Hello everyone!

I have a 1991 F150, reg cab longbox 4x4, that came to me as a 302/auto/electronic shift t case. The trans failed, and i started a swap towards a 351W/ZF5 manual/ manual shift Tcase. My 351W has grown past stock, and i know that the factory speed density system sometimes gets fussy about too much variance. I do know that a mass air conversion is an option, but I'm kind of wondering about swapping on an aftermarket EFI and ditching the factory ECM and assorted wiring.

My question here isnt about setting up the EFi, or if mass air would be better, or any discussion like that. I'm simply asking, what all does the ECM control?? what can be worked around?

Here is my short list of things i have come up with.
1)all engine controls/trans controls, T case controls will be gone. I will have that covered with my manual trans and T case.
2)fuel pump will not get a signal. I'm sure i could wire in a signal to the fuel pump. I am only running a single tank setup on the truck.
3)factory gauges will probably not operate. Speedo is cable driven, but all others probably need to go through the ECM. I can build a custom cluster, Summit Racing and many other places sell gauges.

Now, the things i do not know about.
1)dash lights, exterior lights, radio?
2)power doors and locks?
3)cruise control?
4)HVAC?

I could go full on street rod, gut the thing, and work through each issue will all new circuits, But I'm wondering what all needs or doesnt need the ECM. Any and all help is appreciated.

 

That is a simple answer... the engine and trans. Everything else on the truck will still work but you will have to reattach the engine temp sensors and tach to the factory gauge cluster if you pull all the factory EFI wiring out.

 

so i could wire the gauges to work? that would be awesome.

cruise is my biggest question next. and to verify that my fuel pump idea will work.

 

Yes cruise is completely separate so no problem there and the fuel pump is relay controlled and triggered by the PCM but that makes it easy to control by the other EFI system if it has fuel pump control for example.

 

No prob like said. I'm running Holley HP on my Lightning. The wiring is a little more complex if you want to keep the TFI,I did,or not if you go with an aftermarket dual sync distributor.

Also, if you are interested, I have a NIB Ford Motorsport Mass Air conversion I'll let go cheap. I don't know much about the stock stuff, it says it's for a 5.0 but don't see why it wouldn't work on a 351.

 

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Bootlegger, if you pass on Briansshop's offer, I'd like to ask him about it.

 

This is totally working in my favor! I'm going to continue on with my build, and wake this thread back up when it comes time to get to the nitty gritty.

Briansshop, be looking for a PM.

 

Dragging up this thread again. Sold my 91 longbox, missed it so, and bought a 91 shortbox. It's blue.

The blue shortbox came to me with no engine and a slipping auto trans. I still have the long block 351W i was building for the previous truck, as well as the ZF5 5 speed.

Now, lets get back down to it.

i'll drop the engine and trans in. that part i can handle easily enough. I have a carb intake on it, it may get FiTech efi, it may get an Edelbrock carb I have in the corner. I think, for simplicity, I'm just going to run aftermarket gauges. I will end up running a front dress setup I have off of a 95 F150, utilizing the 3G alternator.

Now, more questions.

1) the engine harness in general, do i take it all, and just pitch it all to the side? Is there anything that needs sorted out of it.
2) to run the 3G alt, do i just get one of the "universal" kits i have seen for sale, that give me the plugs to hook up to the alt, and then wire up my power wires? or should i try to take something off of something?
3) distributor, I'm running a roller cam, I know i need the correct gear to match it. Do i look into an aftermarket standalone dizzy, like an MSD or an HEI knockoff, or do i want to run a Duraspark style setup distributor?
4) fuel system. Before, we talked that i could run a keyed power wire to the fuel pump to drive it, i know the system has a return line, so if i go EFI, it's all set up for that. If i decide to run a carb, what route do I want to go with that?

 

I think the 91 uses those in tank FDM's. This makes for a big headache if you are running a carburetor.Too much pressure and regulating it down to carb pressures is pretty dicey. You also have to come up with some sort of control system. Lots of good info here.

https://www.ford-trucks.com/forums/1...tallation.html

You can eliminate a lot of the fuel pressure by running the in tank pumps from an earlier truck that had the frame mounted high pressure pump. You can dispense with the HP pump for carb use, but you need to add the dual function reservoir to accomplish tank switching.

I am no fan of carburetors and you really should consider an EFI system, preferably OEM.