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Model specific boards => Golf mk2 => Topic started by: jezza16v on 06 May 2010, 20:03
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Hi all, 89 small bumber 8v digi, 170k. When starting up from cold it always runs on 3 cylinders for a few moments then catches on the 4th. Its No1 cylinder thats not firing straight off, I replaced the plugs a couple of months ago which seemed to cure it for a short while, but the problem came back again, I replaced the rotor arm, dizzy cap and leads today but it fired up on three just the same and then settled down just fine. I took the plugs out again and No1 was very dry and tight to get out, the others had slightly oily threads and came out really easily. I've checked the coolant, it seems fine and clean, no mayo in the oil etc. no white smoke, nothing to suggest a HG problem, in fact it ticks over smoothly and runs very well. Just wondering if it could be a sticky injector, if there is such a thing?
Any ideas as to the cause of this problem would be very welcome. :undecided: (BTW tried a search but nothing quite like this)
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At 170k your injector flow rates are likely to be all over the shop and I suspect the injector on No.1 is a bit slow to wake up, which is what's causing your initial poor running.
Fit new injectors and while you're at it, check the wiring is sound.
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Thanks, I've never had injectors out, is it a difficult job?
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No.
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I had a similar issue and it happened to be one of the valve seats that had become dislodged and thus stuck open. The problem started off rather sporadically but got continually worse, to the point that it wouldn't start at all. My engine was on around 175k when I developed the problem, so chances are it could be something similar for you. I also went down the route of thinking it was the injectors at first, only way to make out for sure is to take a closer look in the head.
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compression check the engine with the throttle wide open - no more than 3 bar differance between cylinders , if no 1 is way down then then Rings could need replacing, once it warms up the rings expand and compression comes up and it starts firing.
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We replaced No 1 plug 'again' and it seems fine now, the last plug only went 2k, will have to keep an eye on it to make sure there is nothing causing it to eat plugs :undecided:
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I have the same problem with my 1.6 driver - hope u find the solution
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Hi
I have this on my 16v, also plug 1, I did rocker cover gasket thinking somewhere inside was spilling oil into the plug, may I add it ain't solved the issue, keep at it can't be that hard to sort, :cry: can it
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Well, the new plug lasted for 6 days and now we're back to the same problem. Reluctant to change the plug again as it only misses for about 10sec on startup. Will keep scratching our heads and see what we can come up with, perhaps check out the injector next. Any other ideas most welcome.
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whats it actualy doing to the plug on numb er 1 any chance of pics
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Well, nothing thats obvious, it just looks the normal browny beige colour, mind you I have not taken the latest one out to inspect it yet. As said, it only fails to spark for the first 10 secs then its fine. Were thinking that maybe there is the sligthest HG leak so that under sustained coolant pressure as it cools down overnight there is steam/water weeping into the cylinder so that its damp on the morning start, that might explain why the plug threads were rusty and the plug was a bu**er to get out. The trouble is there is no obvious sign of mess in the coolant at the moment and no significant coolant loss. Will have to take the plug out before the morning start over the w/e and see if its wet? Will also investigate the injector but can't see this as a new plug cures the problem instantly for a few days it seems.
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Just an update for you on this old topic for future reference. We just took the head off and there was a very small leak track of coolant across into No1 cylinder and the piston & valves were pretty black. Also the usual pinky brown residue had a black coating and around the inlet valve it had sort of foamed up into white clumps which disintegrated when you touched them. It seems our original guess at the problem was right after all. The head is pitted slightly where the coolant has been leaking across it so we're going to have to get it skimmed. :sad: