1990 Ford E150 1/2 ton Club Wagon [5.0 EFI] 110,307 Seems while I am sitting inside the van and listening to the external fuel pump whine it will stop whining and the van will die. This problem is causing stalling while driving; I'll drive anywhere from 1 block to 7 miles and in between that distance it will stall repeatedly requiring me to wait anywhere from 30 seconds to a couple minutes before it starts back up. Sometimes it doesn't happen at all where I can go for days without the problem occurring yet now it's almost a daily. The guy before me had replaced the filter and external pump because it was cutting off on him. That didn't solve the problem. I replaced quite a few things such as the tp and egr position sensors, eec and fuel pump relays, IAC valve and recently the ignition coil but the problem persist. Now I am leaning towards so sort of electrical problem resulting in the external pump cutting off (stop making a whining noise) right before the engine dies. What I would like is maybe an explanation of the fuel delivery system's electrical components and perhaps troubleshooting methods. I have dual tanks and have a new inertia switch as well as a tank switch laying around in the event it is the inertia switch. I even have an internal fuel pump (do both tanks have fuel pumps?) Thanks

 

Yes , both tanks have their own fuel pump.

 

I should of kept my chevy

 

I know this is a bit troublesome to do, but can you temporarily rig up a test light to the output of the inertia switch? The lite will stay lit as long as you have the key on and the fuel pump relay is energized. If and when the engine should quit , this would at least let you know if the problem is before or after the inertia switch. What do you think?

 

I've been considering running a test light to the inertia switch to see if that is the cause of the fault. It is not troublesome for me to do that since in the end not only will i learn something but also remove that from the list of possibilities. Underneath the van on the driver side is the external pump. before the pump is a black, apparently plastic canister with fuel hoses coming out and going to the pump.....what is this black container? Upon reflection, it seems that the van idled down and died right along the same time the pump stopped whining. But I'll check the inertia switch today and let you know what I found. The switch is set correctly....just will check now. thanks hanky....really appreciate your time on this issue. hope you find a couple hundred dollars today

 

If I remember correctly, that round plastic thing you asked about, The last time I checked into what that was and what it did, it had something to do with providing a reservoir for a constant supply of fuel on unusual vehicle maneuvers. I'll check further and see if I can come up with a more logical answer. They never gave me any problems on the vehicles that had them so I never looked any further into just why they were there.
I'm trying to think ahead on this , if the pump stops and the test light stays lit at the inertia switch ,then it might be a good idea to place the test lite at the supply to the pump on the chassis.
Then if the pump quits and the lite does whatever it does will help to pin down why the pump stops. What do you think?

 

By the way thanks for wishing I find a hundred bucks, with my luck it will probably be Monopoly money or counterfeit. Have a good one !

 

ok....unbolted the inertia switch to gain access to the electrical connector. Attached a test light to it and turned van to run position and while van running both wires lit up on the test light individually. Unconnected the inertia switch and van died. plugged back in and van starts up. Checked the fuses while I was down there and replaced some that weren't the right amp but still the van dies after either idling for about 5-10 minutes or driving anywhere from 1 block to 7 miles. Noticed the PCM was kinda rusty looking and will probe the wires there to make sure there is constant voltage while van running. Apparently the guy before me brought the van into have it serviced (oil changed I guess) and since then it has been stalling out. I even noticed that the inertia switch has been probed before with no luck. Someone mentioned somewhere (of course) that when testing the inertia switch with a test light that after you start the vehicle the test light should come on for 2 seconds and then go out? Maybe I read that wrong because I assume that the inertia switch needs constant power to keep the fuel pumps pumping. So, it's the the pcm and then below the van to recheck all electrical components, hoses, etc dealing with the fuel system.

 

You are both right. Here is how it works;
When you turn the key to the on position the computer will energize the fuel relay for 2 seconds. If no attempt is made to start the truck the fuel pump relay opens, therefore no fuel pressure. If the computer gets a cranking or running signal from the ignition system the relay stays energized. So if the vehicle is running the circuit through the inertia switch is complete and will be indicated by the test lite. That was why I suggested to connect the test lite to the output of the inertia switch. If the lite goes out before the engine quits you know the problem is the switch or before the switch. If the engine quits first then the lite goes out , its after the switch.
Of course you place that test lite close to the dash so you don't have to take your eyes off the road if you are driving the truck.
Can you find the diagnostic plug under the hood in the engine compartment? Its been a while since I worked on a 1990 and I don't remember which side its on. Anyway there is a way to energize the fuel pump relay so the pump will run constantly. If you can locate the plug I can instruct you how to energize that connection to the fuel pump.

 

Good Morning.....I've been thinking about the oil sending unit (had a bronco with a bad oil pump and it would cut off while driving) and it being defected...Just checked the oil gauge (operating correctly) and checked the oil pressure sending unit (sensor) with the one wire attached to it. This sensor has a hexagonal metal piece coming out of the engine near the oil filter and has a round piece of plastic cap attached to the top with the one wire i mentioned going to it. Where the hexagonal piece and the engine meet is way too oily for me to determine if the unit is leaking (can I run a test light to that wire to check for power?). I'm familiar with the OBD1 tester located inside passenger side fender well......ran a check awhile ago and it came back code 12 air control fault. Replaced the IAC and it ran for about two weeks without cutting off (this is during the winter when the temps were down) and then one day when the temp was above freezing it cut off on me and has been doing that regardless of the temperature outside.