Just installed some long tubes, hi-flow cats, and muffler and a few days later got the check engine light; bank too lean. Pulled the battery wire and it was fine for 4-5 days then came back. I'm using a PSP 4-way chip, 6# lower, and cai. A/F was fine on this chip before the exhaust mods.

It makes sense that it leans it out so no big surprise. I've heard some say that the exhaust richens it up, but I think that's more of a function of going from 4 cats to two and less stuff being "scrubbed" out of the exhaust by the cats. I had not heard of anyone having to re-do the chip for headers though.

Jody

 

I have had zero problems or codes, could it be a faulty oxygen sensor???


D-Day

 

I have seen this problem before. It seems when headers are added the rpm when gear is lower. Your rpm should be adjusted and also after adding headers you should get a new tune because....well I will let your tuner tell you. But there is power to be had after installing headers but you need to know what needs to or has changed.

 

I may be wrong, but I think I am right

when you get a lean bank code, you are actually running a little rich and the computer is trying to lean it out.

Maybee someone can tell me if I am right or not

 

Sorry Don that is not correct. I have found that the O2 will read like .025 or so when the RPM is low (like 520rpms). If you get a lean code and look at the O2 voltage it is always on the low side.

 

Jody, when you install long tubes, you are moving the HEGOs farther from the motor. There is a table in the calibration that the PCM uses to know what cylinders are firing based on the distance of the HEGO from the exhaust port. Going to long tubes will alter your fuel tirms and cause the PCM to make corrections. Most trucks don't set the light, but some do. Whenever I do a chip for long tubes I always correct this table. You might want to send it in.

 

I have had the headers on since Feb. and I just started getting the lean bank code last week I know I have a few exhaust leaks but I can barely hear them with the idler puller making noise and the exhaust banging against the traction bars whenever I go over a bump. Boy I almost hate driving the L right now.

 

So, I wonder if I am running lean. My wideband O2 says I'm not but I have DTC codes rich bank one and rich bank two all of the time.

 

Thanks Sal and the rest of you guys.......good info. I'm planning on a different blower pretty soon so I was avoiding getting the chip done now as it will need to be re-done again with the other blower.

Jody

 

Well I figured out why I ws getting the "Lean Bank 1" and "Lean Bank 2" codes (just in the past couple of weeks)

Turned out that the air intake boot that connects to the throttle body was folded underneath and creating a huge vacuum leak. The truck didn't seem to run any differently and I can't remember when the last time I had that boot off was...prolly around July.

At least it was something stupid

 

I was going to mention that. three days after i got mine it threw the same code. It was a very small vacum leak.