Strange Spark Plug Situation

[EllowViper]

I was doing some tuning on my Creampuff and after a couple of hard runs, it was running kinda crappy. I hooked my ODB-II reader up and the LTFT on Bank 1 (Driver) was pegged at +32.8%. No matter what I did with my ROE tuning software, I could not get it to change. Lots of backfiring out the exhaust, but it still ran strong under boost just fine. Closed loop was terrible. I thought maybe an 02 sensor puked since it was looking really sooty when I took it out. I put two new 02 sensors in but the condition remained. I swapped out my 98 PCM for my 01 PCM but that didn't do anything either. I pulled all the plugs and lookie at #3. Weird. I thought I had fragged my Creampuff running a bit too much timing. I did a compression test and all were around 150-160. I put my one step colder Autolights back in and now its running fine. LFTF on the same tune is right at +/- 3%. Hard to figure this one out.

 

[1TONY1]

Just as a general rule, you should not be running stock plugs with the Roe s/c.

 

[johnk]

I don't think it closed itself, Looks like the piston kissed the electrode on one of those hard runs..... What's that little silver thing sitting on top of the washer on the right side?

 

[Russ M]

Most likely you closed the gap yourself when installing the plug by bumping it against something.

That plug looks a bit lean to me, what are your air/fuel numbers? The heat looks ok, 3-4 threads of heat is ideal.

 

[supraman95]

What is the best plugs to run with the ROE?

 

[EllowViper]

I thought I might have banged the electroid during install but it ran fine for probably 500 miles. I'm pretty careful with installing plugs. LORD knows I've done it enough on this car. I'm running Water **** so reading the plugs can be a bit different than normal since the combustion is so much cleaner. AFR at cruise is right at the normal 14.5-15.5. At WOT, I'm between 11.5 and 12.5 depending on RPM and boost. I usually shift at around 5500 RPM but have kissed 6K just to see if it would pull hard to that point. I was working the timing curve pretty aggressively from 4-6K so I was letting her rev just to see if I could tune to 6k without detonation. It was really screaming and loved more timing from 4-5k. Factory is 22 degrees BTDC from 4-5K and I am at around 24 BTDC at 8 PSI indicated. It would be good to know just what the piston/plug clearance is on the stock plugs. If it is so close that the orientation of the electroid can impact the piston, wow. I can't think of anything else causing it.

 

[Fast Too]

I would go find someone with a bore scope and check the top of the piston for damage

 

[Cobraken]

On one of the Viper truck sites it seems the contact with the #3 sparkplug is the prelude to an engine failure. Check it the piston and rings right away.