Well here I am again. I installed the 302 and gotten over the small issues. This one has got me stumped. The truck starts fine at first. If I let it idle and heat up then turn the it OFF. I can not get it to start back up. This is where I have tried it a few times and noticed.....
1. If it has been running for a long while and I turn it off then turn the key to ON the fuel pump does not sound off like usual. (HEAT ISSUE IN ELECTRICAL?)
2. After coolong for 5-10 minutes the fuel pump regains conciousnes and pumps but the truck still will not start.
3. After cooling 20-30 minutes the truck starts up fine.

All I can figure is something within the electrical system is getting HOT and failing.

Any Ideas?

 

check your ignition connection under the dash, its the first place i think i would look. relay?, i think there is one
does it still crank? still have spark? also it dont cycle on when you turn the ign. on when hot?

 

what year is this vehicle?

 

I will check the ignition connection.
Which relay are you refering to?
Yes it still cranks just does not start up.
Yes it has spark.
After more fiddeling and testing the fuel pump has not stopped working at all. So it is always pumping now.
The engine just does not start up when HOT. I have tested a couple of sensors and relays. They are all OK so far.

'91 F150 with a new 302

 

Try the control module on the distributor, remove the upper radiator hose at the thermostat housing, loosen distributor hold down and turn to get your 7/32 deepwell socket on the bolts, then pull down. they can test this at the auto parts store

 

It is a '91 F150

Checked ignition connection under dash
Yes it still cranks and pumps fuel and has spark.

Checked all ground wires as that was a suggestion from a Ford mechanic. They are all cleaned off and reconnected.

I have not Idea and guess I will have to take it down to a shop so they can diagnose with a computer.

 

It sounds like a ignition module problem to me as well.

This typically happens to the 91-older engines with age.

Make sure you test it before you take it to a mechanic, it may save you some headaches and help keep your wallet thick.

 

I have replaced the Ignition Module after it was tested "Bad" and it is still not starting up when hot.

 

so u have spark, now fuel, i think the pumps are cycled by the distributor b/c when i turn it my dist the pump would cycle, just basic knowledge what u do with it is up to u. i dont know what to check about that. is there any way to put a noid light on these injectors that might help or rule out something. someone has to know exactly what this problem is.

 

Just a thought that maybe you have an in tank pre-filter or external fuel filter clogging w/sediment. Gets worse as engine runs, and will settle, allowing the fuel to flow after the engine is stopped for a while. Good luck.

 

I can drive it for as long as I want with NO cutting out or lack of fuel at any time. I also changed the fuel filter about 100 miles ago so my guess is it is not a clogged line. I will look into any other filters other than the one on the frame.
I just took it for a spin around the block to heat it up and test, after it was at normal running temparture I shut it off and as usual it would not start. As suggested by a mechanic buddy I shot a bit of gas into the Air intake and it started for a second then died. I tried to start it again and no luck. So I shot another dose of gas in to the Air intake and it fired up. Then stayed running until I shut it off. At this point I was back to the same point.... Hot engine = NO START

I have replaced the Engine Coolant Temparture Sensor and oil pressure sensor due to damage. I have replaced the Ignition Module as suggested with no luck.

Although I am learning more than I planned when I started this, it is starting to get on my nervers.

 

You may want to try replacing all the fuses in the fuse box and disconnect the wire harness from the computer and reconnect it. You could also get out and wiggle wires under the hood when it will not start and see if it fires. It has to be a computer or ignition switch problem. I was also thinking it was the module on the distributor but since you replaced that I don't know. Did you put the heat disopating grease on the module? That grease is important for heat transfer to keep that module cool. Since it is firing when you squirt some gas in the intake I would tend to think it was a computer, power or connection problem not allowing the injectors to pulse or something not letting the fuel get up there.

 

I will check all the fuses again but I am not sure where the computer is to unplug and reconnect.
Yes the heat grease was added to the module durring installation.
Well off again to read my Chiltons to see what controls the opening and closing of the fuel injectors to see what could be getting hot. Hope it is not the computer alone that controls that.

Thanks to all for the suggestions. We'll figure it out soon I am sure.

 

you might want to see if your fuel lines are maybe to close to an exhaust system and are over heating (boiling) this would cause it to not start for awhile.

 

I would by some heat tape (insulates the heat from the whats underneath), wrap the fuel rails.