305 TBI to 454 TBI help!!!!

I have a 92 1500 2WD came stock with 305 TBI with 700R4 trans. It now has a 90 2500 454 TBI but still has the 305 computer and chip. The computer number is 16146299 with chip AWHC. With this setup the truck just isnt running correctly. It has what I would call a hesitation at low RPM's and like a surge. Once you get over 3,000 RPM's it seems to run ok. I unhooked the TEMP sensor just as a test to see if it was lean and it ran better. I'm thinking I need another chip or maybe even the whole ECM but not sure which one I need. Any help would be appreciated. P.S. This motor had a idle surge and after reading on the web I put a new ACDELCO pickup on it and set the timing on 12 Degrees with brown and black wire disconnected and it fixed the surge.

If the 454 is stock use the matching ecm and transmission and get wiring diagrams from both trucks to match up the wiring. Thats the easiest way to keep from burning up the engine and transmission!!! My guess is its running WAY TO LEAN and you are going to melt the pistons or something similar. I just bought a 89 c3500 that they did same thing....ran a 454 on a stock 350 computer and blew up the engine, I found a piece of piston ring in one of the intake runners!!

Will a chip for a turbo 400 work on a 700r4 is the thing? None of the 454 comes with 700r4

Here is a link to the gearhead-efi 16146299 information: http://www.gearhead-efi.com/Fuel-Inj...Information-99

It would be awesome if there was a factory 16146299 454 / 700R4 chip, but the link posted above does not show a 16146299 454 / 700R4 chip.

I suggest getting a custom 16146299 454 / 700R4 chip. (send me a private message, PM, for details about getting a custom 16146299 chip)

The 454 injector part # is very important information for a custom chip!!!! There are a few different 454 injector flow rates: http://www.gearhead-efi.com/Fuel-Inj...d-part-numbers

dave w

Or you can have someone burn you a chip:-) but it’s been my experience with 700r4’s that unless you build it with heavy duty parts it won’t last long if you are doing anything besides babying it, reason why I suggested using the stock 2500 trans

Unfortunately as you have found there was no 454/700R4 combo offered from GM .

I had to make my own Hybrid BBC/700R4 calibration but I use a different PCM than you are using .

If I were you I would let Dave take care of a custom calibration for you , he has done a few things for me in the past , always exactly what was needed , and a super quick turn around time , you will have no problems .

TOM