Need help, engine dying

[dangerousdan]

Ok first off, its a late 1986 Lux model, Oval dash, 2.5 8 valve.

So was running fine then just starts missing as driving along at steady revs, get to cross roads and it dies.

On towing back to workshop find it to have no spark.

Take out crank position sensors and clean up, car fires up and runs for about 5 mins fine and then just stops again, no spark.

Take out CPS again and replace one marked D on the block (one nearest back) with a known working spare.

Car fires up runs again for about 5 mins then just stops, no spark.

Left it over night, starts this morning, runs for 5 mins and then stops... yep, no spark.

I would assume with the CPS they either work or dont work.. so Im guessing something somewhere is giving the ECU a signal to cut the spark.... and after a while its reset itself which allows it to restart....
I've read this topic but theres no mention of no spark.
Any thoughts or ideas or checks I can do please?
Thanks in advance

 

[Eldavo]

Have you tried changing the DME relay? They fail when hot and then work again when the car is cold, as soon as it heats up . . . Fails again, rinse and repeat.

£20-30 from a parts supplier or a vauxhall nova part will fit too. Every 944 owner should carry a spare anyway, Clarks Garage tells you how to make a 3 point jumper lead to test it.

 

[zcacogp]

ORIGINAL: Eldavo
.... a vauxhall nova part will fit too.

Didn't know that ... got any more details?


Oli.

 

[dangerousdan]

Thanks, I did print out the 3 point jumper info earlier after reading about it on the thread I linked to in my original post.
Will give that a try tonight. Wonder if the Corsa ones are same as Nova as have 2 of them []

 

[944 man]

Better to buy the revised Porsche part as the Vauxhall-Opel part isnt a deal cheaper.

New DME relay (its actually two relays inside and either can fail).
New fuelpressure regulator.

Neither of these will be money wasted, even if they arent the actual cause, but one probably will be. New fuel filter too!

 

[Eldavo]

ORIGINAL: zcacogp

ORIGINAL: Eldavo
.... a vauxhall nova part will fit too.

Didn't know that ... got any more details?


Oli.

Not really! I've seen the nova relay for sale around the £10 mark before. It has a metal plate attached to it that needs removing as it bolt to the bulkhead on a Nova (and Astra I think).

I've got a couple of spares already so never looked into it further.

944 Man is right though, FPR and fuel filter will be worthwhile changes anyway but my money's still on the DME.