Resetting engine computer for idle learn by removing fuse

[quietdragon]

This post suggests that removing No.13 Clock Backup (7.5A) fuse on the passenger side fuse/relay box is sufficient to remove power from the engine management computer to trigger it to relearn the idle level.

Can anyone confirm that this is indeed the right fuse?

Is there any way of confirming that the computer has indeed reset and forgotten the previous settings ready for re-learning?

[N_Jay]

Originally posted by quietdragon
This post suggests that removing No.13 Clock Backup (7.5A) fuse on the passenger side fuse/relay box is sufficient to remove power from the engine management computer to trigger it to relearn the idle level.

Can anyone confirm that this is indeed the right fuse?

Is there any way of confirming that the computer has indeed reset and forgotten the previous settings ready for re-learning?

Why do you want to reset it?

It is learning all the time.

[krygny]

Originally posted by N_Jay
It is learning all the time.

[quietdragon]

Originally posted by N_Jay

Why do you want to reset it?

It is learning all the time.

The Idle Learn procedure typically requires disconnecting the battery which will reset the engine management computer as a side-effect. The suggestion in that other post was removing the fuse alone was sufficient to reset the computer thus obviating the need to enter radio codes, etc.

There was talk in the another thread about performing this procedure to address issues with poor fuel economy.

I have a relatively new 08 Pilot and the fuel economy is a lot lower than I expected (about 12mpg city driving).

Supposedly the idle learn was done as part of PDI. I thought it worthwhile to perform the procedure again to see if it might improve the situation.

[N_Jay]

Originally posted by quietdragon
The Idle Learn procedure typically requires disconnecting the battery which will reset the engine management computer as a side-effect. The suggestion in that other post was removing the fuse alone was sufficient to reset the computer thus obviating the need to enter radio codes, etc.

There was talk in the another thread about performing this procedure to address issues with poor fuel economy.

I have a relatively new 08 Pilot and the fuel economy is a lot lower than I expected (about 12mpg city driving).

Supposedly the idle learn was done as part of PDI. I thought it worthwhile to perform the procedure again to see if it might improve the situation.

Sounds like people have the "idle learn" concept a little backwards.
You don't start the idle learn by disconnection the battery. It is recommended by Hinda that you DO the idle learn every time the battery is disconnected. There is no need to disconnect the battery prior to doing the idle learn. (I discern this due to the fact that if the idle learn is not done right, Honda instructs you to start the timing over with no mention of disconnecting the battery.
I am very sure that the idle learn process is going on constantly, and the initialization process is just so the car is not driven while the setting data is too far out of range.

I am not sure if the reports of better mileage (usually for only one tank or so before it returns to normal) are a true effect on some cars, or just "measurement error".

P.S. I would easily expect getting 12 MPG with a new Pilot in city driving in the winter, but I am a realist, not an optimist.

[N_Jay]

Originally posted by krygny

Was that intended to be a meaningful comment/question?

[quietdragon]

Originally posted by N_Jay

I am very sure that the idle learn process is going on constantly, and the initialization process is just so the car is not driven while the setting data is too far out of range.

I am not sure if the reports of better mileage (usually for only one tank or so before it returns to normal) are a true effect on some cars, or just "measurement error".

P.S. I would easily expect getting 12 MPG with a new Pilot in city driving in the winter, but I am a realist, not an optimist.

Thanks for the helpful comments.

What are the effects of driving around with the setting data out of range? More fuel consumed? Poor performance?

[whizmo]

Originally posted by quietdragon
Thanks for the helpful comments.

What are the effects of driving around with the setting data out of range? More fuel consumed? Poor performance?

No one knows for sure, but my guess would be slightly rough idle.

As we've discussed in other threads, I'd view it as essentially impossible that the EPA would allow Honda to build a vehicle which a battery disconnect would cause engine issues that would increase emissions or affect mileage.

- Mark

[krygny]

Originally posted by N_Jay

Was that intended to be a meaningful comment/question?

No, not really. Just that machines "learning" is kinda creepy (especially considering that some people I know stopped learning at some point).

[N_Jay]

Originally posted by krygny

No, not really. Just that machines "learning" is kinda creepy (especially considering that some people I know stopped learning at some point).

OK, I get it now.

Remember, we are talking about Hondas, not PT.

[N_Jay]

Originally posted by quietdragon
Thanks for the helpful comments.

What are the effects of driving around with the setting data out of range? More fuel consumed? Poor performance?

My guess is idle emissions beyond allowable.