Mass Air Question, Im Converting

Kdubslugga

Active Member
Jun 7, 2003
1,515
4
38
Akron, OH
I was wondering how to do this, if i get a MAF Engine harness all i have to do is take my old one out and plug the new engine harness into the new computer and i will not have to make any cut in any wires? Please tell me so. Then i need to wire up the MAF harness to the meter and Im done correct???
 
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MASS air conversion instructions from http://www.stangnet.com/tech/maf/massairconversion.html FREE
A9L (5 Speed) computer from junkyard $100-$150
A9P (Auto or in a pinch, 5 Speed) computer from junkyard $100-$150
70MM MAF from 94-95 Mustang GT - $40-$70
MASS Air wiring harness kit $30-$85

The whole thing is probably less than $300 using junkyard parts.

A9L computers are 5 speed only
A9P computers are automatic, but will work with a 5 speed.

The conversion harness seems to work well for most folks. It avoids the compatibility problems in using a harness from the junkyard. Simple and cheap, actually less work that swapping the wiring harness.
Conversion Harness kits & parts
http://www.mass-air.com/
http://fordfuelinjection.com/index.php?p=54

If the idea of moving & soldering wires scares you, here's a list of compatible Mass Air wiring harnesses.

bbunt302
Just for reference, here's a list of all the compatible years:

89 harness should work for 86-89 as long as you're using mass air.
90 harness will only work in a 90. (B/c of air bags and dual dash connectors)
91 through early 92 harnesses should be compatible (single dash connector, fuel pump relay under driver's seat)
Late 92 through 93 harnesses should be compatible (single dash connector, fuel pump relay under the hood)
 
I just did this. I swapped in the complete harness and computer from my old '89 GT to my '87 and it worked like a charm. Make sure to unplug the MAP sensor vacume line from the intake and everything else just plugs right in.
 
Yes that is right, for 86-88 SD systems, only 89 or 90 harnesses will just plug in. 90 harness has airbag connectors, 89 does not.

The ONLY year harness that is a direct swap is an 89 so unless you have access to an 89 harness it is much easier to just use the instructions found here and add the maff harness which can be found in a junkyard or online and then switch the necessary pins in the plug that connects to the computer (which is also found here).

When i did the swap I unknowingly tried to use the harness out of a '90 in my '87 and it turned out to be a nightmare. In the end I ended up using the stock harness which turned out to be fairly easy.
 
oh...thanks for the update! what exactly was different between 87 and 90 harnesses?

A 90 harness will only work in a 90 because of the air bags and dual dash connectors. I also suspect there are some pin differences in the part of the harness that controls the fuel pump relay.
 
well the 86-89 had dual dash connectors too...i think...right? and cant you just leave the air bag connectors unused?

on the other hand, it would be a waste to use a 90 harness on an 88 when theres someone out there that needs a 90 harness lol.
 
Well i just got a harness from an 89 Mustang, so lemme get this straight 1 last time. All I do is take the old harness out and plug the new one in to the new computer correct, no cutting of any wires at all??? How about the part of that write up "which was very good by the way" where they cut wires at the VSS and the Fuel pump relay do i need to do that? All check out the link i supplied in my second post just to make sure i got the write thing!!! Thanks guys!
 
Well i just got a harness from an 89 Mustang, so lemme get this straight 1 last time. All I do is take the old harness out and plug the new one in to the new computer correct, no cutting of any wires at all??? How about the part of that write up "which was very good by the way" where they cut wires at the VSS and the Fuel pump relay do i need to do that? All check out the link i supplied in my second post just to make sure i got the write thing!!! Thanks guys!

The 89 harness is plug and go. There are no wires to be cut or spliced.
 
Well i just got a harness from an 89 Mustang, so lemme get this straight 1 last time. All I do is take the old harness out and plug the new one in to the new computer correct, no cutting of any wires at all??? How about the part of that write up "which was very good by the way" where they cut wires at the VSS and the Fuel pump relay do i need to do that? All check out the link i supplied in my second post just to make sure i got the write thing!!! Thanks guys!

My car didnt have a vss so i never did that part and i havent had any problems, but some people do have problems with the car stalling when slowing down to stop.
 
So the thing i bought is the right thing and is all i need, i dont need a complete new entire engine harness right? Also is the plug that plugs into the mass air meter included in that mass air harness???
 
If you have the complete harness that includes the 60 pin computer,plug, the two 10 pin connectors, the MAF, O2 sensor, Baro sensor, A/C WOT relay, etc, you are plug and go.

If all you have is the 4 pin MAF connector and some wire, that is a cut, solder ,splice & re-pin operation.
 
And now for the final question. Computer selection, I know the A9L is for the 5 speed and an A9P is for both, but my car used to be an automatic does that play any role in to which computer i should get? Should I still get the a9L? I bypassed the NSS when i did that conversion should that still be ok?
 
yes...and even if the a9l would work, the a9p is better. you COULD use an a9l if someone could dig up the info on them...if you unhooked one wire from the 60 pin plug, then the harness would be safe for the a9l. but idk what pin it is. :shrug: