ive replaced everything imaginable on my trucks engine trying to get it to run but with no luck still. she will start, then run for a minute or so, then die.
its a 302 v8 with about 115, 000 miles on it. automatic..
i bought the truck for $1200 and have put about $1000 in parts on the engine. guess i shouldve just bought a used engine and put it in my truck.
any thoughts or ideals would be really appreciated.

 

You may have replaced everything on the ENGINE, but what about more peripheral things, like the fuel system? A weak fuel pump could be starving it of fuel, yet allowing it to start. Have you pressure tested the fuel flow, and visually verified it? Have you changed the fuel filter? I wonder if the fuel cutoff solenoid could allow SOME fuel through but kill it? Do you know about the fuel solenoids? Basically, they're there because you have an electric fuel pump which is potentially very dangerous - if the line gets fractured, fuel keeps pumping, a fire hazard especially in an accident - the benefit, if you like, of a mechanical fuel pump is when the engine stops (like in a crash) the fuel stops. I guess Ford went electric either because of the distance from tank to engine, or flow demand was too great, or electric fuel pumps suit efi better.

If you're getting it running at least, you're on the right track. Another possibility is an electronic fault, like a crack in a component in the computer (I assume these engines won't run without one) or the coil, which causes intermittant failure when warm. You need to check all the vacuum lines, especially with an automatic. That includes the lines that run to the charcoal fuel vapour canister, and the canister itself too. Mine was perforated by a previous battery that had leaked and weakened sections of the plastic. Haven't gotten around to replacing canister yet, but repaired it for now with silicone. The egr valve and other components around the throttle body should be checked and cleaned, too.

Presumably that model has the older type of computer, I think the codes are OBDII? You can either purchase a code reader quite cheaply, or there's a couple of methods you can use without special tools (one needs a multimeter) to read it, if you do a search for a post using a term like OBDII code reading on previous posts, you should find it.

Don't be too discouraged, true, you could have spent what you've spent on a newer truck maybe, but it's a lottery and you might have been worse off.

I spent $2700 cdn on my '92 2wd and now, some months on I'm seeing some good deals on 4wds (which I'd prefer and it's snowing like crazy tonight, I'm glad I don't have to go out tomorrow) some a little newer, but I chose mine because it had low, low kms for its age, and almost no rust. Had to do some work on it, and replaced plugs, wires etc which were really maintenance items at its age and mileage, and the sump leaked oil like nobody's business, new rear exhaust and new exhaust manifolds (the sump issue and manifolds are typical ford problems) but I know I'd have to contend with those things on a truck a couple of years newer, too.

I'm sure you'll get it sorted, if it's not the things you've tried, it's something you haven't tried yet. The home workshop handbooks usually have troubleshooting flow charts which can be helpful.

So we can help you better, maybe you can list exactly what you HAVE done, and whether the truck was running ok when you got it, and if yes, what led up to the issue.

 

How long before it will restart when it quits after running one minute? If it won't restart right away you need to check for spark at the spark plugs while cranking it when it won't start. If you determine if it is a fuel delivery problem or an ignition problem, you will have narrowed it by half. Did you change the fuel filter? I read your previous post through again to see where you replaced the fuel pumps.

 

My first thought is: you should have continued your original thread so we could read back over what you've already said & done. You didn't put NEARLY enough info in this one for anyone to help you.

My second is: if you can't diagnose it yourself, you'd save a LOT of money paying a pro instead of throwing part$ at it. As you see, it's not an effective way of fixing anything.

Third: pjb nailed it. The '84-89 fuel system sucks, and if you don't understand it, it can be #3!! to diagnose. The Haynes manual (PN 36058 w/light blue cover) does an excellent job of explaining it, so pick one up & read it. You should also search FSB for posts by Sixlitre describing the disassembly & cleaning of the "dual function reservoir".



Fourth: masseyman hit another hot topic for '84-91 trucks. The ignition module is mounted to the distributor, and was the subject of a class-action lawsuit because it fails so often. Haynes has a thorough diagnostic procedure in Ch.5 Sec.5 on p.5-5 that only requires a cheap multimeter.