot, then "come back to life" when allowed to cool off. I've cooled them down with wet towells to reduce the heat quicker when trying to diagnose and found bad ones that way before. just my .02

Z

A no spark condition was mentioned. Has the ignition relay been checked or swapped with a known good relay?

FlyingDog

There was mention earlier that the car cranks easily when hot but doesn't fire. That would be the opposite of TBF where the car would not crank well, but could fire.

Champagne

This is the latest update: 3:00PM Central time

The car as idled for more than an hour without issues. We can shut it down and re-start it with no problems.
All that was done really is cleaning some contacts and connectors.
We added some Techron to the tank and Hans decided to hit the road.

He is now at a tire place to get new rear tires. They were due when he brought the car down, but the last braking episode pretty much killed them.

Once the tires are installed, he plans to take the direction of Dallas.
He has Roger's number and the numbers of some of the other DFW members.

But, if the car makes it that far, he is probably good to get home.

Finger's crossed

Paul