Another rough idle, lack of power etc.

[Andystewart 10]

Hi great people out there.

A little help before I splash even more cash. So 96 vr6. Just rebuilt after jumped timing chain. New valves, guides, and seals. Skim head and block, new chains kit top and bottom. Strip down bottom end, everything in great shape, re assemble (all new single use bolts obvs) 130k. So,after this rather expensive repair, she was running great, now running rough, started to have intermittent idle/ power issue, thought was isv, was going to take off and clean but before I got the chance it's now permenantly running rough and gutless. Disconected lead to cylinder 2, no effect. Did same with number 5, no effect. The rest all stalled the engine when disconnected. So....faulty coil pack? Dam car costing me a fortune!

Thanks in advance kind people!

[Keyo 47]

Hi great people out there.

A little help before I splash even more cash. So 96 vr6. Just rebuilt after jumped timing chain. New valves, guides, and seals. Skim head and block, new chains kit top and bottom. Strip down bottom end, everything in great shape, re assemble (all new single use bolts obvs) 130k. So,after this rather expensive repair, she was running great, now running rough, started to have intermittent idle/ power issue, thought was isv, was going to take off and clean but before I got the chance it's now permenantly running rough and gutless. Disconected lead to cylinder 2, no effect. Did same with number 5, no effect. The rest all stalled the engine when disconnected. So....faulty coil pack? Dam car costing me a fortune!

Thanks in advance kind people!

 

Have you got a vgate or a scanner ?

 

This could be an exhaust or manifold leak , or Mass air sensor, or quite a few other things to be honest I would have it scanned for faults or purchase a VGate off ebay for £30. I would check for air leaks especially if you have haad everything disassembled latley. Does it run rough straight away or when it gets to operating tempature?

Edited March 23, 2019 by Keyo

[Andystewart 10]

It was running fine for few months, the recently while idling the revs would drop but not stall, and pick back up a few seconds later, leading me to think it was ISV. Then while driving last night, the revs would drop and during this rough running the car was gutless. But would return to normal again a few seconds later. Now today it was doing this again untill I got home and it wouldn't run smooth at all. This is when I checked the ignition leads and found that disconnecting 2 and /or 5 made little difference. So surely this points to an ignition problem, but is it the coil pack or a Cam sensor or something else?

[Keyo 47]

Not sure to be honest mate as never had a problem as of yet with the rev counter dropping, just rough running engine and that was down to air leaks and a 02 sensor when it got to operating tempature f 75degrees plus. .

[Andystewart 10]

Ok thanks mate, I double check all my hoses anyway.

[Andystewart 10]

So had the ISV off and cleaned with carb cleaner, left to sit in cleaner for hour and then squirt of wd40 and threw it back in, checked hoses for cracks or leaks, all OK there. So next a tried the usual disconnect MAF, ran worse (didn't think that was possible) disconnected cranksensor, stalled as expected. So this leaves me with (I think) coil pack and / or camshaft sensor. I'm leaning toward coil pack, as when I remove ignition leads 2 or 5 nothing happens, doesn't effect the already rough idle, and no spark from the lead to the coil when disconnecting or reconnecting like the other leads do. Anyone agree or think of anything else? Thanks

[Keyo 47]

So had the ISV off and cleaned with carb cleaner, left to sit in cleaner for hour and then squirt of wd40 and threw it back in, checked hoses for cracks or leaks, all OK there. So next a tried the usual disconnect MAF, ran worse (didn't think that was possible) disconnected cranksensor, stalled as expected. So this leaves me with (I think) coil pack and / or camshaft sensor. I'm leaning toward coil pack, as when I remove ignition leads 2 or 5 nothing happens, doesn't effect the already rough idle, and no spark from the lead to the coil when disconnecting or reconnecting like the other leads do. Anyone agree or think of anything else? Thanks

 

Coil packs are a common faiure so would'nt be suprised. If your based in the Midalnds can come over mate and check for codes I have V gate scanner .

Edited March 23, 2019 by Keyo

[Cressa 44]

Interesting that removing 2 and 5 has no issue... but before you replace the coil pack could you consider changing the plugs and leads to these. Swap them round with the working ones . Good luck anyway

[Andystewart 10]

Hi thanks, I'm a lil way from the Midlands, down in Bournemouth. I'll try the plugs and leads swap tomorrow, and borrowing a vagcom Monday so will try all that prior to any purchases. Thanks for the suggestions.

[fendervg 29]

Sounds like a cracked coil pack to me - easy to check using some spray mist at night to see if it arcs - also check the casing for hairline cracks. Some folks recommend a phenolic spacer to reduce heat absorption and damage, and there was a user on here offering some for sale recently.

 

Also check the cam sensor (in the head beside the coil pack) - but first off I would get it scanned with VCDS/VAG.com to see if it throws up any errors that can point you in the right direction and save you some money, as otherwise you will just be replacing every single sensor and component in hit and miss fashion until you fix it and that will work out very expensive.

[Andystewart 10]

Thanks fendervg, would a cracked casing to the coil pack stop points 2 and 5 working? There seems to be no spark on those two, when you remove the other leads they arch back to the coil pack when close enough, 2 and 5 don't.

Thanks

[Andystewart 10]

Anyone got a spare Cam sensor for sale that they are 100% sure works?