VX idle problem/questions

[mcc6]

When I start up my 94 Civic VX (fed), it idles at about 1500rpm. As I drive around it gets lower and lower. After about 10 minutes of driving it settles right at that line that's just above 0 (so I guess that would be about 200rpm, more or less). Isn't it supposed to be closer to 600-700rpm? And is it normal for it to start out so high and then take a while to go down? What might be the problem? Any suggestions greatly appreciated!

[imzjustplayin]

does the car feel like it's running fine? Is the RPM you've got going strictly off the tachometer? You might want to hook something up or do some diagnosis to fix this problem as the engine is unlikely to be idling at 0 RPM or close to it.

[add|ct]

The line is the 500 RPM mark, yes I know its weird. So, its not idling lower and lower, in your case thinking its down to 200ish RPM. That car would probably not be feeling quite right by that point anyway.

...And until the engine is warmed up, it will idle higher than normal. 1500 sounds a bit high, though perhaps not. After its warm, it should be just above the line. It will dip in RPM from time to time with any electrical load other than the engine running, or just when the cooling fan initially kicks on. The RPMs should recover right away to 500-700. 750 is more or less in between he 1k mark and the line in question.

PS: Can't hurt to have the IACV cleaned on these things. Also, until the car is warmed up, the RPMs will run higher. 1500 may be right, its not anything dangerous or really strange, though. I'll try to see what mine idles at in the morning when I first start. It may be related to being in open loop mode as to why the car idles higher. I know there is a reason for it. Overall, it relates back to engine temp.

[add|ct]

Okay, I started it up today at it idled at 1400 RPM. So, your numbers aren't off by much, if at all in context anyway. Ambient temperature this morning was 85* already.

I believe primary factors include engine temp compared to ambient temp outside.

http://www.aa1car.com/library/vacleak.htm

The ECU may be controlling what to have RPMs at when first starting compared to when engine temp reaches a certain threshold.

[mcc6]

Looking at the tach, I can see how the next to bottom line corresponds to 500rpm. I feel silly for misreading that.
So yeah, initial idle varies from 1300-1500, but always settles where it should after warming up. Good to know that's relatively normal!

[add|ct]

Whew, dodged a bullet there.

[imzjustplayin]

heh, lulz