SOLVED: 1988 2.9L 4x4 EXT cab | what fuel pump is the right one for my tank?

[GingerKing13]

Hey gang,

Ive had this 1988 2.9L 4x4 EXT CAB Manual for 7 years and have never been able to use more than 10.5 Gallons until the gauge shows empty and she sputters to death. I swapped the fuel pump out and I still have the same issue.

The first pump I had in there was the straight one that just hung straight down. could only use about 10 Gallons before the gauge read empty and it starved of fuel.

The second pump I tried was the one that makes two bends (45 and 45) and still can only use about 10 gallons before the gauge reads empty and starves of fuel.

I currently have the one that makes two bends (45 and 45), do I just have it rotated the wrong way? Does it matter which way this pump sits in the tank (facing rear vs facing front)? I am tempted to pull the sending unit that's in there now and bend it down to reach the bottom of the tank... Have yall every heard of anyone doing this?

The attached picture of the tank is model I have.

The Fuel pumps I have tried are below with Part Numbers attached pictures:

DELPHI HP10164 (45 and 45) Currently in the tank

DELPHI HP10166 (straight)

Please help me figure out which pump it needs to reach the bottom so I can finally go on some long trips I want to do.

Thanks guys!

 

[franklin2]

HP 10164 is what rockauto calls for the extended cab pickup midship or front tank.

HP 10166 is for a ranger rear tank.

Do you still have the black round reservoir just before the high pressure pump on the fuel rail? Some people think they can get rid of that but when the fuel gets low, that is what it does, keeps the high pressure pump constantly fed with fuel.

We also had a thread recently where the fuel reservoir had some faulty valves inside it. I do not know all the ins and outs of how it works, but it has valving inside it to keep it full of fuel from the return, but also let it return fuel to the tank when it needs to.

You will notice these in tank fuel pump assembly's have no plastic housing or baffling like the newer cars and trucks. These older trucks rely on the dual pumps with the reservoir to keep the engine supplied when the tank starts getting low.

 

[RonD]

Either should work
Is the pickup filter not sitting at the bottom of the tank?

Extended cab should have 18/19gal tank
Only thing that could cause it to stop delivering fuel to the engine is a crack in the fuel pumps OUT line inside the tank, once gas level was low enough it would suck AIR from inside the tank causing rough running and stalling

Not sure you can vacuum lock the gas tank in 1988, test by running with gas cap loose

EVAP system should be Ported Vacuum, not intake vacuum

 

[GingerKing13]

HP 10164 is what rockauto calls for the extended cab pickup midship or front tank.

HP 10166 is for a ranger rear tank.

Do you still have the black round reservoir just before the high pressure pump on the fuel rail? Some people think they can get rid of that but when the fuel gets low, that is what it does, keeps the high pressure pump constantly fed with fuel.

We also had a thread recently where the fuel reservoir had some faulty valves inside it. I do not know all the ins and outs of how it works, but it has valving inside it to keep it full of fuel from the return, but also let it return fuel to the tank when it needs to.

You will notice these in tank fuel pump assembly's have no plastic housing or baffling like the newer cars and trucks. These older trucks rely on the dual pumps with the reservoir to keep the engine supplied when the tank starts getting low.

Yes the reservoir is still intact and functioning at this time.

 

[GingerKing13]

Either should work
Is the pickup filter not sitting at the bottom of the tank?

Extended cab should have 18/19gal tank
Only thing that could cause it to stop delivering fuel to the engine is a crack in the fuel pumps OUT line inside the tank, once gas level was low enough it would suck AIR from inside the tank causing rough running and stalling

Not sure you can vacuum lock the gas tank in 1988, test by running with gas cap loose

EVAP system should be Ported Vacuum, not intake vacuum

I'm not sure if the pickup is on the bottom and im not sure how to really tell as its sealed up when the pump is fully inserted. The only thing I can think is that the pickup is not touching the bottom of the tank but to lose 7-9 gallons of capacity it would have to be wayyyyy off the bottom. After using around 10 gallons fuel gauge reads empty and the truck will sputter and die. The fact that the guage also reads empty when it dies after using around 10 gallons makes me think there is something else going on. I also have no EVAP system it is blocked off at the intake and a vent hose from the tank to get air.

 

[RonD]

Gauge shows EMPTY as well?

Then tank is empty, two different systems there

When you fill it up gauge shows FULL I assume
And after driving a few hours its going down, but drops to Empty pretty quickly

And refill only takes 10 gallon(approx.) and it shows Full again?

Does it look like a Ranger stock metal fuel tank?
There are 2 baffles inside, but they have passages that let fuel flow into fuel pump/float area at the bottom and are open at the top
Maybe baffles are plugged up at the bottom, so when you fill it up gas fills up the whole tank
But fuel pump and float only get, have use of, the gas and level in the center area, or one area, because clogged baffle prevents gas from coming in from other area behind baffle
So gauge is right for that area of the tank
I would run it down to 7-9gal left then siphon the rest out and look in the tank for old sock filters or ?? clogging baffle passages

1988 Ranger gas tank picture: https://i.ebayimg.com/images/g/KnMAAOSwPexfGbZN/s-l500.jpg
Assembly hole is at an angle which is why the pump is at an angle

 

[GingerKing13]

Gauge shows EMPTY as well?

Then tank is empty, two different systems there

When you fill it up gauge shows FULL I assume
And after driving a few hours its going down, but drops to Empty pretty quickly

And refill only takes 10 gallon(approx.) and it shows Full again?

Does it look like a Ranger stock metal fuel tank?
There are 2 baffles inside, but they have passages that let fuel flow into fuel pump/float area at the bottom and are open at the top
Maybe baffles are plugged up at the bottom, so when you fill it up gas fills up the whole tank
But fuel pump and float only get, have use of, the gas and level in the center area, or one area, because clogged baffle prevents gas from coming in from other area behind baffle
So gauge is right for that area of the tank
I would run it down to 7-9gal left then siphon the rest out and look in the tank for old sock filters or ?? clogging baffle passages

1988 Ranger gas tank picture: https://i.ebayimg.com/images/g/KnMAAOSwPexfGbZN/s-l500.jpg
Assembly hole is at an angle which is why the pump is at an angle

Hey Ron,

I attached a picture in the original post with the fuel tank I have (assembly hole in the back flush) and the fuel pump that I currently have in it is the one that makes two slight bends which puts the end of the pump in the center of the tank. If i use the straight down pump (vertical) the pump would be at the very back of the tank. Which pump am i supposed to have if I have the tank i posted in the original post instead of the one that you showed?

Thanks!

 

[alwaysFlOoReD]

I'd think it would be pretty easy to measure both tank and pump to see where the bottom of the pump is in relation to the tank. If the pump is within 1" of tank bottom then it's not the pump length that's the problem.

 

[RonD]

The sender/float is with the pump on the assembly
If gauge is showing Empty and you indeed have "run out of gas" then that would be correct, and Pump is at bottom of tank

If gauge was at say 1/3-1/2 and you "ran out of gas" then pump is not at the bottom of tank

My thinking, since the gauge works, is that inside the tank where pump and sender/float are located is somehow cut off from the whole tank once fuel level is low enough, so 7gal left in ends of the tank but Empty in the center

 

[alwaysFlOoReD]

The sender/float is with the pump on the assembly
If gauge is showing Empty and you indeed have "run out of gas" then that would be correct, and Pump is at bottom of tank

If gauge was at say 1/3-1/2 and you "ran out of gas" then pump is not at the bottom of tank

My thinking, since the gauge works, is that inside the tank where pump and sender/float are located is somehow cut off from the whole tank once fuel level is low enough, so 7gal left in ends of the tank but Empty in the center

True if pump assembly is actually at bottom of tank. If the suction part isn't at bottom then same symptoms. That's why I mentioned measuring to be sure the correct depth pump is being used.

 

[RonD]

But if pump/pickup wasn't at the bottom of the tank the float/sender wouldn't show Empty when the fuel stopped flowing
That's what has me confused

 

[franklin2]

If he is using only 10.5 gallons, and when he goes to the pump he can only get 10.5 gallons back in it, it sounds like it might be a filling problem and the pump is cutting off early.

When you are filling, all that fuel going in at a high rate has to push a like amount of air out of the tank. If you do not keep all this air coming out away from the fuel going in, it will cause the fuel to gulp and splash and cut the pump nozzle off early.

I do not know what they used on the rangers, but the earlier 1980-1986 trucks had the large fill pipe, and then they had a smaller corrugated plastic pipe inside the large pipe. This smaller pipe was clipped up high inside the larger pipe, and was a "conduit" for the air coming out. This system did not work that great.

On the later big trucks up around 1987-up, they changed things around. They have a smaller rubber pipe mounted to where the nozzle inserts at the station, and the fuel goes down the smaller pipe, and all the air goes out in the larger pipe now, exactly reversed from the earlier system. It works much better.

 

[alwaysFlOoReD]

But if pump/pickup wasn't at the bottom of the tank the float/sender wouldn't show Empty when the fuel stopped flowing
That's what has me confused

It's been a very long time since I looked at a pump. If the pump pickup tube is at, say, half way off the bottom, then does the float drop down all the way to the bottom of the tank? Or does it stay at the same level as the pick up tube? If the first scenario, then the Guage would read half full when the pick up tube doesn't suck up fuel. In the second scenario the Guage reads empty even with the tank half full. What I'm getting at is maybe the pump and pickup are not the correct depth for this tank. That's why I suggest measuring to confirm.
Hopefully my thinking is not out to lunch...

 

[GingerKing13]

It's been a very long time since I looked at a pump. If the pump pickup tube is at, say, half way off the bottom, then does the float drop down all the way to the bottom of the tank? Or does it stay at the same level as the pick up tube? If the first scenario, then the Guage would read half full when the pick up tube doesn't suck up fuel. In the second scenario the Guage reads empty even with the tank half full. What I'm getting at is maybe the pump and pickup are not the correct depth for this tank. That's why I suggest measuring to confirm.
Hopefully my thinking is not out to lunch...

I'm thinking this way also and I didn't know about the baffles in the tank so that also may be the problem as this is an older tank.

 

[GingerKing13]

Gauge shows EMPTY as well?

Then tank is empty, two different systems there

When you fill it up gauge shows FULL I assume
And after driving a few hours its going down, but drops to Empty pretty quickly

And refill only takes 10 gallon(approx.) and it shows Full again?

Does it look like a Ranger stock metal fuel tank?
There are 2 baffles inside, but they have passages that let fuel flow into fuel pump/float area at the bottom and are open at the top
Maybe baffles are plugged up at the bottom, so when you fill it up gas fills up the whole tank
But fuel pump and float only get, have use of, the gas and level in the center area, or one area, because clogged baffle prevents gas from coming in from other area behind baffle
So gauge is right for that area of the tank
I would run it down to 7-9gal left then siphon the rest out and look in the tank for old sock filters or ?? clogging baffle passages

1988 Ranger gas tank picture: https://i.ebayimg.com/images/g/KnMAAOSwPexfGbZN/s-l500.jpg
Assembly hole is at an angle which is why the pump is at an angle

Doyou have a reference picture or schematic of what the inside of the tank looks like? Like a cut-away model of the inside design so that I can easily identify where the baffles are and where they could be clogged? I have not been able to find any pictures of teh inside of atnk and do nothave an extra to cut open. Tough to see through that little opening.

Thanks.