Does ecu increase idle in D and R (32rh)? - JeepForum.com
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post #1 of 5 Old 12-04-2019, 07:14 PM Thread Starter
fugitive
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Does ecu increase idle in D and R (32rh)?

If i move gear selector towards D or R but not far enough to engage transmission, I get a rise in rps to about 1000-1100 then it falls back to about 700. Is that the ecu compensating for increase load of D and R? Just curious.

2000 TJ with 32rh

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post #2 of 5 Old 12-05-2019, 06:26 AM
53flattie
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My Ď99 always did that. Not sure if itís SUPPOSED to or not.


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post #3 of 5 Old 12-07-2019, 12:05 PM
Jerry Bransford
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Quote:
Originally Posted by fugitive View Post
If i move gear selector towards D or R but not far enough to engage transmission, I get a rise in rps to about 1000-1100 then it falls back to about 700. Is that the ecu compensating for increase load of D and R? Just curious.

2000 TJ with 32rh
It's not specifically compensating for the transmission being in D or R, it's just keeping the RPMs where they need to be. The computer doesn't know what gear the transmission is in.

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post #4 of 5 Old 12-20-2019, 04:23 PM Thread Starter
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That is strange because the transmission is still in neutral and the rpms rise to over 1000 just the selector is near drive or reverse. Also when going from park to neutral the rpms rise when passing through reverse. AND in neutral it idles around 650. In drive with foot off the gas and off the brake it will accelerate to about 800-900 rpm (like in traffic). There must be a ecu program to open idle speed control motor to "compensate" for when in gear.
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post #5 of 5 Old 12-20-2019, 05:02 PM
Jerry Bransford
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Quote:
Originally Posted by fugitive View Post
That is strange because the transmission is still in neutral and the rpms rise to over 1000 just the selector is near drive or reverse. Also when going from park to neutral the rpms rise when passing through reverse. AND in neutral it idles around 650. In drive with foot off the gas and off the brake it will accelerate to about 800-900 rpm (like in traffic). There must be a ecu program to open idle speed control motor to "compensate" for when in gear.
Again, there is no program in the ECM/PCM to raise the rpms based on the gear selector's position. The computer has absolutely no indication and no clue of what gear a 32RH or 30RH transmission is in. If your rpms are unexpectedly high at times you have problem with either a vacuum leak, dirty IAC (idle air control, or perhaps a faulty TPS (throttle position sensor).
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