Vette acting wierd, help needed

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Sep 20, 2009 | 10:04 PM

fotoboy

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Vette acting wierd, help needed

AF is not stable, bounces from 10.7- 15

The car: 98 c5 m6 stock lower w Head and cam + 125 shot of spray

Series of events:

Got car tuned at CC ran better than ever
Started spraying again week after car still running great
was running a few tanks of 50/50 pump/race gas (what I thought was unleaded but not) lol still running fine
plugged into a friends laptop and car went whacked and we could not get it started or logged into his pc, finnaly got the car running and tool her home
Checked coded and both o2s were giving codes
Changed both 02 senors after figuring out that the race gas I had was not unleaded
Had the car ecu completely reflashed back to stock and the custom tune reloaded
Car has ran great until sat night after a night or fun in Canada on the way home the af started acting up again, right o2 giving another code.
Changed the right o2 again today hopping it was just a fluke bad new 02.
Went for a drive today and not throwing any o2 codes but the af is still wacked. And at times will surge at idle from 2000 to 200.

Thoughts?

Last edited by fotoboy; Sep 20, 2009 at 11:07 PM.

Sep 20, 2009 | 10:35 PM

lucky131969

Tech Contributor

Joined: Jan 2007

Posts: 19,465

Likes: 1,167

From: Dyer, IN

Quote:

Originally Posted by fotoboy

AF is not stable, bounces from 10.7- 15

Series of events:

Got car tuned at CC ran better than ever
Started spraying again week after car still running great
was running a few tanks of 50/50 pump/race gas (what I thought was unleaded but not) lol still running fine
plugged into a friends laptop and car went whacked and we could not get it started or logged into his pc, finnaly got the car running and tool her home
Checked coded and both o2s were giving codes
Changed both 02 senors after figuring out that the race gas I had was not unleaded
Had the car ecu completely reflashed back to stock and the custom tune reloaded
Car has ran great until sat night after a night or fun in Canada on the way home the af started acting up again, right o2 giving another code.
Changed the right o2 again today hopping it was just a fluke bad new 02.
Went for a drive today and not throwing any o2 codes but the af is still wacked. And at times will surge at idle from 2000 to 200.

Thoughts?

It's my understanding that leaded fuel will contaminate cats, if that what you ran, they are probably toast.

Sep 20, 2009 | 10:36 PM

fotoboy

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Quote:

Originally Posted by lucky131969

It's my understanding that leaded fuel will contaminate cats, if that what you ran, they are probably toast.

cats and rear o2 sensors are gone

Sep 20, 2009 | 10:45 PM

lucky131969

Tech Contributor

Joined: Jan 2007

Posts: 19,465

Likes: 1,167

From: Dyer, IN

Quote:

Originally Posted by fotoboy

cats and rear o2 sensors are gone

If he cats are contaminated, their efficiency is gone, therefore the rear O2's will throw codes. Until you get around to messing with it, you could always just have the rear O2's turned off.

Sep 20, 2009 | 10:47 PM

bigleman

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Joined: Apr 2006

Posts: 502

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From: Stn Mtn GA

Quote:

Originally Posted by lucky131969

If he cats are contaminated, their efficiency is gone, therefore the rear O2's will throw codes. Until you get around to messing with it, you could always just have the rear O2's turned off.

but he just said the cats and rear O2s are gone, you quoted it

Sep 20, 2009 | 10:48 PM

fotoboy

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Drifting

Joined: Oct 2004

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Quote:

Originally Posted by lucky131969

If he cats are contaminated, their efficiency is gone, therefore the rear O2's will throw codes. Until you get around to messing with it, you could always just have the rear O2's turned off.

car has had H/C for 4 years and been fine, we turned off the rear o2 sensors in the tune. As stated it is not trowing any more codes and I have checked them all on the dash and cross referenced them with my definitions. The car is a 98 and they are known for having crappy ecu's

Sep 20, 2009 | 11:04 PM

lucky131969

Tech Contributor

Joined: Jan 2007

Posts: 19,465

Likes: 1,167

From: Dyer, IN

Quote:

Originally Posted by bigleman

but he just said the cats and rear O2s are gone, you quoted it

Sigh....I thought he was agreeing. My minding reading skills are just a little off these days. With no specific posted codes, and explanation of the setup on the car. Perhaps I'm just tired.....F-it.