Bank 1 lean....?

I have been trying to get my tune dialed in and I am still fighting with a lean issue on bank 1. It's a 98' camaro... 6 speed. Mods are:

Prc 5.3 heads ( milled to 59 cc's )
mls gasket
custom cam ( 227/228 ... 649/598 ... 111 lsa )
30 lbs injectors
ls6 intake / pp tb
long tubes and off road y-pipe with hooker catback
lid/smoothbellows

Pretty much all the basic mods... Car runs pretty good and I have got it tuned to 26 deg timing with no kr. Under WOT the ltft is 6-9% on bank 1 and 2-3 % on bank 2. At idle, bank 1 ltft is 14-17% and bank 2 is 4-6 %. I have done new plugs/wires, both o2 sensors, new intaked gaskets ( and checked for vacume leaks ) , new pcv system, new injectors and swapped coils on both sides as well as checking the o2 wiring. Also checked the exhaust for leaks ( EVERYWHERE ) ... Is there something I am missing? Please take a look at my tune and log ( this is the latest log and it's only idling.... did the rafig process ... also the log is pre-rafig adjustment, but the ltft trims have not changed since ). Any ideas would be great, as I am out of them :help:

Did you replace the stock O2 sensors with generic or Camaro specific part numbers? The Camaros have an issue that when you install good high flow headers, the O2 sensor doesn't get a good amount of hot air hitting it and it doesn't work properly.

In further detail, the Camaro specific O2 sensor uses a heating element that heats the O2 sensor a little and the exhaust gas does the rest. On a high flow car, the O2 never gets up to operating temp and the wussy heater in it doesn't get it up to temp either. The generic Bosch O2 sensor uses a different ohm heating element and will bring the O2 up to temp whereas the stock O2's WILL NOT (has been proven). You will also get random SES codes and usually on bank 1 (drivers side, something to do with the crossover i assume).

Have you verified the lean condition with a wideband O2? Have you physically looked at the header after a run? Is it glowing hot like from a lean condition (Lean = Extreme EGT). Discolored headers are ok, flaking off coatings and/or cracks at the welds are NOT ok.

More info needed. My suggestion is just try a generic O2 sensor in the bank 1 and see if the issue clears up...OR, find a way to ram more air into the engine. She breaths way too good, obviously.

The header is not glowing after a run and I pulled the plugs ( on bank 1 )and they are a nice tan tone. The o2 sensors were bosch replacements. I have a wideband I am about to install, but the bung is right after the bank 1 o2 sensor and I don't want to tune off that bank if there is an issue.... One thing is when i did the rafig process I had to remove about 20% of air from the desired airflow table. Warm starts require a little pedal assitance to get the idle to smooth out now... not sure if that has anything to do with it?

http://forum.efilive.com/showthread.php?t=10677

answers all here...been there done that.. :)

Quote:

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Originally Posted by The Alchemist

http://forum.efilive.com/showthread.php?t=10677

answers all here...been there done that.. :)

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Yup, this is what I was talking about. Alchemists thread covers it all.

I will be replacing the o2's with the ones mentioned. I got the car on the dyno and the wideband shows 12.9-1 all the way through the band. I am still getting a about 1-2 deg's of KR ( common issue I have heard on the 98's). 2 questions. Is it better to upgrade to the knock sensors to the newer styles, or work with the software to manage the knock. Also, I still have some idle hunting on warm starts. Only when the IAT temps are above 110... What table works with IAT based corrections on start-up?