tell me what this a-tap reading means

[Only4U]

i didn't get to write down exact numbers, but i a-tapped my car again tonight. under heavy loads, as usual, the knock reached a peak of about 3 degrees, and that didn't happen often. my 02s were FINE, and completely normal. my misfires were 0. but the one thing that raises concern is the long term fuel cells. 2 were being watched, and they said i was running lean (like 14 and 16 respectably at WOT) and from what the guy (who was a-tapping) tells me, they should be right at about 0 at WOT. so, this tells me the engine isn't getting enough fuel. source of problem? no whining from the rear, wouldn't think it'd be the pump. not plugs or i'd be having misfires to i assume. fuel filter? bought one tonight, gonna put it in tomorrow, but i doubt that's the main culprit of my problems, if it has ANYTHING to do with it at all. injectors maybe? i set up injector pulse on a-tap but i had no idea how to read that; not too mention, that number jumped around a LOT, but it was always around the ~6 area. so i don't really know what the problem is, but i'm running lean. now does anyone with experience knows what this means and what i should do to fix the situation? also, the more important question, how much is this hurting my performance to be running this lean? thx again.

[Magnus]

Common misconception is that LT's can say you're running lean or rich. They just are a factor of how far off from a STOCK style calibration you are off of.

IE: Your maf readings change yet airflow remains constant, LT's adjust.

IE: Your fuel pressure increased from stock 50psi to 60psi and now more fuel is going in per the same pulse widths, your LT's adjust.

Your post is very vauge. we need an autotap log.

RPM, MAF FREQ, TA, KR, PW, O2's, LT's.

[OneQuickV6]

On my car, with all the ram air and intake goodies....as long as my l-trims stay from about -10 to + 15, I am not worries about spraying the nitrous. They don't really mean you are rich or lean, they are just showing how much fuel is being adjusted kind of. More info would be good, and usually, I'd lean more towards watching your O2's for A/F ratios than the l-trims.

[WickEdSix9838]

i did a base a WOT log on my buds a-tap just for ****s and giggles and it turned out really good...the average L&S trims were -1.686 and my avg O2's were at .886 WOT with about 1* of knock...the only weird thing is when we logged the WOT runs, i think the L trims were not at 0 they were at -1.6, i dont know if it was a glitch or what??

[ January 16, 2003: Message edited by: WickEdSix9838 ]</p>

[Magnus]

STFT's will always be at 0 at WOT

my LT's once were -14% at WOT.. now with my new setup they are around 1.5%

i don't care either way.

[Only4U]

<blockquote>quote:</font><hr>Originally posted by Magnus:

RPM, MAF FREQ, TA, KR, PW, O2's, LT's.<hr></blockquote>

i am trying to get the log downloaded to my computer. until then, maybe this will help us...

by rpm, what do you mean?

maf freq i don't think we logged.

ta?

kr...usually below 2 degrees, but at the heighth of it, i believe i saw a 2.9 in there, usually right around the shifting points in first and second gear.

pw?

o2...like i said, they were normal....886 or something like that. o2s indicated i was running fine, not lean nor rich, that's why i was confused.

a/f was 14.7

[Magnus]

RPM.. engine RPM.. thats obvious
ta.. timing advance
pw.. pulse width

and I swear i've told you before autotap reported air/fuel ratio is worthless.. a waste of bandwith.. don't even look at it. it's not a real # its meaningless..

O2's are where its at.... and wide band o2's are REALLY where its at

[Only4U]

<blockquote>quote:</font><hr>Originally posted by Magnus:
RPM.. engine RPM.. thats obvious
ta.. timing advance
pw.. pulse width

and I swear i've told you before autotap reported air/fuel ratio is worthless.. a waste of bandwith.. don't even look at it. it's not a real # its meaningless..

O2's are where its at.... and wide band o2's are REALLY where its at<hr></blockquote>

ya, you're right. the rpm i KNEW, but i'm not sure what about it you want me to know? cause there are about 6000 different rpm values i could be having you know? ;) you want me to know it at WOT or do you want to know what those values are AT certain rpms?

i don't think we did timing advance or pulse width, but when i get a hold of the log later, i'll let ya know what i have, and you can tell me from there, heh.

correction, we did injector pulse width...it was a wide array of numbers...around 3-4 area at idle and then increased with rpms...not sure what it's supposed to be doing though. i'll get you exact numbers hopefully later on when i get the log.

[ January 16, 2003: Message edited by: Only4U ]</p>

[Magnus]

you need to LOG that stuff... and the values WILL change at different RPM's and that is very important.

[Magnus]

FYI, I have probably 200+ autotap log files of my car alone and 50+ log files from other 3.8 cars.

[Only4U]

ok, well the reading was logged, i know that for sure. but it's on HIS laptop, i don't have it at all. he told me he'd send it to me later this evening through email. i assume i can open it with microsoft excel? cause i don't have a-tap on this computer... worse case scenario, if you got the time that is, i could possibly just send it to you?

[DEE97GTP]

KR doesn't mean much without TA.

The only concern LT FT have are if they are near the max of their range. Somewhere around 20%. If they get maxed out, then your PCM effectively is at the edge of what it can adjust.

DEE

[Only4U]

ya, the last time my car got a-tapped, they were closer to 0, now they are back up again; and the first time i a-tapped they were where they are now. i have no clue why.

[Magnus]

If we want to go into real ADVANCED TECH detail...

long trims really play a role by showing the load to the PCM... and adjust timing and trans line pressures, and cold starts in open loop.