What table should I be looking at?? I'd rather not just go in and start screwing w/ my prom without knowing what does what. After all one could do a whole lot of damage if they screw up. I need to address 3 problems:

1. Change the MAF values for diag. to get rid of my code 33. Already figured out that one.
2. I need to lean the mixture down low (2500 & under). Not sure how to do this. I do konw that my block learn is like 115 so it is running rich. I think that this will resolve my surging idle during open loop.
3. I also need more fuel at WOT. The O2 readings were low 700s so it needs some more up high.

Anyway if anybody has experience using tunercat on a MAF car, I could use a few pointers.

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355 10:1 , AFR 190 heads, LT4 HOT cam w/ 1.6 roller rockers, complete Superram intake, 58mm BBK TB, 24# injectors, screens out of MAF, MAT relocated, March underdrive pulleys, Streetdampner, Crane HI-6 ignition, 160 thermostat, K&Ns, TES headers(Jet hot coated), Mufflex 4' cat back, B&M shift Kit, 2500 converter, and 3.27s.

 

You'll need to adjust MAF tables 1 and 2 in order to lean out your idle. Use a scan tool to determine what your g/sec is at idle. Read this e-mail from Mark on the gmecm mailing list....

Date: Mon, 25 Sep 2000 10:20:27 -0700
Subject: Re: Part Throttle tuning for MAF (was MAF tables have a max of 255)
From: romans@starstream.net (Romans, Mark)
Reply-to: gmecm@diy-efi.org
To: <gmecm@diy-efi.org>

"Initial fuel*(BLM/128) = adjusted fuel. So if the BL is 135 and the maf is reading 50 grams/sec then you need to add about 5.5% to the grams sec maf calibration for the area of 50 grams/sec. So it would be 52.73 grams
sec instead of 50 grams/sec. I would also skew the area around the 50 grams/ sec area
upward a bit too. If the whole map is reading like this then you can either change the injector constant or raise or lower the fuel pressure.
(I think my math is right)
Mark"


You can adjust your WOT lean problem by adjusting the "WOT %Change to Fuel/Air Ratio vs. RPM" table. Raise the values to increase fuel at particular RPMs.

Tim

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TRAXION's 1990 IROC-Z
Best Time = 12.587 @ 107.97mph (1.710 60ftr) on the long runner setup.
All Natural. No Force. No Drugs. Stock Bottom End. Stock Body Panels. Stock Wheels. No Weight Reduction.
Gunning for NA 11's with the MiniRam II and Hooker LT Headers.
-=ICON Motorsports=-
Moderator: PROM board at thirdgen.org

 

I've had good results tuning a '165 by modifying the injector constant. Since your BLMs are lower than 128, I'd increase the injector size slightly in the PROM. Yes, this will lean out the *entire* fuel curve, but you can counter that by modifying the map Traxion mentioned.

To tune the WOT, adjust the WOT enrichment vs RPM table. You need BIG changes in this table to make noticeable results. Don't be afraid to go into the positive numbers, like 130% or more in the upper RPMs.

Oh, and one VERY, VERY important thing I've learned. Make sure, ABSOLUTELY sure, that the fuel pump is getting at least 13 volts at idle. The ecm code has a table that increases the injector pulse width when the fuel pump voltage gets lower. This causes rich running at idle. By supplying the fuel pump with the proper voltage, the ECM won't increase the pulse width. Been there, done that.

Nick