Swapped MAFS, now weird issue

[Dale]

So I had a 4.3l maf on my 5.7l just to get it running. This past week I swapped to the propper 5.7l maf. As expected, it thru my VE table off and I started to adjust it.

I have adjusted it 10 times.... At idle this thing is sputtering running rich and it still is asking for 6-10% more. Other areas it keeps asking for 20% fuel in areas that is already at 91ve. If I raise it more, its going to put my ve over 100.. which if I'm thinking right, that means my motor is actually "boosting" itself correct? My fuel milage has almost cut itself in half.

No way this motor and setup is able to be self boosting. What else should I be looking at that is wrong?

[TAQuickness]

Sound like the MAF is not disabled. Try running thru all the steps of the AutoVE tutorial to get the VE table lined out. Once done, enable the MAF and repeat the concepts of the AutoVE tutorial against the MAF table.

[GMPX]

If you are running the MAF still, is it scaled correctly for the MAF you have? Table B5001

Cheers,
Ross

[Dale]

TAQ, I cant do the Autove because I dont have a wideband.

GMPX. Yes, I always kept the 5.7l maf chart in the ecm...even when running the 4.3l maf. Forgot to mention that, sorry.

[TAQuickness]

A wideband would help you a lot at this point.

[Dale]

It took me 5 months to get money for a maf sensor... and only reason I got this soon was my connection for discount is quitting.

Id take me about another year for a WB. Plus, with the other maf I got it dialed in. This maf is just all over the place. This morning at idle it said remove -3. So I did. On way home its saying add 10. WTF?

[scuzz]

Dale, is the part number different from 4.3 to 5.7?
Ron

[jfpilla]

So I had a 4.3l maf on my 5.7l just to get it running. This past week I swapped to the propper 5.7l maf. As expected, it thru my VE table off and I started to adjust it.

I have adjusted it 10 times.... At idle this thing is sputtering running rich and it still is asking for 6-10% more. Other areas it keeps asking for 20% fuel in areas that is already at 91ve. If I raise it more, its going to put my ve over 100.. which if I'm thinking right, that means my motor is actually "boosting" itself correct? My fuel milage has almost cut itself in half.

No way this motor and setup is able to be self boosting. What else should I be looking at that is wrong?

Dale,
You didn't answer TAQ. Are you adjusting the VE's with the MAF enabled?
Joe

[Dale]

For some reason I didnt get a notice there was responses.

Ron...
4.3 c1500 and 5.7c1500=same part.
4.3 s10 and 4.3 c1500=different part.

I swapped from 4.3s10 to 5.7c1500.

For now, I swapped back to the 4.3s10 maf.



Joe,
Yes, I am adjusting the VE table with maf enabled. Always have.

[TAQuickness]

Due to the way the PCM blends values from the VE and MAF tables, you will need to disable the MAF, as per the AutoVE tutorial, in order to get the VE table dialed in. Once the VE table is right, you can utilize the same principles to dial in the MAF.

[Dale]

Last time I disabled the maf, the car wouldnt even idle w/o my foot on the gas. :bad:

[TAQuickness]

Hm.. Now's probably the time to pick up a WB so you can get an idea of what the fueling is doing.

What mods are on the engine? If it's just a few bolt ons (no cam, stock stroke & displacement) you should be able to start with a stock tune and add 5-7% accross the VE table to get you started. Idle issues could be rough during the first pass at AutoVE, but should line out pretty quick.

[joecar]

Hi Dale,

The motor should run with no MAF (and no O2's also)...
that is the original purpose of the VE table...
do what TA said, a wideband is a very good tool.

[Dale]

TA. Since this is a full custom setup, I guess everything but the CI off the motor is modified. Having major problem getting my idle right. Got it close, then air temps changed and now its all wack again.

Anyway...
350 block
810 swirl port heads
unknown valve overlapped cam
TPI intake
headers
full 3" exhaust
0411/02 express van code


joe, why would I disable the o2's? Isnt that what I need to change my ve table?

[TAQuickness]

You'll want to disable the NBO2's to prevent fuel trimming while you tune the VE and MAF tables.

I would procede by acquiring a WBO2, follow the AutoVE tutorial with a 10% across the board start. You may need to manually tweak the idle range of the VE table and DAF table to establish a functional idle. Once it runs though, you should be able to follow the AutoVE tutorial no problem.

[Dale]

DAF=B4307?

I think my idle problem has more to do with the temp/density of the air... which is another thread and problem. Still trying to search on it.