lordwillin

I've been having a problem with my 1986 F-150 5.0 v8 EFI (single tank) that has been getting worse over a short amount of time. It started off intermittent, and now the truck won't start at all. Everyone I've asked shrugs at this one. I'm including as much detail as I can think of.

When the problem first began, it went like this: the truck would start fine, but if I drove it a good ways (30 minutes, say), enough for it to get good & warmed up (but temp guage reading normal), then parked it for a few minutes, it would not start when I returned. It would just sputter and cough but not really catch. I would have to wait (presumably to let the truck cool?) anywhere from 10-45 minutes to get it to start. After starting, I could drive as far as I wanted, but turning engine off might start the cycle all over again.

If I tried to start the truck before it was "ready" to restart, I could sometimes get it to start up, but after a few seconds or a minute keeping the rpm's up (sometimes long enough for me to put it in gear and start driving!), the engine would suddenly sputter and die, forcing me to wait longer. Also, if the engine was just sputtering when I tried to start it, I could often get it to start (even if it would quickly die again) by cycling the key on & off before cranking it, building fuel pressure by running the pump a few times. So I'm guessing that the problem is with FUEL, not spark. (vapor lock?)

In stage 2 of the problem, I noticed that if the truck was idling or in stop & go traffic, the engine temp on the guage would creep up. If I let it creep up too far (hot) then the engine would die & behave as described above. I don't know why the engine is heating up when idling. Coolant is full. Fan turns.

In the final episode, the truck died, this time 1/2 mile down the road from a successful restart, and would not start again for well over an hour. Once it did, I drove it home (1 hour drive). And that was the end of it: now it will not start at all, just sputters, even when cold.

-- I don't know why it's overheating at idle, & I'm not sure if that is new or if it always did it. I know that the original failures to restart were at normal engine temps.

-- Could the cause of the overheat be connected to the cause of not starting?

-- How could it get worse over time? Why would a problem once associated with a hot (or at least warmed-up) engine now exist when the engine is cold?

Any help with this problem would be a life-saver for me. I live far from town and now I can't even drive the truck to a shop to have it checked. I'll answer any questions and I'm open to doing any diagnostic checks that are recommended. But I do think that all the signs point to a fuel delivery issue. High & low pressure pumps are both good.

Thanks in advance.

klricks

Try running self diagnostics / code read. If you don't know how I have done tutorial. Link in my signature.

82f100

Make sure all vacume hoses are connected and feel the top radiator hose and bottom to make sure they are both hot. If the bottom one is cold then the water pump is bad. I would also check the gaps of your spark plugs and then put in a good gas treatment. Goodluck.

lordwillin

Okay I'll try the code read & everything else, & let you know what I find. Might be a few days before I get back to the computer. Thanks!

coltonarnold

well im not sure if fords have this but i had a chevy beretta that did this, turned out to be the crank sensor n for the temp wise, have u ever put a thermostat in it?