I have an 87 f-150 4wd with a 5.0 302 fuel injected. I was offroad a week ago and tried to cross a river, but it was deeper than I thought. I suck water in my engine. Luckily, after draining the water out, it ran but only for a minute or two, then died. I have found out that I am not getting any fuel pressure to the fuel rail. My high pressure pump works, but niether tanks will work. If I hook up straight power and ground to the high pressure pump it works, but I am not getting power to the pump. I have replaced the fule relay, EEC relay, starter relay, Ignition switch, and I have ran all the test in the manual. I think I have a short somewhere. I am not very good with electrical, so I was wondering if anyone knew where I should start. I traced the power and ground wires all the way to the drivers side fender apron, but no noticeable shorts. No fuses are blown either. I also checked the inertia switch, but is check out. The ECm had some water and corrosion in it, but no shorts. I am thinking of replacing this next, is there any way to test the ECM, my code reader soes not show any codes.

 

Does your truck have a fuel cut off switch?Some years have a button under the pass. kick pannel.It stops the pump in a accident.

 

yes that is the inertia switch, I cant tell if it is just weak, or if it is fine. i dont know how to test if it needs to be replaced

 

The inertia switch should be depressed. Thats the way it is on my 94. If your red button is out/popped up press it back down. It should have 12v coming in and 12v coming outunless its faulty or been tripped. post again if you cant figure out which wire is which and I'll check my truck.
Popa Tim

 

on my 88 f105 302 4x4 i had the same problem. i tore every harness apart lookin for the short. i was getting power to the relay so i just ran a wire from the relay to the dash where i put a switch and then spliced it into the pump power. this way there was power to the pumps with the key on and if i was going to be sitting for a while with the key on but not running i could shut the pumps off. hasnt failed yet. (knock on wood)
hope this helps,
chrono

 

Check out your tank selector switch also. Water does weird things to electrical. I had a similar problem. I got home one day from work and was home about an hour and had to run back to the store, hopped in my truck would not start. Checked all the norms first then got the fuel pressure guage out. No fuel, got new relays nothing, had it towed to the dealership and 500 bones later it was running. ECM had been shorted out and fried by some wires that burnt and crossed. Truck would spin over get fire and even crank with ether. The computer was only 250 and they charged me 250 for labor OUCH bend over. But the ECM could very well be your prob.

 

I just replaced the ECM and it didn't change a thing. I have no clue what else to do

 

[QUOTE=reconrider40]I have an 87 f-150 4wd with a 5.0 302 fuel injected. I was offroad a week ago and tried to cross a river, but it was deeper than I thought. I suck water in my engine. Luckily, after draining the water out, it ran but only for a minute or two, then died. I have found out that I am not getting any fuel pressure to the fuel rail. My high pressure pump works, but niether tanks will work. If I hook up straight power and ground to the high pressure pump it works, but I am not getting power to the pump. I have replaced the fule relay, EEC relay, starter relay, Ignition switch, and I have ran all the test in the manual. I think I have a short somewhere. I am not very good with electrical, so I was wondering if anyone knew where I should start. I traced the power and ground wires all the way to the drivers side fender apron, but no noticeable shorts. No fuses are blown either. I also checked the inertia switch, but is check out. The ECm had some water and corrosion in it, but no shorts. I am thinking of replacing this next, is there any way to test the ECM, my code reader soes not show any codes. what should I do, I dont know where to go from here

 

hey I got it, sorry I havent been on in a while, it shorted out the ecm relay, Ecm, and fuel pump relay.thanks for your help

 

That's quite a short. Consider coating all connections with die-electric grease(around the plug end, not on the actual connections) or at the very least, some slicon spray to keep them a bit more waterproof. Not necessary if you don't plan to bathe your truck under water again, but seems like it might be worth the time.