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Car cuts out on MOT brake rollers and won't restart!

NinjaPower

Hockenheim
Joined
24 Jun 2009
Messages
746
Bit of a strange one this...

I have a problem which happens once a year and at no other time :dont know:

Basically, when I take the car for it's MOT, at some point it is dropped onto brake rollers for a test and then the ignition is turned off while it gets the next inspection.

Then it simply won't start.

Immobiliser beeps like it should, ignition lights come on ok, then the key is turned to start and absolutely nothing happens. No clicks, or whirring, or anything at all. Silence.

The car then gets left for 15-20 minutes and then starts absolutely no problem.

I got told by the garage for the last 2 years that it did that during MOT, but I kind of didn't believe them and assumed that they must have been doing something daft with the immobiliser.

But this time I went to the MOT place myself as I was off work and saw it happen!

Any suggestions at all? It has never ever, not turned over before when the key is turned.
 
That is a weird one, and seemingly connected with your MOT garage.

I assume it's the same garage and so is experiencing identical parameters each time.

The cars take quite a jolt when dropping into the rollers - I wonder is there a inertial fuel cut out on 993's that could be getting tripped ?

I once had a great problem with a Fiat that would cut out when going up long hills, but if you managed to get over the top of a hill it would be fine. Turned out the fuel pipes had become restricted reducing fuel flow which was fine around town, but with foot down up a big hill wasn't letting enough fuel refill the carbs.

The point is it might be something really not obvious so try thinking outside the box a little with this problem :)

Lee
 
Maybe alarm immobiliser going into action when the car suddenly jolts and drops. 

Or as samba lee suggested, inertia switch somewhere? But doesn't this just cut the fuel?

Why would they turn off the engine whilst on the rollers? I've never known a tester to do that.
 
RF interference from some piece of test equipment that prevents the immobiliser from fully disarming? The piece of test equipment is switched off and then the car starts normally?
 
^^^ that was my sort of thinking, a bit like car alarms that won't disarm when you're parked near power lines etc.
 
phelix said:
RF interference from some piece of test equipment that prevents the immobiliser from fully disarming? The piece of test equipment is switched off and then the car starts normally?

My Ferrari 360 owners book specifically states that you will get interface with the alarm near certain RF sources, so maybe.

I recall in the 80's watching characters type themselves as the DOS command prompt when the guys in the model shop next to my office fired up their welder.

Lee
 
Maybe its the ABS logic. Front wheels moving without the rears...
 
Do you have a mercury switch as part of the immobiliser? They used to be common in older cars to stop them being stolen by low loaders....it might be triggered by the jolt.
 
"I recall in the 80's watching characters type themselves as the DOS command prompt when the guys in the model shop next to my office fired up their welder. " WOW!!!
 

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