After header install, rough running

I usually dont venture over onto the lsx side of things around here, seeing how i never owned one, but a buddy payed me to install a set of pacesetter longtubes/y pipe on his 02 z28 auto.

Install went great, but afterwards the car isnt running so great.

when i pulled the o2's out to start out with, the drivers side was white, and the passenger side had all kinds of black crap on it. He had his plugs and wires changed a few weeks ago, and the mechanic said his coils were going bad ( i know nothing about coil packs) When i took it for a test drive, at first when i started it, it wouldnt idle by itself, so i gave it a little gas, just to keep it running and then the idle smoothed out. At first it was running crappy down low, spit and sputtering, falling on its face up until about 3500 then it would pull hard until redline. After i drove it for about ten minutes, it switched, it ran good at lower rpms, but after about 3500 it would backfire a little and spit and sputter. Whats wrong with this thing? It finally threw a code when i was pulling it back into the shop. I dont have a reader, but will take it to autozone in the morning and see what it says. I spliced the o2 wires with the little kit that came with the headers, since he didnt buy the extensions, and am running o2 sims in the rear. The car is running on the stock tune as well. I will double check all plug wires in the morning and make sure everything is connected well. any ideas as to what may be causing this? thanks in advance.

First thing is to check all sensor connections. Unplug and plug back in all the sensors. Make sure that you didn't forget to plug something in.
Check the MAF for dirt and spray clean if necessary.
Check all the coil and plug connections of the plug wires.
Did you make sure to tie back the passenger side wire harness away from the headers? The one that goes from the main harness down the inside of the inner fender.

After I did my header install this past winter, my car wouldn't start AT ALL!!

Turned out, I must have accidentally tugged on the wires going to the crank sensor, on the side of the block in behind the starter. One of the 3 wires going into the plug broke off, and the car would NOT start because of it. Perhaps if something like that happened to your buddy's car, maybe the wire isn't completely broke, but it's making a poor connection? :shrug:

Just something to check out ... good luck with it! :cool:

Thanks guys, i just put the car back up in the air, and am going to double check everything as soon as the motor cools off a little. I spoke with the guy that owns the car late last night, and he said that it was running poorly in the first place though. Im wanting to get to the bottom of it.

I double checked the plug wires, and surronding wires. I had the codes pulled and this is what i came up with.

p0131
p0101
p0151

any ideas?

I double checked the plug wires, and surronding wires. I had the codes pulled and this is what i came up with.

p0131
p0101
p0151

any ideas?

P0101 is MAF problem. MAF not working right is throwing the AFR off causing the P0131 and P0151 O2 sensor codes.
Check the connections to the MAF, clean, or maybe swap it for a known good one.

As many people that post on here about codes and what they are, why doesn't somebody start a "sticky" thread that lists all codes and what they are.....if there already is, please accept my apology, I haven't seen it.

As many people that post on here about codes and what they are, why doesn't somebody start a "sticky" thread that lists all codes and what they are.....if there already is, please accept my apology, I haven't seen it.

Shoebox has a link on his site that gives a breakdown of all the OBD-II codes: http://shbox.com/1/Dtcs.htm

Thanks guys. Im wondering if i somehow did not wire up the o2's right. I just used the splice kit that came with the headers, since he did not buy the extensions. He is going to order a set of extensions within the next day or two. I think i may be able to get this thing figured out. Thanks again for all the help guys!

I don't want you to take this wrong but often the wrong lead is used and this causes the problems. More than once people have plugged the front O2 into the rear O2 harness plug especially on the drivers side where the plug in is up on the block in front of the motor mount.

Sounds like the O2s are spliced wrong and you blew the Eng Sens fuse in the under hood fuse box. Since you spliced the O2s, consider them junk now. Don't buy extensions. Put that money towards buying the Vette rear O2 sensors with longer leads. (Bosch 13111) O2 sensors that have been cut and spliced will cause problems even when wired correctly.

I don't want you to take this wrong but often the wrong lead is used and this causes the problems. More than once people have plugged the front O2 into the rear O2 harness plug especially on the drivers side where the plug in is up on the block in front of the motor mount.



Im sure i got the right plugs because i used o2 sims in the rear which both plugs for the rear were right up by the trans pan, the front plugs were up on the block. And no i didnt take it the wrong way. I wouldnt be asking for help if i didnt want it. Any idea is a good one.

As for buying longer leads for the rear o2 sensors on the vette, im very confused. For one, its not my vette im working on, its a 02 z28. Also, im running o2 sims in the rear due to the off road y pipe and absence of cats. As for my possibly getting the wires mixed up, your right, its possible. But how would this junk out the o2 sensors?

thanks again guys, keep the help/advice coming.

As for buying longer leads for the rear o2 sensors on the vette, im very confused.

What he meant was, if you buy 'vette rear O2 sensors to use as f-body front O2 sensors you don't have to splice wires as the wires are long enough to just plug in.

I think you should bump the price up a little, since he only paid you for the install, not all the trouble that comes afterward.