VR6 Electrical miss...

Started by Number21, June 15, 2012, 02:34:52 PM

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Number21

Hi guys.

I've got an electrical miss in my VR, and it is getting worse so I've got to sort it out. It also idles low upon startup, but the main issue is the miss at low revs. It is a bit intermittent, but it is now fairly frequent (at low revs only).

Now the previous owner told me that the car had recently had new genuine leads which cost a fortune. I'm guessing the most likely culprit is the coilpack, but I suppose it could be leads or plugs too. It is also throwing a fault code for O2 sensor.

Any suggestions? Does anyone have a second hand coilpack for sale or one I could borrow to help work it out by a process of elimination?

rambo_005

My Dad's old VR6 had an issue like this a while back, did it only a few times though and then was fine for years!

I've got a spare coilpack here I'd sell if you want one. :)

timewarrior

mine is doing the same thing at the moment (maybe the wet weather) and it's a nightmare to diagnose without spending a fortune replacing parts that aren't broke. maybe try spraying mist over the coilpack and look for arcing? apparently painting epoxy over the outside of the coilpack can reinsulate it if it has any cracks, could be worth doing before replacing it. i'm gonna do mine so will let you know.
bad temp sensors can cause issues like these too apparently, i know mine has a bad temp sensor somewhere because I have some issues with the electric fan. am replacing it tomorrow and can let you know.
94 Golf VR6 Dusty Mauve Pearl
05 Golf GTI Diamond Black Metallic
04 Golf R32 Reflex Silver Metallic

"The more I know, the more I don't pretend to know"

Number21

Cheers guys. My fans work sweet, the miss has become worse in the wet weather for sure.

Rambo, can you PM me a price for the coilpack, good chance I'll be in the market for one!

BB

It can be the ECU temp sensor usually green or blue and it can very easily be the 106 ECU relay.
The 30 relays in the ABFs give plenty of trouble such as missing and I think the ECU relay in the VR6 is the 106 relay.
Also if your plugs are old they build up resistance which causes miss fires and then that creates arcs in other areas that then lead to ECU malfunctions so always spring for new plugs if they are at all old.
The end is nigh, but the end of what is the question?

Number21

As per my original thoughts, this turned out to be a coilpack issue.

Small crack under the no.5 plug which had been siliconed up at some stage. Replacement coilpack courtesy of Rambo fixed the prob, actually the car is much smoother now even though I thought the problem was intermittent. So much easier when the problem turns out to be exactly what you thought it would be all along, even better when it can be fixed with very little cost in parts!

Had a head scratching moment though when the replacement coilpack caused the car to splutter on startup and stall. Then the old coilpack did the same thing... double checked all the leads were in the right place and then chucked the replacement coilpack back in, and after a rough idle and bit of trouble starting it started to work perfectly after a short run. It is perfect now...  ??? Anyway, the miss is gone, I'm happy!

rambo_005

Glad to hear it's even better than before! 8)

BB

It did that as it cleared the spark plug that had been misfiring Id say.
Give your leads a really good clean and check they have not corroded up the inside where it connects the plug and check your plugs if they are brown or at all old replace them.
I replaced my plugs on my Serena, the old ones were about 2 years old and did not look worn at all really. The difference was still very noticable.
Also cleaned up a set of 8v leads (one of the cheap sets) on Friday and put a drop of oil up the inside where it connects the plug as they were doing the magic VW corroding trick and sanded the rotor. Got a txt from the owner saying it was running amazingly well ;) I would have replaced the plugs as well but the bill was to be controlled to the absolute minimum so I didn't.
The end is nigh, but the end of what is the question?