ws6#17

iTrader: (1)

i just got my Lt's and ORY put on today. i had to replace two O2 sensors, one upstream and one downstream because we couldn't get them out of the old manifolds. When i started the car up it sounded like crap and ran like it too. the mechanic told me it needed new plug wires and we checked it and the 5 wire had been laying against the headers and had melted. i rotated the wire boot so that it tightened the wire and got it away from the header and it ran like a dream. On the way home from the shop my car started backfiring while the car was idling, around 800-750rpm. im gonna change the wires tomorrow but i wanted to know, is this something that will go away with more driving or will more repairs need to be done to eliminate the backfiring?
Thanks

blind527

iTrader: (8)

It seems like it's just misfiring. You should be fine once you replace the plug wires. Make sure the plug wire boots are on the plugs securely too.

LTSpeed

I have no idea if this is the same thing you are describing, but I saw that happen once on an LT1 when they left out a donut in an exhaust manifold. Are you sure the whole pipe assembly is tightened up and without air gaps?

ws6#17

iTrader: (1)

yeah the exhaust piping is all welded up, the end of the y-pipe and at the y-pipe extentions. so i don't think it is a leak at the moment. but ill know tomorrow afternoon for sure hopefully. also should i get some over the valve cover wires? if so what kind would be recommended.
Thanks

NOTAV6

iTrader: (3)

if you had a big change in backpressure that would cause it i have a dump at on pipe right after the axle, and mine backfires a little when the dump is open

97lt1z28

iTrader: (1)

had the same exact thing happen to me, i just replaced the wires with a thin set (mine happend with thick msd wires)

SSweet97

iTrader: (7)

I have MSD 8.5mm wires and have no back fire problem what so ever. BTW, do get the over the valve cover wire looms.

94stanger

iTrader: (4)

usually when you have heat damaged plug wires, they will run okay until the car reaches operating temperature...then they tend to start missing. Just replace them and make sure none are in close proximity to the headers.
I run AS&M headers, and wire routing is a bitch. It took me two sets of plug wires to get it so they wouldn't melt.

HBHRacing

It's simply time to upgrade to high heat wires and cover them in even more heat protection. It's really something that should be done by everyone as soon as they install headers.