No power to fuel pump

[44cents]

Hello, new here but have been lurking for a while. I came to own a 1992 2.3 Ranger with Manual transmission a few years back. Motor was crap from the previous owner, it still ran and drive alright, about 8-9 months ago my father and I rebuilt the whole motor and she has been running like a top, until two days ago.

I broke down at the parts store and spent a few hours trying to diagnose the issue. The motor cranks over, good spark to all the cylinders. However, I don't hear the fuel pump prime or turn on. I had to have it towed because or a lack of daylight and tools.

I checked every fuse 3 times, all good. I had purchased a fuel pump relay at the store and that didn't work either. I checked the voltages being sent to the fuel pump relay, with the key off I get a single 12v constant, with the key on I had 12v, around 6v assuming this is from the inertial switch, and then another connection was 3v. After further reading about what the voltages should be, I suspected the EEC relay was the culprit. I used the new fuel pump relay for the EEC relay after reading they're the same. Sure enough pump primed and it started right up, I let it idle to charge the battery while I buttoned up the under hood fuse box. The check engine light was on but engine seemed to be running perfect and even charged the battery. I shut it off and turned it on again, no check engine light and still running great. However, when I pressed the brake to release the hand brake and drive it, the engine died and wouldn't start again.

Now I am back at square one, engine cranks no problem, good spark, but the pump won't prime and the engine won't start. Voltages are still good at the fuel pump relay. Now for some reason the dome and cargo light wont turn off as well. I found the door switches for the light and when I press the passenger switch closed the light slightly dims .I am at a loss how to solve this, currently thinking of getting a new inertial switch and another new relay, so the EEC and fuel pump relay are both new, and I know they're not the issue. I plan to clean the 2 grounds next to the ECM as well. Any help would be greatly appreciated, thanks.

 

[SenorNoob]

Sounds like you're on the right track with the grounds. I'd check for the strap from the back of the engine to the firewall...

 

[franklin2]

This is a shot in the dark, but 99% of the time when the engine is changed, the ground from the back of the engine to the firewall is forgotten. This is a important ground for the sheetmetal of the truck.

The main heavy ground from the battery goes to the engine block. But the engine/trans and rear axle are mounted in rubber mounts. So is the cab. So this ground from the block to the firewall is important.

 

[44cents]

Well now I have all new relays for the fuel pump and EEC, and brand new interial switch. I sanded and cleaned the grounds at the ECM, near the fender, near the starter, the heavy duty ground from the engine to the firwall, and both positive and negative terminals and wires. Still no luck, I am stumped and confused. I don't understand why the dome and cargo light are stuck on. Maybe this is all because the ECM is done for.

 

[Brain75]

Dome and cargo don't go through ecm - simple dumb short throw pin switches in the jams and the headlight switch/dimmer (on the dash) will turn it on if you go past the detent at the end (max dash illumination). No "courtesy" lights on this old a girl.

I'm guessing you turned up dash illumination to max and tripped dome+cargo (which is actually the ONLY way to get cargo on) on OR you dimmer switch is borked up.

 

[44cents]

Dome and cargo don't go through ecm - simple dumb short throw pin switches in the jams and the headlight switch/dimmer (on the dash) will turn it on if you go past the detent at the end (max dash illumination). No "courtesy" lights on this old a girl.

I'm guessing you turned up dash illumination to max and tripped dome+cargo (which is actually the ONLY way to get cargo on) on OR you dimmer switch is borked up.

Good to know, always wondered how you turned on the cargo light and the dome light when the doors are shut. Must be the illumination dial set to max and not a compounding issue.

 

[44cents]

Okay well I traced all my wires making sure I am getting the proper voltages, which I am. I checked the ECM for corrosion or blown capacitors, everything was perfect. So I finally pulled the bed up disconnected the connector at the top of fuel pump and sure enough im getting 12v right at the pump. At this point its off to the parts store to get a new pump and filler neck. (had some small cracks and was leaking a bit of fuel) I will update when I get the new pump in.

 

[pjtoledo]

after the 12v goes thru the fuel pump it has to be grounded.
a bad ground will show 12v at both input & output of the pump.

 

[44cents]

Just finished and the truck is running great again. The whole time it was just the fuel pump. I really didn't suspect that it was the pump because it was running perfectly before it initially broke down, and after it fired to life once a couple days ago. Thanks for all those who commented, not just on this thread but on the forum in general. I have been helped many times reading old threads here, so thank you.