ECU

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
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IMO the easiest way to go is to find a 89 V8 car and swap the wiring, cumputer and cluster to the 87 but since you have some pieces already stuff the 87 wiring in it, get a maf conversion and ride.
Or just run it speed density.
The engine/trans (drive train) is the same from 86 through 93.

 
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Mstng93SSP

You have a nice rear end there Dave.
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I agree. The year of the drivetrain doesn't matter, 87-93 are the same. I also agree you can just run the engine and trans on the speed density setup. Even if there is a mass air meter in the intake tubing it doesn't really matter as it will do nothing with it speed density and it also will not restrict anything. I believe you have to hook up the vacuum line to the MAP sensor on a speed density car. Tha's about it.

Chris
 

Vinnyc1487

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Why not do what I did with my 87 Gt and get the Holley terminator that’s built for a fox body?? When you find a A9L or a9p ecm and fork over $300 for a 30 year old computer remember the capacitors are only good for 15-20 years and ecm should be rebuilt before placing it in the car. Just a thought to get some newer technology with a much cleaner wire harness for not much more money.
 
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Vinnyc1487

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So at this point I’ve gotten myself in a situation. I thought I would just need the ECU from an 87 5.0 since my car is an 87 4 cyl but I’m swapping to a 91 GT drivetrain. I bought the car from a guy who has done the entire swap but never finished the wiring. So I ordered a ECU for a 87 5.0 online for 130 dollars but the engine that’s been swapped in already has MAF. So now I’m wondering if I’m out the 130 dollars or if I could switch the MAF to speed density and what would be the easiest way to go.

Are you sure the ecm is for a 5.0??? I have not been able to find a A9L or a9p aftermarket in years they are all discontinued.
 
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7991LXnSHO

Now I want a 10 year badge
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If in doubt about the capacitors or used computer, the turn around time for ECU Exchange is short, and the service was great. It was also cheaper than a remanufactured one from a chain parts store last time I looked. The pic is a screen shot of them on eBay.

Yeah I found it on eBay. It’s not aftermarket it was pulled from an 87 5.0
 

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Vinnyc1487

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If in doubt about the capacitors or used computer, the turn around time for ECU Exchange is short, and the service was great. It was also cheaper than a remanufactured one from a chain parts store last time I looked. The pic is a screen shot of them on eBay.
[/Q

The ecu out of an 87 5.0 does you no good that a speed density ecu. You need one out of an 89 or newer hence why you got it so cheap. If it’s not an A9L or A9P you wasted your money
 
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Vinnyc1487

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Would it work if I converted to speed density?
You can make the v8 part of it work but you will be very limited on your modificAtions in the future. Speed density cars are not friendly on any upgrade that changes engine vacuum especially heads, cam, and intake manifolds there are certainty options for all but they are very limited horsepower gains and really not worth the hassle of changing. The reason I recommend an ecm out of an 89 or newer is so that you can convert your car to mass air and be able to do anything you want to it. Just food for thought my friend
 
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D.Piper

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You can make the v8 part of it work but you will be very limited on your modificAtions in the future. Speed density cars are not friendly on any upgrade that changes engine vacuum especially heads, cam, and intake manifolds there are certainty options for all but they are very limited horsepower gains and really not worth the hassle of changing. The reason I recommend an ecm out of an 89 or newer is so that you can convert your car to mass air and be able to do anything you want to it. Just food for thought my friend
Thanks for the advice.
 

D.Piper

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You have the 87 wiring, 91 had some changes and an air bag.
The guy said that the wiring in it was from the 91 and there’s a spare harness that he said he thought was from an 87. The problem is, the 91 harness in there is a bit of a mess and a lot of wires ore clipped and it looks really rough. At this point I’m not sure what to do? Should I try and find a new harness? And what year should it be. The ECU in it is a A9l from the 91
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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You said you were using the wiring from the 87.
Look, my advice would be to find a 87-88 V8 parts car and get the wiring from it, and the cluster, that way you know what you have, it's hard enough to swap a V8 into a 4 cylinder car without trying to piece together one from unknown, jacked up crap.
If you find a 89 V8 car for parts you get the mass air.
90 up has air bags and several wiring changes between 90-91and 92-93 that can get confusing.
If you can verify that the harness you have is in fact a 87 and in good shape then use it.
 
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D.Piper

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You said you were using the wiring from the 87.
Look, my advice would be to find a 87-88 V8 parts car and get the wiring from it, and the cluster, that way you know what you have, it's hard enough to swap a V8 into a 4 cylinder car without trying to piece together one from unknown, jacked up crap.
If you find a 89 V8 car for parts you get the mass air.
90 up has air bags and several wiring changes between 90-91and 92-93 that can get confusing.
If you can verify that the harness you have is in fact a 87 and in good shape then use it.
Okay just one more question, since the wiring changed over the years, would a 89 harness match up to the 91 5.0 or would I have to make some changes? I’d rather run with an 89 because it has MAF and since the engine in it (91 5.0) is MAF I figure that would be the easiest route. My car is an 87 4 cyl swapped to 91 drivetrain.
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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AGGGGGGGGGGG!!!! ONE MORE QUESTION AND I'LL
just kidding :jester: look, stop thinking about the engine being a 91, the engine don't care, if you can find a 89 V8 parts car all the better, if not try to use a 87-88 V8 harness, the 90 through 93 changed wire colors and of course, the air bag, they can be used but extra wires means more work and possibly (at least in my case) more confusion.
Don't make it harder than it has to be.
 
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Vinnyc1487

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Just toss in the towel and sell what you have and buy the plug and play Holley terminator kit and save yourself a TON of time and effort plus you’ll never need to worry about wiring or ecm issues in the future. In the long run you’ll be much more satisfied I promise
 
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