arf ratio at idel

[ony]

how can I ajust the afr ratio at idel , I have got a closed loop idel bin. it needs to be a little richer at idel but the rest of the bin works good, [ smells like the timming is to fast, and the adjusting jets are turned in to far on a carbed engine] don't have a cat, tried setting the timming in the bin back 4 degrees ideled smoother but still smells bad. didn't know if there was something I could change besides the 14.7-1 in the synchronized fuel ratio?

[EagleMark]

Without a CAT it will always smell rich. I don't care how good you are your nose is a horrible AFR gauge.

So that leaves a Wide Band AFR gauge...

The AFR setting or Stoich setting is dependent on fuel. Unless your paying for non ethanol which is 14.7 to 1 AFR? Most fuel is 10% ethanol and 14.13 AFR at Stoich, your narrow band O2 sensor adjusts to Stoich... not 14.7 to 1.

But there is an adjustment for AFR bias at idle based off O2 sensor. It's only a slight adjustment, not real accurate and will only do so much.
"O2 - Idle AFR Bias Value" = Bias used to lower AFR at idle.

[ony]

thanks eagle mark, my idle afr ratio bias at idle is 0.00 in tp I will try 0.50 and see what that does.

[EagleMark]

Was that your V6 bin? I'm used to seeing 109.0 for the V8 as a stock setting.

[ony]

yes its v6, I set it to 100.? it don't smell rich at idle its a to lean smell to me or timming to fast in an old ford smell. I set the open loop afr ratio to 14.4-1 but it stays in closed loop at idle most of the time so I didn't think that would affect it. I been running 14.4-1 in open loop for along time to get rid of the rich smell at idle. lean cruise is still working good went 140 miles [on the high way] the other day seamed to get 20-21.5 mpg an run pretty good just when I stop its got that bad smell. not bad mpgs for a old worn out chevy pickup.

[EagleMark]

That Stoich AFR setting is what's used in Closed Loop.

[ony]

I got to go to the store here in a few minutes I will see if changing the idle bias helps, if it don't I guess I will start dropping scotch in closed loop down,you proble know how many chips I have burned [playing] I get back to work I am going to get a tune on the fly set ups. ever time I change something burn a chip, I think one of my sst 512s is getting worn out have to play with it awhile to get it to program some times.

[RobertISaar]

there could be a couple of reasons for that, usually bad contact on the chip's legs. every once in a while, if i have a PROM that hasn't been installed in anything and attempt to use it, reading/writing to it is a no-go. i end up "polishing" the sides of the legs that make contact with a ZIF socket with a pass or two on each leg with a sharp edge on a knife. VERY little pressure needed, ends up nice and shiny for a couple of months of being uninstalled.

[ony]

that proble what it is, if I put it in my programmer an slide it side to side as I close the lever slowly it usely works,i may need to clean all the little legs. went to the store, now I do have a rich smell at idle not real bad it seams to operate smoother at real low speed, I will drop the bias back to 50.00 an try it out Monday evening if it hot enough here,if I don't data log about the same time of day ever thing changes a lot, for a out side temp change of 70 of the morning an 90 degreez of the evening, I think it the air moisture % that makes my blm change, I notice it changing more when I get on the gravel and dirt roads to the house.been thinking about employing the egr at idle an using the bpw consitn to get it to smell better.

[EagleMark]

As many times as you have burned chips, your legs are probably worn thin? May need a new chip...

EGR at idle is thinking outside the box! Not sure the results are going to be good though?

[RobertISaar]

EGR at idle.... very tricky and slippery slope. it doesn't take much EGR at all to turn a rock-solid idle pretty choppy.

[ony]

I guess that is kindof off the wall thinking, I dropped the % of the egr at 1200 down to 94-95 % it helped with jerking on hot restart as I go across parking lots. the legs on my chips do need cleaned their not corroded but discolored alittle.

[EagleMark]

EGR at idle.... very tricky and slippery slope. it doesn't take much EGR at all to turn a rock-solid idle pretty choppy.

With a vacuum operated EGR I don't think it would have the control to even try?

[RobertISaar]

possibly. i'm used to the 3 tower digital EGR, if i manually switch on the small solenoid at an idle, there's a noticable stumble at first, then the IAC and spark catch up to it, and if in closed loop fueling changes too. if the medium solenoid goes on, big stumble, almost never stalls, IAC/spark/fuel and it gets back to the desired idle speed, but noticable lope happens. switch on large solenoid and it can stall the engine if the idle correction stuff isn't VERY well matched. takes a little longer to get this one back to desired speed, and when it does, it sounds like an entirely different cam.



you know, maybe i do want EGR at idle

[ony]

on a 747 ecm what is [ egr on low vss] in tuner pro. my bin is set to 0.00 ?