I have a 390 v8 in my 65 f-250.

It was having alot of problems with starting, running, etc. It would run great for a few days, then one day could barely idle down the road.

I put new wires, plugs, distributor, cap, points, rotor, coil. Engine ran like a racecar for the last 2 weeks.

Then suddenly today I was cruising down the road at about 20mph, and with no warning the engine just bogged down and stalled.

Since then the car will barely idle. When you start the car it turns over strong and instantly. It idles perfect for about 2 seconds, then suddenly bogs down till it dies.

Since i replaced most of the electrical im thinking its fuel system. I took the carb off and noticed it already has been rebuilt (although im going to rebuild it again). Also detached the fuel line and cranked the engine to see if the pump was working. I got good flow coming from the pump. Fuel Filter was replaced 2 weeks ago when installed new distributor.

So unless the carb rebuild works i have no idea whats going on with this engine. Im pretty sure there is nothing wrong with valves etc as it was running like a racecar earlier this week. I think i would have noticed it.

Any help/suggestions would be so much help

 

Heading out to get a rebuild kit. Was hoping to see a reply with some ideas. As an update though I checked the accelerator pump and it seems to be fine, that was a suggested fix for me, but its shooting 2 perfect streams.


Truck is still doing the same thing. Starts right up, good idle for 2-3 seconds, then idle drops and car starts to stumble till it dies. In Park i can give it gas and it stays alive and the engine sounds "ok". Put it in drive and give it gas and suddenly it starts missing really bad and shaking the whole truck.

Is it possible for the engine to "lose" timing. Like I said its all new electrical and new dizzy. Engine was timed correctly and running perfect for 2 weeks straight, now its acting like this. Which is close to what it was doing before I replaced everything.

 

Check your timing again, it's only happened once, but i have had it move on me before, and retard below 0degress and it ran like crap till i figured it out.

I don't know much but maybe there's something wrong with the idle circuit/screws? Just a guess.

 

If it isn't you timing, check your carb, fuel lines, and filters. It could have pulled up a piece of junk from the gas tank and clogged the fuel line.

Sam

 

I agree with Rusty. Replace the rubber fuel lines and remove any add-on filters that may have been installed (it make a big difference on my truck). Remove the sending unit on the tank and look for debris and that the screen is still attatched. Good luck.

Kurt

 

Dpayne1965: I just noticed you said you already replaced your fuel filters- my guess is you'll need to replace them again. My truck was having the same issue, I'd go through 4 or 5 filters a month, so finally I replaced the fuel line from the pump to the carb and I haven't had any issues since. It turned out the old fuel line was so full of varnish and crud that whenever I bumped it it would break some free and clog up the filter.

Sam

 

also check your vacuum lines , one could have cracked or burnt . easy test is plug them all if engine runs much better start putting one back at a time .