I have a 1990 f150 4x4 with dual tanks and a 302.
The truck ran fine when I parked it, this morning I started it and ran fine for 30-60sec idling, but suddenly died. When I went to start it back up, I noticed the fuel pump didnt kick on. After cycling the key a couple times it did kick on and started for 15-30 sec then died again. Now the pump never kicks on. I ran codes on it and got a 95 (faulty secondary pump circuit). The rear tank had always returned to the front but otherwise ran fine untill a month ago when the pump stoped working on it. so now I have no working pumps.
Ever since I had got the truck it has been a little hard starting and about 1/2 the time I would have to turn the key off and then back on and it started instantly. It started easier cold than hot. A week ago I bought a fuel pressure tester and was baffled when it read practically "0". I could hold it to the floor as far as I wanted and it ran fine so it was getting plenty of fuel. I just figured it was a faulty tester.

Do any of you have any Ideas?
Thanks, Justin

 

A bad fuel pump relay can cause this problem. Just happened to me yesterday. Parked it the other day and wouldn't fire up!, No pumps working, I got out my meter and had no voltage through the fuel disable impact switch. Found the fuel pump relay and found burnt contacts inside. Replaced relay and no problems.

 

Eddie, thanks for the reply. Is the relay located in the fuse panel?

 

No it is not.
It is located on the drivers fender.
But I think you have two bad fuel pumps (FDM).


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Thanks to FTE and all the info on this common problem!

We will be replacing both pumps and the relay. CarQuest auto parts has the front pump for $140 rear for $130 with Lifetime Waranty. A little more than some parts houses but better waranty. Thanks again guys.

 

Rats..... my problem is back again, no fuel pressure! The HP pump is running but the in tank pump is not..... Time to pull the bed off again there's no way I'm dropping a full tank of gas.

 

I got it figured out!
After first trying the relays, I didnt see any results. So I decided to pull the bed and replace the pumps. I started by buying just the front and replaced it. Still no effect. So instead of replacing both pumps (since their about $160 a pop), I took the volt meter and just followed the whole circuit utill I found that there was no power after the switch in the dash. When I put a jumper wire in the plug the pump came on! And the rear pump works too. I tried to get the switch from the auto parts stores and none of them said they had it or could get it. The only local junkyard had a handfull of these trucks but none of them had the switch. All were missing it (someone had beat me to it) and one had a homemade switch installed. The gall at the counter said the switch is usually the first thing sold out of these rigs. I guess this all makes sense. But a 95 f250 had one. Its a different style as far as appearance on the front plate goes, but the plugs the same and with some trimming it looks good as new. I am glad that I replayced the front pump cause now I have no back flow problems and my pressure is back up where it should be. Now it starts instantly every time and I imagine i'm gonna see some better mpg numbers too.
Thanks for the help

 

I did more checking on my truck yesterday after the ditch drained from the rains we had here. Found my intank pump is good(cat knocked off tank wire connector) and the HP is good with fuel pressure 49 Psi. Tracked problem further and found no spark. Took out the SPOUT connector and got spark back but no run, the ECU crapped out on me and was not fireing the injectors or spark! Got the ole STAR tester out and no codes! Then I disconnected battery and reinstalled and got codes and engine started up with no problems. I hate intermittant ECU problems.


ps. anybody needs some kittens? They got dumped on my house by a mother cat and they have been getting into my vehicles causing some problems like my tank wire getting knocked off.