just fully rebuilt a gt engine stuck it my mk2 and it was fine but the timing was out so i set the timing up.

now when you start it, it idles for like a min then wont idle for a min then its fine after that.

also the idle screw is all the way in but it idles at like 950rpm.

if i start it from cold with the blue temp plug off it will idle lol

put a new blue temp sender on it and see if that helps

put a new blue temp sender on it and see if that helps

i was thinking that but its strange how it was working like 2mins before i done the timing.

I think you have an air leak mate.

Check the ISV pipe that goes under the inlet, this happened to me a few months ago.

It would idle high with the idle screw all the way in and when unplugging the blue temp sensor the revs wen't lower when it should go higher..

Also it would idle better when the timing is out as you can control the idle speed by putting the timing out (obviously not the way to do it ) I noticed mine worse when i did the timing.

Edited 30 May, 200917 yr by carver

ok mate cheers i was thinking air leak so where does this pipe go to?

Theres a pipe that goes into the air elbow (on top of the throttle body) follow that down under the manifold and you will see it has a T-peice on it, one part goes to a the manifold and one goes to a weird looking device thats mounted to the waterpump pipe.

ok cheers ill try that when i get home come. how did you find the leak? could you see it?

I squeezed the pipe and the idle wen't down so I knew then it was leaking. You have no chance of hearing or seeing it due to other engine noises, so your best off trying to feel for leaks or squeeze the pipe.

right iv squeezed all of the air pipes and iv had no luck, then iv sprayed brake cleaner on all the inlet parts with still no luck

any know what this could it only doesnt idle for a minute half way through choke and idles at about 900rpm with the idle screw all the way down + the revs will differ sometimes

it does sound like an air leak but i cant find it.

idle control valve?????

Definetly an air leak mate Otherwise impossible to have that screw all the way in and still run.

The ISV might have stick open so might be worth checking that.

Aha! Carver, you may have pointed the finger to my misfire!

Just tried the idle screw - it was 3/4 of a turn out. Screwed it the whole way in and the engine still ran, albeit lumy at ~ 750rpm. Ran from cold all the way to 90 degrees with the screw in.

So... I guess we're thinking of an air leak past the throttle body? Throttle body gasket, inlet manifold gasket, ISV and hoses, brake servo hose, fuel injector o-rings...?

How can you check for these? I heard of the propane torch method...

(sorry to hijack AdrenalinSeeker, but we may have the same issue)

Definetly an air leak mate Otherwise impossible to have that screw all the way in and still run.

The ISV might have stick open so might be worth checking that.

sweet ill try that can this be cleaned out or is it worth buying a new one?

i take it, its the valve that bolts on the waterpipe?

also was having a quick look today and when i unplug the blue temp it does rev higher

Aha! Carver, you may have pointed the finger to my misfire!

Just tried the idle screw - it was 3/4 of a turn out. Screwed it the whole way in and the engine still ran, albeit lumy at ~ 750rpm. Ran from cold all the way to 90 degrees with the screw in.

So... I guess we're thinking of an air leak past the throttle body? Throttle body gasket, inlet manifold gasket, ISV and hoses, brake servo hose, fuel injector o-rings...?

How can you check for these? I heard of the propane torch method...

(sorry to hijack AdrenalinSeeker, but we may have the same issue)

no worrys mate iv been following yours to get some clues on my problem

anyone got a part number for this isv cant find it on vagcat

026133453 I think

VAG cat does have it, though not the easiest to find

Polo/Derby

1994 (in my case)

Engine

Intake System

By what method did you set the timing? There's a FAQ on here showing the proper way to do GT's, just strobing it to a single setting doesn't work, as the ECU won't understand the extent to which it's adjusting the advance and retard.

By what method did you set the timing? There's a FAQ on here showing the proper way to do GT's, just strobing it to a single setting doesn't work, as the ECU won't understand the extent to which it's adjusting the advance and retard.

arr i didnt set it in service mode i will try that but have i now put fault codes on my ecu? will i need the diagnostic plugs?

would i have falt codes on my ecu?? is there anyway of get them of without diagnostic plugs?

bump

I have drove my GT for months with fault codes on it and it wasn't any different once I cleared them to be honest. As long as you sort the problem obviously

cheers

right iv have a proper good read over the FAQ

now because my timing is set up can i just put it in service mode and take it out to get the timing done? then follow the idle settings

also it says that you should dissconect the cam breather is this rely needed?

cheers

cheers

right iv have a proper good read over the FAQ

now because my timing is set up can i just put it in service mode and take it out to get the timing done? then follow the idle settings

also it says that you should dissconect the cam breather is this rely needed?

cheers

right y-day i put the car in service mode and set the idle just how the FAQ says, the idle screw is not all the way down now so i took it out of service mode and the revs went up :s they went to 1200 then slowly came down to 900 but it does this all the time when i come off of the throttle some times it stays at 1000rpm now the car is poping and farting at low revs and smells like its running rich and still wont idle for about 2mins at start up.

beause i put it in service mode do you think that the ecu has read the timing now? oh yes and when i take the blue temp plug off now the revs go down:S

and is the anyway of checking that the ISV valve and blue temp sender?

In my experience if the revs go down with the blue temp out you have an air leak. The ISV only should be working when the engine is cold, after that it shuts and has no use iirc. The best way is to remove it from the pipe its bolted to and run 12v through it while looking inside it.

ok cheers will this explain the poping and farting? or could that be down to the blue temp?

any ideas how I'm going to get 12v through the ISV?

also you said the drop in revs when the blue temp is off is due to an air leak, so will this ISV be causing this or not?

cheers

Edited 21 June, 200917 yr by AdrenalinSeeker

If the ISV is stuck open due to the crap they collect then yeah it would cause it. I tested mine by putting two wires on my bettery and connecting it to the ISV pins. It took me a while to find my air leak and i was driving for about 500 miles with it and it felt alot better after, idled perfect and even quicker because the mixture was more accurate.

It could be causing the poping and farting although with mine it only made the idle high even with the mixture screw all the way in. But it did make it hunt like crazy and do some weird things.