I want to mooch your knowledge like your unemployed brother-in-law going through your fridge.....



I drove my 1988 F250 over to my brother's place for Thanksgiving so my father could take it back to his place to park. My apartment management is getting sick of the big truck not moving. hehe.... The truck was jerking and jumping all the way to his house. I thought it would clear up like it did a few weeks ago but it didn't. When you press on the gas pedal more than 25% it start jumping and jerking. I never drive the rig and it's parked all of the time. I bought it to tow my boat. Me and my dad looked at it and then it eventually wouldn't start up at all. I looked it over disconnected the fuel line at the filter and HP pump. The remaining gas in the line came out on my face (ughh!). The HP pump by the filter still makes the whining (prime) sound when the ignition is turned on. It seems like that one is working fine. I could hear pressure release when disconnecting the fuel line at the rear of the pump (rear meaning the end towards the tank or the pump intake).

The gas gauge also goes wacky on both tanks. It started doing this about a month after buying the truck last summer. Remember that I hardly drive too. I'm trying to figure out which pump to replace? The pump in the tank or the one under the frame? It seems liks the LP pump at the tank to me. Right?

The truck is stuck in front of my brother's house and he's getting ticked. I want to fix it and get it out of there. From all of the smart guys here, what do you think is the culprit here? I'm going over next Saturday to fix it. I have one day to do this.


What's the fastest and most efficient way to replace the low pressure pump at the top of the tank?

Is there a LP pump in each tank?
I have 2 tanks of course.
I hate working on my vehicles but I've been doing it a lot lately cause I'm not rich. I've always had older cars my whole life.
I guess it's kind of a cool feeling after fixing something?

I swallowed gas on Thanksgiving for desert!

Thanks for your help...



Pleeeease help..... Thanks....

 

If it is like my '89 there is a pump in each tank. You might put a pressure guage on the fuel rail and if you've got decent pressure here (33-38 pounds?? Double check on this) then I think you can rule out the frame pump. This would also double check your pressure regulator on the fuel rail which might give these symptoms too. Does this happen no matter which tank your switched to?? If it does this seems strange as having BOTH in tank pumps blown would be unlikely-possible but unlikely. If this is the case I would tend to look for electrical problems that would not allow either pump to run. There is also check valves in the system that could be stuck too but then you would probably see gas being transferred from one tank to the next.

As far as replacing the in-tank pumps- Best to get the tank empty first so you don't have to wrestle with 150 pounds laying on your chest. Take note of position and slack of the electrical, fuel lines etc. and remove the fuel filler flex tube and then the tank straps. Rotate the tank down so you can get to the area of the sender unit at the top of the tank without binding on the fuel and electical lines. Disconnect the electrical plug (this is a four prong and slides UP) Disconnect the two fuel lines (has the same connector retainers as the fuel filter). Now you can remove the lock ring holding the pump-sending unit in (counterclockwise). You can then rotate the assembly out and replace. The unit is an integral pickup-pump-sending unit so everything is replaced with your new one.(and they are kinda pricey too)

Randy

 

Sounds like a TPS problem - have you pulled the codes?
http://www.broncodata.com/tech/codes.htm

 

I remember being able to buy just the pump without having to buy a whole new sending unit when I replaced mine in my '87. I replaced the whole sending unit because it was badly gummed up from years of not being used (previous owner). This is something you can check out when you get the pumps out and can see what kind of condition the sending units are in. If it makes a difference, the pump was from NAPA. Hope this helps.

 

Yeah, thanks for the info EPNCSU2006. I believe there was a lot of changes from 87 to 88 though.

I think my problem may be electrical like Pig Farmer is saying above. I just don't know where to start. Can anybody give me some advice on the best way to troubleshoot this? Thanks.

 

'84-90 EFI use virtually the same fuel system. Start troubleshooting by pulling the codes.

 

I thoght the low pressure pump and the sending unit is a "all in one" unit that goes in the tank?

>I remember being able to buy just the pump without having to
>buy a whole new sending unit when I replaced mine in my '87.
> I replaced the whole sending unit because it was badly
>gummed up from years of not being used (previous owner).
>This is something you can check out when you get the pumps
>out and can see what kind of condition the sending units are
>in. If it makes a difference, the pump was from NAPA. Hope
>this helps.

 

I think most are sold as an all-in-one unit, however, the pump itself can be bought separately (at least for my '87 F150). The electric pump is removable from the sending unit, so if the sending unit is still good and the pump is what's gone, it can be replaced for about 1/3 of the cost of the entire sending unit. Again, this was in my '87 150, so I'm not sure how similar it is to the '88 250.

 

Yeah... But you can take it apart. The truck is "all-in-one", but you can pull parts off it!

 

To All Loyal Ford Truck Fans:
This is the solution to your expensive EFI fuel pump problems once and for all. Please remember this info because a Ford operative will kill me in my sleep for revealing this low buck solution.

As you all know a dual tank EFI F-truck of this vintage has 3 fuel pumps, one in each tank and one high pressure pump on the left side frame rail. If your high pressure pump gives up you won't be able to hear that 2 second whine when you turn the key. That sucks- take 190 bucks to the parts store and get a new one.
However; if you know that pump works but still get the out of gas symptoms then drop the tank and remove the sender/pump unit. Take off the pump and make a pickup out of a rubber fuel hose. Just bend it to rub the bottom of the tank and face rearward. Then hose clamp it to the steel pickup that you took the quick disconnect off. Reinstall the pickup/sender unit and bolt the tank back up.
Now buy one of those square universal fuel pumps from Discount or Napa that cost just under 30 bucks. Ground it to the frame and splice the hot to the hot wire of your original pickup wiring(use a test light of course! If i remember right it's the orange one). Anyway hose clamp to the external tank outlet and use an inline filter BEFORE your new cheap pump. Then run a hose to the fuel splitter(if you have a dual tank) or to the hp pump inlet hose if you've only got one tank.
This works- I now run those cheap pumps for both of my front and rear tanks, and one of them has been going for just over a year. The clacking noise you hear when you turn the key over is just your reminder that they work.

Better yet- when one of them takes a ##### you can return it to Discount for free!!!! HAHAHAHAHAHA

 

Great info PB! What is the easiest way to drop the tank to replace the pump like you said. Are you saying to remove the old, non working pump and seperate the sending unit from it? Do you mean the sending unit malfunctions when the pump goes bad?

Can you explain in a little more detail on how to do this universal Napa pump modification? Thanks bro. This is the info that I've been looking for.



>To All Loyal Ford Truck Fans:
>This is the solution to your expensive EFI fuel pump
>problems once and for all. Please remember this info because
>a Ford operative will kill me in my sleep for revealing this
>low buck solution.
>
>As you all know a dual tank EFI F-truck of this vintage has
>3 fuel pumps, one in each tank and one high pressure pump on
>the left side frame rail. If your high pressure pump gives
>up you won't be able to hear that 2 second whine when you
>turn the key. That sucks- take 190 bucks to the parts store
>and get a new one.
>However; if you know that pump works but still get the out
>of gas symptoms then drop the tank and remove the
>sender/pump unit. Take off the pump and make a pickup out of
>a rubber fuel hose. Just bend it to rub the bottom of the
>tank and face rearward. Then hose clamp it to the steel
>pickup that you took the quick disconnect off. Reinstall the
>pickup/sender unit and bolt the tank back up.
>Now buy one of those square universal fuel pumps from
>Discount or Napa that cost just under 30 bucks. Ground it to
>the frame and splice the hot to the hot wire of your
>original pickup wiring(use a test light of course! If i
>remember right it's the orange one). Anyway hose clamp to
>the external tank outlet and use an inline filter BEFORE
>your new cheap pump. Then run a hose to the fuel splitter(if
>you have a dual tank) or to the hp pump inlet hose if you've
>only got one tank.
>This works- I now run those cheap pumps for both of my front
>and rear tanks, and one of them has been going for just over
>a year. The clacking noise you hear when you turn the key
>over is just your reminder that they work.
>
>Better yet- when one of them takes a ##### you can return it
>to Discount for free!!!! HAHAHAHAHAHA

 

The rear tank in the main one (#1), right? Are the bolts most likely rusted under there? I think the tank is mostly full. I suppose I should drain it (duhh) then proceed to unbolt it then let down? How many bolts are there?

 

Hi hope this helps:

I think Ford considers the main tank to be the front one. Whatever;
anyway-

Each tank has two straps. The rear tank is held up by four bolts, the front tank 2 (the straps hang in slots on the outboard side).
Before the tanks come all the way down try to disconnect the wiring connectors. The lines themselves are pretty tough but you should still try to disconnect them(they're quick connects).
When you get the tank down you'll see a lockring that holds the pump/sender unit. Tap it around counter-clockwise(Duh) to get it off. Then the unit lifts out easy with a little bit of wiggling. To answer one of your questions, You can keep your sender intact and still remove the factory pump. Test it just to be sure. Stick the inlet in water and put juice on it. If it doesn't shoot out it's definitely shot (like if it just pisses out).

Anyway man that should keep you busy for tonight. It's 2:14 in Florida and i gotta go. I'll check the site tomorrow and help ya out more in case.

 

Thanks PB. You are golden. I will do what you say. I'm going over to my brothers on Sunday to do this. Go to sleep brutha Thanks...

 

If you are getting this problem on both tanks, I would be suspect of the tank selector switch. It would be pretty rare for both in-tank pumps to go bad. He also mentioned that the gauge was acting goofy. That would make me to really suspect the tank selector swith.

So, did you get the problem fixed?

Roger Lane