1994 4.0L Ranger. No start condition. The computer isn't powering up.

[Mark Alexander]

Considering purchasing a 1994 Ranger with the 4.0. Guy wants $600 for it, but he’s very proud of the truck. Says it’s been in his family since new, but all of a sudden it won’t start, so he put it up for sale after replacing the fuel pump (no fuel to fuel rail),, Inertia switch, relay, fuses, all to no avail. He took it to 2 different local shops, but they too had no luck and he couldn’t afford the $50 per hour shop rate for extensive troubleshooting. I drove over, and sure enough, fuel pump not running, no fuel to rail.
Was able to get fuel to rail by jumping relay, so wiring to pump from relay is good but still no sign of life from engine when spun over. Figured if we could get fuel up there it would run, but nothing. Spraying start fluid in the intake produces backfire, and plug wires are firing at coils, so there is fire, fuel, but no run. There’s no power from the ECM to the fuel pump relay. That wire (LB/O) comes from pin 22 of ECM, thru the relay coil to energize relay, then comes OUT of the relay as a RED wire which goes thru this spider looking connection, and to the injectors as a parallel circuit to power all 6 injectors.
At this point I have to decide whether this little truck which has new tires, lots of TLC and love applied to it (nothing junky about it) is worth the $600, having it towed 11 miles to my home, and a new ECM which is very suspect. ECM ranges in prices of $99, to $225.....not sure why....Opinions needed please. I’m thinking the ECM is bad and not powering the injectors and fuel pump circuit. Would y’all buy it?

 

[Josh P]

I'd buy it.

 

[BrooklynBay]

Your thread was renamed & moved into the Ranger section. Check the computer relay, computer ground, and the power lead going to the computer. I don't think that the computer is bad. Some older models used fusible links instead of fuses for the computer. Check the fuses as well. Use a test light or a voltmeter on the computer's main power leads. You could use a jumper wire to provide power for testing purposes.

 

[410Fortune]

EEC relay?
The EEC relay is what powers up the PCM which can then power up all circuits and sensors

Ignition switch
The steering column ignition switch is what sends power to the EEC relay when you turn the key

Keep alive power,
check the battery constant power feeds to the PCM, make sure it has power there

Yes I would buy that SOBm take it home and find the issue, it is likely very simple to fix ONCE found...