Engine starts and runs for 3 seconds?

[mcandmar]

Looking for ideas on what can cause these symtoms. Engine cut out last night while driving, any time i restart it will run for 3-4 seconds then cut out again. Dosent matter if i let it idle or hold the throttle open. For those few seconds the engine does run as normal.

Verified the fuel pump is running, and all fuses are fine. Thats about as much as i could do stuck on the side of the road in the early hours of the morning

Cheers,

Mark.

[Skull]

immobilizer?

[S2central.net]

factory immo cuts in quicker than that. Is this on the 7A CQ or the AAN ?

Either way - is there aftermarket immo fitted ?

[pixsaudisex2]

would that not be what happens when a boost pipe comes of ..

[mcandmar]

Sorry it’s the 7A, no immo. Just before it cut out i had come over a hump backed bridge rather quickly, the force from the landing is probably related as it died moments after.

Are there any timing sensors that are only used when the engine is running? i.e. not used for start up.

[S2central.net]

Oh you've been out yumping again in them thar Wicklow hills again - haven't you milado

Oh this is an odd one - I'm no expert on the 7A ECU (MPI system) but it would be very weird if one or more sensors could be broken to allow the engine to start then it die in steady-state.

If the yump has broken something isn't it likely to be a connector, earth strap or something similar got dislodged on the bump... Or at a push - big physical shock on the MAF wire might have damaged it - big stretch there or maybe its just got a bad connection.

If its a sensor gone o/c then VAGCOM or blinks should find it !

[Acidburn]

That is wierd, you've checked the fuel pump which is what I would have suggested first, probably best bet is to have a look under the bonnet for something loose, possibly the earth points on the im.

Did you get any pics or vids of your jumps?

[mcandmar]

Aye was out for a little midnight run at the time :mischeif:

I'll get stuck in tonight with Vagcom and see does it show anything, i couldn’t see anything obvious last night but it was so cold outside and just wanted to get home. Thought it was worth asking incase the symptoms were familiar to anyone..

Cheers anyway, Mark.

[urquattro-island]

have

you looked over the fuel lines?? bent, busted???

[Animal Mother]

you looked over the fuel lines?? bent, busted???

I agree, sounds like fuel vacuum to me too.

[topsparky]

isn't there a cut off switch that breaks on impact so fuel does n't pour out
in a collision
i know vauxhalls and fords have them
not to sure on vag

[mcandmar]

You guys were on the money, it was the fuel pump relay. Fuel pump was doing its prime when you turn the ignition on but wasn’t coming on again when the engine started. Took me a while to figure that out as i can’t normally hear the pump over the noise of the engine.

All sorted now, thanks to ebay i had a spare set of relays

Cheers, Mark.

[Acidburn]

Glad you sorted it and it was a wierd problem, take it to find out the problem you just listened to hear the fuel pump prime or did you listen for clicks from the relay?