1. WLDHRSE

    WLDHRSE Founding Member

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    Can an A9L from an 88 be used in a 93 without any modification?
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  2. cenok is family

    cenok is family Active Member

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    is this 88 a california car? a9l's didn't come in fox's until they switched over to mass air in 89. to answer your question, an a9l will give you no problems in a 5 speed 93 car.
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  3. WLDHRSE

    WLDHRSE Founding Member

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    The 88 has been converted to mass air, but I'm not sure exactly what computer is in it. It is a 5 speed car.

    I didn't think it sounded right but i read a few old posts earlier that said the A9L was used in the speed density cats too.
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  4. liljoe07

    liljoe07 Active Member

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    No it wasnt.
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  5. WLDHRSE

    WLDHRSE Founding Member

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    Hey guys, I haven't had time to look at my 88, which has been converted to mass air, but in the conversion that car would have had to be updated to an A9L, wouldn't it?

    If it is I will just pull that PCM to put in the 93. If not, I will try Autozone...
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  6. 94coupe

    94coupe Member

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    what about a a9l swap on a 94 gt? i have a fox laying around.....what benifiets and how hard is it?
    thanks
    cam
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  7. cenok is family

    cenok is family Active Member

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    it could be either an a9l or an a9p. a9l's were factory in 5 speed cars, a9p's were in the auto's. however, a9p's work fine, arguably *better*, in manual cars as well. they have a more ageressive fuel map/timing curve. i have an a9p in my 5 speed car. a9l's will not work in auto cars. as far as i know, fox ecu's won't work in sn95's without swapping out the harness as well.
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  8. 84Ttop

    84Ttop They make new pistons every day, so why worry? SN Certified Technician Mod Dude

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    A9L in my 91 Gt w/ a C4 and zero trouble here. Car is tuned with a PMS for what that is worth.
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  9. 94coupe

    94coupe Member

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    is there anyone that makes an adapter?
    or a short harness kit?
    thanks
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  10. mikestang63

    mikestang63 Mustang Master

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    You can use the A9P in a stick car but not a A9L in an auto car. The A9P has 4 degrees more total timing in 30 vs 26 , and a slightly more aggresive fuel curve.

    One thing about swapping computers- If memory serves me right, I think the stick and auto have different 02 sensor harnesses. If you swap the A9P out with an A9Lyou must swap the 02 harness or your signal return trace in your computer coming from the 02 harness will burn up. Your computer will still run the car, but it will run in el limpo mode.

    I found this a few years ago on one of the boards and it explains it very well...

    "Factory Auto MAF setups utilize the same Neutral Sensing as the Speed Density Manual or Auto setups. Which as I have stated is the Starter Relay ground, which is also what triggers the Starter Relay to engage. Its like any other common relay coil. And when not hot, will read as a ground through the relay coil windings.

    MAF manual setups use the SIGRTN circuit. Through the Clutch Switch and the NGS switch. The Clutch Switch and NGS Switches are not even connected in a MAF Auto setup, the plug for the Clutch switch is there, but its a dead plug since there is no clutch switch to hook it to. NGS switch circuits are dead also as the Auto cars use a different Trans harness and there is nothing to hook it to. These two switches are the only thing that allows PIN 30 and SIGRTN to be tied together. And they are not hooked up in an Auto Setup. No other way for SIGRTN to get fried from PIN 30 if these are not hooked up.

    Now in crank mode in a MAF Auto car, PIN 30 does have 12v on these plugs. If you go throwing a Clutch pedal assembly and Manual Transmission in an MAF Auto Car, and you hook the Clutch Switch and the NGS, and thats all you do. The ECM is toast as soon as you hit crank. Thats a given.

    Now, know that those two switches are the only connections that would allow the ECM to be fried, and knowing that they "are not hooked to anything" how is it expected to fry an Manual ECM that way? There is no connection to do so in an MAF Auto car. I mean think about it. Speed Density setups use "exactly the same type" of Nuetral Sensing wether its a Manual or Auto trans setup, as the MAF Auto setups do. By the logic some say that a Manual ECM cant be used in a MAF Auto setup because it will fry, then why dont SD manual computers fry?

    A EVTM clearly shows that there is no connection between PIN 30 and SIGRTN in an MAFAuto setup. Which means frying SIGRTN is non-exsistant assuming everything is how Ford wired it. SilverFox proves that if his car is a factory MAF Auto setup.

    Now if guys go putting in 02 harness's from other years that are not compatable then they run the risk of also frying the ECM. That was covered in depth in the 02 harness thread. If guys go throwing in Clutch Pedal assmeblies properly hooked up in Factory wired MAF Auto setups, then fried ECM's is what you will get.

    On the flip side, there is supposed to be a diode on the MAF Auto ECM's on the PIN 30 circuit. EVTM's show it in the harness somewhere, Ive seen one person say its in the ECM. Ive never looked on the ECM, but the EVTM's show it on the harness somewhere for both Manual and Auto setups. Its said to protect PIN 30 from the 12v blast on Auto ECMs during cranking but allow the Nuetral Sensing ground to be recognized. But supposedly the Manual ECMs or harness's dont have this diode. And its only an issue with Manual ECMs in Auto setups if the cranking period is for a long period of time. That issue is like a golden goose egg."
    Last edited: Nov 14, 2013
    #10

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