Generation IV External Engine - Issues under WOT
02-24-2012, 11:12 PM
I recently purchased a 06 c6 z06 with a cam, headers, intake, exhaust and im after replacing the spark plugs and a oil change im now having an issue under throttle. Normal driving the car runs fine no issues but as soon as your foot gets a little heavy i start getting a sputter as i go through the rpm range. I used the same spark plugs that where already in the car (NGK V) with the same gap. Im not getting a cel but that could be because of the tune. I pulled the spark plugs and they are all looking white like the car is running too lean. Is it possible im having issues with an o2 sensor? Any ideas would help.
02-24-2012, 11:24 PM
You might check all your vacuum lines, MAF sensor, etc. It could also be a bad coil or wires.
02-25-2012, 12:37 AM
I think you may have solved my problem. Checked the MAF and had a nice coating of oil on it along with the intake. Cleaned and ill check the results in the morning.
02-25-2012, 09:57 AM
You might have cracked the porcelain on one of the plugs ?
That's what it sounds like...
02-25-2012, 08:05 PM
Well i cleaned the maf with cnc maf cleaning spray and you can def feel a difference but im still getting almost like a misfire when running at wot. I checked all the spark plugs and they all looked normal no cracks other than it looks like the car is running lean.
02-25-2012, 08:22 PM
Whats your gaps, curious?
Also, did you check them all with a tool?
02-25-2012, 09:50 PM
Possibly the MAF is going bad....because when you go WOT the MAF comes into play, where normal driving its just the 02 sensors taking care of things.....as I understand it. And not all of our PCM's will throw an SES or a code until things totally fail, and then still sometimes they still won't..........our PCM's are still stuck in the "idiot light" days.....
02-26-2012, 08:24 AM
The MAF is always in play, cruise or WOT. The O2's are only used in cruise conditions. So, if it's OK in cruise but not in WOT, it's not the O2's. Check your plug wires, ohm them as you move them around.
the plugs being white are probably because of the cam. Mine (LS7 with a BIG cam) are white because the overlap on the cam flows gas/air out and the O2's think it's running rich when it's actually lean. It's really not a problem, because at WOT your ECM reads from a table instead of from the O2's.
02-26-2012, 09:55 PM
Replaced the MAF and still having the sputter. Im going to check the gap and plugs again tonight. I going to try to gap them a little smaller to see if that helps. Also I was thinking it was just the cam but under cruise control I feel it kinda hesitates and catch itself? I know bolt ons but this is the first cam car iv had so im not sure on everything....yet
02-26-2012, 11:19 PM
all plugs gap is set at .035
02-27-2012, 02:06 AM
i had a similiar problem in my c5 z same thing it was ok under cruising cond.. but when you put the pedal on the floor it would sputter it turned out to be the ground wire thats hooked up behind the cylinder head was making a false contact had a (copper or brass) contact end replaced it was cheap terry at vettech found the problem i could have never guessed the problem it
happend from one moment to the other i went for a cruise got home let the car sit for about an 1hr and then started it again to go to a friends place and when i go to get on the gas it started sputtering wierd .. so that turned out to be my problem hopefully that helps
02-29-2012, 07:45 PM
Well problem continues, it finally calmed down and ran fine for a little bit but then it started again today. :( ill check the grounds and make sure everything is connected. I havnt been able to pull the voltage yet but im working on that next
03-01-2012, 10:35 PM
Well maybe im being overly optimistic but i may have found my problem. After taking out the spark plugs and replacing them with TR6IX plugs i went ahead and took all the wires off the ignition coils.. There is one coil with a fairly large chip in the plastic housing where the wire boot meets the coil. Is it possible that im not getting a good connection at that coil and the cam is vibrating that connection causing a problem that comes and goes?