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Hello all,

I am now a proud owner of abe.998 civic lx, d16y7 manual 5 speed. However, I found a few issues with the car. The biggest problem that I found right off the bat was a horrible idle problem. The engine would drop frequently between 200-500 rpm when stopped. This didn't include electrical accessories running and would have the steering column straight.

To get to the point, I did a lot of searching in these forms for threads pertaining to idle fixes and causes for idling issues. It seems fairly simple but there are many different recommendations regarding this. So, I cleaned out the ICV, throttle body, and have adjusted the idle screw to the point where I hit about 780-800 rpm (or at least so I believe since I don't know what rpm the small line right above the bottom of the needle is, unless someone could tell me) when the radiator fan has cycled twice. However, there seems to be an extremely strong vacuum from the screw after I adjusted it, fairly loud as well., just to get the idle where it should be.

Is this bad that there's such a strong vacuum coming from the adjusting screw? I've also heard that adjusting the throttle cable can sometimes help but it seems alright. If I screw the idle scree closed, my engine rattles and struggles. Could any of you pros give a few words of advice I might have missed?

Thanks,
Kurt

 
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I'll go way out on a limb and guess the IAC valve might be stuck closed.

You say you cleaned it, but how did you do that? Did you make sure it can move freely?

Have you tried tapping on it?



Any codes?

 
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ICV is practically spotless now that I cleaned it, it had quite a buildup so I figured that would fix the issue. I used brake cleaner to clean it out, and the valve has no resistance when moved with my fingers. Maybe it's a sensor issue?

I have no codes which is puzzling me. From things that I have been reading, people claim that the idle screw should really only be turned up to a max of about 2 full rotations, but I'm quite positive I've gone maybe 3-4 full rotations before my idle speed is in check. I also notice that the RPM's tend to go over 1K when the engine is slightly warm (after about 10 minutes of driving) which I'm sure is not good. But any less and I'm practically close to stalling, especially since the clutch is getting worn from age and it tends to bounce when engaging into 1st.

 
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New problem,

My CEL finally illuminated after cleaning the idle control valve, gives code P0505. What I am wondering is what position the valve should be in by default, I had also removed the plastic piece on the other side of the ICV which I realized holds the valve in a certain position within the housing. So, do any of you know what position the valve should be reinstalled in?

My car fluctuated greatly in RPM today, between 800-2,200.

I need help! My gas pedal now also seems to stick when going to shift, makes the car jump. I have to press rather firmly on the gas pedal just to get the engine to match with clutch, never did that until my CEL came up today.

No bueno...

 
Rep Power: 518

P0505 tells me the PCM does not have control of the idle speed.
If it's now idling high and surging, I'm gonna guess the IAC is now stuck open or you have a large vacuum leak.

If you use your finger to block off the port in the throttle body for the IAC, does the idle speed drop and stall the engine (or try to stall)?

 
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I believe I might have fixed it tonight, worked on it for hours trying to get this thing straightened out. I was noticing that the throttle plate was sometimes getting stuck when the throttle cable was released quickly. I had to remove the throttle plate from the throttle body, cleaned the whole damn thing with a wire brush, then reinstalled. After I had to also adjust the stop screw that catches the throttle cable plate in a specific position when the gas is released. This seemed to do the trick, or at least for now. I haven't had the chance to drive it completely yet as I have just finished this at 1:30 am.

I believe the reason I got the P0505 code was due to the fact that I might have installed the Idle Air Control Valve in backwards. I found a stock image of the inside of the ICV online and matched the picture to mine. Drove the car a good hour, RPM's never went below 700. So, overall an accomplished night! But the real test will be tomorrow when I need to drive in the heat as I noticed it tends to get too low when over 90 outside despite having set the RPM with the radiator running as instructed in the manual.

I'll give an update later today!