1.8T Golf 98 (AUG) running rough

[Jayc530]

It appears as thought it isn't firing on all cylinders. I've changed plugs and swapped coil packs and injectors around to discount them - if I disconnect coil pack for 1, 2 or 4 it makes it worse, if I disconnect 3 it makes no difference.

So I was wondered, other than wiring, what else it could be?

[VAGMAN54]

have you done a compression test ? if it isnt electrical it must be mechanical or it could be the switching of the coil on No3 or the injector switching !

[Crasher]

Also possibly the coil amp on the air box, a big problem on cars with aftermarket induction kits.

[Jayc530]

It's fully standard. If it's a compression problem, why would it have no effect when I electrically disconnect no. 3 coil pack or injector, it still runs rough compared to when I disconnect no. 1, 2 or 4 coil pack or injector?

Where abouts are the other items you mentioned?

Thanks for your help.

[VAGMAN54]

no compression ......no power......i think that should have misfire detection if you scan the car it should confirm which cylinder its on

[Crasher]

That engines ECU does not have misfire recognition.

Does number 3 behave the same if you fit the coil pack off another cylinder? If it does, then I agree, a compression test should be next.

[Jayc530]

Yes it does. I've swapped coil packs and injectors around and it's still the same - if you disconnect 1, 2 or 4 it gets worst, if you disconnect 3 it stays the same. The same is true for both coil packs and injectors.

Would there be any other indications of a compression issue?

What determines the ignition/injection sequence, could it be that?

[VAGMAN54]

if it was an ignition/injection sequence it simply wouldnt misfire on one cylinder it would affect them all and thats if you could get it running

[Crasher]

I agree with what VAGMAN said, you need to do a compression test.

[corbie]

im having the same problem with cylinder three on my car, did you ever get to the back of this problem....