[simpleman744]

have an 88 gt with a9p computer car starts and runs when you shut it off it refuses to start for another hour turns over fine but wont start put 87 computer in it works fine but lacks performance someone tapped a mass air flow harness in at the computer harness any help to use the a9p would be appreciated

 

[squekster]

have an 88 gt with a9p computer car starts and runs when you shut it off it refuses to start for another hour turns over fine but wont start put 87 computer in it works fine but lacks performance someone tapped a mass air flow harness in at the computer harness any help to use the a9p would be appreciated

The A9P computer is for mass air and auto.
The 88 mustang came with mass air from
the factory. The 87 mustang came with the speed
density system. Since the 88 mustang came
with mass air then it is unlikely that mass air
sensor harness was spliced in. You could swap
another A9P ecm to see if that is your problem.
These computers are expensive so I wouldn't
go out and buy one until I was sure that was the
problem. You should look into other possibilities
that might be causing your situation first.

 

[new8514]

Only the 88 Cali models came with factory mass air.

You should review mass air conversions and look everything over again, the wiring, mass air meter, MAP sensor open to atmosphere, etc...


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[NothingButPower]

1989 was the first year for all around mass air. A9P is for autos, A9L is for manuals. The A9P also gives you a bit of a performance boost since it was tuned for the slush box to make it competitive with the standard trans. I can't think of a reason why it wont start though.

 

[87frankenstang]

Yeah, I drove my LX around for about 8 months before I tore it down. Ran fine with the A9P computer and a 5-speed. Not sure if the computer gives you a performance boost though, I never heard that. I think the idle control strategy is a little different to account for the weight of the torque convertor or something though...whatever it is, its insignificant at best. Like I said, drove mine 8 months with no idea it had the "wrong" computer.

How you tried pulling codes? First thing you should do. There are a few codes that can show up that report something wrong with the ECU itself. Also ignition components can cause what you are seeing. Earlier this year I dealt with a dist. pickup going bad, sometimes would cause the vehicle to not start after shut down until it cooled down for a bit. look for the "erractic PIP signal" fault. Tell tale sign its the dist. or TFI module.