greenmeanie

A little help with some advise on proper diagnosis would be appreciated. My wife's allroad is suffering from the dreaded random misfire problem. Background is the car is a 2001 manual with 97K miles. I checked the plugs and they look good and have about 20K miles since change.

I can't remember the exact DTC numbers but with VAG com I get
- O2 sensor resistance too high intermittent B2 S1. I interpreted this as the passenger side precat O2 sensor and replaced it. This did not cure the misfire.

- 16648 Mutliple random misfires.
- Misfire on cyl #4
- Misfire on cyl #1

Having used the search function I would interpret this is being either a failed coil pack or two or the ignition control module. My understanding is that it is rare for a coilpack on an 01 to fail and would be suprised if two went at once. Having said that,if coil pack #4 failed would the engine try and compensate leading to misses on #1 cyl or vice versa?

I also understand that there is one ignition control module for each bank. In this case swapping the connectors won't help as I have a miss on both banks so how would I identify if I have a problem with only one?

Would anyone care to offer some help nailing down this fault? My pregnant wife is not too happy riding around in 100°f heat in my old Land Rover.

paulroad

yes, yes and yes....

Its rare for the CPS to go on an 01, but it can happen.
Pull the cp on cyl 1 and swap with cyl 2.
pull the cp with cyl 4 and swap with cyl 5.

Clear the codes... run the car.. wait for the cel and see if the missfires return to the new locations.

If so, its the cp.

If the misfilres are the old locations it may be the ignitors...both banks are going.

TerminA8r

Fill up tank with Chevron gas and add a bottle of Techron.

Click

Cheers

greenmeanie

The techron solution sounds plausible. This started within about 1 minute or a few hundred yards of filling up with a new tank of juice. Of course, it was a Chevron station so there should have been techron...

I'll play around with the coil packs tonight just to eliminate them.

Thanks for the info.

all123

you should also take into consideration that 1 and 4 are front two cylinders, so there might be a connection. changing places with plugs and coils is a good idea. 1for2 and 4for5

blackIIIroad

This seems to be happening more frequently on these 01's. My bet is on the power stage outputs (the ignitors) The fact that it's happening on both sides could mean -as stated earlier by paulroad- that both are on there way out. I would still switch them (ignitors on air box) to see if these misfires exhibit any new symptoms and or changes.

greenmeanie

Well just to finish up on this and give those that follow a reference point I can now say that is was the ingition amps. I went through the practice of swapping coils and plaugs and the misfire didn't move. Swap the ignition amps and the misfire moved from cyl 4 to cyl 5 on one side.

I ordered a new set from PureEMS very late on Thursday and they arrived Saturday. Both amps plus shipping were about the same cost as the dealer was for one so I am happy. 1/2 hour later and she was purring like her usual self. Then another hour after that because a stupid plastic T-fitting in the coolant tank lines broke as I was putting on the plastic covers so I had to go to the hardware store and make up a replacement out of brass fittings. All back good and happy now. The Vagcom earned its keep again.

Thank you for your help gentlemen.