5.0 Carb to EFI

dangerranger83 · Nov 2, 2013

Have a few quetions on this that searching hasnt fully answered. Buddy of mine says he has parts off his old 87 Mustang 5.0 that he is going to give to me, computer, fuel rail, stock 19lb injectors, intake (his brother has an explorer intake setup)?? etc.... Anyways I couldnt find anything on what, if any, other wiring harnesses could plug into the computer and work with it since it is a speed density computer and not a MAF and if a MAF wiring harness could be made to work with it, NON HO wiring harness work from the same years (such as the crown vics) or ones that are SD or one from an f150. I know that the 2.9 harness can be made to work with the non HO 5.0 computer by simpliy splicing in two more injectors but that is a batch fire setup and Im not sure that an HO setup is like that or not.

My truck has everything fuel system wise on it for EFI already, had a 2.3 FI in it at one time, just have to put in a new high pressure pump.

I dont plan on doing any major upgrades either hince why Im not worried about have a SD setup. My 200hp is good enough for me. I just want better mileage and reliablity.

RonD · Nov 2, 2013

IMO, MAF probably wouldn't be worth the effort, MAP, air temp and coolant temp sensor should be with the EFI system.
O2 sensors should be there if it was EFI before.

Very good site here for older EFI
http://oldfuelinjection.com/?p=1

In the tech section there is an EFI swap for V8 which is a good read and has links to wiring needed.

dangerranger83 · Nov 3, 2013

Guess you haven't seen what I've done to my truck over the years. Assuming that I have the o2 sensors is a bad one. I don't even have the original exhaust, wiring or o2 sensors left on my truck.

I know the tech library has a good write up of what is needed, but that's for the non HO 5.0 installment.

I'm just seeing if anybody knows what computer harness will do the job from what is listed above of what potential donors are more commonly available in a jy. Rarely do I see a mustang and what's rarer is one that hasn't had its entire setup ripped out of it.

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Downey · Nov 3, 2013

IMO mass air would be worth it.

http://www.rjminjectiontech.com/?p=4

that used everything from a mustang. this is what i place to use when i do a 5.0 swap

dangerranger83 · Nov 3, 2013

But the thing is, I'm getting a SD computer and trying to keep this on the cheap as humanly possible side.

If I was getting a MAF computer, then I would go maf but the ft covered his car years ago to maf from sd hence why he has the computer laying around, along with all these stock parts because he upgraded everything under the hood of the car.

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dangerranger83 · Nov 3, 2013

From what that webite on the old FI setups, I can run a non FI wiring harness. Only difference that was said was the order that the computer fires the injectors due to the HO timing. I just need to find a SD vehicle from the type and years list and be good to go.

bearsrngr · Nov 4, 2013

Correct, you won't be able to use a speed density crown vic injector harness because of the H/O cam firing order. Use mustang, T bird or mark vII speed density harness

dangerranger83 said:
From what that webite on the old FI setups, I can run a non FI wiring harness. Only difference that was said was the order that the computer fires the injectors due to the HO timing. I just need to find a SD vehicle from the type and years list and be good to go.

dangerranger83 · Nov 4, 2013

I compared the mustang, crown Vic , tbird and Mark vii pin its and the only differences I saw was the crown Vic has VSS in its computer connector. Other then that, the pin outs on the connectors are the same to the computers.

What that tells me is HO or not, the harness are the same, it's just the computers that are different and what makes them different is when the injectors open dye to firing order. You can run an HO computer on a non HO engine, it's just the idle that you will notice a difference, so long add you keep it SD setup.

My engine is HO, I put an 85 mustang cam in it.

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Twister · Nov 4, 2013

I found this pdf a while ago on the inter net, it is a basic tech write up for converting from carb to the maf setup. Don't know if it would be of any help.

dangerranger83 · Nov 4, 2013

I would have to get a maf computer if I converted over to a maf set-up. But since I will be getting an sd computer, then I will need an sd harness. But as said, you can convert an sd setup to maf.

But I will take a look at it, can't hurt to.

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Twister · Nov 4, 2013

dangerranger83 said:
I would have to get a maf computer if I converted over to a maf set-up. But since I will be getting an sd computer, then I will need an sd harness. But as said, you can convert an sd setup to maf.

But I will take a look at it, can't hurt to.

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Its all good, it just seemed like a good reference because it has a pin out of the maf comp and wiring harness.

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bearsrngr · Nov 4, 2013

you'r probably right, for some reason I was thinking the (salt and pepper)wire harness to the injectors was wired different for the non H/O but I may be all wrong on that. Been too long since I messed with that stuff. I actualy have a crown vic and a mark vII harnes I should dig out and look at some time.

dangerranger83 said:
I compared the mustang, crown Vic , tbird and Mark vii pin its and the only differences I saw was the crown Vic has VSS in its computer connector. Other then that, the pin outs on the connectors are the same to the computers.

What that tells me is HO or not, the harness are the same, it's just the computers that are different and what makes them different is when the injectors open dye to firing order. You can run an HO computer on a non HO engine, it's just the idle that you will notice a difference, so long add you keep it SD setup.

My engine is HO, I put an 85 mustang cam in it.

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dangerranger83 · Nov 4, 2013

Willing to sell them for cheap?

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dangerranger83 · Nov 3, 2015

Update...ya I know old. I have a setup from a 93 mustang they will be going on next spring, just a few things left to get.

Elutheros · Nov 5, 2015

I'm running an HO 5.0 with the A9L ECU and a 1989 Grand Marquis (speed density) wiring harness converted to MAF. Just had to add a couple wires to the harness to some empty pins on the ECU. Works great. See the following video for details:https://www.youtube.com/watch?v=mnnTgXkHU9Q

5.0 Carb to EFI

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