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84 B2 2.8L swap to 92 4.0L - transmission and wiring questions


I've noticed a lot of people lately using weary instead of wary.
Weary = tired
Wary = careful
 
aye
meanz......


aye motherfogger
 
um....you....uh.......errr
 
but be weary...if its shorted...it will start welding...and that means hot....burning skin and fire.....its half the fun
Well, ran this test this evening. No welding or fireworks, but also no change.

I've gone back a few steps - the fuel pump relay isn't closing. Eec relay is closing and sending voltage to the fuel pump relay, but voltage isn't going through it.
 
and the fuses?

any picture of what your working with
 
Fuses are good. Even with key off I'm getting 12V to the fuel pump relay on the yellow wire, as I should. I pulled the relay out and put a jumper in the block, and the fuel pump kicked right on. So why isn't it closing when triggered by the power from the eec relay? I would think it's a bad relay, but I've tried another known good relay, and no change.
 
I'm not sure what year and how much donor vehicle wiring that you're using here in the '84. Assuming that you're working with wiring from a '92 donor.

Generally for that period, the EEC relay when triggered then powers one side of the coil on fuel pump relay; the EEC then grounds the other side of the fuel pump relay coil to trigger it to make the pump run.

Some pics of what you're working with would help.
 
Yep, this is all from the '92 Explorer. EEC relay is working and sending 12V to the fuel pump relay on the red wire.

The EEC grounding the other side of the fuel pump relay may be my issue.

IMG_20240107_201823704.jpg
 
so you may have knocked out the pc ground and the pc is probably not lighting up
 
yes the pcm. make sure there is power and ground at the pcm
 
going across the trigger posts of the relay:

if you have voltage on the input but not the output (of the coil) there are 2 options
1-the coil is open/broken
2- the current is flowing thru the coil then on to ground. the coil is a load (for the trigger) so if current is flowing thru it there will be a voltage drop, 12 to ground.


if there is voltage on BOTH of the coil/trigger posts then there is no ground allowing the current to complete it's circuit.

so do what Bobby says, check the PCMs ground.
 
WooooHoooo! Fixed! My wife even took it out for it's first spin tonight since the motor swap. I hope to get the second drive tomorrow.

So my relay problem ended up being a ground issue, as you all led me to. Specifically, PCM ground.

So who's up for a game of "Name That Connector"? Discovering that these two connectors are identical led me to the solution.
IMG_20240108_170151006_HDR.jpg
 
Lack Of Ground Is The Root Of Most Electrical Evil.

- From the gospel of Zap, the patron saint of us poor frustrated automotive electricians
 

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