I am doing a full frame off restoration on a B2. I have two 1986 B2's that have 2.9L in them. One had a good running engine with a bad frame the other had a bad engine with a good frame. When trying to get the bad engine to run on the truck with the good frame my fuel pump turned on and ran perfectly. After completely swaping the engine, drive train, and steering column and hooking everything up to the truck with the good frame, my fuel pump is not turning on when the ignition is turned on. I have hot wired the fuel pump to the battery and after doing this they both turn on (high pressure and low pressure). Knowing that they both work I next tested all the relays and fuses in the truck and they all worked. I also tested the interia swith on passenger side underneath the dash and it works. With the fuel pumps hot wired to the battery I have tried starting the vehicle and it wont start. Also I have pulled one of the spark plugs and there is no spark when trying to turn it over. I have swithced and tried using both computers from both vehicles but still there is no success. I also went back to original steering column and hooked up the wiring to the ignition and still no fuel pump turns on. I know my next step is going to have to be to get a diagnotstic test but that means me towing it and going through a lot of trouble to get it there. If anyone has any ideas or suggestions about why this fuel pump is not turning on I would really appreciate.

 

I'd probably start by checking the power supply circuit to the PCM. Is the EEC relay closing? All the wiring going to the ignition switch intact? Fusible links blown? Gut feel is that something didn't get plugged in when you swapped engines.

 

Sounds like u covered all the bases, it'd almost have to be a bad wire or fusible link somewhere.