INTERMITTENT STALLING

[Guest]

fivefifty back again unfortunately.

993 C2 TipS, PreVar 1994

Peter Tognola has had my car last couple of weeks and has sorted the Hot Start problem
by replacement of O2 Sensor as all advised. Unfortunately the intermittent stall remains.

Peter will have it hooked up to his laptop next week or so to try to spot the gremlins -
the symptom is engine cutting out completely at any speed, hot or cold which at 70+
on the M4 is not recommended!! It is awkwardly intermittent, sometimes not occurring
for days.

The loom was recalled in '04 and most of the obvious things checked - Peter's looking
at reference sensor function amongst other things, but the problem's proving difficult
to locate.

The wiring loom needed work a year ago when I bought the car, and so I'm suspicious
this could be the cause ...?

Any further ideas welcome....it's a problem that's badly denting the enjoyment
of owning an otherwise fantastic car.....

Thanks
Tom

 

[MrHappy]

I had a similar problem on a B*W I once owned[:'(], every so often the car would stall and grind to a halt (not easy to steer with no power steering!). No pattern to it at all, high speed, low speed, sitting in traffic etc. Sometimes I could start it again straight away, other times it was a ride home on the back of a lorry. B*W had it back several times and nothing would show up on the diagnostics. Eventually they changed the fuel pump and it never happened again. If it's not the DME then it may be the fuel pump.

This also happened with my MG but I used to just hit it with a BFH, not sure I'd recommend it here though!

David

 

[kennyboy]

If it's not the fuel pump, consider the ECU.

 

[Guest]

Another casulty of the same problem also seeking some help!

Mine is a 993 C2 1993

The wiring loom recall check did not appear on the Porsche website, despite coming with paperwork to confirm this had been done, so I took it to Porsche Colchester in 2005 just to check out. The loom had been replaced, but they claimed the fault was the distributor so they changed it, unfortunately the car stalled on the way home, so the problem was not resolved. It went back to my service agent - Autostrasse - who changed the CO2 sensor and the car then ran fine for few months.

Last year the problem started again, normally within the first half hour / 20 miles of a journey, and to overcome the concern of stalling on a busy road, we avoided the usual routine of taking car out of garage - switching engine off to park - then starting up again to commence journey. In the meantime the service agent has been scratching their heads as to the fault cause, as the OBC does not indicate a fault.

Our latest thought is the Porsche Block system - does this have an imobilisor within it that could have developed a fault and is actually cutting the fuel off to the engine? It seems like the fuel cuts out when driving and if you are lucky to bump start the car she just backfires and kicks back in again - if you coast she stalls completely and you cannot start again for approx 5-10 minutes. Has anyone had problems with this alarm system?

Guidance welcome, but my car technical speak is limited.

Many thanks
Sarah Goldsbrough
PCGB Member

 

[Guest]

Hello Maurice,

The DEM relay has been replaced, and at the same time they replaced the fly wheel sensor, cylinder head temp sender, and final stage ignition unit.

When the car has stopped it does not crank when you try to re-start. All you get is a single click sound when the key is turned. It has to be left for a couple of minutes before it will fire up. On one occassion last year in the very hot weather, when the car was pretty hot too, I had to wait for over 10 minutes before it would start again.

To try to explain what actually happens:-

• travelling at a reasonable speed the car with develop a cough / hesitance and then the engine cuts out,
• If you are quick enough you can change gear and bump start it - it will then give a back fire and carry on the rest of the journey no problem.
• If you are not quick enough, you coast, pull over and try to re-start.
• Normally it will not fire up straight away - it does not crank - just a single click can be heard
• Wait a couple of minutes and it starts up fine
• It only happens once on a journey it is not continuous
• It normally happens within the first 20 miles of a journey

It almost seems like two problems - one of fuel starvation for the engine to cut out, and immobisation / electronic when you try to re-start straight away. Hence our latest possible cause being the Porsche Block alarm system?

Hope the description was helpful.

Thank you.

Sarah

 

[zrcg1]

Stab in the dark #1 .....

Bad earth from battery connection? (yes, it does happen on 993's)

 

[zrcg1]

Stab in the dark #2 ....

MAF Sensor?

 

[jboult]

Re: Stab in the Dark #2...

I don't know about other people's experience, but when the MAF started to fail in my 944 it would still crank, it just wouldn't fire (and you could smell the unburnt fuel). Tapping the MAF smartly usually fixed it...!

John

 

[Guest]

Dear Maurice,

Thank you for this suggestion, I will contact them this week. Just out of bizzare interest, took the car to Holland for the weekend, for a charity fun run, she ran beautifully the entire weekend, and not a single cough, splutter or problem at all! It if is the Porsche block system then it could be the actually locking / unlocking that lets it know to switch off - I currently park the car in the garage and do not bother to lock it, so will do this in future as an 'experiment' until the specialists can give me a verdict.

Regards
Sarah

 

[Porker993]

ORIGINAL: MrHappy

I had a similar problem on a B*W I once owned[:'(], every so often the car would stall and grind to a halt (not easy to steer with no power steering!).
David

The worst thing about stalling a modern car is not only do you lose the power steering, but the assisted brakes also. Can be quite a shock ! Hope you get it sorted out soon Sarah.