I am hoping someone here can help. I took out a 350TBI and put in a 454TBI and it runs way lean at idle and under load runs like hell. can someone tell me what to do to change this. i think i read on here somewhere you can program the ecm or burn something. oh yeah this is for a 88 suburban. and the 454 is out of a 94 step van that we don't know the vin to.

 

sorry no response. i was out of town. what year is the recipient of the 454. i assuming that you swapped the whole engine and not just the tbi unit. if so then the chip needs to be reburned with the 454 spark and fuel maps. if just the throttle body then the chip will still need to be reburned with the "pump shot " and ve tables needing adjustment along with the pe spark tables. either way its time to learn chip burning. I hate to sound like a broken record, but read the stickies. very informative. if more questions after reading then just post up. on the hardware side of things, the iac wiring is different on the 454 vs. the 350, as is the fuel pump. the 305/350 fuel pump wont keep up with the 454(engine and tb swap).

lets start with the above and we'll go from there.