Tuning '94 chev Suburban Big Block

[rsicard]

Dave:

When you converted to MPFI (batch fire) from TBI and installed the jumper of the MEMCAL, how much change, in engine running quality and, did you have to make to the off idle fuel map? The way it happened for me is that the engine ran rough. Did not have an AFR setup so don't know what happened. Will repeat with AFR setup to get clue as to what is happening. Any experience that can be shared would be greatly appreciated. Thanks for your response.

Rolly

[dave w]

I use an Excel spreadsheet to "Crunch" the data log to correct the AFR's, see attached.

I went "All In"; I modified the memcal, .bin file, and PCM resistors before I started the engine for the first time. I then went to work on the tune immediately after the initial start up.

dave w

[1BadAction]

I went "All In"; I modified the memcal, .bin file, and PCM resistors before I started the engine for the first time. I then went to work on the tune immediately after the initial start up.

dave w

I agree brother, not like you can easily (mechanically) go back to TBI anyways, I don't see why anyone would want to play "just the tip" with this particular conversion. I was going to get a second computer and memcal to do this myself, but then after a few minutes of thinking about it, it hit me... WHY? If I have the kinda time it takes to go back to the TBI intake, then I'll have the truck parked and enough time to convert the ECM back also. Hell the ECM changes are the fastest out of the whole ordeal.

Watching this thread myself, I have about 90% of what it takes to do the conversion on my Suburban. Just need to find the proper RP/Mercruiser injectors and a few other chicken shit items so I can get this thing back together in a timely manner. I hate letting a vehicle sit an extended period of time.