badass 2002 z28

iTrader: (5)

I had my car a-tapped and found out that i was runing way rich so i went and got a MAFT. Here's the thing...what do you guys suggest i set my MAFT at?

My Ltrims were maxed out at 25% @ idle & WOT
My O2's were reading 940-965 @ WOT
and i didn't have any misfires

I don't have easy access to an autotap so i was wondering if i supplied these numbers if you guys could figure out what my setting should roughly be around.

Right now i have the MAFT set at 10% rich (base) and 8% rich (WOT). Is this around where i should be? The car still seems a little on the rich side.

any help would be appreciated. I just want something to told me off until i can either dynotune my car or have it autotapped again.

really slow truck

do you seriously have it set at 8% rich at WOT? or did you mean lean? considering ur 02s were at 940-965 at WOT i would want to send in less fuel not more fuel...

bryan

badass 2002 z28

iTrader: (5)

well i was told that when you set the MAFT to like 8% rich it does the opposite and leans it out, or am i wrong?

Colonel

No, if you set it %8 rich it will be richer than at %0.

With Ltrims at %25 your computer is getting a REALLY lean reading. You should get a too lean DTC. You need to find out why it's like this. Could be a vacuum leak, an exhaust leak (this would give a false lean but would show on only the bank or banks that the leak was on), a faulty MAF sensor, messed up injectors (again, only on the bank(s) that the bad injector(s) was/were on.)

Was this %25 reading on both banks and under what condition? Was it during closed loop? Idle, part throttle or WOT?

It would be of GREAT help to have easy access to Autotapped to fix this problem.

[ December 04, 2001: Message edited by: Colonel ]</p>

Bad30th

iTrader: (13)

I noticed you have the !EGR mod. I had a vacuum leak from a leaky o-ring seal when I chopped my EGR that brought my LTrims up to about 20-25%. Check the seal at the EGR tube for vacuum leaks, or even re-seat that seal if it's questionable.

+25% means you are running VERY lean at idle, and 940-965 O2's at WOT is very RICH. I would look for a vacuum/air leak past the MAF (EGR mod with bad seal is a big culprit). If you aren't leaking anywhere, I'd start with +10% (2nd notch) on MAFT base. Drive for a few days varying load/rpms to re-adjust your ECM, then ATap again to see where you are. Once you get the base set to between 0-+10%, see where your O2's are at WOT. They should be .880-.910mV. Adjust your MAFT WOT setting to get you there once the base setting is tuned.

So a search for MAFT tuning, you'll find lots of useful info.

Good luck,
BadAss30th

Lane

iTrader: (1)

What mods do you have?

Pro Stock John

iTrader: (34)

A few years ago when I ran the Whisper MAF ends I would see 23-25% L trims...

Keep in mind that the max reading and correction is 25%.

I would add fuel to the base until the Ltrims are like 0-10%.

badass 2002 z28

iTrader: (5)

So i should richen up the base setting and lean out the WOT setting?

My car's not setting any codes so i don't know what's up.

[quote]Was this %25 reading on both banks and under what condition? Was it during closed loop? Idle, part throttle or WOT?<hr></blockquote> It was both banks and it was a constant 25% @ idle & WOT

[quote]What mods do you have? <hr></blockquote> Lid, !FRA, !EGR, Fenco mod, MAC headers w/ OR pipe (o2 sims), full 3" cat back with cut-out.

Colonel

Yep, if you've done the !EGR mod then that's probably it. I had the same problem once.