idling at 650-750 rpm?

Bad92GT

The 5 Minute Plan Man

Jun 10, 2004

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Feb 21, 2006

#1

• Feb 21, 2006

• #1

Lately i've been doing alot of work to the car, new cam heads intake and such.. and i've been unhooking the battery so the car hasnt gotten the correct break in period until saturday. (motor only has 25 miles on it if that).. Before hand, it would run somewhat rich and at 900 rpms.. but it just randomly broke in oneday while i let it idle for maybe.. 20 minutes, and then it started to idle at 650-750. Thing is, the cam is a fairly big one, .530/.540 lift so its a very lumpy, choppy idle that causes the car to bump around. Is this the correct spot or should i adjust it up?

 

stang8urimport

Autozone Junkie

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Jun 21, 2002

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Daytona Beach, FL

Feb 21, 2006

#2

• Feb 21, 2006

• #2

Factory idle is right around 650 rpm. That's where mine idles.

 

Bad92GT

The 5 Minute Plan Man

Jun 10, 2004

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Feb 21, 2006

#3

• Feb 21, 2006

• #3

alright then.. sorry i didnt want to sound like a retard but the difference is pretty big from where it DID idle to where it does lol thanks

 

HISSIN50

"How long does it take to get help in here?

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Nov 29, 1999

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Feb 21, 2006

#4

• Feb 21, 2006

• #4

If you find the idle to be unstreetable, bumping it up is not a bad idea (I would probably take it up to 900 RPM or so, warm idle with no load).

If you had not let it idle for this long before, you simply might not have reached full warm-idle-trim before this.

Otherwise, and other than the IAC relearning since the battery was disconnected, I cant think of a reason for the idle change.

Good luck.

 

Bad92GT

The 5 Minute Plan Man

Jun 10, 2004

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Feb 21, 2006

#5

• Feb 21, 2006

• #5

well a friend of mine told me the computer had to get its idle strategy back.. i followed what he said and thats what happened.. the cars timed at 18* with 42#s of pressure at the FPR

 

HISSIN50

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Feb 21, 2006

#6

• Feb 21, 2006

• #6

The computer can add air (via the IAC) to raise the idle, but it cannot remove air to lower the idle. Just something to remember when thinking about this stuff.

 

Bad92GT

The 5 Minute Plan Man

Jun 10, 2004

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Feb 21, 2006

#7

• Feb 21, 2006

• #7

well it idled down from.. 900+ to 800-900 on saturday.. i went to GA on sunday and monday.. and started it up today when i got home and it just idled at 750.. i suppose thats how

 

ninety15.0

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Mar 10, 2004

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Feb 21, 2006

#8

• Feb 21, 2006

• #8

As my new motor broke in the idle dropped down by about 150 rpm as well....i wouldnt worry too much unless its so choppy that the car feels like its going to die...then bump it up a tad. I think mine idles at like 850-950...just what it likes.

 

HISSIN50

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Feb 21, 2006

#9

• Feb 21, 2006

• #9

Based upon the recent posts, I think my point was misunderstood. If the idle is set correctly (hot idle, IAC disconnected), the idle can go no lower than that setting.
Yes, the idle can be lowered if the IAC has the capacity to do so (if people set the idle incorrectly). But once the idle is set as above, the only way it should idle lower than that setting is if a load is placed on the motor and the IAC happens to not function.

Your friend seemed to have the same thoughts I did about the idle relearning (what I posted above your post).

Good luck.