4.0 Fuel Pump on a 2.9

[VF Gunrunners]

So I'm in the middle of dropping my tank to replace my 2.9 fuel pump in the tank and need to know if on my 87 B2 i CAN JUST SWAP IN A 4.0 PUMP AND i CAN JUST DELETE THE INLINE PUMP Or should I buy a walbro high flow pump ? still running a 2.9 but I am going to swap for a 4.0 later and don't wanna buy twice

 

[monsterchuck]

I can see no reason why you wouldn't be abe to swap them out, just make sure all your fuel lines from the sending unit foreward can handle the higher fuel pressure. A Walbro high-flow pump would be uselessly overkill.

 

[adsm08]

Well your scenario has a few quirks to it.

The 4.0 sender assembly will not work for you. I don't think it is deep enough for one thing, which would make part of the tank unusable. The other issue is that in 89 the resistances on the fuel level sensor changed, so the gauge would not work. If you get just the pump that will work, but is kind of a half-ass repair since it doesn't replace the FLI card while you are right there. Aside from that it does work and has been done.


On the other hand the 2.9 fuel system produces enough pressure and flow to run a 4.0 and the twin-pump system in my 87 is working just fine for running the 4.0 that is under the hood.

 

[VF Gunrunners]

I just want to get rid of the extra pump but It sounds like it's more trouble then its worth Thanks guys

 

[Surrey]

In 89 they started using a single pump with the 2.9l, but judging by what Adsm just said, you wont get a proper gauge reading with one...?

 

[adsm08]

Well depending on how you are going to do your 4.0 swap there is another option.

If you plan to swap the whole dash like some guys do, instead of making the wiring work with the earlier dash then you can go get a fuel pump for an 89 or 90 BII. That will have everything you want/need.

 

[adsm08]

In 89 they started using a single pump with the 2.9l, but judging by what Adsm just said, you wont get a proper gauge reading with one...?

The issue isn't one or two pumps. The issue is that the resistance range for the fuel level sender changed in 89. If you put an 89+ fuel sender assembly in an 88 back vehicle and try to run the early instrument cluster the gauge isn't going to read correctly.

They did the same thing to the oil pressure sender. My 88 BII has an 89 engine in it. The oil light is off with the engine off but comes on when I start the engine because the oil pressure sender reads backwards from what the light on the dash is designed to see.

Same with this guys question. He can drop the 89+ fuel pump in his tank, but his fuel gauge will not read right. Now if he goes and swaps in the dash from his donor vehicle when he does the 4.0 swap then the fuel gauge would work correctly again.

 

[RonD]

Ford fuel sending units and gauges

Empty / Full
73 Ohms/10 Ohms-----pre-1989 Fords
16 Ohms/158 Ohms----'89-up Fords

So '89(or newer) sending unit would have 16 ohms when tank was empty, '88 gauge would read that as 3/4 full tank

With full tank, 158 ohms, '88 gauge would read below Empty

 

[VF Gunrunners]

I'm thinking of going with a 1998 obd 2 4.0 so I may have a lot more problems

But so in 1989 even on the 2.9 it sounds like they went to a single pump so if I get on of those I still have to change out the dash does any know if the 89 or later gauge cluster will connect to the 87 dash wiring ? I will be running the 2.9 for a while

 

[adsm08]

OBDII will be really interesting. I am still trying to sort out bugs from grafting an 89 harness into an 87 dash.

Yes, in 89 the Ranger vehicles went to a single fuel pump when the Ranger lost it's twin tank option.

The 89+ cluster won't bolt into the 87 dash (wrong shape), the wiring is not direct, and the brown plug is the wrong shape.


At the end of it I think your best bet is to stick with the twin pump system for now, until one of the pumps craps out again. Both of my original pumps lasted well over 20 years, so its not like it is a super unreliable, complicated system.

 

[VF Gunrunners]

Yeah obd 2 if I do it will be real interesting and a pain in the butt may just go 1994 and say screwed also sounds like I'm just gonna stick with dual pumps for now until I can pull dash and full harness

I'm running a 1988 engine harness 88 ecu with EGR delete now

I might just grab an 89 full harness firewall back from a 2.9 or 4.0 for my 4.0 swap

Hey does any one know where I can get a locking hub rebuild kit for the dana 28 ?

Thanks guys