Hello fellow Ford Owners,

I am new to the world of owning a Ford truck and to this forum. I have read through several posts and there seems to be a wealth of knowledge in here. Maybe with this great knowledge, someone can show me something I have overlooked with my truck.

First a little history.

I bought an 81 F100, 300 CID inline 6-cylinder, 4 speed on the floor, from the original owner three weeks ago. The guy I bought it from had done several things to the truck. He had the motor replaced (1000 miles on new motor), AC converted, and replaced fuel pump and filter. Truck ran, but would not idle and had no power. He said the truck had done really well until one day it gave up the ghost. I runs extremely rich and turns the cat converter cherry red.

The motor is very tight. The compression test revealed cylinder pressures of 160 to 153 pounds.

After getting the truck to my house, I ran through the usual list of tune items in hopes of fixing the problems. After new Plugs, wires, cap, rotor and air filter, the truck would start easily but not idle and had no power. Now I have thrown nearly every possible idea I have at the truck. Tried new EGR valve (old one is back on), ign module, voltage regulator, resetting float, cutting exhaust pipe (eliminate cat conv back pressure, moved dist back and forth one tooth and pulled and resealed exhaust and intake manifolds.

I have not pulled the timing gear cover off yet. Don’t think the gear has jumped a tooth ( new motor). I am leaning toward the ignition stator in distributor. Any advice anyone can give me would be greatly appreciated.


Thanks for the help now.

Gary

 

take your CAT off and knock out the guts and put it back. run it to see if it runs better. if it does (which it probably will) replace with a new CAT if you have emissions testing or want to have the truck stock.

i saw you cut the exhaust but dont know what you mean?

anytime i've seen converters/exhaust turn cherry is when it's plugged.

the other thing could be that the heat riser valve is stuck in the closed position.

don't run your truck this way if you can avoid it. you'll burn your valves.

 

Get it running, and while keeping it running, carefully look down the carb. If you can't see down in the carb, then the choke plate is shut, choking the engine too much.(But I think you know that already)
While looking down the carb with the engine running, you should see NO liquid fuel. You will see liquid fuel when you move the throttle from the accelerator pump squirters, but if you see any liquid fuel dripping from the round boosters, then you still have a carb problem. You said you re-set the fuel bowel level, but the float could be bad(heavy with gas), or the needle and seat could be wore out. Also on rare ocassions, something happens to the fuel pump, and it seems to have too much pressure and overwhelms the needle and seat. But I would look in there first to see if you do have raw fuel dumping in the engine.

 

Hey Gearheads,

Thanks for the insight. I got the truck running today. The replies from you were helpful in triggering my mind. The exhaust was already eliminated from the picture but the carb was not 100% ruled out.

I resealed the manifolds, put another carb kit and float in and retimed the motor. The truck came to life and is now running. (i need advice on setting the air/fuel screw and a good reason why it will not increase rpms when I turn the idle screw in.

It was still running rough and misssing so I changed the plugs and wires again. I then swapped in a new coil.

Runs but there is still a slight miss in the truck. Odd to me is that it only misses when I hear an exhaust leak. If the leak is gone the motor runs smooth. I need to have the manifolds resurfaced and trued up.


Thanks again for the help.

Gary