I've a problem with my 79 F250 4x4 351M engine starting for the first time each day. When I turn the key, it just cranks, and cranks, and cranks some more until I get fed up and drive another vehicle or it eventually turns over. Once it starts, it's fine for the rest of the day unless it sits for an extended period of time.

Last week I drove it to a local Ford dealership hoping that it could be figured out quickly and then be fixed and on my way. Five days later, issues with the tech being pulled off for another job, etc. I got a call from the service manager telling me the tech thinks it may be the carb but did not want to tear into it not knowing for sure if that is the problem.

My thoughts are that it could be the carb because there rimes when I am driving for awhile I then I experience a hiccup like the carb is not getting fuel. In the past couple of months, I have replaced the air filter, the pcv filter, fuel filter, and wrapped the fuel line in thermal tape to avoid vapor lock.

What thoughts do you have? Should I do a tune up and replace the coil, distributor cap, wires, plugs? Adjust the carb/ replace? Any advice/ experience would be greatly appreciated.

 

I'd throw a quicky rebuild and then tune the carb to take it out of the equation.


Does your rig still have emissions equipment applicable to a 79?

 

It's all stock, nothing has been changed on it.

 

I would normally attribute hiccups to an ignition or vacuum issue. However, in your case it seems intermittent and random.

Instead of throwing parts at it, I suggest a detailed visual inspection to look for bad electrical connections, a split vacuum hose, and small things like that. .. plus the quickie carb rebuild... I bet the choke is outta whack.

 

So you have difficulty cold-starting it, but it runs and warm-starts just fine? Definitely sounds like the carb - most likely something in the choke or fast-idle adjustments. Has it always done this, or did it start recently? Are you pressing the gas pedal to the floor to set the choke before cranking? Does an extra pump or two of the pedal make a difference?

 

My '53 ford sedan did this. I unhooked the fuel line on the other side of the pump and saw it was taking 11 cranks before fuel made it up to the carb, which accounted for the extended cranking, but then running fine. A new fuel pump fixed the issue for me. My guess is there was a pinhole somewhere in the line that didn't affect pumping fuel up, but did allow the fuel to flow all the way back to the gas tank each time I turned it off and let it sit.

 

To answer Brian....it hasn't always done it, it seems that after I had an issue with vapor lock that it began and has been getting worse. I've tried the extra pump or two on the gas pedal but it doesn't appear to make a difference.

rglowaki....I wouldn't be surprised if it were a fuel pump and that, along with a carb adjustment, might worth trying.

The vacuum might be a possibility, I'll take a look tomorrow and seek if I can isolate the problem.

 

This is the same issue I had. A small crack at the auxiliary fuel filter I added let bubbles into the fuel line. It took several cranks to get it primed.

 

X2 on ck all your soft rubber lines and hose clamps. Sounds like it could a bad power valve in the carb...so yes a rebuild of the carb is in order. If it will start with the gas pedal held to the floor, that is a sign of a bad power valve in the carb, so says my carb guru.

Is your choke elec, and working properly? Usually fuel pumps work or don't. Have you ever dropped the tank and insp/cleaned the fuel sending unit pick up tube filter sock?

I am battling the same issue with the blue truck.

 

I agree it sounds like a fuel priming issue.. You won't regret tossing a 20$ rebuild kit in that old motorcraft either..

 

I'll look into rebuilding the carb.

 

If you can fix a $35 million Longbow (new), you can fix a vintage $25 carburetor.

 

I got a good chuckle out of this. I can imagine him working on an apache helicopter and needing a 35 cent o-ring to fix it. (of course being the military that 35 cent o-ring will cost $3500.00)

 

I can't tell you how many times we couldn't order parts because of no funds only to go across the flight line to get a part, like an o-ring, for less than a dollar! It does happen!

 

That kind of nonsense didn't happen during the Reagan/Bush 41 era... If we ordered it, we got it.


I tried to order an F-14 Tomcat ... it got passed the maintenance chief, the maintenance officer and all the way back to the supply clerk who nearly typed it in.