Gentlemen:

Would like to resolve the TBI to MPFI (batch) injection situation wherein jumpering from 2nd DRP to 4th DRP. Going back to March of 2013 the following was posted:

"Mod'd the 16197427 ECU. Put jumps across the two current sense resistors. Also put a jumper on the Memcal per the photo from HP tuners. Installed the ECU in the Suburban and started it up. Wow does it run shitty. Shut down the truck, removed the ECU, opened it up and removed the Memcal jumper, re-installed it in the Suburban. Ah, back to running smooth. Don't know the pin layout of the Memcal so I will stay away from jumpering it for now. Set up TunerPro RT to record BLM values at idle and off idle. Open loop at idle, it fills the BLM cells with 128. Set up TP to record off idle BLMs. Ran the Suburban for several miles to warm it up, varied the speed, RPMs, gears to fill in as much of the off idle BLM cells as possible. Then came back and parked at the house. Went back to idle BLM map, varied throttle to fill in as much BLM cells as possible. Captured all with MS Excel spreadsheet."

Getting better at tuning GM TBI 7427 ECMs. Trying to reason what happened when going from 2nd DRP to 4th DRP. Wow dId it run shitty. Must have been too lean? Still trying to figure out why it would run lean.

Any ideas you fellows? Please advise. Thanks.

Rolly