I have an Edelbrock MPFI on a 502HT. The ECM that was chosen is a 16197427 BJKW broadcast code. It is supposed to be the broadcast code used in a '95 GMC 3500, but it seems like the OEM constants are very strange, and do not make sense for the OEM 454 or any engine for that matter. Take a look:

Fuel Cutoff Eng Speed________________ 0.00 RPM
Fuel Resume Eng Speed_______________ 0.00 RPM
Fuel Cutoff Speed __________________240.00 MPH
Fuel Resume Speed ___________________2.00 MPH
Main Spark Bias ______________________20.04 Deg.
RPM To Bypass WOT Delay __________1000.00 RPM
WOT Delay Period __________________158.00 Sec's
Max Speed for Idle Fuel Table __________93.00 MPH
Max Speed for Idle Spark Table _________0.00 MPH
Max %TPS For Idle Fuel _____________40.63 % TPS
Injector Flow Rate (Per Bank)_________ 318.39 #/Hr
Cylinder Volume (per Cylinder ) __________26.40 CID
EGR On, (TPS) _____________________31.25 % TPS
EGR Off, (TPS) _____________________41.41 % TPS
EGR On, (Eng Speed) ___________________0.00 RPM
EGR Off, (Eng Speed) ___________________0.00 RPM
EGR On, (Low MAP Window) _____________49.51 Kpa
EGR Off, (Low MAP Window) _____________10.40 Kpa
EGR Off, (High MAP Window) _____________10.40 Kpa
EGR On, (High MAP Window) _____________10.40 Kpa
Minimum MPH Tto Enable EGR _____________0.00 MPH
Maximum RPM To Enable BLM ___________200.00 RPM


The above set of constants are for the OEM, as well as what my engine is set up with. Do any of these numbers make sense? Its almost as if the definition is wrong. Could that be the case? The tables look reasonable, one or two points are a little odd, but most are what one would expect.

 

Are you using $0E ecm definition with it ?

W/t1500

 

I was using $OD, as that is what seemed to work the best when scanning. I also saw Howell using $OD when we recalibrate some stuff. Late last night, I tried $31 which is much, much better, but is still not right. I don't see a place where I can find $OE definition.

 

http://www.moates.net/fileman/index....neral%20Motors

W/t1500

 

Thanks, that helped a bunch. I don't see anything weird, it all looks normal. Calibration might need touching up, but at least now I know what I'm looking at. There is an interesting constancy at WOT, between my butt meter and AFR settings. Now I get to play .

 

Yep, those factory AFR settings tend to dip lean on WOT tip-in and then go overly rich though the mid-range to drown out the cats, then slowly lean back out some toward top-rpm. Wasteful on fuel and kills power.