mccl6927

So i think i need to finally ask for help. i have a 350 running on a 7427 pcm. i swapped over to TPI and am having a hard time getting this thing to run properly. ive searched and searched and have found a "tbi to mpfi" zip file but on the website i found it, i dont have permission to download files. all other searches have turned up contradicting info. ive tried setting flags that other have used but still cant get it to run well. as of now i believe i have my battery voltage offsets correct but am not sure what i need to do as far as max/min sync to async, min bpw allowed, etc. or if i should leave that stuff alone.
I can start it pretty easily. it idles very rich and slowly leans out to something tolerable. once it hits closed loop it gets a little lean and bounces from time to time. any throttle at all sends it rich and keeps it there. if i hold it at say 1700 rpm it will swing wildly from 1700 to 800 running way rich to way lean. at a steady vehicle speed it does the same wild swing and surge.
any ideas or clues here? Im about ready to ditch the computer and fork over the dough for a 7730 ecm.

350, manual, ported swirlport heads, vortec cam, ford bluetop (#24???) injectors, stock tpi intake, tpi fuel pump, 43.5 psi fuel pressure, 7427 pcm. TunerPro.

Six_Shooter

iTrader: (2)

Have you done the PCM hardware modifications that go along with the TBI to MPFI swap with the '7427?

mccl6927

i bypassed the two resistors, which i think ill check again just to be sure the solder held, but i didnt do the memcal jumper. As i understood this was not needed.

Six_Shooter

iTrader: (2)

The MEMCAL jumper is more important to do than the resistor bypass, from what I understand, since this sets the hardware injector firing scheme. From experience with other ECMs, if the cylinder select setting in the bin (which should be set to 8 cyl,. not TBI in your application), and the hardware select don't match that the engine never seems to run real smooth.

mccl6927

well shoooooot. I'll go fix that then report back. hopefully this is my only problem and others may learn from a stupid mistake.

mccl6927

So that was exactly my problem. I dont know why i was confused in thinking the memcal mod was redundant and unnecessary. Now, off to tuning the beast. Thank you for your help.

Six_Shooter

iTrader: (2)

Good to hear.