GolfGTIforum.co.uk
Model specific boards => Golf mk2 => Topic started by: H981CVV on 23 March 2008, 10:18
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I've got a H plate 16v golf, it likes to hunt for idle, when the engine is dead cold its okay for a minute but once it has been going for a minute it rise's and drops between 100 r.p.m, so 950 - 1050, now i've been playing with it for a while an am slowly running out of things to try with regards to what forum members have suggested. ive carried out the following work with no success :-
clean out i.s.v really well, checked wiring then tried a different one which i also cleaned and new it worked.
cleaned all the breather pipes, removed and blew through etc then connected and checked for leaks.
removed the 3 temp senders on the side of the head and checked that they all worked with a multi meter, cleaned and refitted.
replaced both sets of injector o rings with genuine volkswagen replacements, and cleaned injectors.
replaced the control unit behind the dash with a new one.
replaced the module in the scuttle panel with a different one that i no worked.
new plugs, leads, cap, and basic bits.
and it still does it!!!! what else can i try? replacing the warm up valve? enrichment injector?
please help
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I had an idle problem a while back. Weirdly, mine was solved by an oil flush and change as the oil was contaminated and the [excess] vapour coming from the crankcase breather was screwing the idle up. :undecided:
Anyway, during my attempts to solve it I made a fairly comprehensive list of idle possibilities:
http://www.golfgtiforum.co.uk/index.php?topic=71501.msg569972#msg569972
From your list, I would say the most likely culprit you've not mentioned is the idle switch!!
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okay thanks for the speedy reply, i give it and oil change every 3000 miles and it doesn't seem to have a bearing on idle, it had a new idle switch fitted due to failure which i forgot to mention, once its warm i.e oil 100 degrees it idle okay. Could this switch be so incorrectly set up that i will still cause this? i was under the impression that its just pretty much plug and play. Also the o ring on the idle screw, i take it this is the brass hex screw on the throttle body can you completely remove it and check it then just replace it but how do you put it back where it was? screw it in all the way and count the turns?
Also that list is great, i did put a different e.c.u on it that i new worked okay.
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have you had the timing, CO and idle set up correctly?
Changing all those bits will have altered any setup you had anyway.
Take it to a MOT testing place or garage and ask them to set it to 2%CO and idle 1000 +/- 50. (Crackcase breather unplugged and airbox hole blocked, RED SPADE connector at coil disconnected) timing should be 6BTDC, if std.
If it still won't settle at a steady idle, another to try is the ISV control module under dash.
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Also the o ring on the idle screw, i take it this is the brass hex screw on the throttle body can you completely remove it and check it then just replace it but how do you put it back where it was? screw it in all the way and count the turns?
From what you said above, it sounds like Rowlers has hit the nail on the head. Get it setup at a garage, although you can have a go yourself too:
http://www.golfgtiforum.co.uk/index.php?topic=22031.0
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If that doesn't work try swapping the three temp sensors on the end of the head under the dizzy around. It's the most random solution ever but fixed my erratic idling a treat :)
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check the resistance at the WUR!
you might have to change the whole thing!
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i've check the three temp senders on the head and they are all fine! im going to check the o ring for the tick over screw and if thats okay i will have the co2 set up properly. hopefully it will be okay. i will keep you posted.
Ben
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i have just noticed that in the co2 adjustment post, it stats that if the engine isnt hunting when hot or cold the co2 is correct, mine is fine when cold and fine when hot so has this ruled out co2? also when it is idling okay the r.p.m drop nice and steady to the correct 1000 + - 50. so does this all point to the bypass screw o ring?
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i've check the three temp senders on the head and they are all fine! im going to check the o ring for the tick over screw and if thats okay i will have the co2 set up properly. hopefully it will be okay. i will keep you posted.
Ben
Have you swapped them around. Definitley one to check, mine all looked fine but one of them when connected to the dash was red hot then freezing cold then red hot etc. Got a new one from ECP and it sorted it out.
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yes, i have switch them all around and thought i had cracked it then the next morning it was the same.
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...mine is fine when cold and fine when hot...
Eh? Is it fine or not??
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no its not fine anywhere in between, like i said. It idles okay for a few minutes when dead cold and once dead hot i.e oil temp 100 degrees it idles okay aswell, but constantly in between these two engine temps it hunts. Now as far as i can make out in the co2 adjustment post it clearly stats that if it idles okay when dead cold or hot the co2 level sounds right.
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Ah, gotcha. Thats a tricky one.
If it was me, I would double check your temp senders, then double check ignition timing, then have the CO2/Idle setting properly done. (But thats just a guess)
A good way to check your temp senders is to get the car up to temperature, then swap the dash temp gauge wire over each of the senders and see if you get exactley the same reading. This doesn't check the wiring of the two other temp connectors though!
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I am not too clued up on the Kjet system, but to rule out the breather system, remove the breather pipe from the plenum or induction system and block the hole, and let the engine breathe overboard, then take the car for a spin. If that cures it, then the engine may indeed have a breathing problem, that could indicate rings or crankcase compression, or both.
Another thing you can try is when the engine is nice and warm, spray WD40 around the injection\induction system. If you have a vacuum leak, the revs will go up and the engine will react with the spraying.
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Might want to look at things like the injectors. They only have a life of 80-90k in the first place so are probably due for replacing, plus its not a bad change anyway as you will find the engine increases in power afterwards. Could be as simple as the injector spray isn't very good during warm up.
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thanks for your replys, im going to have another stab at it tomorrow and see how i get on. Check air bypass o ring, double check temp senders on head, and if all else fails get some new injectors?!!
anyone have an idea of how much a new set of genuine injectors is?
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Anyone have an idea of how much a new set of genuine injectors is?
Don't buy genuine - I bought merc brass one's off ebay for about £17 each, plus they are supposed to give a slightly better spray pattern. Email this seller and ask which one's will fit a Mk2 16v...
http://stores.ebay.co.uk/LR-SPARE-PARTS
PS... Then you can say you've got the same injectors as a Ferrari Testerossa!!
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Just to add... Purely an opinion, but I doubt your idle issue will be due to your injectors.
If you want to test them, you can pull out each one in turn, pop it into a clear jam jar, bridge the fuel pump relay, turn on the ignition and then lift the metering head plate to cause them to spray.
This is highly dangerous though. Put it this way... When I did it, I had a fire extinguisher VERY close to hand at all times!!
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thanks, but after inspecting the condition of the injectors, cleanin them, and the fact that even before you said i believe that the problem seems far more simply than major injector issues i think that i can safely say it was a loose fitting air bypass screw o ring. even though the condition of it seems okay i think it might have been a bad fit. im just waiting for tomorrow morning to double check its cured it, as i obviously had to get the engine warm to set the idle properly and when its warm it idles fine!! hopefully its cured it but i wont hold my breath.
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you will not cure this idle prob without getting the CO and idle set up on a gas tester! The K-Jet just can't cope with random changes to it bits!!!
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i definatley will get the co set up, but it the guide on here as ive said before it reads " if it idles fine when hot or cold the co2 level is okay" and as mine idles perfectly when cold and hot and only has issues when warming up surely this means the co is correct. plus all ive change is the injector o rings so surely this wont alter the co2 drastically as the condtion of the old seals was almost perfect.