It runs if I 'hot wire' the fuel pump...

[Spdrcer34]

1988 Ranger XLT
2.9L 2WD M/T

The Ranger has BRAND NEW Fuel Pumps, and a BRAND NEW Relay...
{edit} I'm not sure if the CORRECT relay was replaced...{end edit}

I have gotten both pumps to run if I direct wire them to the battery..

Then I installed them, and when I cycle the key, the tank pump primes, like it is supposed to.

The Hi-Pressure Pump only gets 3-6v to it....

If I hook up a direct wire from the Batt (+) to the single connector under the master cylinder for the Hi-Pressure pump, the pump kicks on, and I can start the truck....drive it around no problem.

ONE TIME, and ONLY ONE TIME, I was able to pull the 'hot wire' out of the connector, plug the OEM one in, and it would stay running, I even drove it around the block this way. But I stalled in the driveway, and the Hi Pressure pump wouldn't power back up....so I pushed it into the driveway, hooked up the hot wire, and it fired right back up....

So....now what?

Ryan

 

[kimcrwbr1]

Start at the pumps and work your way back to the battery with the hot jumper wire. Jump both sides of the inertia switch and fuel pump relay. That would be one way to isolate the fault. If both pumps work with the jumper wire the grounds are probably good you just have to find the fault in the circuit. Bad wire, connector/s, inertia switch/connector, relay/connector.

 

[Spdrcer34]

I did that...

I started at the pumps. I removed them and tested them individually. Both tested fine.

I tested the wires at each pump. I am getting a full 12v at the tank pump. But I was only getting 3v at the Hi Pressure Pump. There was no spike to 12v at first turn to 'Run'...just a constant 3v.

I followed that wire up to the single wire connector under the brake booster/Master Cylinder assembly. I disconnected those wires, and tested the Tan wire that plugs into the Black/Pink wire....that only has 3v coming out of it. So there is no voltage loss from that connector, to the pump...

That is when I 'hot wired' the pump with a direct wire from the Battery (+) to the Pink/Black wire to the High Pressure pump. The pump spun up, and gave me 40psi at the fuel rail! I started the engine, and it ran!

I tried a couple times to swap the 'hot wire' for the OEM tan wire at the connector, and 1 time I was able to keep the engine running. But every other time (8-10 other times) The engine just died a few seconds after swapping the wires.

The truck runs with the inertia switch plugged in, when I hot-wire the pump. And it runs when I install a jumper wire on the plug for the inertia switch, while also hot wiring the pump.

I did some more investigating, and I don't think the PO replaced the correct relay. He replaced 1 of the ALL BLACK relays near the Blower on the Passenger Fender. When I un plugged it with the engine running, the engine immediately died. No 1 or 2 second delay. It just stopped running. So it must have been an Ignition, or ECM/ECU Relay...

I was looking up part numbers online, and the Fuel Pump Relay that is shown on the AutoZone website has a 1/2 Green Body. I can't quite get to the Green Relay that is in the truck. It's right below the 'new' relay that WAS replaced (the one that killed the engine when I unplugged it).

Is the Fuel Pump relay 1/2 Green, 1/2 black in the 1988 Ford Ranger? The one in the truck is the OEM one, as evident by the Ford Logo stamped into the top...

What options do I have besides spending $50.00 on the new one from AZ? What other Ford cars used the same part?

Ryan

 

[Mike828]

I did that...
Is the Fuel Pump relay 1/2 Green, 1/2 black in the 1988 Ford Ranger? The one in the truck is the OEM one, as evident by the Ford Logo stamped into the top...

What options do I have besides spending $50.00 on the new one from AZ? What other Ford cars used the same part?

Ryan

It is green and black in my '87 B2, and it only cost like $15 at O Reilly and $22 at Ford.

 

[Spdrcer34]

the cheap ones at oreilly's is all black.....was yours all 1/2 green 1/2 black when you swapped it out?

Ryan

 

[Mike828]

The one in the B2 was green and black. I thought it was dead but it turned out to be a ground had come off the battery.
I tried a bunch of relays from several stores they were all black, including one from the dealership which I'm still using.
$50 for a fuel pump relay is nuts.

 

[Spdrcer34]

Is there a test procedure for the relay, to check if it is good...

Ryan

 

[Spdrcer34]

I FIXED IT!....I FIXED IT!

It was the Fuel Pump Relay.

I stopped by the wrecking yard today and picked up a couple fuel pump relays...just in case I grab 1 bad one.

I got home, and plugged the 'new' relay....and the engine fired right up...

No hot wiring the pump, no tricks...it just runs like it is supposed to!

Ryan

 

[Tims03svt]

Cool glad to see you fixed it. To answer your question yes you can check a relay. It's really very simple.

 

[jessezipper]

lol i am having the same issue , except my inertia switch is good, pumps are good all relays are brand new. im left to deal with the computer ground or computer issue so im taking it to an electrical shop.