As title, the situ is a bog standard Mk2 Golf 16v on K-Jet. I'd like to sort the idle on it. It will start, tick over fine. One on the move though, when lifting off up to junctions, it stalls, so it's a real occupation heeling / toeing to keep it running. What should I be looking for to fix this? If it were a carb, I'd be looking for a blocked idle jet or air leak on the idle circuit, but this is K-Jet...
I THINK it's the throttle micro-switch not operating Chris as I've been having similar problems, but I await a CGTI Mekon to turn up with some facts.
I've just had a similar issue, though it wouldn't idle/even try to catch the revs at junctions so perhaps the cause is different? Anyway, long story short, i used some injector cleaner (as it was to hand) to clean out the isv and fortunately its near enough returned it to how it was before. I followed the advice on here for cleaning but soaked, shook and repeated over 48hrs as the first couple of goes didn't shift much muck. Trouble is it seems like it can be a multitude of things with this issue but given how simple it is to clean the isv i'd make it one of the first things to do beyond the very simple inspections.
mine did this and it was the over-run cut-off valve. disconnect the plug to it and see if it still does it
I'm bad with the terminology on these - is it this we're talking about? Found behind the Metering head, attached on a capillary line + 2 prong plug:
thats the cold throttle enrichment valve, the over-run valve is in the same area but is the black plastic one oh and make sure the plugs are the right way round, the over-run valve has a plug with yellow/black and black/brown, the cold throttle valve has a black and a white wire
Thanks for the responses. I've done a search around the forum, and there seem to be a few idle-issue threads! In amongst them, I found the suggestion of checking the coolant temp sensor for the ecu on the side of the head. Agree/disagree? So the plan is: - ISV (never touched one - is there a cleaning thread around?) - disconnect over-run valve - check over-run valve wires not swapped with cold start enrichment - swap coolant temp sender for ECU
yep, also do the same for the isv sensor. there are 3 single pin temp sensors on the head, one for ecu, one for dash and one for isv unit. make sure all 3 look good and wires ok, look at the resistances and try swapping the dash sender wire about and see if the reading on the cluster changes. with the isv i leave them buzzing and submerge in petrol, white spirit, thinners or whatever and give a shake to clear out the crud. sometimes does the trick! also check the idle switch linkage. the lever which presses the switch is indipendant of the main throttle linkage, and it should move feree and spring closed on its own without any assistance. if not take off the 13mm nut and the lever, spring and 2 plastic bushes will come off. clean it all up and refit, taking extra care not to catch the spring in the bushes as it'll stick again. then make sure the throttle always closes to the stop freely, if not make sure cable is in good condition and not adjusted too tight.
Some problem here, I disconnected the 5th injector and the engine stop to do it, it only happened on cold starts, (when 5th injector earth), so I have some electric issue that activate the 5th injector when micro switch is not pressed. Someone know if problem was solved?
if its a later car there is an over-run cut-off valve on the airbox, its a small metal valve. this has a 2 pin plug with black and white wires, plus a vacuum line. It should close only when it detects a hard throttle event, and it should only get voltage from the idle switch when the throttle is open
Hi RJ I think you mean the fuel enrichment valve, the metalic one, now I have this valve disconnected and it doesn't happend so the valve is working properly getting voltage from idle switch when throttle is open and sending it to 5 injector that's the reason why I think the problem could be on the electric temperature probe which sends earth to 5 injector too much time.
edit: oops thought this was another thread I was posting earlier yes sorry the metal one is the throttle enrichment valve I was talking about earlier. the over-run cut-off is there to catch the revs if you lift off at high rpm. its the black plastic one round the back of the airbox.
^^ The overrun valve, bypasses the metering head vane on lift, thus shutting off shut of fuel flow. Similar to a modern car, that cuts injection on the overrun. It's actuation is via the ECU control box. The enrichment valve only works via the throttle switch and manifold depression, during the warm up period as dictated by the thermo timer. This description suggests the diaphragm in the canister may be shot and allowing the enrichment valve to remain closed circuited during warm up.
