I have a 400 SBC with a TPIS Mini-Ram. I have a 6870 ECM and #30 injectors. I can not get this car to run lean and am getting ready to buy #24 injectors.
I found that when I set the injector pulse width to the very edge of small the car will stall. then when I move it up only a few USECs the car goes rich. I moved the MAF tables with the same results. My final idea was to cut the fuel pressure back. I found that the only time the car went lean is when the fuel was off. Am I missing somthing. How do the counts in the MAF table correspond to the injector pulse width that is in LV8s. Is it possible the injectors are just to big?

Frank

 

Possible, yes. It can only go down so far with pulse width before it can't anymore. The injectors become erratic. I'm not saying this is your problem, just saying it is possible.

 

Frank, you have mail (yahoo account).

 

This might sound stupid but have you tried the injector constant?

 

This is one of the issues with the 6870 ECM for 1985. The injector constant is not available. They have a full table on pulse width. When I bring this all the way down the motor stalls. Then I increment it up and then it goes rich, imediately

 

i have had the exact same fuel (over)delivery symptoms you describe. super ram with 24 pounders-pressure up, 108 was the number i saw most always. pressure down-im talking 35 psi, she would idle ok-still phat but ok.and suffer on the top end.most everyone who has increased the displacement and injector size, that i have spoke with describes similar problems. because if the math is done the increased injector size is fairly proportional to the added displacement. 305's at 19 lbs. 406's at 24lbs(or slightly larger depending on the method used to rate). i think it has something to do with how the 870 reacts to the increased idle airflow that you get with a increase in displacement. cant scan actual gps at idle because of the fixed 1K idle along with the other 160 baud poo-poo, but stock 305\350 ive seen are showing 7,8,9, at idle.with the 406 in my 85, at 1000rpm i was seeing gps #'s of 12,13. now have ditched the 870 in favor of a 165 and dfi,and the 30 pounders are here ready to go in. swapped ecm got me able to scan accurately, dfi got me a straight hose where the maf once was. dunno if this helps-other to let ya know that it isnt an uncommon problem, from what ive seen.