VR6 misfiring...

[freddy_t 0]

Alright guys, another spot of trouble with the VR. Replaced the heater matrix on sat (in heavy rain) and the engine got extremely wet. Decided to flush coolant system whilst i was at it so a lot of water from that went over the engine too! I didnt think much of it until I drove it last nite, first couple of mins she drove fine but then occasionally started to misfire especially at low revs. Then after 5 mins or so was misfiring constantly and running on what sounds like 5 cyclinders.

 

Drove 50 miles today and around 20 last nite and I hoped engine temperature would disperse any water that may be causing it to misfire but it hasn't, still misfiring.

 

The car ran fine before the engine got soaked in water on sat prior to changing the matrix. Worring that I may have dropped a cyclinder checked the oil cap for mayo but its fine. Oil is clean and its not overheating.

 

Can anyone suggest some tests to eliminate any possible problems.

 

Cheers in advance

Fred

[Dogzyboy 0]

Sounds like the coilpack to me. Having similar problems myself just now. I did the Plant Mister test today (spray the coilpack with the mister & look for sparks / arcing) & it's confirmed that my coilpack is shot.

 

If you do a search on the topic you should find tons of similar posts.

[andyVR6 0]

check down where the plugs are. if the holes are full of water then i'd drain them somehow. dont take the plugs out if theres water down there.

failing that check all the usual stuff especially the dizzy if its and early VR with manual dizzy unit.

[freddy_t 0]

Nah it has a coilpack. Are these expensive? Is it possible that water may have leaked in there? How would you recommend removing water if its sat aound the spark plugs?

Would it help removing ht leads indivdually from the coilpack end indivdually to isolate which cyclinder isn't firing and go from there?

 

Cheers

[dub envy 0]

Try a wet and dry hover to get water out from the spark plugs..

 

My coilpack is fcuked. £132 (with dealer discount).... :(

 

I can see sparks on the outside of the cp when the car is running! Looking forward to a nice drive on sat when I put it on!

[freddy_t 0]

Ok cheers guys.

Is it a possibility that water has affected the coilpack then? Just find it too co-incidental after a lot of water went over then engine.

 

That test you carried out on the coilpack to check its effectiveness how do i do it? remove leads?

 

Thanks

[dr_mat 0]

Coilpack, leads and plugs can all be adversely effected by dousing in water, obviously.

BUT that effect should go away when the water evaporates off, unless they were faulty in the first place.

[Dogzyboy 0]

To test:

 

When it gets dark, get the engine warm & whilst running, use a plant mister to lightly spray water over the coilpack & leads. If either the leads or the coilpack are faulty, you should see arcing (sparks) in the area you've sprayed.

 

I did this last night & saw sparks on the outside of my coilpack, confirming to me that it's knackered. The cheapest I've seen is a Beru one on vwspares.co.uk for £133 inc VAT & delivery. I'm going to order one soon.

[freddy_t 0]

Ok i will try spraying the coil pack later! Ive also been by a mate with a mk2 VR to remove leads from the coil pack end 1 by 1 to find out which cylinder isnt firing, he then suggested taking the lead of the cyclinder that isnt firing and swapping it with one that is! Is this safe and effective? thanks

Fred

[double-6s 0]

Sounds logical enough to me mate.

[Roger Blassberg 0]

Coilpack works in 3 pairs; if one cylinder fails, so does its twin. Please be careful about pulling leads off; don't do it with the engine running as we are dealing with tens of thousands of volts which will give you one hell of a jolt. And the bonnet safety catch is strategically placed to slice your scalp when you jump back.

 

Best wishes

 

RB

[Critical_Mass 10]

OUCH!