Installed BBK longtube headers and engine runs better without oxygen sensors!!!

[Ishman 306]

I've been trying to track down this probem I've been having after the BBK ceramic coated longtube header install. The car would idle like it had a huge vacuum leak half the time and it would buck and pop up to 3000 rpm, and then after it hit 3k rpm all the sudden run fine! I've tried just about everything (and I mean everything!, even put in new engine harness) until last night i unplugged the O2 sensor harness, and wham idles smooth as silk and doesn't buck or pop. What gives?

Scott

 

[pwcracer]

Isn't there something with long tubes that needs to be corrected in the ecc? I know when I had my tweecer there was some things I had to change due the longtubes. Same with the chip I had burned..

 

[SVT32VDOHC]

You needed a tune.

 

[juiced_94gt]

you need a tune, when you install longtubes the o2 sensor is further downstream and they dont heat up like in the stock location, mine did the same thing and my tuner told me it was because of the lt's now after the tune it runs like stock.

 

[stykthyn]

do you really need the sensors?

 

[Fox8950]

I wouldn't drive without em. When your not WOT they decide the fuel mixture do they not?

 

[BK_CAULEY]

the sensors are there for a reason and the reason your car runs better with out them is because they are probably damaged and giving false readings.

 

[Ishman 306]

I've considered getting a tweecar. The O2's themselves aren't the probem, I've tried 3 different sets!!! lol

Someone mentioned that the Air Intake Temp sensor works in conjunction with the O2's and maybe that sensor could be bad and when I unplug the O2's it goes into open loop and ignores the "bad" AIT??? any thoughts?

Scott

 

[bullitstang1313]

Its like svt32v and juiced_94gt said, you need a tune. Since the O2 sensors are now farther away from the engine they need a longer time to warm-up properly. Since the ECM doesn't know that, it thinks that the O2 sensors are warm and it causes the A/F ratio to be wrong so it starts changing fueling to componsate. You definately need to have the O2's in order for good driveability and proper closed loop operation.