85 F-250 fuel/wiring issue/confusion

[adobe]

My 85-F250 with big engine had the solenoid go out--replaced that; the ignition commutateur interrupter was replaced prior. I goofed up the small wires to the solenoid, but then realized all the small wires go to the positive side which I corrected. Engine turned over great, but no gas into carb. Poured gas into carb, engine started right up. Went under vehicle, listened for fuel pump noises, moved the tank switch to other tank, no gas, pressed button under right side dash for reset, all this after I checked the fuses. Looked for wiring diagrams, could not find one I could read, much less comprehend with the number codes. Changed a relay on left inner fender well with new unit. Looked at wires with fuseable links but saw no burn/other marks. Two realities: 1) I am not competent in electricity, and 2) I love this truck, had it for years and intend to keep it, as I am retired, etc. I am more than open for your help and ideas, methods of approach, diagrams, even crystal ball solutions prior to me giving up and having it towed to a shop miles away and being forced to rob a Circle K to pay the repair bill! Thank you ahead of your advice...

 

[Fellro]

If you have a carb you should have a mechanical pump. The tank switch then only controls the tank the fuel gets pulled from, not a pump in tank. It can then be the mechanical pump failed or there is a problem in the fuel lines letting air in instead of making a vacuum to pull the fuel with.

 

[adobe]

I previously looked under the vehicle, thinking the fuel pump would be on the driver's side of the engine, did not see it, but maybe it is hidden behind the smog unit...meaning I am going under the engine bay again and if I find the pump you will be my new best friend as I place a dunce cap on my head! Thank you very much for this information, for the engine does have a carb...date of manufacture is 07/85.

 

[adobe]

I previously looked under the vehicle, thinking the fuel pump would be on the driver's side of the engine, did not see it, but maybe it is hidden behind the smog unit...meaning I am going under the engine bay again and if I find the pump you will be my new best friend as I place a dunce cap on my head! Thank you very much for this information, for the engine does have a carb...date of manufacture is 07/85.

 

[adobe]

Whoops, that would be behind or hidden by the power steering pump ass'y which I just observed standing in front of the engine bay, next up under the vehicle (when it gets warmer outside!).

 

[Fellro]

Looking up parts I see it both ways, electric and mechanical. If electric, it may be as simple as a bad ground connection that got disturbed when you were working on the solenoid. It also requires a signal from the distributor to energize the fuel pump if electric. There would be a relay somewhere to engage the pump. Most likely you will find a wire where you were working that is either broken or disconnected. The fusible links at the solenoid can appear to be connected when actually are failed. Simplest way to check is give them a tug. If solid, they should be fine. If you can stretch them, it is failed.

 

[adobe]

I got under the truck and found no fuel pump but did find hoses going to the tanks, both front and rear, thus electric fuel pumps. Will next try to chase down those wires from the solenoid...but I could really use an accurate 85 F250 wiring diagram that is large enough to read easily and if code numbers a break down of what those codes mean. I want to thank those who have offered help and know that I am following your advice as best I can and will continue to do so.

 

[Fellro]

Check the blue fusible link to verify good/connected to the battery supply side of the solenoid.

Found this:

The fuel pump will NOT run with the key in run and the motor not running or when you cycle the key. The only time the fuel pump is supposed to run is when the starter is engaged or when the motor is running.

That said you can:

1) Jump the oil pressure switch. Then the fuel pump should run with the key in run and motor not running.
2) Jump from battery + to the small I terminal on the starter solenoid. This will send power to the fuel pump.

otherwise, check the fusible links at the starter solenoid to make sure they’re good.

 

[adobe]

Fellro, thank you very much for providing me with a potential solution. IF IT WORKS, you become my new best friend. If it doesn't you still remain my new best friend because I will have eliminated other issues. I will keep you posted on my efforts. Again, thank you and I do appreciate the wiring diagrams.

 

[Dustydust]

I previously looked under the vehicle, thinking the fuel pump would be on the driver's side of the engine, did not see it, but maybe it is hidden behind the smog unit...meaning I am going under the engine bay again and if I find the pump you will be my new best friend as I place a dunce cap on my head! Thank you very much for this information, for the engine does have a carb...date of manufacture is 07/85.

I have an 85 f250 460 it is carbureted and has an electric fuel pump in the tank.

 

[Fellro]

True, 460 trucks didn't have the mechanical pumps.

 

[adobe]

Guys, this week I am going to tackle the fuel pump issue once more. Have been out of pocket for some time but wish to thank you for the help and comments.