I am trying to figure out what computer would be the best ot use on my 90'mustang GT 5.0 HO Mass air that I am installing into my Early Bronco. The A9L or A9P?

 

The A9L is more agressive, and was used with stick shift Mustangs. The A9P was for automatic cars (AOD, so it would work with stick or auto), and was less agressively tuned.

 

Thanks for the info. I guess you can't put the A9L in automatics? I'm sure a chip would bring it up to speed with the A9L.

 

I think as long as it's a non-electronic automatic, the A9L would work ok, but I'm not completely sure.

 

Get the fuel injection book by Probst and compare computer pinouts to make sure pinouts match up.

 

If you use an A9L (stick) in a wiring harness for an A9P (auto) the A9L will be fried unless you pull a certain wire out. Get a book on Ford fuel injection. Motorbooks has one to add to the one above. Good luck and enjoy!

 

Thanks, I will look for a good book. Those CPU's are expensive and it would be a shame to fry one.

 

A friend of mine has been running an A9L with non-electric AOD in his 86 Mustang for years without any problems. I don't recall removing any wires to make it work. We did have to install a mass air conversion harness into the existing 86 harness because the 86 was origionally speed density. But those wires went into the plug where there were empty holes.
Now I'm interested cause I am putting in this exact combo into my 92 Ranger.

 

Was it a Ford kit? They make different kits for auto and manual. Also was your friends car originally an automatic or did someone do an engine/tranny swap on it? Does it start in gear?

 

The kit was from Pro-M if memory serves. This was back when the Mustang thing was in it's infancy. It definately was not a ford conversion harness. It had the stock 302 HO with the AOD already there. I don't know if a previous owner swapped transmissions. I don't know if it started in gear or not.
I have a guy waitin on money for his A9L. I'm gonna tell him to hold on for a few until I hear more on this.
Come to think of it, I believe we had to move one wire or mabey two from one position to another in the plug that goes into computer itself. I am next to certain that the instructions on the conversion harness said those were for emissions functions though.
I will try to run this past my local Mustang speed shop and see what input they have.

 

Pin 30 goes to Neutal Drive switch on autoamatics and Neutral Gear switch on manual. You had to move Thermactor wires to different pins and add Vehicle Speed Sensor and Airflow Meter wires. Maybe a few others.

 

The thermactor wires are exactly what we moved now that you mention it.
The car didn't have a speed sensor and we never installed one. The car still runs great today and the lack of the speed sensor didn't seem to have any adverse effects on it.
I don't remember moving any other wires but we did this about 9 years ago or so.
Is there really that much of a difference between the auto and stick computers as far as performance? I know that everyone salivates over the A9L but I have never heard how big of a difference it really was. I was drooling just cause everyone else was I guess.

 

That frying the cumputer stuff came right out of a Ford Windsor Small Block Performance book. Also mentioned 92+ computers retard timing at high rpm to protect hyperuetic pistons and input shafts during high rpm shifts. Think maybe the auto version has higher idle.

 

Do you know the name of the book and the author. I would like to take a look at it.

 

That was the name of it but that's about all it said on comps. Motorhaven has a book on tuning and modifying fuel injection on this site. Click on Fuel Injection.