skaffy03

I have an 04 Tahoe and I've put long tubes on it. I have a few plug wires that touch the headers and I've done what I can to keep the boot from touching the headers (used some header wrap on the boot and I also zip tied the wires out of the way so they don't touch the primary)

I get 11mpg in town and maybe 13 on the highway and I've never replaced the wires.. only plugs. I'm dumb.

anyways, I was out looking at my truck at night and the engine was on and I FAINTLY saw the plugs arcing on the header and also at the coil. I really really focus to see the arc as it was barely visible.... but it's there. My wires do have some slight burn marks/melting on the ones that were extremely close to the headers.

Would this have any effect on mileage? I also noticed a more than normal rough idle when it was about 10 degrees outside two days ago. It also doesn't seem to have the "pep" it used to. Time for new wires?

black00chev

iTrader: (2)

Yup! Might as well replace them all right now.

Im fighting that same battle on my truck. I bought the ebay "hump" headers and can not for the life of me, keep the #5 wire from burning up. I even bought thermal boot protectors and those are even getting burned through! My last ditch effort is to double up the thermal sleeves and pray thats enough. I can tell when they are getting too hot. Like you said, it looses its pep and the idle isnt quite right.

skaffy03

I have the same eBay headers, the $320 ones. Well, that's what I'm assuming you're talking about. I don't have the burning, melting issues with the #5 or #7 cylinder spark plug wires, only on the passenger side plug wires (the boots are touching there, but no boot touches a primary on the driver side). The wires on the #5 and #7 plugs WILL touch the primaries, but to remedy that I just zip-tied those two wires together and then a second zip tie to that and around a bolt close to the coil itself. But not too tight as to destroy the insulation or kink the wires.

If you want, I can get a picture of my cheesy fix there. $2 fix and they're still fine, but that's probably because that side has new wires from when my buddy ripped a boot off the driver side helping me change plugs... passenger side is where i'm seeing the arcs.

On a side note, I have no CEL, but I do sometimes notice my air/fuel gauge will drop to around 13.1 while cruising at 70mph and stick there for maybe 10-15 seconds, then come right back to normal range. Would this be due random/intermittent/bad spark due to these bad plug wires? Exhaust also reeks of fuel all the time.

FFDP

iTrader: (2)

If you are catless with those headers it will smell like raw gas and just plain ole catless exhaust smell.

The random drops to a lower AFR are known to happen if you never reconnected your rear o2 sensors when you installed the headers. The computer is trying to do a cat test but there is no cat/o2 sensor.

skaffy03

Would the PCM try to do that test even if I had the tuner remove the rear O2s in my tune? Or, better question, is it anything to even think twice about?

FFDP

iTrader: (2)

Even if you remove the codes from he computer (set them to no report), the cat test will always happen if the rear sensors are unplugged. This cat test can not be shut off unlike the 07+ NNBS computers. It's not a real problem at all, but its rather annoying in my eyes to see it happen. I just shut the codes off on my truck and zip tied the sensors to the frame to keep it from doing the test at random. It will only do 1 test once it hit closed loop and thats it.