DanielRicany

Yeah you need to make sure that the AFR is even all across the board. How lean is lean?

colter

Ideal BLM is 128. I think actual lean is over 138 BLM. It's my understanding the computer can only compensate rich/lean in the 118-138 BLM range. So I think any BLM outside that range is actually running rich or lean inside the engine.

Some say you're okay as long as BLM doesn't hit 160. But I believe 160 is just the limit on the data you see and not a limit on what the computer can compensate.

So looks to me to keep the BLM in the range of 118-138, but more ideally try to get it to 123-133. That way there is some room there for example if you get bad gas, or gas with more than 10% ethanol or something that could affect BLM in that tank of gas.

DanielRicany

I try to tune with the average of between 124-132 BLM for each given MAF cell. For MAXIMUM and MINIMUM BLM within each cell, I do not like to see anything outside of 118-138. So if those pop up I will attempt to correct it. Also, the PCM can only adjust fuel until 108 or 160 BLM. After that, the fueling will be whatever it is.

colter

I've read the 108 and 160 aren't computer max adjustment points. That they are just limits on data that you will see. For example in the tune, you can lower 108 or raise 160 to see data below and higher than those stock limits.

But they say the computer can only adjust inside the 118-138 BLM range. So if you are running 145 BLM's, then you would actually be running lean inside the engine as it would be too far out of the adjustment range for the computer.

383vett

You two should exchange phone numbers. Colter would have his car tuned by now.

Billygoatkid

I'm not that lean, just a little up top.
i got a bung welded into exhaust to put a wideband in now.
i had gone the wrong way at first few attempts at maf change.
correct formula is:
take avg blm number / 128 = thus number X maf number in table.

once I do a few more runs I'll adjust the pe table.

its weird how my original table has negatives and less on higher rpm . I posted it earlier.
on the histogram around town if I punch it, it shows lean cell

Billygoatkid

If I think I'm lean wot I don't see how increasing values in pe table would be a bad thing to try? Nothing to lose because I'm adding fuel right?

DanielRicany

You should have your MAF tables tuned correctly first so it makes it a lot easier. Tuning AFR by RPM is tough.

Billygoatkid

ok I have a wideband in place and I'm ready to try running wot

where do I start with tunerpro?
the coolant table or rpm vs wot

thx

DanielRicany

You're probably better off adjusting the rpm table instead of the coolant table actually so that way you don't have to worry about cold WOT being off.

GREGGPENN

I tend to agree though I question the "stock" PE vs TEMP values I've seen in the AYPY bins found on the net.

From what I've seen, they are all set with 22% enrichment though that's higher than max torque AFR would dictate. When I do the math for gasoline, 10% gasohol, or 15% gasohol, they all would require a 17% bump to get to maximum (rich) PE enrichment.

Because I didn't tune with a wideband, I don't know how that translates to actual AFR but the dyno runs (I did) lend me to believe it was pretty accurate.

As such, I lowered my PE vs temp values 5% across the board. I know different elevations can affect what you "need". I'm in an "avg" location where I doubt that applies. (To be honest, I did have them 10% leaner for most of the past 5 years w/o discernible issue...then I read it's better to be 5% rich than 1% lean.)

Other considerations are: economy and that you can also read where HP might benefit from a PE on the leaner side of enrichment. I think the stock AYPY bin can provide clues -- if you think about it.

EDIT: I'm also befuddle by how many posts I've seen over the years recommending a bump in fuel pressure via AFPR. When it LOOKS to be rich from the factory, it seems counter-intuitive that more fuel would help. In fact, if anything it seems like slightly less would increase HP (for most areas of the country). Of course, there are people who rotate their distribute (to bump timing -- above it's already "hot" setting). Maybe 89 had the richest, hotest BIN of choices out there?