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Hello,
I'm new here, but have done some searching for this info.
For some reason, either age of the posts or the web nanny here at work, I can't seem to view the pertinent pics.
My situation is that I'm going to look at a truck,
'99 F350 Regular Cab 4wd V10, with manual transmission, that has been parked for several months and won't start. The owner says that he thinks it is the fuel pump, because he no longer hears it whining when the key is turned on. I went ahead and bought a new pump and relay, because it seems like it's a good idea to replace the relay proactively, even if it's not the culprit.
From what I've gathered here, the relay is located behind the radio. Is that correct? If so, what is the best way to access that? Is pulling the radio a major job, or require special tools?
I'm planning on lifting the bed to get at the pump. Should for guys be able to handle that job?
The fuel pump relay on a 1999 SD with a gasoline engine should be under the hood in the power distribution box next to the master cylinder.
4 able bodies should be enough to lift the bed. The problem will be getting to the bed bolts through the bedliner if it has one, and then coaxing the bolts to become loose enough to remove. On a vehicle that old they may need to be cut off. It might be a good idea to plan on having replacement bed bolts available.
It isn't that big a deal to drop the tank and change the fuel pump. With the tank removed from the truck you can thoroughly clean the tank more easily than with it on the truck.
Either way you are going to need Ford fuel line removal tools.
I dropped the tank on my '01, and it wasn't hard at all. Biggest thing: Pump out all the gas you can. What I do is take a piece of 5/16" fuel hose, remove the Schrader valve in the fuel rail, hose clamp the hose to the fuel rail where the Schrader valve was, and using a Holley fuel pump I keep around, pump the tank dry.
Dropping the tank is easy. I'm not sure if yours is the same as mine, but mine was plastic, and the fuel pump and float are all held in by what looks like a big Mason jar lid ring. Unscrew it, and everything comes right out.
Hardest part was disconnecting the fuel line while dropping the tank slightly.
Are those fuel line tools, one size fits all, or do I need to get a specific size?
The only fuel tank I've ever pulled was on my '95 Bronco and it was a pain to get to the bolts between the body and tank. I've helped replace pumps on Chevy trucks and we always just lifted one side of the bed for access. I guess this led me to assume that was the easiest way. Maybe I will just pull the tank.
I have found that a pair of cambuckle straps is much easier to deal with than a jack especially when working on gravel. Even if the tank is full, it is no problem to gradually lower it just enough to get everything disconnected and then finally lower it all the way to the ground. The cambuckle mechanism is much easier to deal with in this application than a ratchet strap.
Also double check the fuel pump inertia switch to make sure you are getting power past it. It's behind the toe kick panel on the passenger side. Just a push button. Way back when the 1999's were stolen a lot I wired in a manual fuel pump disconnect through this switch.
Fuel pump relay is behind the radio on a 1999. Removing the radio is probably the best access especially if the radio is factory with the release holes. It will still be tight but you will see it in there with at least one other relay. I cycled my key while feeling for the "click" to isolate the correct relay. I replaced mine when I did my pump because I was told a weak relay can be hard on the pump. Not sure if that is true but the relay was cheap so I did it.
I replaced mine when I did my pump because I was told a weak relay can be hard on the pump. Not sure if that is true but the relay was cheap so I did it.
It's definitely true - in fact, I realized that in 3 family member's vehicles I worked on, where the fuel pump died after their mechanic replaced it, the relay was going bad, and caused the fuel pump to run with low voltage, and overheat and die.
A friend of mine had THREE fuel pumps put in his Thunderbird before I said what the heck! And replacing the relay made it stop eating pumps
... I realized that in 3 family member's vehicles I worked on, where the fuel pump died after their mechanic replaced it, the relay was going bad, and caused the fuel pump to run with low voltage, and overheat and die. ...
I've been wondering about this same issue.
If I measured correctly in our 2002 Excursion the pump is drawing 15A.
The relay is rated at 20A, which is fine, but in the long run...
I added a 40A relay which is triggered by the stock relay.
The 40A relay is fed by it's own line from the battery.
The original 20A Ford fuel pump relay on the back of the fuse panel now just triggers the 40A relay and has only .2A going thru the contacts.
I also added a switch to return the circuit back to stock.
So far after 2k miles no problems.
It's definitely true - in fact, I realized that in 3 family member's vehicles I worked on, where the fuel pump died after their mechanic replaced it, the relay was going bad, and caused the fuel pump to run with low voltage, and overheat and die.
A friend of mine had THREE fuel pumps put in his Thunderbird before I said what the heck! And replacing the relay made it stop eating pumps
Interesting, that's good info right there.
First thing I would do is change the relay. Don't even mess with the pump if the relay is bad. No need to change a possibly good pump.
08-26-2016, 07:30 PM
