cammed 4.8 going very lean 5200rpm+

[LOWnEASY]

4.8 on 91 octain 214/220 111.5 cam
all stock except crappy cia(can tell from mmy ait's) and cam. so as you can see in my log, im am going very lean. i know i need to adjust my power enrich but how muck is the question. i dont want to do any more pulls untill i get an idea of how much fuel i need to add with out hurting any thing
iv seen that you only increase by .01% but im sure i need more than that but how much more. i do know its any ones guess but a genral idea would be nice

OK, here's a recap.
I tried adding fuel via pe table and it had no affect. It does seem when the ait's are lower, it stays "richer" a little longer but still falls on its face. I'm going to get a fuel pressure gauge asap. Any other ideas why its going lean all the sudden? And also why my IDC and MAF are hitting g that little "drop"? Does the drop in the IDC indicate loss of fuel?

[LOWnEASY]

maybe my PE don't need adjusted and its something ells? im lost! so what is causing me to lose fuel in the top end? i have a walbro 255 and a full tank of gas so it should be getting fuel too the rails

[5FDP]

Look at your O2 mv numbers, they completely die out once you went past 5200 rpm. That is not suppose to happen.

This is just my opinion here, but your PE afr that you want is a tad lean. I know they say lean is mean in some cases but you are upwards of 12.8. I'd figure you'd want it around 12.5 and perhaps getting a tad richer past 6000 rpm to some lower 12's to make sure you have fuel there.

[LOWnEASY]

The o2 MV is what I was seeing that led me to know I wasn't getting enuff' fuel. But another big question is "why is it dropping so quick?" Its like I shut the fuel pump of almost.

[LOWnEASY]

I'm not trying to use my stock o2's for wot, but I don't have the funds for a wb, so I have to make do for now to at least get me up to the top of my shift point. I don't care if it runs pig rich, I'm not after "max effort" with the tune yet. So how much should I add to the pe table to get me back in the ball park? .01%, or .05%?
Say I have a AFR of 13.0 and I add .01% to the PE table, what will that bring the AFR down to. Like I said, I know its any ones guess, but there has to be a "rule of thumb" for it. Right?

[Shane Hewitt]

Do you have a known good (or new) MAF you can throw on the truck? Judging by the dips in the MAF reading starting at 5:48.297 of your log, and by comparing your log to a bone stock 4.8 datalog I have on my laptop, I'd say you have something going on with your MAF.
When comparing to the stock datalog I have here, basically the higher your rpm goes, the less "believeable" your MAF reading is......anything above 4500'ish rpm or so the MAF reading just sort of flatlines instead of climbing , and actually tapers off as you're getting into what should be the meaty rpm range for a cam like that......something is not right.

[LOWnEASY]

Maf is only ~3 months old. Maybe a small vacuum leak that isn't there till higher rpm?

[Shane Hewitt]

I ask this as a legitimate question, not to be a smart-ass......is the MAF installed facing the correct direction (screen towards the air filter)?

[LOWnEASY]

yes, facing the correct direction. i added some fuel to the 5200+ in the pe table seemed to help some and was pulling harder but still not right
here are some more logs fist log is the first run, notice my iat's ar in the 80's but as they climb the more it leans out...

[LOWnEASY]

well even after adding fuel, its still leaning out at 5200+ im also thinking the maf doesnt have a direct relation to the lean condition im seeing, because its showing lean well before the maf dip. not saying that there isnt a problem with the maf, but then again i am a noob at this
this is tearing me up. iv been searching all day and cant come up with any helpful info...

[LOWnEASY]

OK, here's a recap.
I tried adding fuel via pe table and it had no affect. It does seem when the ait's are lower, it stays "richer" a little longer but still falls on its face. I'm going to get a fuel pressure gauge asap. Any other ideas why its going lean all the sudden? And also why my IDC and MAF are hitting g that little "drop"? Does the drop in the IDC indicate loss of fuel?

[LOWnEASY]

Any one?

[POWERZONE]

Any one?

Are you doing these WOT/ PE pulls with a wideband?

If so, I do not see AFR commanded or AFR error PIDS.

I would refrain from doing anymore WOT pulls until you get the tune panned out. You have some serious KR occuring.

[LOWnEASY]

No wide band yet. Going to order one this week.
I'm hoping the lean condition has some to do with the knock retard. I went in my timing tables and pulled the same amount the KR histogram was showing and it didn't change any thing. So its either something to do with the lean problem or false knock.

[POWERZONE]

No wide band yet. Going to order one this week.
I'm hoping the lean condition has some to do with the knock retard. I went in my timing tables and pulled the same amount the KR histogram was showing and it didn't change any thing. So its either something to do with the lean problem or false knock.

I do not recomend doing any more WOT pulls until you get a wideband and are able to log AFR commanded vs AFR error percentages. Right now you are majorly risking the health of your engine and you have major KR issues.

[93camaro_zzz]

Yeah, you are commanding like 35* of timing at WOT in the 6000-6700 regions. That is a metric crapton of timing. Also, like powerzone said, if you are not tuning this with a wideband, you should be.

[LOWnEASY]

Waiting on the wide band. Also, haven't even paid atintion to the timing up that high yet. Thats the way it came from the tuner for the swap before the cam install, but the shift points were also 5800 with that tune. So that will be addressed asap.

Say my pe commands 12.5 my wideband reads "lean" and fuel pressure is good, what would be the next step?

All in all, a person couldn't ask for a better motor to tune, if she blows due to my noob tuning its only a ~200 short block and a weekend of wrenching

[R0G3R]

It's gonna read lean regardless because you haven't modified your VE or MAF tables. Once a wideband is in place you should adjust your tables according to the percentage they are off.

[93camaro_zzz]

Waiting on the wide band. Also, haven't even paid atintion to the timing up that high yet. Thats the way it came from the tuner for the swap before the cam install, but the shift points were also 5800 with that tune. So that will be addressed asap.

Say my pe commands 12.5 my wideband reads "lean" and fuel pressure is good, what would be the next step?

The next step would be to add fuel to the car via VE changes or MAF calibration.

[LOWnEASY]

OK, so judging by the narrow bands, its lean. What should i add or subtract frkm the ve and maf tables wile I make the first hit or two with the wideband and go from there? I would rather it be rich and "tune up to lean". (Assuming its not fuel pressure related) I'm not trying to make any one do the leg work just a little confusing