Open Loop Running Lean

[NewV]

I cannot seem to get my previously dialed in AutoVE and MAF tune to run any richer than 14.9 average. I had the VE nearly perfect under 4K RPM then did the same with the MAF which I added back in. Now all of a sudden it runs lean.

Could it merely be the temperature change? It was all dialed in between 55-65 degrees F and the weather is now 28-35 degrees

I did rewire my WB but it seems to be behaving like it did before. Weird thing is if I run the bi-directional controls and command say 13.7, I get exactly 13.7 when I let it idle on its own it seems to hunt up and down from 14.4 to 15.3 and averages 14.9. Its seems like something is trying to force the 14.9, I even tried a new tune with 14.2 commanded and still averaged 14.9.

My wideband guage seems to display pretty erratically but comparing against my old dialed in logs it did the same. Does anyone else's wideband readings seem to constantly fluctuate?

Any ideas on what to try next? I even threw in an old CL tune as the WB is wired in to emulate the NB. Guess what the average AFR was? 14.9 :help2:

[TAQuickness]

Have you checked for leaks in the intake and exhaust systems?

[NewV]

Have you checked for leaks in the intake and exhaust systems?

I have check the intake and will look at the exhaust tonite but I don't hear anything noise wise. Its just so weird that I can bi-directional make it hold any AFR and the gauge will match. Makes me believe the WB is working properly.

[TAQuickness]

so if you use BIDI to command 14.9 you get it?

What is the commanded when you get the 14.9 (non-BIDI)?



let it idle on its own it seems to hunt up and down from 14.4 to 15.3 and averages 14.9


This is what makes me think you have a leak.

I have a leak in my intake manifold that I cannot pinpoint. I get a very mild hunting, but more noticble is the difference in actual AFR's from bank to bank. I can manipulate this with BIDI and B3647 so the effect is non-destructive.

[NewV]

So if you use BIDI to command 14.9 you get it? Yep, I get 14.9 or whatever I command +-/.1
What is the commanded when you get the 14.9 (non-BIDI)? 14.2
This is what makes me think you have a leak.

I have a leak in my intake manifold that I cannot pinpoint. I get a very mild hunting, but more noticble is the difference in actual AFR's from bank to bank. I can manipulate this with BIDI and B3647 so the effect is non-destructive.

I was thinking maybe I have a grounding problem as I haven't removed the WB simply rewired it. It was originally plugged into the cig lighter for power and all I did was splice the wires and hard wire it into the same power/ground source.

But, since the BIDI works I'm thinking my power/ground are ok but I've botched the tune somehow. I weny over the AutoVE checklist again last night with my current tune and it seems to be the same except for the MAF which I have now turned on (and I thought had tuned). I think I'll dump the MAF again and see what I log on the drive home tonite.

[TAQuickness]

The lights on now. The MAF is more sensitive to evironmental changes than than in SD. I think you have the right idea by returning to SD as a test, but likely the problem is the MAF cal needs adjustment for this particular condition.

[NewV]

Update, I disabled the MAF and averaged 14.8 AFR versus the 14.9 with the MAF, both in OL. I don't want to redial the VE and MAF in the cold conditions which are unusual for Texas (as you know TA). Guess I'll go back to closed loop and wait till it warms up some.

The only assumption I can make is that cold air is denser than warm air hence my lean condition.

[Chevy366]

I
My wideband guage seems to display pretty erratically but comparing against my old dialed in logs it did the same. Does anyone else's wideband readings seem to constantly fluctuate?

I kind of wondered that myself , mine does , but don't know if it is normal or not .
I suppose exhaust gases are not always the same content all the time .