Neutral Safety switch

EFI in old mustang '92 A9 computer. Car runs great in neutral but won't accelerate up to speed at all, chokes and dies.

No neutral switch hooked up so I can't get codes when engine is running.

How can I clear the error to get the codes? Can I just coonect pin 30 and pin 46 to complete the loop?

Pin 30 Transmission Neutral Interface

Pin 46 Signal Return

I do have a T5 but I don't recall if it has the neutral safety switch on it I'll have to look when I get home. If it does, how do I hook that up? Pin 30 to one side and Pin 46 to the other?

Thanks for the help!

Engine is originally from T5 car. Computer - bought reconditioned one at Auto Zone for manual shift 1992 Mustang. It's an A9, but there were several to choose. I told the bozo behind the desk and he plugged it in his computer so figure out the one I needed.

I am seriously thinking this thing could be junk. Might try new ECM.

I am getting code 66 tho - mass air meter voltage below .4. Might junk the Abaco DBX meter and go back to a stock one, or maybe try a C&L heard good things about those.

Any thouights on my plan?

Using aftermarket harness. It was never specified whether auto or manual when I got the harness. This is an interesting point tho and one I never considered... but I'm not sure of the differences? The harness was missing several pins, which I added back like the neutral safety switch. But everything else just plugged right in.

Computer is A9L for manual shift 1992 5.0. Autozone special, rebuilt. I am wondering if it's junk after getting code 98 hard fault, sounds scary

To get codes, I tried to ground pin 30: to the body, to the key, to the negative battery post, that didn't work at all and I still got no codes.

Then I tried to connect pin 30 and 46 (signal return, read that in Ford Motorsport manual). That did work, kinda - But I still only get 2 codes 66 and 98.

Talked to a guy today who highly recommends making sure all grounds are good so I have to double check all that. He even says make sure no paint on engine where it's grounded, and to ground computer directly to battery. Can't remember if I did.

Thanks for all the input everybody!

Mustang5L5 said:

I'm getting the feeling this is a Automatic harness equipped vehicle with a 5-spd computer.

In which case you need to either put an Automatic computer in, or switch the O2 harness out to a manual trans o2 harness, or modify the harness

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