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Discussion Starter · #1 ·
hi i got my mustang up and running good thankfully to some of the good people on here but i noticed something the other day when i was working on my tail light and turn signal issue my mustang used to be a auto and previous owner switched it to a manual well when they did it they didnt change the computer so my reverse lights are always on so i just took the bulbs out. what other issues will this cause me if any. i know where i can get a A9L computer for $100 bucks but if this is going to be my only issue ill gladly drive the car without reverse lights. as of right now im not having any other issues with the car so if any one has a few good reasons as to y i should spenf=d the money and change it please let me know thanks
 

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Your reverse lights won't have anything to do with the computer. It's most likely a faulty switch in the transmission. These are generally about 10 bucks and can be easily checked with a multi-meter.

As far as the auto computer, I wouldn't change it. Some T5 guys prefer an auto computer over a manual. The timing advance kicks in sooner on the auto which makes nice in a race. I say if it runs fine, don't mess with it.
 

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Discussion Starter · #3 ·
o wish i would of looked at that a day ago i just bought the manual computer i still have the auto one to. i talked to a guy the other day and he said the opposite of what ur saying he said the the A9L would increase what u said so now im torn on which one i should use
 

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An auto computer has a more agressive timing curve, any of the moderators on here will tell you that. I think if im right the A9L will let your car run a little richer though. As far as the lights when the auto was in there, there should have been a neutral saftey switch and the wiring for the reverse lights is in the same section of wiring. Ive never personally done the swap but this is what ive heard, hopefully someone will correct me if i'm wrong. hopefully this link will help you out, let us know . . .

http://www.allfordmustangs.com/forums/5-0l-tech/160069-t5-back-up-light-harness.html
 

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the auto computer does have a more aggressive timing curve,and the computer has nothing to do with your reverse lights,or controlling shift points with an auto trans,contrary to popular belief..
 

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Discussion Starter · #7 ·
An auto computer has a more agressive timing curve, any of the moderators on here will tell you that. I think if im right the A9L will let your car run a little richer though. As far as the lights when the auto was in there, there should have been a neutral saftey switch and the wiring for the reverse lights is in the same section of wiring. Ive never personally done the swap but this is what ive heard, hopefully someone will correct me if i'm wrong. hopefully this link will help you out, let us know . . .

http://www.allfordmustangs.com/forums/5-0l-tech/160069-t5-back-up-light-harness.html
ill have to give that a look see tomorrow to see if it is right
 

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the only good thing about a a9l is tuneability,if you got a auto computer keep it.back in the day before chips and mass air meters and all the aftermarket parts were available this was a top mod,it offers a lil more timing and more fuel as well,if it works and runs good keep it,trust me
 

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Discussion Starter · #10 ·
the only good thing about a a9l is tuneability,if you got a auto computer keep it.back in the day before chips and mass air meters and all the aftermarket parts were available this was a top mod,it offers a lil more timing and more fuel as well,if it works and runs good keep it,trust me
well im planning on putting a turbo of some kind on my car in the future aka if i have the money this winter and if i do that then i would need to have the car dyno and tuned so would the A9L be better in that case.
 

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i dont see how one computer is "more tunable" than another..

they all have the same "basic program",with slightly different variables..which a tuner can change ANY of them..so whats the diff???
 

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Discussion Starter · #12 ·
ive switched the computers and must say only thing i noticed was a slight change in the idel and that was slight. as far as reaction time to the throttle or ne thing else like that must be so minimal cause ive not noticed it.
 

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if your gonna turbo it chances are you will "probably" want to get a pms or somekind kind of piggyback system anyway,so the actual computer wont matter
 

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Manual/Automatic EECs
There is a hardware difference between an auto processor & a manual processor. The difference is the way the NDS [neutral drive switch, manual transmission] & the NSS [neutral safety switch, auto transmission] are wired. They are both wired to the same pin#30 but the auto trans wiring grounds the pin to the starter solenoid & the manual grounds to signal return, during crank mode there is a voltage spike sent to pin-30 so the auto trans processor has a diode on pin 30 where as the manual processor doesn't, most of the time this won't cause a problem unless you get into a prolonged crank condition.

Those that want to convert their automatics to manuals, and swap the ECM, need to clip the wire going to pin 30 or else the ECM will fry the trace off the board. This leaves the manual EEC unable to dump codes, which looks for the loop through the neutral sensing switch of the T5 transmission.

O2 Sensor Wiring
Make sure you have a 5 speed O2 sensor harness when using an A9L or you will fry the trace also. The damage is common when people mismatch harnesses and use an automatic O2 sensor harness with an A9L computer.
For a Manual: The looped wire should connect the Blue/Yellow wire to the Purple/Yellow wire.
For an Auto: The looped wire should connect the White/Pink wire to the Purple/ Yellow wire.
If the white/pink wire( start voltage) is connected to the blue/yellow wire. It will fry "ANY" ECM you put in there. No matter if it’s an Auto or Manual ECM
 

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Disregard the above post (Mods if you could remove it that would be good) - it is older info which I have now deleted - this is the most recent info I have on this.......

Manual/Automatic EECs
There is a hardware difference between an auto processor & a manual processor. The difference is the way the NDS [neutral drive switch, manual transmission] & the NSS [neutral safety switch, auto transmission] are wired. They are both wired to the same pin#30 but the auto trans wiring grounds the pin to the starter solenoid & the manual grounds to signal return, during crank mode there is a voltage spike sent to pin-30 so the auto trans processor has a diode on pin 30 where as the manual processor doesn't, most of the time this won't cause a problem unless you get into a prolonged crank condition.

Those that want to convert their automatics to manuals, and swap the ECM, need to get the correct 02 harness, or re-pin the old one. The easy way to avoid any problems is to check for voltage while cranking (clutch down) on pin 46 - if you have power there while cranking, the looped wire is in the wrong place...

O2 Sensor Wiring
Make sure you have a 5 speed O2 sensor harness when using an A9L or you will fry the trace also. The damage is common when people mismatch harnesses and use an automatic O2 sensor harness with an A9L computer.
For a Manual: The looped wire should connect the Blue/Yellow wire to the Purple/Yellow wire.
For an Auto: The looped wire should connect the White/Pink wire to the Purple/ Yellow wire.
If the white/pink wire( start voltage) is connected to the blue/yellow wire. It will fry "ANY" ECM you put in there. No matter if it’s an Auto or Manual ECM
 

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Disregard the above post (Mods if you could remove it that would be good) - it is older info which I have now deleted - this is the most recent info I have on this.......

Manual/Automatic EECs
There is a hardware difference between an auto processor & a manual processor. The difference is the way the NDS [neutral drive switch, manual transmission] & the NSS [neutral safety switch, auto transmission] are wired. They are both wired to the same pin#30 but the auto trans wiring grounds the pin to the starter solenoid & the manual grounds to signal return
right,but the actual difference is not in the computer itself

its in the wiring harness

your first sentence is a bit misleading


also refer you to post #16 in this thread

http://www.allfordmustangs.com/forums/5-0l-tech/240176-computer-question-1988-mustang-gt-2.html
 
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