First of all, want to say 'hey' to all my fellow Ford fanatics. This is my first post on this board, but I've been 'lurking' for quite some time and I love the wealth of information available on these forums.

My question is regarding the potential use of an A9L Mustang ('92 GT) ECU when I'm driving a 351W with a C6 which will soon be converted to mass air. Will I be able to use the A9L manual-transmission computer with my C6 auto? If not, I can find another variant (like the A9P, for example) but A9L's are a lot more common in my area - if I can use the A9L I will.

Also, if I were to use the wiring harness from this same '92 Mustang GT would it be compatible 'as is' with the connectors on the engine sensors/injectors? Would it just be easier to switch some of the wiring around in my existing F150 harness and add a few pins for the SEFI wiring/dual O2 sensor/etc.?

Lastly, do I require a MAF Sensor from a 5.0 Mustang or can I use any MAS which is calibrated for my stock 19# injectors?

I just want to make sure I have all my ducks in a row before I muck around with all of this stuff.

Thanks to any and all for your help!
MR

 

The A9L will probably work fine. I don't think any of the pins are different. The only thing I can think of is how the NDS switch works with an automatic. That's the circuit that tells the computer whether the clutch is in or not - not sure what to do with that when there isn't a clutch. An A9P would likely be a little better, but I think the A9L will work fine.

With the wiring, I would use the truck harness, and then add to it by taking parts of the mustang harness. I went this route with my mass air conversion. I stripped down the mustang injector harness, and just used the 10 pin plug for the injectors, the power for the injectors, and for the canister purge valve. I then attached the pins and wires from the mustang harness that controlled the injectors (with the other side of the 10 pin plug) and ran that into the truck harness for sequential injection. For the dual O2 sensors, I just split the signal wire from the single so that it sent a signal to both inputs on the computer. If you haven't seen Bjorn's site yet, it would be worth a look - he covers many details there: http://brembs.net/cars/maf_conversion/ .

I have a 75mm bullet MAF meter from Pro-M that I bought on eBay. I bought it along with 24 lb injectors, however, the meter is currently at Pro-M getting re-calibrated for 19# injectors. Bjorn also had to get his meter recalibrated, so that is something to think about if you choose to buy one on eBay. New, they are right around 200 bucks - I found the best price at Arizona Mustang Performace (www.ampperformance.com). Might be worth buying one new if you know the calibration is correct. Even a meter calibrated for larger injectors is a shot in the dark, because all it does is fool the computer into thinking there is less air going into the engine, which is fine for fuel flow, but for ignition timing, it is terrible. I had severe pinging at part throttle, even with the timing retarded.

Do you have a y-pipe for the intake hoses? Just another thing to keep in mind as you try to have everything lined up.

 

Honestly, I would get the MAF and the PCM together if possible. I think the slope for the "truck" air meters is a little different than the one for the stangs, which may cause some surging when idling. But from one 5.0 stang to the next, I believe they're all the same.

EPNCSU2006....what are they charging you to recal your air meter?

 

$100 is what they quoted me. Hopefully it will be the last time I have to calibrate it - they know what the application is, and should trim it accordingly. I called Pro-flow up a couple times asking about what they take into account when they calibrate it, and feel pretty comfortable with it.

 

Good deal....let us know what happens when you get it back and install it on your rig.

 

Will do!

I'm anxious to give it a whirl once again. I'm in search of some 19# injectors with a tad less miles on them than my stock injectors and hopefully ones that work properly (I think one of them is stuck open).

 

Sounds awesome, fellas! Thanks a million for your answers - that's exactly what I was needing to hear!

Actually, the Brembs site is the reason I'm even thinking of attempting this all by my lonesome rather than getting it done in-shop (read: just sticking with speed density and leaving out major mods until I can AFFORD to get it done in-shop). His instructions are great, and really sort of 'held my hand' through my learning process with this. I posted here for a few case-specific things and you guys came through with flying colours... everything I had planned was suggested, and everything I think is a 'small issue' you guys seem to think will be unimportant as well.

Regarding the possible idle surging issue, after the MAF conversion I plan on dropping in a cam which is going to chop my idle to pieces anyway, so I'm not TOO worried about a bit of idle/near-idle roughness or surging. Good info to have though - I might have been left wondering what was up when my normally GREAT idling engine started to go off the reservation on me.

Appreciate the help fellas!
MR

 

The NDS switch isn't required by the automatic ECM so don't bother connecting it.

And I'd recommend using the mustang harness, with the truck engine, with the mustang ECM. I've done it both ways and found using the mustang harness a little easier, and more plug and play. If my memory isn't failing me, I had to repin the truck harness (3-5 wires, not a big deal).

A wiring diagram of your under-hood harness from your truck, and a wiring diagram of the underhood harness of the donor mustang can confirm if I'm correct, or incorrect. Better to be sure

 

You'd have to change a lot more of the mustang harness to match it up to the rest of the truck that you would have to change on the truck harness to match it up to the computer. The NDS switch is on a manual transmission computer, in an automatic truck, that's where I'm a little fuzzy. Wiring diagrams are definitely a must. Also a good book you might want to take a look at is Ford Fuel Injection and Electronic Engine Control by Charles D. Probst. Make sure you get the one for 89-93, since there are a couple different versions. I used Bjorn's site as the basis for my swap as well, so I know exactly where you are coming from.

 

Sounds good... yeah, I figured re-pinning the truck harness would be the ultimate plug-n-play solution since it's basically a disconnect/re-pin a few/reconnect the same bits (with a few more injector wires, etc.) rather than messing around with what's going on at the business ends of the mustang connectors.

Really looking forward to getting this done - just need to find myself a 5.0 mustang MAF at a good price (probably ebay or the local junkers) and I'm set!

Cheers, fellas... very, very much appreciated!
MR

 

Let us know how it runs when you get it finished.....good luck!

EPNCSU...Sent you a PM.