Engine Misfire - troubleshooting help

[BOTTLEFED]

So a fellow VCA member is having some issues with his Roe S/C FE GTS. He took it out the other day and did a few pulls. Then, as he was getting on it, it just hesitated and started running badly. He babied it home on what seems like misfiring.
I went over tonight and we started troubleshooting.

First off there were 4 codes. 1 was misfire - cyl10. 2 was misfire - cyl1. 3 was misfire - random. 4 was misfire - cyl9.

Cleared the codes and started it. The car idles rough and very rich. We unplugged the cyl10 spark plug wire and there was no change in the idle. There was good spark from the wire.

We pulled the cyl10 plug and it was wet and black. Not carbon encrusted, but like it was running rich on it for quite awhile. Definitely no damage or sign of detonation. We checked cyl1 plug and it was perfect (nice tan). Then we pulled cyl6 and cyl8 and they were both black but not wet.

Replaced the cyl10 plug with a brand new one. Restarted the car and no change.
The LTFTs were off. Bank1 was normal at -4.6, but Bank2 was at 32.8.
Also, Bank1 O2 sensor #1 was reading normal at about .90 - .80V at idle, but Bank2 O2 sensor #2 was down at .24V the entire time, even when the engine was revved. The rear sensors are out of the exhaust and read 1.0V on Bank1 and .80V on Bank2.

We need to connect up a laptop to see what the VEC is set at. He has multiple cards and we tried a different one and there was no change.

I'm thinking O2 sensor, but it is reading and doesn't throw a code.
The car has ran well for over a year and never had tuning issues.
Can you guys give us some ideas on other things to change or test?

TIA

 

[bluesrt]

i would say not a 02 for a problem like you state- first get a stethascope and listen to the injector pulse- or check the coils for fire- wichever u want to do first-- list your case in manner after these checks- we will go from here------

 

[BOTTLEFED]

Yes, there is good spark.
I didn't listen to the fuel injectors because they seem to be working since it is running rich.

 

[2001 GTS]

Was there a cam change?

 

[BOTTLEFED]

Was there a cam change?

I don't think so. It still sounds like the creampuff cam.

 

[mjorgensen Woodhouse]

If the plug is that wet have you smelled the oil for the presents of fuel? Scoped the cylinder for any missing metal?

 

[Viper Fever]

Tim thanks for posting.
My gts has run flawlessly up to this point with out one problem.

I did talk to Chuck Tator. He suggest to get rid of the msd spark plug wires.
Put new spark plugs in. Compression test.
Re flash computer by unhooking the positive cable grounding it to the frame
to clear memory then restart viper.
These are the basics and will a least answer questions or create a few more.

 

[BOTTLEFED]

Interesting.
Compression test was gong to be my next suggestion Carl.
We can always swap my AB wires over to your car just for TS purposes.

 

[99 R/T 10]

Do you have the upgraded fuel injector clips? Another possibility is one of the injector leads popped off for a split second. If this happens it will fry the circuit board in the Vec 2

 

[Viper Fever]

Tim I have a brand new stock set of wires. Chuck said he has had nothing but trouble
with the MSD wires. Compression check might as well while we have the plugs out.
Do you have one or do I need to buy one(compression checker ) Carl

 

[Viper Fever]

99rt/10
I do believe they are the upgraded fuel injector clips. But if you did fry the circuit board
how would you know is there a check other than sending it to Sean.

 

[BOTTLEFED]

Tim I have a brand new stock set of wires. Chuck said he has had nothing but trouble
with the MSD wires. Compression check might as well while we have the plugs out.
Do you have one or do I need to buy one(compression checker ) Carl

I've got one.

 

[BOTTLEFED]

99rt/10
I do believe they are the upgraded fuel injector clips. But if you did fry the circuit board
how would you know is there a check other than sending it to Sean.

As long as the comp. check was good and there are no spark issues, then the fuel injection syst. will be suspect.
Once we get the VEC connected to my laptop, we can check the fuel trim settings and log injector duty cycle. That should tell us if the VEC is controlling the injectors properly.
If we need to, we can swap my VEC3 for yours for some TS.

 

[99 R/T 10]

As long as the comp. check was good and there are no spark issues, then the fuel injection syst. will be suspect.
Once we get the VEC connected to my laptop, we can check the fuel trim settings and log injector duty cycle. That should tell us if the VEC is controlling the injectors properly.
If we need to, we can swap my VEC3 for yours for some TS.

That's the best way, but if I remember right, dansauto had issues similar to what yours sounds like. It turned out tot be the circuit board.

 

[martyb]

I took my MSD's off because I had misfires, replaced with factory wires and the issue was solved. I have AB's wires on my new car, and would not think of using anything but AB's moving forward.