Pin 30 Question?

[larrym1961]

I did a test on PIN 30 today because I am curious as to what is going on there with my car ie: grounding vs. voltage. At testing I have a constant ground at PIN 30 with my clutch pushed in or out and in gear or out of gear.

Since I did an AOD to 5 speed swap and my car was originally a speed density car converted to mass air, my O2 harness does not have the jumper wire like the later mass air cars do. So I also performed a voltage test @ PIN 30 while cranking the starter and I get 9 volts @ PIN 30. What I understand is any kind of voltage @ PIN 30 can cause damage to an A9L ECU. But I have never had any issues using the A9L other than a temp high idle when pushing the clutch in as I do using a C3W ECM.

Does anyone think there is damage to the A9L regardless of it seems to function just fine? And If I am going to use the A9L should I make that PIN a constant ground with no cranking voltage going to the PIN such was cutting the PIN wire and grounding it or is there something else I should be doing to make it work correctly?

 

[liljoe07]

Voltage at PIN 30 is normal with cars that were Auto from the factory. What you dont want is voltage at PIN 46. That's how these transmission swap guys get into issues on the Mass Air cars. You never hear about those issues on the SD cars. I wish I knew the wiring better on the SD cars, I would be able to tell you how Ford differentiated between Auto and Manual setups.

 

[larrym1961]

Thanks Liljoe07 guess I won't worry about a little voltage @ PIN 30. My A9L is still in good shape as I inspected it today and found nothing burned in it. I had read in a post on another site you replied on, that you had a similar wiring set up on your Mustang as mine and had done a trans swap and grounded PIN 30 to make it work properly with your A9L? I am speaking of idle dropping down instead of hanging a bit longer when the clutch was pressed in.

 

[liljoe07]

Thanks Liljoe07 guess I won't worry about a little voltage @ PIN 30. My A9L is still in good shape as I inspected it today and found nothing burned in it. I had read in a post on another site you replied on, that you had a similar wiring set up on your Mustang as mine and had done a trans swap and grounded PIN 30 to make it work properly with your A9L? I am speaking of idle dropping down instead of hanging a bit longer when the clutch was pressed in.

My case was different. I had an SD 02 harness with a factory mass air engine harness. The reason I did what I did was because it is better to make the ECM think the engine is in Neutral all the time, then it is for it to think its in gear all the time. Which is basically what you have now( constant ground at pin 30, equals and In Neutral state). Consequently, it is probably the reason for your hanging idle.

We could probably figure it out how fix it, but it would take you doing some wire tracing. Or possibly switching out the engine harness and 02 harness for one from an 89.

 

[larrym1961]

Once again thanks for the info. I have entertained the Idea of switching to a 89 and later harness also. But I think for now I will stay with what I have and live with the short "hanging Idle". I have done it since 2002 when I made the trans swap. It's more worth it to me to have that little annoyance and have a manual trans over an auto.