Not your typical cutting out problem

[andykram]

91 Mk2 16v

This is an unusual one. I know all about the usual cutting out and idling problems but see if you can work this one out.

First thing in the morning the car starts up no problem. Within the first half mile (always within this distance) it sometimes cuts out. It does this while moving, not at a standstill nor even with the clutch dipped. The battery light comes on and the oil light flashes. I have to pull over, start it up and off we go again. it does it either once or twice then it's absolutely fine for the rest of the day, even when it's been stood at work all day.
The unusual bit is that it doesn't do it every time it's used. This morning, for example, it was absolutely fine. Yesterday, it did it the twice and was then fine.
It's just had a big service, ISV buzzes as it should, once it's settled it idles solidly at 1000 (it's a bit up and down for the first five minutes) and in all other respects is fine. O, the only other thing I can think of is that the battery went flat recently when I didn't use it for two weeks so I now keep it on a trickle charger when I'm not doing to use it for a few days. However, it was cutting out before the battery went dead anyway.

What the chuff is going on?

[mk2bal]

I'd go over the lot if I was you. Check all wiring, engine and gearbox earths are all m+e sound, check battery connections are good, check overrun valve for function and secure-ness (they can hold open, and come loose), check inlet boots for splits, use carb cleaner to assist you with this.. Check all temp sensors and terminations of them on side of head. I'd basically pull/tug/ inspect everything you can under the bonnet, as you may have a loose connection somewhere right under your nose. Not saying you haven't already, but some people don't look over things 1st, they just ask here what's wrong. My 16v runs sweet as a nut, and doesn't miss a beat, but from when it was installed everything has been proved/tested along the way, and nothing seems to give me grief. There's plenty of test methods available for testing certain 'suspect' items..

[KRdubber]

what he said p.s my valver did the same but i traced it to isv temp sender.

[SoundillusioN]

Just my 2 pence worth but I had almost exactly the same symptoms that totally stumped me and really started annoying me... Turned out to be a corroded earth strap from battery to body.  Battery side looked fine, mounting to the body was fooked.  Replaced it and it never happened again.

[KRdubber]

another thing check your hall sender isnt loose/cracked.mine did the same.with the engine running just wiggle it a bit and see if it cuts out but be very gentle with it.

[andykram]

Thanks everyone. I'm sure it will be something really poxy or loose, particularly because of the fact that it doesn't do it all the time. I will do some checks and report back. It's the only thing at the moment that's preventing this car taking on epic status!!!!

[andykram]

Thanks everyone. I'm sure it will be something really poxy or loose, particularly because of the fact that it doesn't do it all the time. I will do some checks and report back. It's the only thing at the moment that's preventing this car taking on epic status!!!!