88 F250 Supercab long bed, 351W C6 4x4

I drove the truck to work the past few days. It's a recently acquired vehicle, and the little shake down runs have turned up a few issues, but nothing major. wrong.

In the morning, the truck runs great all the way to work. It's been around 60deg each morning.

Coming home, the truck runs great until I get about 3 miles from the house. It's 17 miles one way...so it does 14 without a hiccup.

When I got into town, it started acting like it was running out of gas. Idles great, but any slight touch of the gas pedal and it tries to die out. I don't think it's bogging out, more starving for fuel. Right around 80deg outside temp, but the truck stays nice and cool without overheating at all.

Started it up a few minutes ago and all symptoms are gone. Fuel pressure checks out at 35-40psi. Coil is brand new, along with cap and rotor. There's only one fuel tank, the rear was removed due to a leak at one point or another.

I need help figuring this one out. Codes come up with "fuel pump secondary circuit failure" "no battery voltage fuel pump monitor circuit".

Could this be as simple as a relay heating up, or does it sound more like a fuel pump/tank issue? I don't want to chance it dying very far from the house since it's such a large vehicle...I doubt that my Exploder would be very happy towing it

 

My 87 f150 300ci was acting very simular. it would be running well until it heated up then just cut out and turn off. I changed the relay and it hasn't given me a problem since. I'd say give it a try, the relay costed me 8 bucks at napa. I'd say try changing it.

I hope this helps.

 

Haha, you not the only one dealing with this. I can drive my truck all day in wind. Won't give me a problem. Idling though, it leans out then dies, and won't start till it cools back off.

I have fuel at the rail, and the pumps prime everytime and even have spark. I'm replacing the fuel injectors (the ones currently installed are out of a junkyard truck that sat for a while). I think they are overheating and just shutting down (the fan that blows air over the injectors will come on when it finally stalls). Gonna change that relay as well, just to be safe.

Starter's dead now so I gotta get that too.

I'd check for spark good spark just to narrow it down.

 

That is DTC96, I know that because it is one of eight codes that my '89 F-250 belched out. And I have been plagued with similar problems as you describe. I bought the truck back in November and I have been struggling to figure it out. I have already changed the IAC valve, temp sensor and all the plugs. My next change is going to be the fuel pressure regulator, that and my fuel pump cut out on me once in the driveway. I'll probably change that too. Thanks to the help of one of the members here, I discovered that all of the fuel relays were removed, so that could me giving me the code 96. And there is a separate fuel pump power switch mounted on the instrument panel.

 

I changed out the fuel pump relay and drove to work today. No problem at all. It's a bit hotter today than it was when I had the problem, so I'm hoping that was the issue and that it's now resolved.

Tossing some new spark plugs in right now...it seems the PO didn't own a gap tool and they were all in the .55-.60 range. Might explain why the 351 has felt a bit anemic on the top end.

 

Well, it's been in the upper 90's here and the problem came back.

I stopped at the store the other day after a 20 minute drive, came back out 10 minutes later and couldn't start it.

Managed to get it running again after waiting 10 minutes or so and pumping the gas pedal a little bit. Limped it to work.

When I came back out 12 hours later it had cooled down and started right up. No problem on the drive home at all when it was around 70deg. outside.

 

Yup, i've got the same problem, only when its hot outside. the first time i thought i was the filter so i changed that and i didnt have a problem until tomorrow, when it started to stumble. i stopped in at the parts shop to buy a filter and couldnt get it running again. let it cool down, changed the filter and she fired up again. im looking at the fuel regulator or the in-tank pump.

 

I put a new in tank pump and sender unit today. Hopefully it solves the problem. At the very least, my fuel gauge works now so at least I got that fixed.

 

Haven't had any trouble starting it yet. Ordered a new oxygen sensor to see if I can get some power back. Seems like it's still lacking a bit of power. It can't even spin the tires when it's wet out.

I think a 351w should be able to spin the tires without much effort.