Bank 2 ltft

**20WS601** · 10-06-2008, 01:44 PM

Is it normal to have a variance in you ltfts at idle? One bank being leaner than the other like at 3.13 and constant? would this indicate an exhaust leak at the header collector thats messing with the 02 sensor? The other side appears normal and Ive never noticed this before. Any thoughts. Thanks

**Doc99SS** · 10-08-2008, 04:23 AM

Usually, its a difference between the O2 sensors themselves. First thing to do is to switch the Os from side to side, and check if the LTFTs follow the new placement of the O2s. If the LTFTs switch with the O2 placement, then its the Function of the O2s. If the LTFTs do not switch side to side, then it could be a exhaust leak, or you have a slight flow difference of the injectors from side to side.

I have about a 5% difference from side to side for my LTFTs.

**20WS601** · 10-08-2008, 09:10 AM

Well I stopped by the exhaust shop for cheap peice of mind turned out I had about 5 small holes around the collector.... So the did a better weld all the way around and things have checked out and the cars back to normal. I to have a the same flow difference between banks. Which I guess is a result of cam and tune. Thanks for the reply

**spydaloc** · 11-06-2008, 04:19 PM

cammed ls1 5.3 2001 truck motor, sanderson shorties with spintech xl's muffler's no cats, getting lean code on one side and rich code on the other side. Any suggestions as to how to resolve this problem - it doesn't idle at all and runs high idle when in drive. Been dynoed at 312hp/322tq at the rear wheels. Any help much appreciated.

**20WS601** · 11-07-2008, 04:43 AM

Is it the ls1 or the 5.3? and what kind of car. I would check your exhaust for leaks. make sure the the lean sides header gasket isnt leaking. and maybe look around for a vacuum leak. I believe carb cleaner sprayed around the intake and such can help pin point a vac leak. check all your connections between the maf as well. I would start with the lean side first. see if you can figure that out and maybe it will help the rich condition in the other side.

**spydaloc** · 11-07-2008, 10:49 PM

it is the 5.3L from a 2001 chevy truck. I have the engine & a 4l65e WS6 transmission in my 1987 s10 2wd pickup. Sprayed cleaner all around the intake looking for leaks, but saw none there. There is an exhaust leak, albeit a small one up near the passenger side header collector area. its the only leak I hear from inside the car...

**20WS601** · 11-09-2008, 07:38 AM

Well id start there. I once had a bad air pump valve on the driver side and same thing hapened and the car drove horribly. so if its near the collector and the 02 sensor that should fix part of the issue. the high idle not so sure. have you had it tuned? your dyno numbers look pretty good from what
i see i think chevy rated that engine at 295.