Gti Keeps cutting out - Help/direction needed

Have a bizarre cutting out issue that as of yet i am unable to solve, could really do with some help as it is driving me mental.

Right… what append was:

Bought my 83' 1.8 gti cabby and realised this cutting out issue soon after, since then this is the relevant work completed:

*New fuel pump & relay
*New main fuel lines
*Full 16v conversion with ISV (incl metering head etc)
*New exhaust system incl manifold
*New fusebox

Problem occurs if you break hard, go over speed bumps a bit quick and sometimes for no reason at all.

The only thing i can think is that it could be an electrical fault in one of the looms or ignition switch maybe.

Anybody have any suggestions?

Cheers

do you hear the fuel pump run on for a few seconds when the car cuts out? do all the dash warning lights come on?

rubjonny said

do you hear the fuel pump run on for a few seconds when the car cuts out? do all the dash warning lights come on?

rubjonny, ello m8. Both answers i will have to check when i get it home tom eve, but off the top of my head:
fuel pump running on - dont think so
dash lights - i think yes

I will confirm tom though, what you thinking buddy?

if you dont hear the pump this would suggest a fuel cut, rather than ignition. if the engine stalls or cuts out due to spark or ignition power to coil or whatever, you will hear the fuel pump run on for a few seconds

the fact the warning lights on the dash came on suggests that the ignition live from the switch is ok, if it was that causing it then the dash would die as well. this isnt 100% proof mind as it could still be a problem in the bay side or a damaged wire to the coil or something.

Right fuel pump does run on but not for long, dash lights come straight on

sounds like a problem with the ignition in the engine bay then, have a look at the wiring to the coil, dizzy and tci-h unit (bolted in the scuttle area, 7 pins on it)  check the TCI earth to the battery -ve as well.

does it bump start if you lift the clutch while moving?

rubjonny said

sounds like a problem with the ignition in the engine bay then, have a look at the wiring to the coil, dizzy and tci-h unit (bolted in the scuttle area, 7 pins on it)  check the TCI earth to the battery -ve as well.

does it bump start if you lift the clutch while moving?

Wiring to the engine bay has been out and redone as part of the conversion so was thinking that would be ok, probelm was there before the conversion.

Do you mean will it bump after it has cut out or generally?

I had a similar experience a couple of times when I'd not driven mine for a while.

I giggled the keys in the ignition barrel and its never done it again. I know it may sound simple (and it is) but think of it this way - if you bunch of keys has a load on them, eventually it will pull on the barrel, especially if its an old one. The barrel becomes worn in normal use also so it turns more easily than a modern car so it 'switches itself off'.

It may have absolutly nothing to do with your problem but it is worth considering before you lay out a lot of money on parts & labour.

Dan

after it has cut out
have a look at the over-run cutoff valve if you fitted the ISV system, on mine it would cut out at random dipping the clutch to change gear, but never when just driving along.  I could restart the engine by bringing the clutch up.  I swapped it for another and the problem was solved!  It doesnt sound 100% like your issue but its worth a look.

this is the black/grey thingy behind the airbox with 2 chunky pipes, a vac feed and an electrical plug. Not the metal thingy on the back of the airbox, thats the cold throttle enrichment vac switch

Right,
I think ive got this problem nailed down but need some input on pin-pointing it.

(For the purpose of this explanation my fuel pump "PRIMES" when i turn on the ignition - aparently not technically correct but life is too short   )

On my corrado when it was still a 16v the fuel pump would prime when you turn the ignition on and had a quite purr to it when the engine was running and fuel was suppled.

Now, on my Mk1 it primes when you turn on the ignition, however if you said it runs for 3 seconds - it changes note after 2secs to a buzz, almost like there isnt enough fuel to complete the prime (nb the main pump & relay is new)

Also if you get the fuel sloshing around in the tank the sound from the fuel pump changes to this loud buzz and then disappears once the fuel settles a bit.

Could it be that the lift pump in the top of the tank isnt delivering enough to the main pump? would this shortage cause it to cut out?
Am i barking up the wrong tree and everybodys pump sounds wierd?

if its an 83 it probably doesnt have a lift pump, pop off the L pipe to the inlet side of the pump and check its not broken down, also while you're there check the inlet side of the pump itself, some have a little mesh basket and if so it'll be full of crud by now.

if that checks out then it could be the swirl pot in the tank has gone tits up, or just you have some crud oin the tank that keeps blocking off the inlet

Def has a lift pump as ive had it out.
swirl pot?

ok ifit has a lift pump then id say yeah, its probably buggered!  swirl pot not fitted to lifterpump mk1s, they use a plastic fuel reservoir next to the main pump instead.

pop the lifter pump out and check the filter on the bottom, if it all looks good gsf sell em for cheapy