injector stuck open..i think? 16v

[patersom10]

hi Guys,

I think I have a problem with a stuck open fuel injector, the other day I was driving along and it started revving by itself. it then seemed as if the engine was flooded and cut out. it will start but the revs go up and down on there own with alot of smoke coming from rear of engine, i put some more fuel in with injector cleaner in last night and started it, I got alot of smoke and it swallowed up the fuel straight away.

does this sound like a stuck open injector to anyone, the oil and coolant are fine.

would be greatful for your thoughts..

thanks, M

[Kitch]

Sounds more like a jammed fuel pressure regulator to me. Can't see one cylinder being able to speed the whole engine up - I'd just expect a misfire if the injector jammed (which I've never heard of happening before).

[mat_fenwick]

An engine won't rev without air - you must be getting an air leak somewhere after the throttle butterflies.

[docchevron]

what colour was the smoke?

[patersom10]

white, it happend before but cleared on start up, has done 800+ miles since.

[Way2go]

the other day I was driving along and it started revving by itself.

That sounds like the 2nd butterfly in the throttle block is sticking open. This butterfly returns only under spring pressure but if the shaft is dirty or dry (needs 3in1) then it does not always return to closed when the main control butterfly is barely open or closed.

[mat_fenwick]

This butterfly returns only under spring pressure

I didn't realise that - I'd assumed they were just linked together!

[patersom10]

thanks, I best take it apart and have a fiddle. cheers guys.

[Kitch]

This butterfly returns only under spring pressure

I didn't realise that - I'd assumed they were just linked together!

The staggered opening ones are (which weren't fitted to 16vs), but some of the others have one that is opened by the primary butterfly but closed by spring pressure.

[Way2go]

This butterfly returns only under spring pressure

I didn't realise that - I'd assumed they were just linked together!

The staggered opening ones are (which weren't fitted to 16vs), but some of the others have one that is opened by the primary butterfly but closed by spring pressure.

I knew this problem from when I put the GTi back on the road after a lay up but a clean and 3in1 sorted it. Although mine is an 8v Gti it does have the Motronic 3.1 with a MAP sensor so I am assuming that it has close similarities to the 16v in this regard.

[Kitch]

I knew this problem from when I put the GTi back on the road after a lay up but a clean and 3in1 sorted it. Although mine is an 8v Gti it does have the Motronic 3.1 with a MAP sensor so I am assuming that it has close similarities to the 16v in this regard.

Most 16vs are ML4.1, or 1.3. Think 3.1 was the cat-equipped cars. But I've seen butterflies of differing brands on all sorts of cars. Had a staggered one on mine until I realised it was sapping power!

[Way2go]

I knew this problem from when I put the GTi back on the road after a lay up but a clean and 3in1 sorted it. Although mine is an 8v Gti it does have the Motronic 3.1 with a MAP sensor so I am assuming that it has close similarities to the 16v in this regard.

Most 16vs are ML4.1, or 1.3. Think 3.1 was the cat-equipped cars. But I've seen butterflies of differing brands on all sorts of cars. Had a staggered one on mine until I realised it was sapping power!

Yes realised 3.1 wasn't on 16v's but not for cats I don't think as mine is just pre-cat. Nice thing about 3.1 is that it works with wasted spark so no troublesome dizzy either. Engines always been smooth and responsive on this better than a previous jetronic.