my are in headers but it dont run right now

**mikey gavin** · 01-18-2011, 07:29 AM

so i just put 1"3/4 to 3" long tubes headers and a 3" y on my ls1 but on the way home it started running like crap back firing when i would put it down could this be cause i dont have rear o2s off yet?

**98maro** · 01-18-2011, 07:45 AM

You Have to tune your PCM.

**0rion** · 01-18-2011, 07:52 AM

definitely an issue there with the install. Are your front O2's hooked up? Check for cracked plugs or plug wires that weren't installed all the way.

**mikey gavin** · 01-18-2011, 08:52 AM

yeah it has front ones they are new they are 13111's but yeah no tune yet so it had plenty of power in first but at low rpm's and i get oln her it starts doing it but i stll will burn um with no problem in first

**pajeff02** · 01-18-2011, 09:06 AM

The headers alter the airflow characteristics through your engine so your Volumetric Efficiency (VE) table is now off. However, it shouldn't run that bad. Like 0rion said, it sounds like you have something else going on. Any SES codes popping up? Was the battery disconnected during the install? Are the plug and coil connections fully seated -- 1 click on the plug and 2 clicks on the coil?

**mikey gavin** · 01-18-2011, 09:09 AM

i didnt unhook the battery i didnt think i would have to..it wasnt that bad till i got on it after driving it about 4 or 5 miles but it never really got that bad

**Knight** · 01-18-2011, 09:11 AM

Agree with checking ^. Also, you might want to check your header bolts and connections to make sure they are all tight. Make sure the header gaskets are good as well.

**mikey gavin** · 01-18-2011, 09:18 AM

well i just went out there and 3 wires were loose 2 of them went on 2 clicks the other was loose on click all on the coil end. think that was it?

**Knight** · 01-18-2011, 09:22 AM

Originally Posted by mikey gavin

well i just went out there and 3 wires were loose 2 of them went on 2 clicks the other was loose on click all on the coil end. think that was it?

Quite possibly. Run it and find out.

**mikey gavin** · 01-18-2011, 09:24 AM

yeah but i dont wanna drive it on these salty shity roads im in wi lol

**Knight** · 01-18-2011, 09:26 AM

Originally Posted by mikey gavin

yeah but i dont wanna drive it on these salty shity roads im in wi lol

Understood, I'm in NE Ohio so I know just what you mean. I'm willing to guess that was the source of your problem though.

**35th-ANV-SS** · 01-18-2011, 09:37 AM

So you were basically running on 6 cylinders...I would say yes, that was your issue.

Like mentioned, after a LT install, a tune is NOT a necessity, but recommended.

**mikey gavin** · 01-18-2011, 09:49 AM

i hope that was it

**Cutlass** · 01-18-2011, 01:56 PM

sounds like you found the problem. the other possiblity that came to my mind was a O2 sensor wiring melted against the headers.

**Demon_Z28** · 01-18-2011, 04:29 PM

Originally Posted by mikey gavin

i hope that was it

Happened to me before lol, Was wondering why my car was running so rough, Spark plug wire on #8 didn't click all the way in there. Running on 7 cylinders lol.

**0rion** · 01-18-2011, 04:49 PM

Originally Posted by Cutlass

sounds like you found the problem. the other possiblity that came to my mind was a O2 sensor wiring melted against the headers.

that's some more good advice right there. It sounds like the spark plug wires were your problem but if not check that wiring.

**mikey gavin** · 01-19-2011, 10:07 AM

well i went out and looked from what i could see out there in the snow everything looked ok but its not up in the air so its kinda hard to see but it looks fine

**GarySS396** · 02-17-2011, 09:43 AM

I have somewhat the same problem after installing LT's and ORY. I only have the front 2 O2 sensors and car seems to run fine but it has a flat spot and it sucks the gas and pops real loud when letting off the pedal. Since I have the SLP loudmouth exhaust I'm assuming I need a muffler to add a little bit of back pressure. New plugs and everything hooked up properly! The car is a 1999 Z28 with a 6 speed manual tranny.

**mikey gavin** · 02-17-2011, 10:47 AM

i think i might of found the problem on mine i have a cracked plug on the porsolin part i havent got one yet to see if that fixes it, but that worries me now cause it looks like it was burnin fine. but i under load is when mine acts funny if i give it (wot) it pops loud and just dont have the power it did. like at 40 mph in 4th if i give it a little gas it sounds like its out of gas by the way it pops and feels. after i did the the car seems to shake a little more that it did..

**JayTA98** · 02-17-2011, 04:17 PM

Originally Posted by mikey gavin

i think i might of found the problem on mine i have a cracked plug on the porsolin part i havent got one yet to see if that fixes it, but that worries me now cause it looks like it was burnin fine. but i under load is when mine acts funny if i give it (wot) it pops loud and just dont have the power it did. like at 40 mph in 4th if i give it a little gas it sounds like its out of gas by the way it pops and feels. after i did the the car seems to shake a little more that it did..

A crack plug will cause issues. when was the last time you changed the plugs? maybe is time to put new ones in.