I just had a crate motor put in my truck. 88 f250 460. it runs great. starts fine when its cold, but when its warm it will start, sputter, than stall, or turn over slow like a dead battery. I am not getting any codes.

Is this from the new motor still being tight, or am I missing some thing.

Thanks
Bob

 

check the ground cable.

 

And the timing.

 

Try another starter if you can. I had a simular problem with reman'd units and finally ended up with an oem NEW unit thats been fine for 4 years now.

 

try a voltage drop test over your pos and neg cables when this happens they could be hot and building up resistance.

 

checked ground and double checked since you menchened it. good ground. checked timming, good. the starter is 1 and 1/2 year old.

Is the voltage drop test the same as a load test, or just watching the voltage as the truck is started?

thanks
Bob

 

With your volt meter hooked up 1 lead on the positive bat post the other on the positive bat connection, when you crank your engine over you want to see close to 0 volts no more than .3 volts if this is good move down the line to the next connection,
You will do this on both pos and neg bat cables. It is best to check it when the problem is there. Any excessive voltage that show up on your meter is voltage the starter is not getting ( drop). You also want to watch for swelled cables, cuts in insulation can allow corrision to start working turning the wires green and starting the resistance problem. A common place for this to happen is between the bat connection and the first 3 or 4" of the cable Good luck

 

With your volt meter hooked up 1 lead on the positive bat post the other on the positive bat connection, when you crank your engine over you want to see close to 0 volts no more than .3 volts if this is good move down the line to the next connection,
You will do this on both pos and neg bat cables. It is best to check it when the problem is there. Any excessive voltage that show up on your meter is voltage the starter is not getting ( drop). You also want to watch for swelled cables, cuts in insulation can allow corrision to start working turning the wires green and starting the resistance problem. A common place for this to happen is between the bat connection and the first 3 or 4" of the cable, Good luck

 

Ill check that tomorrow. all of this leads to the turning over slow, that hapens after it starts, sputters and stalls more than once. if it would stay running the first time I might not get to the turning over slow. I checked the temp. sensor it seemed ok.

thanks
Bob

 

It still could be a weak starter like Popa tim says and just not good enough to handle the new engine If your able to do a ampere test it should draw around 180-200 amp max.

 

I also got to thinking about how the truck would start warm, then sputter and stall. It could be possible that you have two problems that seem to happen at the same time. The turning over slow could be the starter, and your start then stall could possibly be the ignition module, since they are a known problem in these trucks. The ignition module would not affect your ability to crank, but would cause the truck to run poorly and then stall. Unfortunately I think I am grasping at straws here since the most common symptom of a poor ignition module is that they fail start completely when warm and work when cold, not start and then die. Good luck

 

It acted better today. temp sensors seemed ok I thought I would see more chang than I did.It smells ritch when it stalls, makes me think it is still cold starting or "chocked". I have not ruled out the starter for the slow crank. I have another module here I can give it a try.

thanks
Bob

 

Is this truck efi or ford's half way between crappy feed back carb?

 

efi

88 f250 4x4 460 efi zf 5speed