Ok heres the scoop i've got an 88 ford f-150 with 330,000 miles and my old motor kinda just went kaput so i dropped a reman motor from o'rielys (where I work) well i got the motor all chromed out and painted the block and replaced about everything on the sucker having to do with the motor well that was the good part. HERES the bad well i got it put in and i done it all myself well i fired her up and drove it RAN PERFECT after a couple of vacume line rearranging lol but anyway i got in it last night and it idled up like it was out of gas and then just spluttered out and died well i immediatly went to the liquid gold station and got me 15 dollars worth of gas brought it home poured it in and it started and then died then i got to listenin and my fuel pump is running constantly and i have no idea what the problem is so if there is anyone out there that might could suggest me some things to check or buy to fix my problem i would greatly appreciate it

Thanks alot ole_smokey[img]file:///C:/WINDOWS/Desktop/100907_03391.jpg[/img]



[img]file:///C:/WINDOWS/Desktop/100907_03391.jpg[/img]

 

First off, those pics don't work because you're trying to link to a local file on your machine. You have to host them on a site like imageshack or ----------- and then link to THERE.

Onto the problem. If you have two fuel tanks try using the other one and see if the problem goes away. If no luck then remove your fuel pump relay and test it by grounding the 86 pin and applying +12v to the 85 pin. When you do this you should hear (and feel in the relay) a distinctive CLICK, this is the sound of the relay closing it's circuit. When you take the +12v off of the 85 pin you should hear it make the CLICK again, this is the sound of it switching open and breaking the circuit. If you don't hear both clicks then your relay is bad, possibly stuck in the closed position causing your pump to run all the time.

Here is the location of your fuel pump relay, courtesy of Bill (subford)'s photo:

 

i've looked that truck over under the hood and i cant find any fuses the only fuses that i know of or my handy dandy chilton book know of is the ones under the dash on the inside and to beat it all my chilton or my haynes doesn't say a thing about the fuel pump relay

 

Not sure about an 88, but in my vintage the fuse box is on the driver fender well. I believe yours should be in that general vicinity... Maybe someone else will chime in here. But your FPR is definitely going to be in the engine compartment fuse box, not on the interior fuse panel.

 

thanks brother i appreciate your help but i sure hope someone chimes in here lol

 

The fuses are in a plastic box in the engine compartment, drivers side.
It has been awhile since I sold my 88, but the FPR is in the engine compartment. It is about 1x1x2 in dimensions. It does not look like a fuse (of course)
Look for the words POWER DISTRIBUTION - and open the box up.

 

thanks for the help man but do you think that is what the problem is ? and also would it be the lil black box mounted beside the air box ? this is starting to bug the crap outta me

 

Haha yeah it's the black box mounted next to the airbox. You never bothered to open it and look inside? Doesn't it have POWER DISTRIBUTION on top? That's okay. Yeah, have a look inside there and test the fuel pump relay like I suggested.

If you're sure that the fuel pump is running all the time then my bet is that this is your problem.

 

well when ya turn the key on your suppose to hear the fuel pump run to build up the right amount of pressure and then it should shut off but what i am hearing is the pump running constantly but ill take a look

 

On a 88 there are two relays located on the middle of the driverside plastic wheel well housing. Same area where the diag. test connector is. The relays are covered by a black plastic cover. One relay is the fuel pump relay and the other relay is for the computer.

The fuel pump relay has the following colored wires at its socket.
Red, Brown, Tan/Light Green and Yellow.

If the ignition switch is off and the fuel pump is running, the relay must be stuck in the energized position.

If the fuel pump only stays running with the ignition on and engine not running, for some reason, the computer is energizing the fuel pump relay by grounding the Tan/Light Green wire.

In normal operation if you turn the ignition key to run the fuel pump runs for about a second then shuts off. If he computer receives reference pulses from the distributor indicating the engine is cranking or running, it will keep the fuel pump relay energized.

Here's a schematic of the fuel pump relay. The schematic for a v8 is basically the same. The brown wire is 12 volts to the tank selector switch and then goes to the fuel pumps. The Yellow wire is hot at all times and comes from a fusible link. The computer grounds the Tan/light Green wire to energize the fuel pump relay.

 

The box is about 4 in x 7 in and you can tell when you open it what it is.
I should look like the picture posted earlier when opened.

Does the fuel pump run when the truck is off - key out the ignition,etc.- if so you will have to replace the FPR.

 

ok i've got two f-150's and ones an 88 and ones an 89 the 89 has the 4.9 and the 88 has the 5.8 and i fount the fpr on the 4.9 so im guessing that the 88's should be in the same place but on the 88 the lil box mounted beside the air box is about 2 by 3 and i have to take 2 lil bitty metric bolts out of it to even see whats under it and the fuel pump only runs when i turn the key on and once i turn the key on it dont shut off so im guessing it could either be the control mod cuz i got it from auto zone bout 4 days ago but surely it hasnt went bad this soon but ima take them bolts out and see what i can see under it and also when i turn the key on in my 89 i can hear the fpr clicking and i cant hear it on the 88 so i guess it would be the frp on the 88 but thaks alot on everybody flyin in and helpin me

 

Never dismiss the possibility of buying a faulty part from the auto parts store. This happens ALL THE TIME. It has happened to me personally. Which "control mod" are you talking about that you replaced with an auto zone part? If this is a critical engine part I would recommend not using auto zone parts for replacement... They are generally crap and NOT uncommon to be bad right out of the box.

 

The fuel pump running constantly like you say is a classic symptom of a bad computer...but check all the relays first though.

 

(In normal operation if you turn the ignition key to run the fuel pump runs for about a second then shuts off. If he computer receives reference pulses from the distributor indicating the engine is cranking or running, it will keep the fuel pump relay energized. ) right there is my trouble i found the relay and when i turn the key on it clicks and when i turn the key off it clicks so the only other thing there is is the control mod on the dist and it being from auto zone lol but yeah the control mod on the dist is the problem so i do believe ima go buy a brand new one from work tomorrow and put her on tomorrow night but hey guys i really do appreciate the help you guys helped me alot especially at 325 in the morning THANKS GUYS ole smokey o yea and ill try to get some pics up of the ole girl sometime so you all can see her she truly is beautiful