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Sudden, temporary, loss of power

Ewan

Ewan

New member
Driving home tonight I stopped at some lights. I pulled away when they changed, but after about 50 yards the engine suddenly cut out. On about the fifth attempt of turning the key, over a period of about 30 seconds, the car restarted and drove perfectly.

But only for about another mile, when the same thing happened again. I was doing about 15 mph in second, just pulling into the gym car park, and it died again. This time it restarted quicker - maybe on the third attempt.

After my workout the 2 mile journey home was fine. But obviously something's wrong.

Your thoughts/advice please!
 
DME Relay located in the fuse and relay box, classic symptoms, change i,t they are circa £23
 
DME was replaced about a month (200 miles) ago - so is presumably okay. FPR was replaced about a year (1000 miles) ago - so hopefully also okay.

But the car is due an oil change service and replacement fog lights, so I'll have the garage check while it's there.
 

ORIGINAL: Ewan

Driving home tonight I stopped at some lights. I pulled away when they changed, but after about 50 yards the engine suddenly cut out. On about the fifth attempt of turning the key, over a period of about 30 seconds, the car restarted and drove perfectly.

But only for about another mile, when the same thing happened again. I was doing about 15 mph in second, just pulling into the gym car park, and it died again. This time it restarted quicker - maybe on the third attempt.

After my workout the 2 mile journey home was fine. But obviously something's wrong.

Your thoughts/advice please!
Click to expand...

Is the idle stable when its running?

is it still on the AFM or has it got a maf?
 
The idle is steady, at about 950rpm. Still running AFM.

Think I'll take a different car to work today. It's not fun sitting in the middle of the road with no means of propulsion!
 
When I first had my coupe it would cut out occasionally and usually restart, DME relay improved it for a few months but then it returned - It was the coil failing - It was worse in hot weather.

Other things are may be a loose flywheel sensor or a faulty alarm. Over fuelling I would expect to be accompanied by black smoke, under fuelling I would expect to affect the idle, either should show up on the plugs.

My cab very occasionally looses power and will not rev at all but it will still tick over, unplugging the AFM and replugging cures this, I need to investigate it, the wiring to my AFM looks quite kinked and the top hasn't been off but its only done it twice in c5,000 miles so its a round to it job.
Tony
 
Sounds electrical to me, fuel type issues have always caused poor running in my own experience, where as sudden cut-outs have been electrical. Unfortunately that does not narrow it down much. It would be easy for an auto electrician to find if the car failed to restart and they were able to test in in the faulted condition. Are you in the RAC/AA, they could also diagnose it if it lets you down when you're out and about.
 
Minor comment - the fact that your DME relay is nearly new does not mean that it has not failed. As they are quite cheap and it is useful to have a spare one in the glovebox, you might invest in another one just to rule that out.
Another problem area that I had was a duff alarm/immobiliser system - common problem as usually these cars are on their 3rd or 4th aftermarket system...
 
Thanks for the contributions. I'll certainly try another new DME - cheap, and can't harm.
 

ORIGINAL: 944Turbo

When I first had my coupe it would cut out occasionally and usually restart, DME relay improved it for a few months but then it returned - It was the coil failing - It was worse in hot weather.

Other things are may be a loose flywheel sensor or a faulty alarm. Over fuelling I would expect to be accompanied by black smoke, under fuelling I would expect to affect the idle, either should show up on the plugs.

My cab very occasionally looses power and will not rev at all but it will still tick over, unplugging the AFM and replugging cures this, I need to investigate it, the wiring to my AFM looks quite kinked and the top hasn't been off but its only done it twice in c5,000 miles so its a round to it job.
Tony
Click to expand...

I had the same issue, unplugging the connector and spraying in some wd40 seemed to cure it. Eventually changed to a MAF and never had the issue again so I would blame the AFM and not the wiring in my case, I'll bet it's the same for you.

Stuart
 
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