Scanmaster read 023 @ 0.0 What does this mean??

[SLZ]

I took off from a light this morning and the car pulled good (no running issues) but I noticed the scanmaster locked in that pull at 023 @ 0.0 timing. I have always seen the scanmaster #'s go all over the place (on the o2 side) while the car is running. The car has been running rich and would lock in between 780-870's normally when I accelerate enough. This is the first time I have accelerated and the scanmaster showed me this low #. Car operates fine with no noticable issues. Was there detonation? Please LMK.

Also, is the scanmaster o2 #'s suppost to be all over the place when running or steady around 750-800?


Thanks, STEVE Z

 

[Missouri T]

Which Mass Air do you have? Stock? LS1? LT1? 4" Full Throttle?

023 at WOT is scary lean.
Yes the O2's do dance around constantly.
I think the only time they sit still is with a Turbo Tweak chip at idle.

No other driveability issues to report? Idle? Stumbles?

 

[SLZ]

The MAF is a stock Advance Auto replacement. No idle, drivability issues except it runs rich/drinks gas. (Scanmaster has a code 45 on it w/no SES light on). I would like to get rid of my rich condition (changed the o2 sensor twice). I wonder if the replacement MAF has caused this condition (never was there before the original MAF died).

 

[turbojd]

Those aftermarket stock replacement mafs are horrible, it's hard to find a good one if you do. I would buy a translator and an 3" LT1 maf or an LS1maf and be done with it.

 

[Missouri T]

I second that.
To heck with the "rebuilt" ones.

Go to Full Throttle and look into their 4" intake and mass air.
It's the latest and greatest.
Mike has them on sale here on the board, look under advertisers specials and Mike Licht.
Hell of a deal.

Face it, you WILL be getting some sort of aftermarket mass air.
It's a shame you already spent the money on a "rebuilt" stocker.

 

[johnnyttype]

what kind of o2 sensor r u using? if u think its the MAF u should have some sort of warranty on it and take it to advance and swap it. or upgrade it like mentioned before! what kind of chip do u have?

im not sure but i always thought the MAF did not affect WOT because the car went into power enrichment. unless it is specific to the type of chip being used. i use a turbotweak and it idles around 800, all over the place cruising, and WOT is 750 to 850.

 

[Real-T]

That is correct, the MAF does not "really" affect WOT in the PE mode (if your chip has one) but in order to do so the MAF number must be pegged at 255.

If the MAF is marginal and the Airflow readings are less than 255, the then the ECM will fuel according to that.

Now, if that "less than 255" airflow is bogus (and at say 14psi WOT it likely is) then the fuel will be way lean.

As an aside, make sure you fuel pressure is up during a WOT blast.

Even having the vacuum line pop off the regulator can cause your 02s to be that low.

Note: an O2 in that low a range usually indicates about a 15:1 A/F ratio........maybe even leaner.....

 

[johnnyttype]

That is correct, the MAF does not "really" affect WOT in the PE mode (if your chip has one) but in order to do so the MAF number must be pegged at 255.

If the MAF is marginal and the Airflow readings are less than 255, the then the ECM will fuel according to that.

Now, if that "less than 255" airflow is bogus (and at say 14psi WOT it likely is) then the fuel will be way lean.

As an aside, make sure you fuel pressure is up during a WOT blast.

Even having the vacuum line pop off the regulator can cause your 02s to be that low.

Note: an O2 in that low a range usually indicates about a 15:1 A/F ratio........maybe even leaner.....

thanks that clears things up for me:smile:
last time my car said .023mvs was when the heated element in my heated o2 kit took a dump, which apparently takes the whole sensor out!

 

[2 QK 4 U]

For what it's worth...

I had the same problem and it was my fuel pump.

I was getting like 032 and 028 O2s. Car would take a dump about 60 feet out.

 

[TT/Ameasap]

I was always under the impression that if the 02's are showing that low then it is cycling over .999 into the 1000's. Correct me if im wrong because running that low would have blew something up.

Just my .02