7.5L 460 electrical problems

[adeezy9183]

hey guys i know this is a little off topic but the fordfzone.com site hasn't given me any replies and i was told to check this site out. here goes:

i have an'88 f-350 with a 460 in it. i bought it in wv and was drivin it home to md and made it like 45 minutes and it started hesitating and stalling out. once i stopped at a light, it stalled and wouldn't start back up. i had it towed it to a shop and once they unloaded it, it started right up and ran fine. the mechanic said he let it idle for an hour and it didn't do anything. drove it back and forth; couldn't find anything wrong with it. so i towed it back down here and drove it to and from work for about a week or so and the day before yesterday coming home from work it did the same thing. started hesitating and stalling after driving around 15 minutes, but i managed to make it home. yesterday morning i went out and it started right up and drove it to work and did the same thing after around fifteen minutes but managed to make it into work. after work i started it up and it started doing the same thing immediately. the truck has no check engine light on. the distributor, coil, alternator and starter have been recently replaced (still look brand new). new air filter. new radiator and hoses. the only thing that hasn't been replaced are the plugs and wires, and i'm doing that tomorrow. also, it only has the front gas tank. the the front and rear fuel tank switch doesn't work. i can hear the fuel pump when i turn the ignition on. any ideas? thanks

 

[Seabronc]

This has all the symptoms of the pickup inside the distributor. When they go bad, they short out as the engine gets hot. It is just like someone reached over your shoulder and shut the engine off. Then when the engine cools off it starts just like nothing is wrong.

Good luck,

>-

 

[Yardape]

Along with Seabroncs excellent advise I would check your fuel system. Could be a plugged fuel filter, or could be fuel pump picking up junk in the tank and suffocating the fuel pump causing the hesitation you described. Then when the engine shuts off the pump stops sucking and the crap falls back down into the tank.

 

[Yardape]

My F250 was doing that same thing. I put in a brand new tank fuel pump and sending unit. Ran decent for a little while, but then started doing it again. Couldnt find the problem, and I had bought the truck as a parts donor for my Bronco anyway so I stripped it. Well a month or 2 ago I broke the tranny away from the engine and found that the vaccum line from the shift modulator was full of tranny fluid. So that tells me that the engine was sucking in tranny fluid that whole time and could certainly cause those problems as well. Figure maybe you can check that to satisfy my curiousity. Also I pulled the plugs, they have about 150 miles on them and they are fouled up bad. Looks like someone cooked bubble gum on them.

 

[adeezy9183]

thanks for all the quick responses guys. now, the unit you're talking about inside the distributor. it's brand new because the distributor is brand new, so i don't think it's that. I am going to go with something in the fuel system. possibly the fuel filter. i put some sea foam in the tank yesterday and also put some down the air intake. it started up and ran for about 30 seconds with me applying a little throttle but it shut right back off and wouldn't start. I haven't tried starting it today but i will after i get off of work. when i broke down the first time and wouldn't start i crawled up under neath of it and had a buddy turn the ignition on and i heard the fuel pump so it's not that. as for the fuel filter, where would that be located? I am also changing the plugs and wires in the next few days. i got some MSD wires i had on a 5.0 modded mustang that should work if they're long enough. thanks guys.

 

[adeezy9183]

also one more thing. up until yesterday after work, the problem only occured when the truck was warmed up, but when i started it after work it started hesitating and stalling immediately. just FYI. thanks again...

 

[Yardape]

fuel filter should be on the drivers side frame about where the fender meets the door.

 

[adeezy9183]

thanks yardape. do these trucks come stock with an in tank fuel pump or does the pump run along the drivers side frame rail? i'm asking because mine has a pump running along the frame rail. would the filter be before or after that? i'll have to take a look at it this evening. thanks

 

[Justshootme84]

My 88 F-350 with the dual tanks has the external pump on the driver's frame rail, then an in-tank pump inside the primary or forward tank. The filter will be behind the frame pump if you're looking at the truck from the front. JSM84

 

[Yardape]

On my 89 the filter was ahead of the frame pump. between the pump and the engine. And i'm pretty sure both tanks on mine had an in tank pump, definately had one in the front tank, and one on the framerail as JSM stated.

 

[BroncoJoe19]

Is an '88 fuel injected or is it a carb?

It was in '90 that they switched to a single fuel pump in the tank, if you have one under the truck beside the frame rail, I suspect that you have FI. With FI, you should have about 35 psi at the fuel rail, less than that, I do not believe a FI system will work.

You can certainly pull codes even if the CEL is off.

How to scan FORD on board Diagnostic Trouble Codes (DTCs) in your driveway

Howto Pull Codes 1983-1995 Broncos, Mustang, F series Trucks, Econolines, 302, 351 and more

As the instructions state - prior to pulling codes check for vacuum leaks!

Since your electrical system has been pretty much replaced; my guess would be with your vacuum system, and or your MAP, but check the vacuum lines and pull codes before you change the MAP on a whim.

 

[Justshootme84]

Yes, the 88 F-350 460 is EFI.

 

[BroncoJoe19]

Thanks JSM84. I just checked my book and it should have between 35psi and 45 psi, at the rail.

The low pressure pump (the one in the tank) should deliver 6oz in 5 seconds.

 

[adeezy9183]

hey guys. i just changed the plugs out and the fuel filter out and it is still doing the same thing. I have one question. when i turn the ignition on but don't start it, should the fuel pump run continuously? I have no idea what the problem could be. i am stumped

 

[BroncoJoe19]

when i turn the ignition on but don't start it, should the fuel pump run continuously?

No... it should run for a few seconds to build up pressure to 35-45psi, and quit.

If you're stumped... let your onboard computer tell you what it sees. Pull codes. All you need is a 4 inch piece of wire and the ability to count to ten.

 

[bobstrat]

ignition module maybe? located on your distributor base. picture here, yours is the one on top.

picture

 

[adeezy9183]

is their anyway to test the ignition module without pulling the distributor and all off of there? i know the distributor is brand new. does a new distributor come with a new ignition module too, because it looks new as well. also, what is the firing order because i took the wires off the top of the distributor. thanks

 

[Yardape]

15426378

 

[adeezy9183]

hey guys, i bought a haynes manual and i was gonna check and make sure i had the firing order correct. it says in the book that the black terminal on the distributor cap is where the number one spark plug is. BUT, their is not black terminal on the cap? what do i do? thanks