Series 3 4.2L High Idle Speed
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From: Milwaukee, WI USA
Series 3 4.2L High Idle Speed
Hello everyone,
One of my last bits to sort on my Series 3 4.2L is getting the idle speed to the factory spec which is I think is 550rpm (could be wrong on that). It’s currently at ~1200rpm. I’m having trouble finding the proper procedure for setting the idle. Any advice?
Thanks in advance!
One of my last bits to sort on my Series 3 4.2L is getting the idle speed to the factory spec which is I think is 550rpm (could be wrong on that). It’s currently at ~1200rpm. I’m having trouble finding the proper procedure for setting the idle. Any advice?
Thanks in advance!
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From: Pacific Northwest USA
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Joined: Apr 2014
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From: Milwaukee, WI USA
Thanks Doug. I have the idle speed set at 850 rpms now. Smoothed our considerable. I checked for air leaks by lightly spraying mass air flow sensor cleaner at the areas that air could enter, found no leaks. I turned in the idle screw (7/32” Allen) all the way in and that’s what got me to the 850 rpms. Should it be lower, or is that rpm acceptable?
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From: Walnut Creek, California
For my way of thinking, still a bit fast. My two cars are not jaguar powered. Each idles nicely at 500!! The DOHC needs a bit more. When mine was still DOHC, it was a bit "lopey" at 650. Not an issue, to me at the time....
Carl
Carl
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Joined: Mar 2008
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From: Pacific Northwest USA
Thanks Doug. I have the idle speed set at 850 rpms now. Smoothed our considerable. I checked for air leaks by lightly spraying mass air flow sensor cleaner at the areas that air could enter, found no leaks. I turned in the idle screw (7/32” Allen) all the way in and that’s what got me to the 850 rpms. Should it be lower, or is that rpm acceptable?
850 in "Park"?
If so, that's higher than spec but, honestly, that's about where they like to run. It's certainly not so high as to be a problem. Lower then that they often struggle, in my experience.
It should drop down to about 700 in gear
The fact that that it won't go any lower indicates a fault which should be correctable....with some time and effort. Your decision
Cheers
DD
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From: Milwaukee, WI USA
The 850 is in park, and it runs fairly smooth. I'd like the ability to get it to spec even if I increase the idle back up to 850. I didn't remove the air distribution body, but I did spray some carb cleaner in it to try to flush out any gunk. Throttle cable has very little slack, so I know that adjustment isn't to blame for the higher than spec idle.
-Alan
-Alan
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