Lazy front O2 after Header install.

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10-24-2010, 04:03 PM

#21

GMCtrk

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Quote:

Originally Posted by Suddog

Will Speed density work until I get my new o2's? I set the MAF to 0 and did a run log. LTFT on bank 2 were around +25 area...then stayed there until I opened up the throttle. Now they stay at +13 on bank 2 and -13 ish on bank one.

I thought SD mode would take the o2's out of the equation? Could my fuel trims be out of whack again?

SD takes the MAF out of the equation. To disable the o2 sensors (open loop) you need to disable long term and short term fuel trims.

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10-25-2010, 12:26 PM

#22

axekick

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Thats not very safe, though, unless you're watching your air fuel ratio with a wideband O2 sensor. If you want to do it anyway, you can just set the Closed Loop Enable temp to maximum value so that it never goes into closed loop.

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10-25-2010, 12:35 PM

#23

BlackGMC

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Quote:

Originally Posted by Suddog

Sounds like you have an exhaust leak to me...Did you use the factory exhaust gaskets???

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10-25-2010, 02:34 PM

#24

Suddog

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Quote:

Originally Posted by BlackGMC

Sounds like you have an exhaust leak to me...Did you use the factory exhaust gaskets???

Factory gaskets were reused at the head, but at the collector, used the supplied gaskets. AC Delco O2's are on there way, gonna take a week to get here.

I'm gonna pull the injectors to see what they look like, if needed, I will swap them with replacements I bought. The thing that bothers me most is all this occurs at around 170ish ECT. Once warm it goes away. Now it is more frequent even in SD.

Could a massive air pocket create this dilemma? What is the best way to burp the cooling system?

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11-01-2010, 02:57 PM

#25

Suddog

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Any last thoughts on this subject? O2's finally arrived. Just don't want to put them in and have them fouled by the LTFT's.

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11-01-2010, 05:37 PM

#26

budhayes3

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Quote:

Originally Posted by Suddog

Any last thoughts on this subject? O2's finally arrived. Just don't want to put them in and have them fouled by the LTFT's.

I'd try the new O2's first and log their activity to make sure that their switching rapidly like they should...if they're still lazy I recommend getting the headers coated.

Some guys have used a "Corvette" O2 sensor that supposedly has a hotter heater element and it has worked for them...I don't have the part number, but I know that I've seen a Bosch Corvette O2 sensor part number somewhere in the GM section...