in general will raising the flow rate (i.e. for 22 to 23.5) tend to lean (raise BLM) mixture? I just finished my 2rd burn and have the VP/Kpa/RPM figured out, i need to raise a little here and lower a little there, but at least I understand what i need to do!! Just need to set down and change ALL those constants--and reburn and try again. The car seams a bit smoother on accelleration, I basically lowered all constants by ~15% the first burn. It was very rich. Thanks for the great information. Mike ------------------ 90'GTA L98 Blk/Blk leather 355-4 bolt aluminum heads 10/1 forged pistons comp cams 510 lift 320/330 @.050 114 LSA full crane gold RR, 1 3/4" SLP headers ported lower/SLP runners 52mm TB, 24# SVO inj. T700R4 rebuilt by ME. all the trick stuff. superior shift kit. Fairbanks 9 clutch-noburn/.5" TV boost/Vette servo/Kevlar band/all new bushings etc.etc.etc.

Yes, increasing the injector flow constant has the same effect as leaning the overall engine (raises the BLM) at all rpms/loads.

It causes the ecm to shorten the pulse width in anticipation of the larger injectors. But because they are the same injectors, you go leaner.

Obviously, decreasing the injector flow constant does the opposite and richens the engine.

[This message has been edited by Glenn91L98GTA (edited February 24, 2001).]

Be very careful playing with injector constants instead of tuning the engine...keep in mind the EGR calc, accel enrichment calc and decel enleanment calc's are all based on the correct injector constant, just to name a few.
-Carl

To remove an overly rich condition I changed my injector flow constant from 22# to 25# (almost a 15% change) along with removing a massive amount of fuel from the VE tables. Everything is working great.

I am running 46 psi of fuel which does add more at higher load/MAP readings but at lower load/MAP, increased fuel pressure has its least effect. Just to give you an idea how confusing it must get for the poor ecm.

Since your fuel pressure has been raised it has effectively made your injectors larger so you can safely change your injector constant. Trying to help the newbies here to save confusion.
-Carl