EFI Conversion, which computer?

[4WHLFUN]

Adding mustang EFI to original 302 with C4. Which computer do I want? A9L manual EEC or A9P auto? I was told the manual computer was the one to use with my C4.

 

[Amac70]

Doesn't matter use what ever one you can get your hands on and wire accordingly.

 

[roan65]

Typically you can run either A9L or A9P with an auto. It is reported you can get some drivability issues when using the A9P with a manual.

Im not sure which wiring you are using. if you are using stock mustang harnesses THE MOST IMPORTANT THING IS TO MATCH THE 02 HARNESS TO THE COMPUTER!!!!!!!!!
There is at least 3 different wiring configurations on the o2 harness. If you use an 02 harness from a manual on an auto computer you will fry the computer. Always double check!

 

[ransil]

Typically you can run either A9L or A9P with an auto. It is reported you can get some drivability issues when using the A9P with a manual.

Im not sure which wiring you are using. if you are using stock mustang harnesses THE MOST IMPORTANT THING IS TO MATCH THE 02 HARNESS TO THE COMPUTER!!!!!!!!!
There is at least 3 different wiring configurations on the o2 harness. If you use an 02 harness from a manual on an auto computer you will fry the computer. Always double check!

read this

http://classicbroncos.com/forums/showthread.php?t=172541


I use the computer I can get cheapest

 

[roan65]

Great info ransil. One last ring I would add. You can re-pin any o2 harness to what ever computer you have. Using a small pick to release the wires from the connector allows you to rearrange the wires where you need them. Just make sure you follow the wiring diagrams.

 

[barronj]

The knowledge on the board is amazing.

 

[KyleQ]

The knowledge on the board is amazing.

That is true, but lots of research is done all over the palce and is pooled here because we have a lot in common.

I nearly had a Pirate moment and was goign to post to use the search button, or even Google, as there are two PCM's that are THE SINGLE MOST COMMON pcm's for swaps in nearly any EFI V8 swap.

Have fun- but the mention of the O2 harness is good as many miss that and fry a $100 PCM in moments...

 

[70_Steve]

I heard a rumor that the timing curve on the A9P is a little more aggressive, but have no specific information to prove that.

I do know that the dashpot setting on the A9P is a little irritating. I've got a stick (NV4500) and have the VSS hooked up. The dashpot setting keeps the engine RPMs up at ~ 900-1000 as I coast to a stop. Then the RPMs drop to 650. Makes it difficult to get a smooth start if, say, the light changes as I'm coasting to a stop and want to keep moving. I've gotten used to it, but really wouldn't mind if it didn't happen...

 

[76Broncofromhell]

Supposedly the base timing on the auto computers is better. I swapped my A9L to the A9S in my GPW and did notice a bit better off idle performance. Nothing scientific, just my observation.

 

[4WHLFUN]

Thanks for all the info. I was not aware of the O2/harness differences!! I plan to use the RJM or painless harness.

 

[ransil]

Thanks for all the info. I was not aware of the O2/harness differences!! I plan to use the RJM or painless harness.

the specific O2 harness should not be a concern, any used harness should be opened up and inspected and reworked to fit the Bronco then you just add a 3 pin weather pack to configure it for an Auto or manual computer

 

[KyleQ]

the specific O2 harness should not be a concern, any used harness should be opened up and inspected and reworked to fit the Bronco then you just add a 3 pin weather pack to configure it for an Auto or manual computer

EXCEPT if you dind't know about the multiple combonations of PCM's motor and trans configurations you could still melt the PCM...

 

[ransil]

EXCEPT if you dind't know about the multiple combonations of PCM's motor and trans configurations you could still melt the PCM...

you could but its your own fault for not figuring it out before you plug it in.
I write the tranny type on my computers with a sharpe