Volkswagen Passat Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
159 Posts
Discussion Starter #1
Uploaded lates version of VAG-Com today and plugged up my 2000 V6 to it for some experimentation. No DTCs. Measuring block 014 showed cylinder 1 misfiring with a value of 1 to 8 as length of time elapsed. Pulled into my garage and removed spark plug #1 and it looked fine. Reinstalled. Recheck shows cylinder 1 misfiring still but not as bad as quickly, but now also showed cylinder #3 misfiring slightly.

Started my way up the measuring blocks group by group. The groups that measure both o2 sensors showed the two of the four, one on bank one and one on bank 2 going from ON to OFF and back. After I did the removal and reinstall of plug #1, 3 ofthe 4 values would change back and forth from ON to OFF and back. The values for the two sensors before the cat are withing limit. The two behind the CAT are off by 1 without fluctation. Bentley indicates that is unacceptable.

Original owner, 64,000 miles on it. Replaced OEM plugs with Boch+4 at 43,000 miles. Original plug wires. Can;t really say theres is a performance problem but there is a slight missing feeling at idle, but my idle speed is at 780 since I changed the timing belt back in August 2003.

Any suggestions on where to start in the diagnosing of this? Thanks.

Ed
 

·
Registered
Joined
·
2,281 Posts
Early signs of ICM failure? I know a small number of misfires are "normal" and nothing to worry about. But if there is a slight missing you may have a wire that is going bad or ICM that is beginning to give up the ghost. Just a couple suggestions until the big guns get here. ;)
 

·
Registered
Joined
·
168 Posts
forgive me of being a nuub but what is an ICM. reason being is my passat is misfiring so much now at low rpm acceleration that i need to be more specific to my dealer just doesnt seem to be getting a fix for it.

pls help.

ganx14
2003 v6 30v passat glx.
 

·
Registered
Joined
·
168 Posts
thank you kindly. and after reading the post you left something that other people explained was they were having studdering that evened out after moderate acceleration. this is exactly what im encountering at low rpm acceleration i get these studders or misfires that even out at moderate acceleration.

tommorrow morning im going in for my service 4th time for these misfires which are becomming more prevelant car only has 12.7kmiles on it. I will ask them politely to check the icm make sure thats not failing. The last time they said ignition wire # 2 failed and they replaced it with another wire. But after 1week of driving Boom back to the same old misfiring and more often...

thank you for the info maybe this will help me more to explain to the dealer.

ganx14
2003 glx v6 30v

ps sorry for highjacking the thread :)
:bow: :bow: :bow:
 

·
Registered
Joined
·
3,946 Posts
I doubt it's the ICM. You would have CEL if ICM was on it's way out. Most likely you have carbon deposits on your valves. Add Techron to 2 or 3 tanks of gas and take it to the highway for some extended high speed driving once in awhile. This is known problem with V6 when mainly driving in stop & go traffic.
 

·
Registered
Joined
·
168 Posts
I have done that remedy back in november puting tecron as per advised by dealer. 2nd time reset the computer. 3rd time replaced ignition # 2 wire. last week i had the dealer service technition drive car with me and it hesitated several times. Service Tech said car is misfiring again. must run a complete diagnostic maybe another ignition wire is failing. these misfires are bad if i continue to drive like this. Yes i had my blinking CEL's come on often starting at 7500miles. this is my 4th time bringing the car into VW shop now at 12.7k. so im going to ask to check the icm.

wish me luck
Ganx14
2003 glx v6 30v
:nervous: :nervous: :nervous:
 

·
Registered
Joined
·
159 Posts
Discussion Starter #8
Boris, I will try the Techron treatment as a first fix. I live in the country and most of my driving is on country road and highway with little stop and go. I doubit if it is the ICM also. My main concern was is it the rear O2 sensors causing the misfire of is the misfire causing the O2 readings to be off? Plug wire would be second fix. Third??
 

·
Registered
Joined
·
159 Posts
Discussion Starter #9
Well, this morning, I have taken my car on a nice road test. All pertinent measuring block desired results were achieved. It took a while to get some of the tests to go from "OFF" to "ON", but afte they ran, I got the ok from them. The O2 sensors stayed in the ON position.

Yesterday, when I wrote this question, I was idling in the driveway and reving the engine to try and get the rpm values to run the tests. Apparently, the car had to be more than the CAT temp listed in Bentley, running under throttle RPM and not at idle RPM, etc.

Only trouble now is that meausring block 15 shows cylinder one misfiring often and cylinders 2 and 3 intermittently. Cylinder 4-6 show no misfiring.

The plugs look grey and good at the firing tips. Is it more likely than not that the plug wires need replaced to correct the misfiring?
 
1 - 9 of 9 Posts
Top