Is my idle high and what does it mean?
02-14-2005, 09:43 PM
#1
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Join Date: Aug 2004
Location: SE Michigan
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Is my idle high and what does it mean?
My cars pretty much all tuned up but i noticed that it seems to idle high but it could just be me.
ITs a 97 z28 and it idles at 1100 in park and 900 in gear. Does it mean anything and do i need to do anyhting about it?
ITs a 97 z28 and it idles at 1100 in park and 900 in gear. Does it mean anything and do i need to do anyhting about it?
02-14-2005, 09:52 PM
#2
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Join Date: Oct 2003
Location: Franklin, NC
Posts: 413
Re: Is my idle high and what does it mean?
The thing that comes to mind right off the bat is a sticking idle air control valve. It's located on the passenger side of the throttle body. I took my entire throttle body off last year to clean it up, and the little port that the IAC valve is in was loaded down with all sorts of build-up.
Also possible, but unlikely, is a vacuum leak. That could cause a high idle, but would probably be compensated for by a properly functioning IAC, and would cause it to run horribly since MAF and MAP sensor readings would be off.
Also possible, but unlikely, is a vacuum leak. That could cause a high idle, but would probably be compensated for by a properly functioning IAC, and would cause it to run horribly since MAF and MAP sensor readings would be off.
02-14-2005, 10:25 PM
#5
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Location: Franklin, NC
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Re: Is my idle high and what does it mean?
I may be mistaken, but I believe that the stock idle is supposed to be 800 in Neutral, and 500 in Drive for an A4. Mine idles almost exactly at 800 RPM according to my Scanmaster, but the stock gauges have it somewhere around 850-900. Still no where near the 1100 that yours is idleing at.
02-14-2005, 11:01 PM
#8
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Location: Franklin, NC
Posts: 413
Re: Is my idle high and what does it mean?
Nope, nevermind. Click here and scroll down some. 
Stock programming for an A4, fully warmed up, is 550rpm in gear and 650rpm in neutral. There is a cold idle table:
A4:
COOLANT TEMP - IN GEAR - IN NEUTRAL
-40 ------- 800 ---- 1200
-19 ------- 800 ---- 1200
+3 -------- 800 ---- 1200
24 -------- 800 ---- 1000
46 -------- 800 ---- 950
68 -------- 800 ---- 900
89 -------- 800 ---- 900
111 ------- 800 ---- 900
132 ------- 750 ---- 850
154 ------- 650 ---- 750
176 ------- 550 ---- 650
>176 ----- 550 ---- 650
If the idle doesn't match properly, it may be a problem with the IAC valve, or plugged passages for the idle air flow. Check the IAC valve "counts" with a scanner, and see how it reponds.
A4:
COOLANT TEMP - IN GEAR - IN NEUTRAL
-40 ------- 800 ---- 1200
-19 ------- 800 ---- 1200
+3 -------- 800 ---- 1200
24 -------- 800 ---- 1000
46 -------- 800 ---- 950
68 -------- 800 ---- 900
89 -------- 800 ---- 900
111 ------- 800 ---- 900
132 ------- 750 ---- 850
154 ------- 650 ---- 750
176 ------- 550 ---- 650
>176 ----- 550 ---- 650
If the idle doesn't match properly, it may be a problem with the IAC valve, or plugged passages for the idle air flow. Check the IAC valve "counts" with a scanner, and see how it reponds.
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