I just purchased a really nice 2001 F-150 Lariat 5.4L 4x4 in June. Unfortunately now I'm starting to have some problems with my truck, and I don't know what to do next.

My truck is not starting from time to time. Most of the time it works great but on occasion it won't start. It turns over, cranks fine, just doesn't start. Sometimes I'll let it sit a day or two, try it again and it'll start fine. Other times it won't start at all. While running, it runs absolutely great, however I'm running out of free AAA tows pretty darn quick.

I've taken it to a very highly rated mechanic twice and they can't get it to 'act up' when their machinery is hooked up. According to him, I'm not getting fuel from time to time. The MAJORITY of the time it works, just occasionally does not. He claims that the only thing he's hooked up is wires to test the fuel relay. Initially he thought possibly the wires stabilized a bad connection in the relay, so he left them on and taped them there to see if that helped. I didn't have any issues for a week and it drove great all week, but now we've got the same problem. I can't start my truck which is forcing me to drive my wife's Chevy, and that makes me sad.

I didn't have time to test and wiggle the relay to see if that's the problem yet because I was running really late for work tonight but plan on testing it first thing in the morning.

I haven't quite ruled out the fuel pump completely, however, they normally just 'up and go' in my experience. I know that a lot of times if its the fuel pump you can bang on the bottom of the tank with something to jump start the pump to take it in and get it worked on. Of course (and I'm glad, cause I go mudding from time to time) my truck has skid plates on the bottom of the tank so I can't quite test this. Banging on the side however did nothing.

I'm not quite sure what else it could be, so I figured I'd ask the experts. I'm REALLY hoping its not the fuel pump cause where I'm at the fuel system replacement runs to the tune of $740 installed, and I really don't want to have to break it to the wife and family that there's not going to be a Christmas this year.

Any help would be appreciated.

 

Definately sounds like a fuel delivery issue. Not sure if your mechanic thought it was the fuel relay, why he did not replace it. Have you replaced the fuel filter yet?

 

I haven't personally checked it, no. No idea how. My mechanic said it was an electrical issue and that it wasn't the filter. Whether he checked it or not, I have no idea. I'd like to think he did?

 

New news:

I was reading about this, and found this thread here:

http://www.f150online.com/forums/v8-...ump-relay.html

It appears this guy has a similar problem with his Expedition. I "flicked" my relay, and sure enough it fired right up without an issue.

I guess what I don't understand is how can the adjustment of the fuel pump relay (ie; flicking it with a finger) cause it to fire up if it's a fuel pump issue? That doesn't make sense to me.

I'll start with the relay I guess.

 

Got a new relay from the parts store; sprayed some electric cleaner in there, let it dry, then threw on a TINY tiny bit of dielectric grease on the relay prongs. It fired right up again, so I drove it around the block, turned it off, and fired it up again and had no issues. Hopefully this fixes the problem. I'll keep everyone posted and will post in a week if I've got no more issues, or sooner if I do.

 

Welllll...

I'm thinking this has to be an electrical issue. When theres lots of moisture, I keep having this problem. Today it rained, so for sure, no start. If I push down on the relay however and have my wife crank it, it starts right up. For whatever reason it seems like the added pressure completes a loose connection or something that eventually goes loose again over time.

Anyone have any suggestions? I'm thinking its obviously NOT the pump because the relay and pump aren't even remotely close to each other, and adding pressure to the relay wouldn't magically cause the pump to start working again that I'm aware of.

 

replace the relay... and clean the connections... ..be sure the connections arent burnt on the back side

... its not a pump problem if the relay movement fixes it

 

damn jsut seen you replaced the relay.......

but i would check the wires were the relay plugs in..

 

Took it in to an automotive electrical repair shop; all the wires tested out fine. They got it to 'act up' twice, and got a Primary Fuel Pump Circuit Fault code, but that doesn't really say much. They rigged/bypassed the inertia switch since that can potentially cause problems and tried also replacing the PCM relay. Didn't charge me anything cause he's not sure it fixed the problem.

I'll update as needed.

 

Well, still having the same issues.

So far I'm trying to determine the things its not.

Fuel Pump Relay: REPLACED
PCM Relay: REPLACED
Inertia Switch: BYPASSED

When they hooked up their tester, like I said, I got a P0230 Fuel Pump Primary Circuit Fault error, but after another crank, the error vanished and the truck started right up.


Hopefully someone can help me a bit with some questions I still have:

1.) What is included in the Fuel Pump Primary Circuit? Does it include the pump itself or just the wiring? I'm out of ideas, so maybe this really is the issue. Banging on the relay could have been a coincidence.

2.) Does the computer have any effect on the fuel pump?

3.) I do have an OEM security system I believe ( as evidenced by having a flashing 'ANTI-THEFT' light that constantly flashes on my dash while the vehicle is off) and I know on some vehicles such as the Oldsmobile Alero, the security system can screw up and block fuel flow to the engine. Is this how the F150 system works as well? Would I receive that error message if it was the security system?

Thanks for any help.