New member swapping 4.3 for 5.7 tbi

[gar925]

Hello All! I've been a frequent reader of the forum (especially recently), but never registered. I have a 1994 K1500 5-spd that I'm trying to finish up a 4.3 to 5.7 tbi swap on. I'm new to working on SBCs and not finding a lot of useful help here in WV.

I found the Jasper 5.7 in a 1990 Cadillac Fleetwood with 89k documented miles. Engine started and ran great in the donor. I have the 5.7 in my truck and running. Trying to button up a few things to get it running great. I'm using the 4.3 wiring harness and ECM with 5.7 sensors.

I'm currently getting a code 43 (ecm/knock sensor) and low idle. I've talked to some other people who have completed a 4.3 to 5.7 swap and they claim that the 4.3 chip can be used for the 5.7. The truck is running "ok," but I think it could be better. I ordered a Jet 29404-S chip and realized it wouldn't fit my 16197427 ECM. Jet tech support told me that I needed a chip for the 5.7 that their performance chip could piggyback on.

I'm having trouble finding the correct chip for my ECM. I figured it was time to join the forum and ask for expertise from someone who knows. Any help would be greatly appreciated.

[dave w]

I've been thinking most, if not all, 94 K1500 with a 5.7 would have an automatic transmission. Maybe you can program your own chip with the modified attached .bin file? You have the option of using an adapter board to use a chip you program for yourself, see attached pictures. I think the Code 43 is because you will need a different knock sensor. Based on personal experience, I would use the knock sensor for a 1994 K1500 5.7 liter with AUTOMATIC Transmission with the 16197427 computer.

dave w

[gar925]

I've been thinking most, if not all, 94 K1500 with a 5.7 would have an automatic transmission. Maybe you can program your own chip with the modified attached .bin file? You have the option of using an adapter board to use a chip you program for yourself, see attached pictures. I think the Code 43 is because you will need a different knock sensor. Based on personal experience, I would use the knock sensor for a 1994 K1500 5.7 liter with AUTOMATIC Transmission with the 16197427 computer.

dave w

I didn't have any intentions of programming a chip. I'm not certain how to get started. I'll have to look on the forum and figure it out.

The donor was an automatic that only used 1 knock sensor. The 4.3 had 2. I added a 2nd to the 5.7 that was for a manual shift. I'll try swapping that one out for a sensor for an automatic.

[1project2many]

The donor was an automatic that only used 1 knock sensor. The 4.3 had 2. I added a 2nd to the 5.7 that was for a manual shift. I'll try swapping that one out for a sensor for an automatic.

Both sensors should be from the 4.3 / 7427 if you are using a 4.3 / 7427 chip. Because the 7427 was never used with a manual transmission and 5.7, and because you have dual knock sensors, no stock chip will be exactly correct for your truck. You should find someone who can, or you should learn how to, program custom chips. And since you can pull off this engine swap then I'm sure you can program chips.

[gar925]

Both sensors should be from the 4.3 / 7427 if you are using a 4.3 / 7427 chip. Because the 7427 was never used with a manual transmission and 5.7, and because you have dual knock sensors, no stock chip will be exactly correct for your truck. You should find someone who can, or you should learn how to, program custom chips. And since you can pull off this engine swap then I'm sure you can program chips.

The knock sensors on the 4.3 didn't fit the 5.7. The auto trans donor came with one and I purchased one for a 5-spd (wasn't aware there was a difference) to go in the other side. I'll probably try Dave's suggestion and see if the KS for an auto trans will work.

This swap has been outside my budget for a while now. I'd like to find someone that can program and get me running as soon as possible. However, it would be nice to find someone that can both get me running and help me learn to program for future mods.

[dave w]

A Used 5.7 Liter Memcal / Chip is a low cost option? According to the information I have available to me, the Memcal / Chip (code BPSA) for sale in the ebay link below is for a 1995 Van 5.7 liter with Manual Trans using the 16156930 computer (electrically identical / interchangeable for a 16197427 PCM).

http://www.ebay.com/itm/CHIP-BPSA-35...xWBJim&vxp=mtr

More information on the 16156930 Computer http://www.gearhead-efi.com/Fuel-Inj...Information-31

dave w