How lean can I safely go during cruise? I'm trying to tweak my Open loop table for better mileage but don't want to melt a piston in the process.
Once I get set into OL permanently, is there anything else I should be looking at tweaking?
How lean can I safely go during cruise? I'm trying to tweak my Open loop table for better mileage but don't want to melt a piston in the process.
Once I get set into OL permanently, is there anything else I should be looking at tweaking?
Born on 11/20/06 07' GMC Sierra DMax EC 4x4 HPT
SOLD:2003 Silverado ECSB 4x4, LQ9, Patriot LS6, TR230/224, 31lb inj, TB Stall, HPT & LC-1.
While looking at a log from today I noticed something weird. Why does it look like my O2 sensors are turning back on for short periods and causing my AFR to go back to stoich? Seems to happens usually around idle or parked.
Last edited by Zick; 04-04-2006 at 03:38 PM.
Born on 11/20/06 07' GMC Sierra DMax EC 4x4 HPT
SOLD:2003 Silverado ECSB 4x4, LQ9, Patriot LS6, TR230/224, 31lb inj, TB Stall, HPT & LC-1.
Looking at your histograms, the LTFT & STFT are 0 so your in open loop.
Are your O2 sensors still plugged in?
16.0 - 17.0+ AFR is getting lean.
Russ Kemp
Take a look at your open loop fa vs temp vs map tables. To have a 14.7 commanded afr, you need the value of 1 at operating temps (14.7/1 = 14.7)
Of course you would need to be richer for cold starts.
A value of .90 is 16.33 afr !
Russ K
O2s are still plugged in, and I have my WB wired in acting as a NB as well so I cannot unplug that one.Originally Posted by Russ K
I have it set for between .90 - .95 once it hits operating temps.
I realize how to figure all that out already. I've only modified my OL F/A table when the engine temp gets up to operating condition and then I leaned out that area. The rest is stock, so its still rich when cold.Originally Posted by Russ K
What I'm trying to figure out is why when I'm in gear and say at a stop sign not moving, why does my AFR go rich to 13.7-14.7. I have it set for .95-.90 at operating temp and idle Kpa, but for whatever reason it is dumping more fuel than it should.
Born on 11/20/06 07' GMC Sierra DMax EC 4x4 HPT
SOLD:2003 Silverado ECSB 4x4, LQ9, Patriot LS6, TR230/224, 31lb inj, TB Stall, HPT & LC-1.
Just checked the scan data again, your open loop fa multi table values mostly match the commanded afr as scanned. Yes at certain map/coolant temps your commanding 14.68, but the wide band is not. If you want say a 16.0 afr, fill the table areas with .9175 at all maps from 176 & up ect. Then use the afr % error on the histogram to set your ve table.
Russ Kemp
Russ,Originally Posted by Russ K
The only problem is that the system will pick the *richest* AFR between Stoich and OLAFR. So the leanest you can actually go is stoich.
If you plan on going back into closed loop Stoich is the leanest you will go.
EC
Always Support Our Troops!
Ok, for example; this is while in gear and stopped.Originally Posted by Russ K
Temp = 192
MAP = 46
OL F/A = .90
this condition I am seeing 14 AFR.
So if I understand you correctly, your saying that my VE table is off at that spot and needs to be adjusted?
Still, why are my O2 sensors kicking on at this moment too?
Born on 11/20/06 07' GMC Sierra DMax EC 4x4 HPT
SOLD:2003 Silverado ECSB 4x4, LQ9, Patriot LS6, TR230/224, 31lb inj, TB Stall, HPT & LC-1.
Originally Posted by EC_Tune
Well right now, its going richer than stoich cause I'm seeing around 13.8 - 14.3 while in gear and idling.
Also, if I can get this problem fixed I probably won't be going back to Closed loop ever.
Born on 11/20/06 07' GMC Sierra DMax EC 4x4 HPT
SOLD:2003 Silverado ECSB 4x4, LQ9, Patriot LS6, TR230/224, 31lb inj, TB Stall, HPT & LC-1.
Your commanded afr varies by map, thats why I would set the OLFA table to .9175 at all maps from 176F and warmer. Then log your commanded afr, it should then stay at 16.0 from 176F and warmer.Originally Posted by Zick
If it does, use the afr % error histogram and copy & paste the error % to the ve table. Make sure dfco is disabled first.
The O2 sensors will still report mv when in open loop, the pcm will just ignore them.
Russ Kemp
Ok, I have everything from 176-212 temp and 20-65Kpa set at .90-.95Originally Posted by Russ K
I did not set adjust anything higher than 65Kpa because I don't want to lean it out under load.
So far when logging I see that the Commanded AFR is reading correctly until I come to a stop light. As soon as I come to a stop, my commanded AFR goes back to Stoich. Why is it doing this? I am in the Map and Temp to be commanding leaner but its ignoring this.
I realize that usually the PCM goes for whatever is richer but why does it only do this when stopped and not while moving?
Born on 11/20/06 07' GMC Sierra DMax EC 4x4 HPT
SOLD:2003 Silverado ECSB 4x4, LQ9, Patriot LS6, TR230/224, 31lb inj, TB Stall, HPT & LC-1.
I just noticed that you need to copy your open loop fa table to the open loop alcohol fa table. The help file says this table is used for flexible fuel capable calibrations only. I would give it a try.
Russ Kemp
Hmmm, didn't think that would be getting used but I'll give it a shot. I can't think of any other table that would be getting used during idle except for the OL F/A table.Originally Posted by Russ K
I'll report back.
Born on 11/20/06 07' GMC Sierra DMax EC 4x4 HPT
SOLD:2003 Silverado ECSB 4x4, LQ9, Patriot LS6, TR230/224, 31lb inj, TB Stall, HPT & LC-1.
Coping that table has helped stabalize my AFR at least, but something is still causing my idle to go back to Stoich.
But running like this I've been getting pretty good gas mileage.
Born on 11/20/06 07' GMC Sierra DMax EC 4x4 HPT
SOLD:2003 Silverado ECSB 4x4, LQ9, Patriot LS6, TR230/224, 31lb inj, TB Stall, HPT & LC-1.