SteveG

SAND?!!

concor

I jumped the fuel pump relais in that video and connected and disconnected the battery to start and stop it.

Dutch 928 fan

Hi Concor, I am in Zuid-Beijerland (near Rotterdam), so a bit far away to just drive up and down and have a look at your car.

Did you exchange the battery? Just to make sure it did not completely die.
Even though the alternator gives 14 Volts, does not mean the battery can hold it or handle the current.

Good luck. Leo.

Catfood

Have you tested your vacuum? My 928 acted just like yours did when my intake manifold had a leak in it.

concor

Well, a change.
It doesn't shut off anymore!

A new problem arised though.

Now it doesn't get higher than 1800-2000 rpm. If I give more gass it just sounds like it's choking on fuel and the rev meter won't get any higher... Any ideas?

EDIT: Last things I did last night before the change:
- put the airbox back on. I removed both the upper and lower tightening screw around the MAF. Maybe I turned it too hard which could causing the MAF to fail and thus it went into disconnect mode?
- removed LH and EZF connectors to check throttle ohms
- was cleaning a mass point right above the right coil and tried to pull out that coil but failed
- was cleaning two connectors at the right front

EDIT 2:
It was running fine 30 minutes ago. I just pulled the LH connector, sprayed some contact spray on it, let it dry for 20 minutes and tried it. It's back to the old behaviour. It's hesitating every couple seconds again like it did the past month and it will go over 2000 rpm no problem. So my guess is it's the LH connector for now. Problem is, I put back the LH connector a couple times and twisted the cable and I cannot get back to the new behaviour where it runs steady and won't go over 2000 rpm. Ah well, maybe the LH connector wasn't connected properly and I just connected it proper again and the whole stuttering issue is completely somewhere else. That's a possibility too.

TheoJ

It sounds a bit like like the flywheel sensor is missing impulses. Not related to the LH connector I'd say.
regards

concor

Great, I just opened up the EZF ecu to check for water because there was some dirt on it. Now I've put it back together and tried it. When the engine started I heard a metal scraping sound so I stopped after 1 second. Then it didn't want to start anymore... No starter engine sound, just a little click from the ce panel. The dash lights do light up and the volt meter works.

Can I try to start it with a disconnected EZF ecu to see if I just broke my EZF ecu? And can I try it vice versa, with a disconnected LH ecu and a connected EZF ecu?

pjg

Recheck your temp sensor II connector, pin 1 should be green/red and pin 2 green, based on photo #8 it looks reversed to me or the plug was forced on backwards, I do not see the keyed slot on the harness plug for the notch on the sensor so it is hard to tell if it correct or not.

John Speake

You have a problem with the starter circuits, nothing to do with the EZ-F. I think if you disconnect the LH and EZ-F it won't make any difference to the no-crank problem.

concor

Well, good news, it's starting again! I opened up the computer again, put it back together and she's starting again. Thing is, she's still quitting on me after a few seconds like the very first video.

I was wondering. I have a bit of an oil leak at the back, probably from the transmission or the diff. Is there any chance it cuts out because it's oil out of oil back there? That all the oil dripped out and a sensor keeps telling the engine to cut out? Thanks!

Dutch 928 fan

Hi Concor,

Have you tried a new battery in the meantime? Just because your old one is charged does not mean it is o.k.
A damaged battery disrupt the electrical system.
Just like when my drive belt for the alternator ran off: battery fully charged, but no way you can drive the car. The electrics will go crazy.

Leo.

concor

We exchanged both the EZF en the LH with different computers. There is are two small changes, the car now runs for about 10 seconds instead of 2 seconds and the fuel meter is maxed to 25 liters/100km instead of 0 liters/100km.
The strange thing is that when we put the plugs back on the original computers, it does exactly the same. So it is not the computers, but there is something did change. We exchanged the computers by simply twisting the brain connectors and not removing the old computers first. Any idea why the changes occur?

I had the car taken away to a specialist. He asks me what I want him to check first, he has spare 928 parts.

concor

FIXED FIXED FIXED !!!!!!!!!!!!

It's fixed! Whoohoo! Finally. My specialist went ahead and tested a couple more things when eventually he was about to build out the start interruption thingy. He pulled up the thing from behind the CE Panel to see where the wires were connected. Tested it if it still worked and it ran for 30 minutes! He then removed the whole start interruption thing and reconnected all the wires and it works flawlessly again!

The hard part was that that start interrupter was 3rd party and was put in on a later date sometime during its lifetime. Also, the company that developed the start interrupter went bankrupt about 10 years ago. So the problem wasn't even original from Porsche! And I missed it because, well, I don't know much about cars... Actually the first thing my specialist asked was 'maybe that start interrupter'

It put me back about 750 euro's eventually, but hey, I'm a happy geezer. Also, I'm deducting that from taxes so I pay only 375.
After 2,5 months I go drive again! And just in time for the classic car tours in June! It's gonna be great!

THANKS EVERYBODY!

Bill Ball

You get to deduct car repairs from your taxes? Wow! Most 928 owners would never pay any taxes if that were the case here.

So, the problem was part of an aftermarklet car alarm system? Someone usually suggests that right away, at least with complete starting failures. Yours was a bit weirder than usual.

Pretty car!