Lumpy Idle and Lack of Power (intermittant) 8v

[V33DUB 0]

Ok so I've searched around this forum and (my corrado being an 8v) on the golf gti forum.

 

Problem:

In the last week my car has developed a problem where it is lumpy / rough on idle. The needle move a little up and down but not massively but you can hear and feel that its lumpy. On pulling away there is a definite lack of power / umph. This lasts for about a minute and then all it runs ok until the next set of lights / stop. It seems to be worse at the beginning of a journey. Because of the lack of power I have to really put my foot down to move and there is a slight smell of burning, not overpowering, no smoke etc but a slight smell and this is not on every occasion but I've noticed it a couple of times (could be completely unrelated and as there are other cars on the road could even be one of them!).

 

What I've found so far:

ISV - I don't believe my 8v has one?

Throttle Body - Cleaning. Also I've read that the 16v throttle body has wires that can break, fail... is the 8v the same?

ECU Temp Sender

Fuel Pump Relay

ECU Relay

Oil Breathers

Check Earthing points

 

Do any of these jump out at anyone as being the problem or is there something completely different?

 

Cheers as always guys

[StArRaDo 10]

I'd also start w/basics and pull your spark plugs. Amazing what they can tell you just by taking a good look.

[davidwort 0]

definitely check the temp sender on the front plastic water flange on the head, cheap enough to just replace anyway

do all the usual plug/leads/dizzy cap and rotor arm checks/replacement - again cheap enough to just replace if they are in any way suspect or old

there is an ISV, it's at the back of the head above the inlet manifold

you can check the throttle potentiometer with a multimeter, it's easy to remove and fairly simple in operation, quite cheap new too.

[tentonhammer 10]

I'd say the ISV. As far I'm aware the 8V should have one? Or at least the Golf GTI 8V's do anyway. I could be wrong though.

 

Had a very similar fault recently with my 16V - Wire come away from ISV terminal.

 

Ten Ton

[V33DUB 0]

Cheers people!

 

Ok so...

 

1 - Replace the temp sender on the front plastic water flange on the head

2 - Replace plug/leads/dizzy cap and rotor arm

3 - ISV, it's at the back of the head above the inlet manifold.... What exactly am I checking for?

4 - Check the throttle potentiometer with a multimeter... Got the Haynes manual for the Golf which covers my engine... will the location, removal of this be in there?

 

Thanks again, very helpful

[tentonhammer 10]

"3 - ISV, it's at the back of the head above the inlet manifold.... What exactly am I checking for?"

 

Check for any loose connections / corrosion on ISV terminal etc. Remove ISV completely and clean /soak using carb / brake cleaner, check for signs of wear / gunk etc. Your ISV may need replacing if you've done some serious milage. Check breather pipe, remove and clean if necessary.

 

Best of luck,

 

Ten Ton

[davidwort 0]

this might help, mk2 gti but basically the same layout:

www.clubgti.com/downloads/ISV_clean.doc

[Supercharged 2]

Check plugs and leads first - also look at vac hoses!

[tentonhammer 10]

davidwort - Good guide, I don't see why it would be any different.

 

Pretty straight forward really but man does a faulty / mucky ISV f*ck with things

[V33DUB 0]

Ok so my ady 8v engine doesn't seem to have an isv. Can't see one and according to the Haynes manual it's controlled by simos 4s engine management rather than digifant (2E engine code). ISV is listed in the digifant instructions but not the simos.

 

Got a temp sender, black and green 2 pin listed for the ady engine. Turns out mines a 4 pin black and yellow, listed on etka as for the 2E engine. Right mongrel engine mine! Haha

 

Anyways started to check things today until it started ****ing it down! I took off the air box and maf. Engine runs a lot smoother without them. Does this suggest the maf is the source of my woes or at least rule out anything?

 

Relays are warm after running for half hour so I'm guessing they're fine.

 

Going to remove, clean and check the throttle body tomorrow. Along with checking the leads, plugs, dizzy etc