RPM is high but gradually goes down...

**rna800** · August 25th, 2008 10:54 AM

Guys, I need your opinion on what seems to be the problem in this.

About 2 days ago I noticed when I started my car, the RPM shoots up to 1500 and it stays at 1300. While it was traffic, I noticed that it gradually goes down until it reached the line in between 700 and 800 while idling. Added to the oddity, even if I am traveling at around 40 to 60 kph, the rpm is passing the 2000 mark.

Today, I really observed and timed it and this is what I came up with:

1st start: RPM * 1500 but it will go down to 1300
* 1 min 30 secs: RPM * 1000
* 2 mins 10 secs: RPM * 900
* 3 mins 40 secs: RPM * 800
* 5 mins onwards: RPM is in between 700 and 800

If it's in between the 700 and 800 mark and I tap the accelerator pedal about let's say 2 to 3 inches, it will shoot up to 1600.

At first it's the idler but if it slowly goes down, I don't think that's the problem. The engine is as quiet as before and there are no signs or signals telling me that the engine has a problem.

I called Honda Fairview since they were the one who replaced the RACV (Rotary Air Control Valve) about two to three weeks ago. They told me maybe an adjustment is needed but there is no need for me to be alarmed... hopefully.

So guys, maybe you could help me a little bit. Thanks!

**niky** · August 25th, 2008 02:08 PM

Most likely it's just the control valve needs adjustment.

**rna800** · August 25th, 2008 05:47 PM

Thanks! What's odd is I had that replaced about 2 weeks ago and it's just now that it happened. I will just have them checked it.

**niky** · August 25th, 2008 10:36 PM

Yeah, it happens... could be you just need your hoses and fittings checked, and the valve adjusted... possibly the "cold idle" is tuned a bit too high. Not a big deal if it doesn't stick open when it's hot. If it does, then that's a problem.

**v6dreamer** · August 26th, 2008 01:34 AM

Does your car idle rough or the speed cycle up and down. You probably have a bad idle air control valve. The purpose of the idle air control valve is to keep the engine’s idle smooth. The engine’s computer gives the idle air control valve the feedback it needs to hold a constant rpm. The idle will be around 1000 rpm’s or more ( like your's) when not in gear and around 800 rpm’s in gear. Check those hoses also for abnormality, like crack or loose.

Bring your car back to honda still in warranty, something has done not right. Could it be a bad parts when they changed your idle air control valve.

**rna800** · August 27th, 2008 05:12 AM

Originally Posted by v6dreamer

Does your car idle rough or the speed cycle up and down. You probably have a bad idle air control valve. The purpose of the idle air control valve is to keep the engine’s idle smooth. The engine’s computer gives the idle air control valve the feedback it needs to hold a constant rpm. The idle will be around 1000 rpm’s or more ( like your's) when not in gear and around 800 rpm’s in gear. Check those hoses also for abnormality, like crack or loose.

Bring your car back to honda still in warranty, something has done not right. Could it be a bad parts when they changed your idle air control valve.

I don't notice any rough idling. The sound of the engine is as smooth as ever and it runs smoothly. I don't even hear it roar but when I look at the rpm, it's really high and it's all over the place especially when I reduce speed and step on the gas pedal again since just a tap would really make it shoot up.

**v6dreamer** · August 27th, 2008 11:13 AM

Originally Posted by rna800

I don't notice any rough idling. The sound of the engine is as smooth as ever and it runs smoothly. I don't even hear it roar but when I look at the rpm, it's really high and it's all over the place especially when I reduce speed and step on the gas pedal again since just a tap would really make it shoot up.

Have you ever notice of losing accelaration power in your car from standstill acceleration or even passing other car on the freeway that whenever you step the gas pedal your RPM shoot up?

**rna800** · August 27th, 2008 01:58 PM

No sir, not that I can recall losing acceleration. The engine runs smoothly whether idling, moving from a standstill or cruising. I don't even hear any strain in the engine. It's really smooth. It's just that when I look at the rpm, it's above 2k with speeds around 40 to 60. I don't have any idea when this started since I noticed this about 2 to 3 days ago when the first time I started the engine I looked at the rpm and to my surprise I saw that it's above 1k which I knew immediately that it's not normal.

**v6dreamer** · August 28th, 2008 02:05 AM

There's a few different things that can cause your problems, fortunately most are easy to check kailangan lang ng tiyaga.

First: Check your throttle body for carbon build up around the throttle valve causing it to stick open. If carbon found, crank engine and and stray carb cleaner down throttle body to break up carbon. You will know when problem is fixed, it will drop to normal. You may notice the car run a little ruff at first, but once the carb runs out of system it will idle normal again.

2nd: Check your throttle Cable. I've only seen this a few times, but the throttle cable will bind or come partially off the throttle lever, causing throttle valve to open. If you see a problem with throttle cable, replace if binding, or adjust if cable is partially off throttle lever.

3rd: You will need to take your car to a shop to check and see if the computer is comanding such a high idle. If this is the case you will need to replace the ECU (Electronic Control Unit).

4. Recently, honda change the IACV in your car, so I would strike on that but I wont totally ignore it since never happened before this problem till recently.

Usually one of these things will be your problem on a honda. Good luck and hope this helps!

**rna800** · August 28th, 2008 08:52 PM

Thank you so much, sir, on your detailed information. Since I am not mechanically gifted unlike you and the other tsikoteers here, which I envy so much and hoping that I could also become someday, I don't think I could do all of those. It might worsen the problem if I touch the engine.hehe But at least when I bring it to the auto shop, at least I have an idea on its causes and I could also give advises on what's causing it(thanks to sir v6dreamer.hehe)

Sir, is the IACV (Idle Air Control Valve) the same with the RACV (Rotary Air Control Valve)? Coz it's the RACV that they replaced.