1994 Ford Ranger XLT regular cab 4.0L V6 5 speed manual 2WD.

Couple of months ago when I filled the truck up it refused to start. It would run, but really low (~3-400 RPM) and very rough. I blew it off as bad gas (it was Walmart...after all...) and changed gas stations. No more problems for a while. Then it did it again. I figured it was because I was chugging the tank full to an even dollar after filling up, sure enough didn't do it next time and it started fine.

Last night I go with one of my friends to get gas. Didn't chug it full (never do anymore). Rough, low idle. Well hmmm... Try it again. Nadda. I notice when I turn the key to RUN prior to start...the fuel pump doesn't come on. It does that for about 2 minutes. Then bam, I hear the fuel pump start right up, pressurize the system, and get that beautiful, quick and easy start I'm accostomed to.

It ONLY does this after filling up with one exception. If I stop and start the truck a few times quickly, it will do it. I dunno if it was the fuel pump the one time I did that though. I didn't think to listen. A month or so ago I kept moving around the high school parking lot to get better spots as I saw them (don't do that anymore...too many accidents, I park way out there now). About the third time I started it in a row, bam nothing, low idle. Cut it off, left it there, that afternoon it started fine.

I'm thinking fuel pump, as is my dad. Now...do I have two fuel pumps (LP and HP) or just one? Which one would this involve. I went to Autozone to see if they had the pump. Nothing from Motorcraft at Autozone, and we're ONLY buying Motorcraft so where is a good place to get them?

I understand pulling the bed is easier than dropping the tank, is that correct? How do I go about pulling the bed? How much work is it and how much does it weigh? Do I need to run the tank down low before doing this?

Sorry for the long post, just wanna cover everything. Thanks guys.

RP
Zach

 

Before doing the pump make sure it's not the relay. Either keep a meter with you and check for power at the interia switch or just replace it since they're cheap.

You have one pump, remember it's easier to pull the bed back.

 

Where is this relay, how would I go about replacing it? And how do I test it?

 

It was under the power distribution box on my 1989, I'm sure on of the guys that have/had a 94 can confirm the location on yours.

The easiest way to see if you have power from the relay is to check it at the inertia switch with a meter, pull the connector off thde inertia switch, probe the hot side with the + from the meter and ground the -, turn the key on.

The relay should pull out just like a fuse.

 

If you come to suspect the fuel pump power relay after Ken's tests, you could try swapping it with the heater blower power relay & see if things straighten up. If so, replace the fuel pump relay.

They are located under hood, in the power distribution box. The relays location should be noted on the box cover.
Let us now what you find.

 

This just happened to me. In my case, it was the fuel pump relay. The position of the relay is labeled on the underside of the power distribution box lid in the engine compartment.

Don't search the Haynes manual for it - it doesn't say where it is. I spent a couple of frustrating hours looking for it, then just happened to flip up the pwr dist box cover, and there it was, right in front of my eyes. Of course, this was after I checked the inertia switch, fuses, and tracing wiring all over the place.

I pulled it out - its a standard 5 blade relay, and you can replace it with almost any other similar relay. I used a Bosch, and problem solved. The Ford part number is FOAB-14B192-AA. Canadian ford dealer wanted $12 CDN for a new one. I had purchased several Ford relays from a local surplus electronics store several months earlier (without knowing what they were for) for about $1 apeice. Low and behold, they had the correct Ford number for the fuel pump relay, so I was laughing.

 

Forgot to mention - I later bench tested the "bad" relay, and it clicked on and off like its supposed to, and there was continuity between the proper terminals. I didn't bother trying to put it back in the truck.

 

Hey sorry for the long absensce. Anyways, I'm hoping it turns out to be this relay. The problem is the "problem" is intermittent to begin with...so I don't have a way to really check it, if that makes any sense. Like tommorow (it's sleeting at the moment...eh) I plan on checking power at the inertia cutoff switch and switching the relays. Where can I get one of these relays? Would Autozone or Western Auto likely have it? I mean the temp plunged from 85 yesterday to 28 right now...so I need the heater blower motor lol.
I REALLY want to avoid pulling the bed if I can help it, as I have NO idea how to do this. I already have the fuel pump, new strainer, and new filter. If nothing changes tommorow I may swap them in anyways (better safe than sorry?), but I have to pull the bed to do that, as I don't intend on dropping the tank, which at the moment is like 3/4 full.
How does one pull the bed? Plain and simple please, I gotta explain it to my dad lol. Thanks.

RP

 

It's pretty straightforward, there's six torx bolts holding the bed on. Be prepared to WORK to get them out. Spray 'em a few times starting a day or two before you try to take them out. Undo the screws holding the gas filler neck to the bed. Disconnect the lights from the rear or the bed so you don't rip out the wires.

Two guys can move the bed back a foot or so and rest it on the back wheels. That should give you plenty of room.

 

Ok I'm seeing four Torx's. Two at the very front and two towards the rear. We replaced the pump relay today. Cheap and easy...figured it would be good to replace it anyways. I never found a heater blower motor relay to switch it with. But either way.
We're going to replace the pump next Sunday whether it really needs it or not. Figure it's 12 years old, it needs to be replaced. Tiny little pumps on our trucks.

Anyways, I'll let you all know how it goes.