A9L Mustang Computer

[a67and77]

I'm going to change from manual to an auto C4, can I still use the A9L computer. How do I wire the NSS into the Bronco?

Thanks,

 

[rjlougee]

You can still just use the A9L EEC, the C-4 won't effect that.

As for the NSS, it should go inline between the ignition switch and the starter solenoid so the RED/BLU wire won't engage the solenoid unless the shifter is in the correct position. Personally, I never run them; however it can be disconcerting to start the Bronco with the tranny in gear and have it start driving off without you...
Joe

 

[av bronco]

A9l is a 5 speed computer,I have the same delema. heres a thread on it.
http://sbftech.com/index.php/topic,25116.15.html

 

[Viperwolf1]

A9l is a 5 speed computer,I have the same delema. heres a thread on it.
http://sbftech.com/index.php/topic,25116.15.html

If the ECU type (manual or auto) is matched to the harness type, it does not matter what type of trans you use. You can swap the trans without issues.

 

[a67and77]

I'm using the Ford Racing harness based on the 93, and have the choice on the plug to wire manual or auto, I just left all that unplugged and thought that I could do the same when I have the C4 in. The engine doesn't know what's behind it at this time.

 

[rjlougee]

A9l is a 5 speed computer,I have the same delema. heres a thread on it.
http://sbftech.com/index.php/topic,25116.15.html

This issue is only applicable when swapping EECs withing the confines of the original factory wiring harness. The way these came from the factory the jumper wire to input into pin#30 of the EEC was contained in the HEGO harness, so you had two different part numbers for the auto vs. manual HEGO harness.

Once Ford started selling the harnesses as retrofit pieces, it was available under different part numbers. M-12071-C302 is the main harness.
M-12071-E302 is the engine/injector harness, this also contained two different HEGO harnesses, one for the auto and one for the manual. The harness/EEC really does not care one little bit about what tranny is in the vehicle, it's just so the correct input is plugged in for pin#30. This harness was based on the '93 Mustang wiring.

Once Ford started selling the new EFI project harness, 12071-A50 it uses a totally different design which incorporates a RCM that uses a logic circuit to prevent the EEC from setting the code#67 and allows the Cylinder balance test to be conducted without actually simulating "neutral".

In this case the guy is already using an A9L, so it makes no difference what tranny he puts behind the engine, as long as it's already working, nothing will change.
My $.02
Joe

 

[4lofun]

i had to connect the two wires the ford harness manual says at the brown connector by the eec test plug, and then the two wires at the hego harness connector. verified by disconnecting pcm plug and had continuity between pins #30 neutral input and #46 signal return. now the idle is setable and not stuck at 1200 rpm.i have the older harness i think as i bought 5 years ago

 

[a67and77]

At this time with the manual tranny installed the wires in the brown connector for m/t pin 30 inputs and a/t pin 30 inputs are not connected to anything and the engine has been running fine for 6 years. Should these be connected? So far it sounds like I can run the auto in it with no effect.

Thanks all,

 

[methcat]

i had to connect the two wires the ford harness manual says at the brown connector by the eec test plug, and then the two wires at the hego harness connector. verified by disconnecting pcm plug and had continuity between pins #30 neutral input and #46 signal return. now the idle is setable and not stuck at 1200 rpm.i have the older harness i think as i bought 5 years ago

do you technically have to connect the wires? i "think" really you just want to ground #30, then by default there is continuity?

 

[methcat]

At this time with the manual tranny installed the wires in the brown connector for m/t pin 30 inputs and a/t pin 30 inputs are not connected to anything and the engine has been running fine for 6 years. Should these be connected? So far it sounds like I can run the auto in it with no effect.

Thanks all,

you'll be fine without, but there is some eveidence that you may get a better idle with it grounded...
http://sbftech.com/index.php/topic,7333.0.html

 

[4lofun]

i dont think grounding is the right thing to do. i understand it as if you have manual pcm pin 30 and 46 need to be connected. pin 46 i believe is a 5 volt pcm generated output. i just connected these wires and idle seemed better. but i then took intake off due to coolant leak. so i havent totalally verified the results.

 

[Viperwolf1]

i dont think grounding is the right thing to do. i understand it as if you have manual pcm pin 30 and 46 need to be connected. pin 46 i believe is a 5 volt pcm generated output. i just connected these wires and idle seemed better. but i then took intake off due to coolant leak. so i havent totalally verified the results.

Pin 46 is signal return, essentially a secondary ground system for the sensors. If you have a good ground on the harness it is the same thing as chassis ground, zero volts.

 

[rjlougee]

Should these be connected?

They do not need to be, but as long as you have no connection on pin#30 you will always get the code#67 when checking codes and you will not be able to run the Engine Running test procedure or the Cylinder Balance test.
Joe

 

[a67and77]

They do not need to be, but as long as you have no connection on pin#30 you will always get the code#67 when checking codes and you will not be able to run the Engine Running test procedure or the Cylinder Balance test.
Joe

Not sure where I would connect anyways. The instructions say on the brown connector the white/purple to crank only source, green/purple and the purple/yellow to the manual tranny nss however this was if using a T-5 tranny according to the instructions. I don't have a nss and dont have the white/purple connected because I thought this was for an auto only connection. The check engine light does cycle at startup as normal and I hear the pumps cycle then the engine light turns off when running. Not sure what I should do with these wires but like I said has been running.

Thanks,

 

[methcat]

i have a manual ecm and just grounded my 30. it idles noticably better than without it grounded, runs the same otherwise...

 

[a67and77]

Which one of these wires I mentioned in the plug would be grounded? All three have reference to pin 30. The white/purple says goes to 12v crank only but on ford fuel injection the reference for this harness says white/purple gnd for 30 a/t only, green/purple sig rtn 30 m/t, and purple/yellow nds 30. The white/purple can't be a ground if it's connected to a 12v crank.?:?

 

[Viperwolf1]

Which one of these wires I mentioned in the plug would be grounded? All three have reference to pin 30. The white/purple says goes to 12v crank only but on ford fuel injection the reference for this harness says white/purple gnd for 30 a/t only, green/purple sig rtn 30 m/t, and purple/yellow nds 30. The white/purple can't be a ground if it's connected to a 12v crank.?:?

I don't understand your confusion. You said there's a connector to select type of ECU.

Pin #30 either needs 12V in crank (auto) or signal return (manual) connected to it.

 

[a67and77]

I don't understand your confusion. You said there's a connector to select type of ECU.

Pin #30 either needs 12V in crank (auto) or signal return (manual) connected to it.

I have a choice on the plug to use connection for manual tranny or auto tranny not pic type of ECU, the ECU is for a manual and I will eventually go to an auto tranny with the same computer. I left all those wires undone because it didn't appy to either situation-nss on a manual or using an auto tranny. I understand that the way I have it now won't matter what tranny I put behind it because the engine doesn't know anyways. I was just wondering which one of those wires to connect to ground out pin 30 since all three have a reference to it so that I can read codes. Maybe I'm just reading too much into this.;D

 

[Viperwolf1]

I have a choice on the plug to use connection for manual tranny or auto tranny not pic type of ECU, the ECU is for a manual and I will eventually go to an auto tranny with the same computer. I left all those wires undone because it didn't appy to either situation-nss on a manual or using an auto tranny. I understand that the way I have it now won't matter what tranny I put behind it because the engine doesn't know anyways. I was just wondering which one of those wires to connect to ground out pin 30 since all three have a reference to it so that I can read codes. Maybe I'm just reading too much into this.;D

The plug is to select the type of ECU used. Actual type of trans does not matter.

Purple-yellow wire goes straight to pin 30. This is the wire that needs to be connected to something.

Green-red wire is attached to signal return, or ground. Attach the purple-yellow wire here for use with your manual ECU.

Red-blue wire is attached to the starter solenoid. It is 12V in crank then when cranking stops it essentially goes to ground. Only connect the purple-yellow wire to this IF you have an auto type ECU. If you connect this with a manual type ECU bad things will happen inside the ECU.

 

[a67and77]

Thanks, now I have all the info I need to finish up...you guys are great;D