The truck in question is a '96 f150 with a FI 300 backed by an m5r2 tranny. The truck is a great truck, but the engine just feels like it could use a lil more oomph. Plus i feel like i owe it to the old girl, ya know as a reward for being so reliable. So the project is to put on an Offy C-series manifold, with a Summit 600 cfm vac secondary carb and a new non computer controlled dizzy. Will be doing a full write up with lots of pictures and info sometime in the next few weeks. Have all the parts just finding time time do it. Iv'e been researching on many different forums for a number of years on this so when i do it it gets done no muss, no fuss(I know it probably won't but one can dream right?) Now i know just about every aspect of this swap due to the many people who have done it before me. But the one thing nobody seemed to cover was wiring. So as i understand it all the wiring for the FI is to be removed. But specifically what would that entail? Cruise control doesn't work at the moment(not a very big concern.) Speedo is run off of the rear axle directly so i don't have to touch that. Tach is run off the dizzy so that can be left alone and modded to the new dizzy. Coolant temp is mechanical so no change there. Oil pressure guage is mechanical so no change there. Anything i'm missing? Everything else other than lights radio and ignition/starter can be cut out correct? Please no FI trolls, i understand FI is the end-all-be-all But this is the route im going. Now unless you FI trolls know anything about the surgery of your sacred FI harness then troll away, but if not, yes i have heard the good news and im not buying it, so don't try sellin' it. Write up for this project will be soon, just want all my ducks in a row before i start this.

 

I'd try to advance the timing to get that oomph back before anything else.

 

How are you going to modify the fuel supply system to work with a carb.?

Interesting project, looking forward to the write-up and photos

 

Sounds like you're gonna do whatever you like so I won't bother

 

texinwa, The timing has been adjusted, as the consensus on the forums is the engine likes the timing at 12 degrees vs the stock setting of 10. But there wasn't any noticeable difference to the engine.The PO had the timing set to 14 degrees when i got the truck from him. Dropped it to 10, with some noticeable (but not much) kinda sluggishness, so bumped it back to 12 and felt better. Fuel economy stayed about the same (16city/20hwy) Pedal power to me at least seemed unchanged. rla2005, the fuel system the obvious choice would have been to go to a mechanical pump for the carb, but seeing as i didn't want to open up the bottom end to clean out metal from drilling the block as mine has no hole(the mounting boss, but no hole.) for the mech pump. So instead i'm going with a frame mounted electric pump which maxes out at 6-7 psi as per summits recommendation that fuel pressure be no greater than 7 psi. This will be mounted just ahead of the fuel selector valve so as i can keep my dual tank setup. Drop power from the two in-tank pumps and just let the fuel bypass em. Run a 3/4 or 5/16 (more than likely 3/4) rubber fuel hose from the pump to a fuel filter then the carb.

 

There is no external fuel selector valve on your model year truck. Ford switched over to in-tank high pressure pumps and internal valves in 1990 for gas engine F-series trucks.



I am not aware you can siphon though the in-tank pumps and associated check valves. If it does work then you will be pulling fuel from both tanks assuming the high pressure check valve (supply side) in each tank opens up when the frame mounted pump you are installing is turned on.

 

So as far as wiring goes... My plan is this. Reuse the existing tach wire and power wire for coil, Unplug, cap off, and hide the other wires that would be running to the old dizzy. Leave the other gauges alone. Run the choke positive to the starter side of the staring solenoid so when you turn the key to cranking it will feed power the choke. But if I do that, then when the engine fires and you put the key to ON it'll cut power to the choke? I know not to put it on the same line as the coil as it'll drop power going to the coil.... So where would yall recommend it going? (For some strange reason the PO decided to wire the solenoid on the starter for the drive gear to the starter solenoid.....? Solenoid to solenoid....? Weird.....) Leave the wires alone for the interior(radio, windows, lights,...etc), and just pull out the computer. I don't think i should have any "Check Engine" lights showing up as the computer will be gone correct? Does that Just about cover it? Or am I missing something? Or multiple things? Help is greatly appreciated. If anyone wants the old MAF stuff for converting a speed density 300 just PM me and we'll talk about it.

 

rla2005, Excellent points. This is why asking first helps negate headaches down the road. I wasn't aware that there wasn't an external selector valve. I thought they kept it till the next Gen. Huh.... Well that complicates things a lil. Would it be possible to mount an NOS, aftermarket, or OEM selector valve and remove the in-tank pumps but place a piece of hose or metal tube down into the tank through the top of the pump mount in place of the pumps?

 

Hey SixerFixer. I have the same identical truck as yours. Out of curiousity I'd enjoy watching this build and seeing if you can pull it off. Please include photos and maybe even a video or two if you can do it. As for me, I'm perfectly fine with the fuel injection but if you posted a leftover parts list at the end of the swap I might be interested in picking up some spare FI parts for my truck.

 

The OEM fuel tank selector valve for gas engines is activated via pressure from the in-tank pump (low pressure). It's expensive and will not work for your project unless you retrofit the earlier model low pressure in-tank fuel modules. Which may not physically fit the newer tank.

Pollock makes a fuel selector valve that is electrically activated. It is re-packed by Standard Motor Products, Part# FV5. To get this to work I suggest you remove the fuel pump and check/shuttle valve assembly from the FDM and replace it with a metal tube. Also see if you can rig a way to retain the factory sock filter at the end of that tube on the supply side. Extend the return tube to also terminate near the bottom of the tank.

For the sake of safety use an oil pressure switch inline with the electric fuel pump you are installing. Also run this through the inertia switch. The oil pressure switch will turn on when the engine is cranking/running. The inertia switch is a backup in case of an accident.

 

you could always do this

 

evan_nugget,
Yeah i can do a list at the end of it. And of course im going to put up some videos of it. Lots of pics and a couple videos. I'll try to detail as much of the process as possible. Btw your truck and my truck could be twins, same paint colour, same cab, is yours a grey cloth interior? Only glitch is mines a 2wd not 4x4.(i wish)

 

Double post

 

Triple post

 

Well mine started out with a vinyl bench but now its got an XLT grey bench. I'd say they're close enough to be fraternal twins.