Question about mass air conversion

[Philly5.0girl]

I want to do the mass air conversion. I have the wiring kit and the sensor, and am planning to put a cold air intake on the car.

My question is this, I have a computer for a 90 5.0 automatic (A9P) will this computer work? I'm reading up on the conversion and some people say I can use my computer but need to switch some pins, but other people say you have to use an MAF computer.

I'm asking because I don't know if anything with this computer is different because the 90 had an airbag, or can I just use my computer thats in the car?

[Evil86lx]

You must use a MAF ECU for it to work. I believe that a automatic ECU will work in a 5 speed car. I may be wrong about the auto ECU. I've alway's used 5spd ECU's.

kyle

[eric5oh]

If it is a A9P from a 1990, it is a mass air computer and will work with 5speed or auto (it is really for an auto though) You do not have to switch pins unless you bought the cheapie ($39 or so) wiring harness. Buy the Ford one and switch it out.

[Desperado]

i use the a9p with my five speed car. it works just fine. i also used the cheapie harness and moved the pins. it was easy and took about a hour to get the wiring done completely (20 mins was trying to snake the mass air harness through the firewall down to the computer).

you need to move 2 pins and run 2 wires. the pins are for the thermactor stuff and the two wires connect to fuel pump relay under the driver seat and to the speed sensor wire off the tranny. if your car is 86 or older the speed sensor wire can be found right in front of the center console. if it is 87-88 it is in the driver kick pannel.

here is what it cost to do it the cheapie way and move 2 pins and run 2 wires

stock MAF used 10.00
mass air computer 75.00
wire harness from DMP 49.99


---------------- Total Cash 135.00 bucks.
i would rather do the pin move and save 300 + dollars.

i cut my speed density intake tube at the correct length and used a K&N filter. it looks factory that way and you don't have to buy the intake tube or you can spend money for a cold air kit.


If you need help or have any questions feel free to call me anytime. i have done this conversion a kazillion times. i figured out that i wasted money on buying the conversion kit for 500.00 bones. never had 1 problem by doing it the cheap way. plus you get that good feeling knowing you just saved enough cash for a new intake to go with the maf conversion.

link for harness from DMP
http://www.dallasmustang.com/index.m...c643f04&p=8822

instructions: i use both links. print them out and use them.

http://www.corral.net/tech/powerplant/maf_tech_2.html
http://www.stangnet.com/tech/maf/massairconversion.html

the second link refers to the VSS (vehicle speed sensor) as being behind the driver kick pannel. well on a a 86 mustang i found it comming up from the driver floor on the tranny hump behing the console. look under the car cand you will see where it goes in the car on the driver floor. follow it up to behind the console to tap into it..

call me if you have ? i will pm my number to ya

[n20capri]

It's very easy to do if you have any automotive skills at all...lol. I did it on my car years ago and recently on my dads 87 Lx. The first time I used the ford kit this time I got the harness...both times I had to change around and add some wires...

It's very straightforward...

Good luck

[Philly5.0girl]

My car is an auto, so the computer will work, I just wanted to be sure there wouldn't be a problem with maybe some kind of sensor since there is no airbag or anything.

I know I have the good harness although I can't remember the manufacturer so I guess I won't be needing to switch pins around.

I got lucky again with this one, I bought this 90 LX for parts (it was hit hard in the rear, has frame damage) but the front of the car is perfect and its white (the notch we just bought for our project is white too and we needed some body parts) plus the car has the silver ponies with brand new tires, the harness, computer, 140 speedo gauge cluster, a 4.10 rear and a perfect gray tweed interior. Even the hatch is still good and I only paid $500 for the car. Plus it has all the fuel lines and spindles and whatnot I need for the 4cyl conversion we are doing on the notch.

Thanks guys!

[83sixer]

I've got another Mass Air conversion question - I bought an '88 HO engine (minus headers and harness - $400), and I have a harness from a '90 four-cyl mustang, would I be able to convert the 4cyl. harness, as long as I use a 302HO computer? If so, what changes would I have to make?

[Mike Croke]

I don't think the 4 cylinder harness will work. There are several reasons such as the placement of sensors like the throttle postion and water temp (ECT). Also, the 5.0 uses two O2 sensors and obviously has 8 injectors.

[Philly5.0girl]

83 sixer, I don't think I'll be needing the harness from the 90 if you need it

[mfpmax]

Pull the 4 banger engine harness and toss it...well...in the corner, never know when you may need to cut something off it.

[Cobra Jet]

i use the a9p with my five speed car. it works just fine. i also used the cheapie harness and moved the pins. it was easy and took about a hour to get the wiring done completely (20 mins was trying to snake the mass air harness through the firewall down to the computer).

you need to move 2 pins and run 2 wires. the pins are for the thermactor stuff and the two wires connect to fuel pump relay under the driver seat and to the speed sensor wire off the tranny. if your car is 86 or older the speed sensor wire can be found right in front of the center console. if it is 87-88 it is in the driver kick pannel.

here is what it cost to do it the cheapie way and move 2 pins and run 2 wires

stock MAF used 10.00
mass air computer 75.00
wire harness from DMP 49.99


---------------- Total Cash 135.00 bucks.
i would rather do the pin move and save 300 + dollars.

i cut my speed density intake tube at the correct length and used a K&N filter. it looks factory that way and you don't have to buy the intake tube or you can spend money for a cold air kit.


If you need help or have any questions feel free to call me anytime. i have done this conversion a kazillion times. i figured out that i wasted money on buying the conversion kit for 500.00 bones. never had 1 problem by doing it the cheap way. plus you get that good feeling knowing you just saved enough cash for a new intake to go with the maf conversion.

link for harness from DMP
http://www.dallasmustang.com/index.m...c643f04&p=8822

instructions: i use both links. print them out and use them.

http://www.corral.net/tech/powerplant/maf_tech_2.html
http://www.stangnet.com/tech/maf/massairconversion.html

the second link refers to the VSS (vehicle speed sensor) as being behind the driver kick pannel. well on a a 86 mustang i found it comming up from the driver floor on the tranny hump behing the console. look under the car cand you will see where it goes in the car on the driver floor. follow it up to behind the console to tap into it..

call me if you have ? i will pm my number to ya

You hit everything dead right on....

I did this same exact conversion back in 1990 - when converting pre 1987 Mustang 5.0's to Mass Air was basicaly unheard of and practically a brand new "idea".... in fact, in my pics of my prior 86 GT in the General BS forum on here, you can see the "conversion" harness coming off the MAF unit and going ove near the strut tower.

To get it through the firewall to the EEC - from inside the car, just push out the EEC large rubber plug out of the firewall. To persude it in coming out faster, try and peel it back from the engine bay a little and squirting WD40 all around it, this way it will be lubed for removal purposes.

Once you have removed it from the firewall, either cut a hole into it to fish the new MAF conversion wire through, OR just slit it from one area to the center, being careful not to splice or cut the main EEC wires in the harness bundle. If you slit it, just slide your MAF conversion wire down to the center of the bundle now. When the rubber plug is installed back into the firewall, the "slit" will close up and you won't even see it.

I can't justify spending the $300-$500 for any MAF conversion harness - be it the FMS conversion kit, or paying someone to modify a harness, etc.

I too have never had ANy issues at all with the "cheapy" method and it works 100% = so the decision is - do you spend the $40 or $400 to get the SAME results??

[Philly5.0girl]

I bought the harness from my friend for $40 because I gave him a deal on a complete 89 harness I had, he wanted to use the entire harness for some reason.

[Desperado]

i have found that there is no need to spend tons of money. the only other thing i forgot to say is i do not use the wire taps to put the power and ground wires on. i take the time to cut the power and ground wires and solder the connection and use heat shrink tubing. i have found that years down the road the quick splice connections can corode some and cause glitches. so solder the red and black wires to the harness at the computer.

besides that you are paying all that extra money for nothing. is it really worth the 500 bucks to have someone make a plastic connector for you? plus what they don't tell you is with that kit it makes it next to impossible to get the computer back in the kick pannel. that piece that plugs into the computer between the harness is thick also prone to losen due to vibrations and can cause speratic symptoms.

i will post pics of how it looks in the engine bay tonight.