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so this may have been anwsered but i was not able to see it .i have a 1989 mustang complete harness(front to back of car ) that i am putting in my 1981 mercury capri i currently have a a9p computer ,what if any mods do i need to complete to use said computer i dont really care about hanging idle any help would be great . thank you
 

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aod to t5 swap

I swapped in a t5 in my 93 5.0 aod car. 4 years ago and 50,000 miles and I've had not one problem. I didn't hook up the neutral saftey switch at all but I did hook up the mt wiring through the floor but thats it and i'm runnung all the aod stuff a9p.
 

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I swapped in a t5 in my 93 5.0 aod car. 4 years ago and 50,000 miles and I've had not one problem. I didn't hook up the neutral saftey switch at all but I did hook up the mt wiring through the floor but thats it and i'm runnung all the aod stuff a9p.
Because your still running the A9P thats why.
 

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help with computer short

1987 lx 50 5 speed, 89 mass air engine harness with 02 harness"susposed to be a 1989 harness with the 02 harness jumper wire from pin 1 to pin 6, car ran fine,shorted out powermaster alternator from battery to alternator case had big short, burned out the computer, ignition switch, and starter solenoid, replaced all, then everytime i start the car with my clutch pedal to the floor i short out the computer, didnt matter if it was a 5 speed computer or automatic, i replaced the clutch switch also. i sent my computers out to be repaired and they told me the burnout was pin 46 signal return, i replaced my engine harness with another 1989 engine harness and i used a 1988 02 harness, "from what neomustangs put out" my 1988 harness must be mass air because it has a jumper wire from pin 1 to pin 5 in the 02 harness. with that harness in the car the car starts and runs but runs rich with the a9p computer, when i put the other 02 harness back in i blow the computer when i put my foot down and off the clutch, can a 02 harness that was working in the car before the short go bad?i even changed the 02 sensors and i pulled the dash back and checked the whole dash harness and found no bad wires or plugs..?????
 

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get the correct evtm for your year car, verify pin locations.

You can re-pin it correctly.

trying to figure over the web, is difficult.
 

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get the correct evtm for your year car, verify pin locations.

You can re-pin it correctly.

trying to figure over the web, is difficult.
I have an 88 cali special harness in my 87. Is it ok if I use my 87 o2 harness with it? Just want to know before I finish my five speed swap

sent using tapatalk for corral ;p
 

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I don't have those evtms, but you can buy them from helm publications
 

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Did you figure it out bud?
 

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After reading this thread and reading some of the great replies with lots of info, got me to thinking.

My 87 has been converted to mass air and from AOD to a Tremec 5 speed. My original 87 speed density A.T. O2 harness remains in place. I have used both a C3W A.T. ECU and the A9L M.T. ECU and my car idles exactly the same with both computers, has the high idle hang for a few (5 to 10 sec) when I push the clutch in then it idles down to where I have it set @ 900 RPM. Of course when rolling to a stop it will have the high idle until I stop because it is working off the VSS then it idles down.

Because the '87 O2 harness does not have the jumper wire I have been able to safely use the A9L without burning up any circuits. But every since I did the AOD to 5 speed swap my car has never "acted" like a factory 5 speed car (Idle coming down after the clutch is pressed in or revving the throttle and letting off). I thought after I swapped from the C3W to the A9L it would idle like a 5 speed car should but it does not.

Would that be because I still have the original A.T. speed density O2 harness in place?
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I have ordered a 87 to 93 M.T. O2 harness to put in when I use the A9L ECU That way I will be matched all the way, M.T. with A9L ECU, M.T. trans harness and M.T. O2 harness. Maybe after I install the M.T. O2 harness it will idle like a 5 speed car should.

I have since found out the 1987 speed density O2 harness used the same harness for the AOD and 5 speed trans.
 

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there is no desired idle rpm of 900rpm, unless you changed it in the ecm

did you?
 

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I have an SCT eliminator chip on my EEC it is supposed to have a base idle of 900 rpm programed into it.

But anyway I have my base idle set at 900 rpm with IAC unplugged and spout connector disconnected so there was no timing advance while I set my base idle speed. According to Ford Racing Tech, 900 RPM is the recommended idle speed for a 5.0 with a E303 cam which I have so that is my desired RPM.
 

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I have an SCT eliminator chip on my EEC it is supposed to have a base idle of 900 rpm programed into it.

But anyway I have my base idle set at 900 rpm with IAC unplugged and spout connector disconnected so there was no timing advance while I set my base idle speed. According to Ford Racing Tech, 900 RPM is the recommended idle speed for a 5.0 with a E303 cam which I have so that is my desired RPM.
you have base set at 900rpm without the IAC

and your desired with the IAC is 900rpm

really?

you may need to read up on how the ECM actually knows what rpm its at.

very unlikely that you have a commanded closed IAC at idle.
 

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you have base set at 900rpm without the IAC

and your desired with the IAC is 900rpm

really?

you may need to read up on how the ECM actually knows what rpm its at.

very unlikely that you have a commanded closed IAC at idle.
I can't disagree with that.

I just still don't understand why my car has never idled down. Within a few seconds as opposed to 5 sec or longer after I push the clutch in at a stop even with a A9L. Whether I use the C3W or A9L it is the same. It never has since I did my AOD to 5 speed swap. I want it to act like a factory 5 speed car would.
 

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because air is getting in

with the iac unplugged you should have ~0.34DC, or 0.015-.20 lb/min less air at idle coming in.
 

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Reviving an old thread here. I have a 90 GT with that was a 5 speed car that I put a tremec 3550 in and built a 347 stroker. I have a hot start problem where after driving for 10 minutes or so, when I shut the car off I must wait 40 minutes or so to start it back. If I try to start it back after just a few min, it may start to turn over once or twice reallllly slow and then nothing, like the battery is completely dead.

I did swap out the computer to a A9P awhile back. The battery is relocated to the back, but I have an extremely large ground(welder lead) going from the battery up to the block for the ground. The car has long tube headers which are awful close to the starter and I have heat wrap around the starter. Trying to narrow down if its the heat soak from the headers or now possibly a computer issue.
 

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slow cranking is most likely not ecm related

what is the voltage at the battery during slow cranking?

when its running what is the voltage at the battery?
 

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Check out this video. It walks through the Calibration differences of the two computers and the problems you MAY experience if you try to use the auto computer with the manual transmission. Ultimately, with a custom tune you’ll be fine either way. But just running the stock computers as is, you’ll probably have better driveability with the 5 speed computer.

 

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YOU CAN DOWNLOAD binary editor for free and look at the calibration differences
 
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