CAT3

iTrader: (9)

Ok, swapped out the headers from 1 3/4 to 1 7/8; swapped from true duals to Y Pipe and single bullet for now; swapped out the stock rails with tuned 34# injectors. Finally got the **** started today, decided to log it, and B1 at idle creeps quickly up to +25, and while cruising can come down so low as to +10.9, WOT I dont know. B2 was idling slightly negative, cruising slight negative to slight positive, but pretty stable.

-Tuned the injectors using spreadsheet, as I always do.

-No fuel leaks

-Looking at the B1 O2, it seems to hang a little at low numbers for quite a long time, then finally gets somewhat active when compared to B2. Will be swapping the B1 O2 out and seeing if it helps.

-Checked the coilpacks, all wires are connected tightly, and no wild sparks arcing

-Reset fuel trims, didnt help any.

I am thinking if it not the O2, then it must be a rolled/dirty/? injector o-ring, as I have seen where even though it doesnt leak fuel, it can suck air in, giving mad + LTFTs at idle/cruise, but not as bad at WOT or heavy load. Anything I am missing?

tici

iTrader: (1)

Have you swapped the O2's? (B1 vs B2).
If the problem persists you could have a leak somewhere. Leak in the headers means that air is sucked in... sounds strange but it's true. False air would tell the O2's the AFR is lean and will cause positive LTFT's.

Have you reused the old injectors? If new are they flow matched?

Do you see misfire on some cylinder?

Bad o-ring... put some water on the edge and see if the engine suck it in. 25% LTFT means that you have 25% more air coming in... not really from a bad O-ring!

My guess it's a bad O2 or a leak.

Chris81

iTrader: (1)

I'm thinking bad O2, a car i'm tuning on right now had the EXACT same problem on B2..

How does the voltage on that O2 sensor look? If thats the problem the voltage will be too low and the O2's won't switch.

tici

iTrader: (1)

Two things caused this problem in my car:

I installed a set of new injectors and one of them was bad. I ended up buying 8 new flow matched Bosch injectors.

Once I used an anti seize copper grease for the O2. It was a little quantity but the sensor didn't like it. I then installed a new sensor. The old one is still fine after the cats but too slow for adjusting fueling.

SMOKINV8

iTrader: (6)

Look for black marks around your header flanges, thats a quick way to tell if you've got an exhaust leak. You can also use a little smoke in the area to see if it gets sucked in anywhere, or pushed away. I use little aerosol smoke detector testers for this so I can direct the smoke.

Also, if you've got a laser thermal gauge (not sure what the common name is) with the laser pointer that checks temp, you can see which cylinder(s) are firing weaker than the others by the temps.

CAT3

iTrader: (9)

Thanks for the inputs, going to swap out the O2 now. Couldnt swap last night, so here we go. I do believe the exhaust leak also, I normally mention that myself, especially when its close to the O2 to suck air in on reversion, or if its up stream. Thanks,

CAT3

iTrader: (9)

I'm going to chalk this one up to a set of manifold gaskets I had to reuse my old ones when I swapped from the Jet Hots to the Kooks and well.....they leaking like BAD! I did the easy one and swapped the suspect O2 since I had a few laying around, not real responsive at idle, but they work great on the throttle, and then I could finally tune my ears around the loudness and heard the high pitch LEAKSSSS