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Engine management light


Lubilu
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Hi all,

Im posting this for my gfs 2003 1.0 lupo SE.

The engine management light came on and stayed on, so we took it to be scanned by our local friendly VW specialist. The faults came back as - mulitple random misfire on cylinders 1, 2 and 4. However the car ISNT misfiring!? So we reset the codes and the light went off until rev'd. We then had the coil pack changed and reset the codes again. Everything was ok for a day or so then the light came back on. So we tried a different brand coil pack, when i fitted it I hooked it up to VAGCOM and reset the codes. Again it went out for a day or so, then it came back on again??

Bear in mind the car isnt actually misfiring, judging by A) the VW mechanic, B) another mechanic at another garage and C) me. Its just gone through an MOT and the emissions were spot on.

The light seems to flash when going the motorway and my gf says it seems to flash whilst going downhill - coincidence/related?

What else could it be?

We've ruled out the coilpack, it cant be the lambda sensor as its passed its emissions (with the light still on). The chances of 3 spark leads or plugs being faulty at the same time is very slim.

Any ideas guys/gals. Anyone else had this problem?

Any help appreciated. :)

Edited by Lubilu
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It doesnt take much of a missfire for the ecu to pick up on this,

sorry to be the bearer bad news but it may well be valve seats as we see quite a few of these now, we take the head off and re-grind the valves

I would always check the compressions first though just incase it is plug leads etc

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change all your plugs plus clean throttle body mate to be safe, see if that solves it. could possible be a faulty lead as well.

Andyp - I assume you're referring to one of the HT leads. Ill do the above and see what happens.

It doesnt take much of a missfire for the ecu to pick up on this,

sorry to be the bearer bad news but it may well be valve seats as we see quite a few of these now, we take the head off and re-grind the valves

I would always check the compressions first though just incase it is plug leads etc

'We take the head off and re-grid the valves' - Im judging you're a mechanic, going by how you said that, Is the above a common problem?

The car seems to drive fine though, and if you rev the engine at idle theres no inkling that its misfiring, Its an odd one.

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Andyp - I assume you're referring to one of the HT leads. Ill do the above and see what happens.

'We take the head off and re-grid the valves' - Im judging you're a mechanic, going by how you said that, Is the above a common problem?

The car seems to drive fine though, and if you rev the engine at idle theres no inkling that its misfiring, Its an odd one.

Yes im a VW technician, it is quite a common problem, with certain engine codes you can put it onto the diagnostic machine and monitor the amount of missfires the engine is doing whilst idling, sometimes these can be so slight that you cannot notice it just by listning to the engine, but the ecu can pick these up by the engine speed sensor checking the difference between the crankshaft rotation speed on each cylinder firing.

But dont totally rule out HT leads , try the leads first as its the cheaper option and go from there.

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change all your plugs plus clean throttle body mate to be safe, see if that solves it. could possible be a faulty lead as well.

^^^What he said. The plugs are due to be changed at 4 years or 40K, whichever comes first. I used NGK BKUR6ET-10 plugs, and noticed it idled smoother straight away (car was 4 years old with 22K miles)

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ANY LIGHT NEVER SEEN IT COME ON... ITS MENT TO BE ON WHEN YOU START UP ???

yeah the engine management light and the EPC lights will come on when the ignition is switched on. They will go out after a couple of seconds of the engine being started

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the engine management light and the EPC lights DONT come on when the ignition is switched on ?? Is my car ****ed works fine ???

either that or someone has taken the bulb out lol

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yeah somebody is way ahead of the game lol

oh by the way i had the same problem just changed my brake light switch and it fixed it that was just missfires on the diagnostics too but the guy at autohaus said that it might be it being as my brake lights don't work

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  • 2 weeks later...
yeah somebody is way ahead of the game lol

oh by the way i had the same problem just changed my brake light switch and it fixed it that was just missfires on the diagnostics too but the guy at autohaus said that it might be it being as my brake lights don't work

Really? :confused: Ill take a look but its doubtful.

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if you dont have any brake lights then its your switch, i cant see having no brake lights causing a misfire. Have yoyu managed to do any of the stuff mentioned bar the post regarding the switch?

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if you dont have any brake lights then its your switch, i cant see having no brake lights causing a misfire. Have yoyu managed to do any of the stuff mentioned bar the post regarding the switch?

Unfortunately not, no. The girlfriend uses the car alot on an eve so its hard to work on unless its the weekend and thats if nothing is happening. It'll get done... eventually lol

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  • 2 months later...
Unfortunately not, no. The girlfriend uses the car alot on an eve so its hard to work on unless its the weekend and thats if nothing is happening. It'll get done... eventually lol

Right guys, wait for this. After weeks of being unable to sort this problem, it looks as though its sorted. The girlfriend got in the car and went to work, on getting back in to go home she discovered the car wouldnt start. A quick ring to the RAC and they said it was the battery, so £50+ later the old apparently drained battery was replaced by a "RAC" battery :lol: Now the light has gone off since having the new battery and hasnt come back on. I can vaguely see why the drained battery could make the engine management light come on, with the ignition sys etc being electric and if the battery is weak.... maybe i dunno, possibly someone could elaborate on that.

So end of problem. Shame we're £60 down for buying a new coil pack. Oh well...

:D

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