Fuel pump location 1991 7.3 idi 2 tanks

[jonleroy2506]

Hey all,

got a few questions about fuel pumps on my truck. First of all, I have two tanks, do I have 2 pumps? Second, where are they/it? I was just driving it after getting the dash put all back together after fixing an electrical issue (or so I thought) when the truck quit and won't start. Need to know where the fuel pumps are so I can see if they are working. I have fuel at the injectors and fuel/water separator, and while cranking the engine and bleeding the fuel/water separator fuel definitely bleeds out, so I'm not sure what the problem is. My fuel pump relay is sending power to the pumps. Could this be a timing issue? I have been having electrical issues that i'm working through, is there an electric component to timing?

 

[franklin2]

If it is factory original, you have one mechanical pump mounted down low on the front pass side of the engine. It's hard to see, the best way to change it is pull the front tire and then pull the corner of the wheel well back.

 

[dgr]

Fuel pump relay? Where is that?

Since you were just working on the engine harness, I would check for power on the green red (or is that red green?) That feeds power to the shut off solenoid on the injection pump. Search for a pic so you have the correct plug. Turn the key to on and then disconnect and reconnect the fuel shut off solenoid. You should hear a click each time.

 

[jonleroy2506]

I already checked the Injection pump solenoid, and it's working fine

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[jonleroy2506]

The fuel pump relay is on the driver's side in the engine compartment there are two relays there by the diagnostic port, one is for the fuel pump system

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[dgr]

Follow the hard line down from the fuel filter. Factory and it would be hooked to the mechanical fuel pump on the side of the engine.

Don't know about a factory electric fuel pump setup. If it has an electric pump, you should get fuel at the schrader with the key on and not cranking.

But if you're getting fuel to the injectors, then it doesn't sound like a fuel pump problem ....

Ninja edit. No electrical component on the timing.

 

[chillman88]

The fuel pump relay is on the driver's side in the engine compartment there are two relays there by the diagnostic port, one is for the fuel pump system

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What year truck? I assume it's the one in your Avatar so 87-91?

If you have a fuel pump relay you either have a truck that someone installed an aftermarket electric pump on, or you have a gas truck that someone converted to diesel, or you have a powerstroke. To the best of my knowledge no IDI ever came from the factory with an electric pump.

The only relay I know of on the driver's side is for the trailer package, although I'm sure there could be another one there though.

You said Diagnostic port, you must have an automatic transmission?

If you really do have an electric pump you will have to trace the fuel lines to find it because it will be aftermarket and could be anywhere.

Crawl under the truck on the passenger side front and look up towards the alternator. You should see the mechanical fuel pump on the side of the block.

You're diagnosing the fuel system but it sounds to me like you need to check your glow plugs. You have fuel at the injectors and the Schrader valve bleeds while cranking so you SHOULDN'T have a fuel problem. I'm not saying you don't, but if you were fixing something electrical then you could have an electrical problem now.

Have you verified power to all the glow plugs yet?

 

[franklin2]

Look at your VIN on the windshield or your title. Count over 8 digits, you should have a "M". If you instead have a "G" your truck was originally equipped with a 460, which would explain the fuel pump relays.

 

[jonleroy2506]

I know I started this thread on the topic of fuel pumps, but turns out I was just running wayyyy low on fuel and drawing more air into the pump than fuel... Lol should have checked that first. Someone tell me I'm not the first person to do that

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[dgr]

You're the second.

It's common for our trucks to break off the showerhead pickup in the tanks and start sucking air at 1/4 of a tank.

 

[jonleroy2506]

Okay good to know, I was honestly quite relieved when 10 gallons of diesel and some bleeding was all it took to fire right up. I wasn't all about the idea of dealing with a fuel issue on top of my electrical

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[hesutton]

It's time to pull the sending units on the tanks and look at the fuel pickup on the bottom of the senders. Like stated above, they tend to fall off the sender over time and you can't get fuel from the bottom 1/4 of the tank. The front you can remove without much trouble. The rear, typically you need to loosen the bed bolts enough to raise it to have the clearance for access to the sender (unless you have a body lift on the truck).

What I've done is replace the failed fuel pickup (looks like a shower head) with a short piece of diesel rated fuel hose. I cut a couple of "V's" at 3 and 9 o'clock on the bottom of the fuel hose to keep it from sucking on the bottom of the tank.

Heath

 

[nelstomlinson]

Classic Diesel Designs is selling a sump kit to convert our tanks to put the fuel lines on the bottom, no silly shower head needed. I plan to do that as I go through my fleet. This business of drawing fuel out the top seems pretty goofy to me.

 

[Cubey]

Look at your VIN on the windshield or your title. Count over 8 digits, you should have a "M". If you instead have a "G" your truck was originally equipped with a 460, which would explain the fuel pump relays.

The cluster would say "unleaded fuel only" in that case. Highly unlikely someone would swap that too.

 

[jonleroy2506]

Fuel cap cover says diesel fuel only, it was originally a diesel. Found the mechanical pump in the block

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