[DML] UPDATE: PROBLEM FIXED Re: Idle gradually increased to 1700 RPM during warm up

["dmc_5180" <dmc_5180@xxxxxxxxx>]

Ok, After finally getting back my car today. I had the time analyze the situation better.  With a cold engine I fired it up, It went to about 900-950 rpm  which lasted about 15 seconds and then began climbing to 2000 rpm steady. After about 2 minutes running at that speed the EXHAUST starts turning colors. This time I am able look at things closer and see the BOTH sides are starting to glow. MY PREVIOUS STATEMENT OF the LEFTSIDE ONLY WAS UNDER HURRIED CONDITIONS AND TURNED OUT TO BE INACCURATE. MY FAULT SORRY.   So, after some over the phone diagnostic help from DAVE SWINGLE I found the cause to be a STUCK IDLE SPEED MOTOR. The valve was stuck in the open position. CARBONED UP. With the key on you could hear the motor buzzing Trying to work but it would not budge on it's own.  I was able to see into the port that connects to the CSV pipe and watch the valve with power applied. No movement at first. I stuck a small screwdriver into the port in an effort to see if the valve would move. It did not. Dave said, the Valve should rotate freely. Mine did not.  However, I was able gently pry the valve shut. Their was noticeable drag moving the valve. Then I put power to it again and the valve started moving back to the previous position.  I repeated the process 4-5 times to loosen things up and then was able just pry to valve open while the power was applied. The motor was finally able to push back against my prying.  I reconnected the short hose and FIRED IT UP.  ROCK STEADY @ 775.  

Oh YA just for grins, I increased the RPM to 2000 to see if the headers would still GLOW. Well, I am happy to say they DO NOT.    This confirms that with the Idle speed motor stuck open it caused the very LEAN running condition. 

Thanks to everyone for all the suggestions and tips. 

Dennis



--- In dmcnews@xxxxxxxxxxxxxxx, "dmc_5180" <dmc_5180@...> wrote:
>
> This is a never before seen problem on my car during my 16 years of ownership.  I went to start the car this afternoon , it had not not been driven since the DMCMW open house weekend  3 weeks ago.   The car fired right up as usual Idle was stable at 775  +/- 25 with a very subtle hunt but virtually stable.  I walk away from the car after 20-30 seconds  I'm letting it warm up.  I was  getting a few things from the trunk of my other car to put in the D. While I had my head in the trunk of the other car The RPM starts to gradually increase on the D. I did not think too much about it Figuring that the Idle Micro switch might not be tripped. I walk back over the D get in driver seat  to see the IDLE is at a steady 1700 RPM .  I tap the Pedal a few times  NO change. OK, I Go back to engine bay to make sure the Micro switch is depressed. It IS. Then I happen to Look down at the Left EXHAUST HEADER. This Is a JET-HOT coated system.  The header starts GLOWING and IS increasing rapidly.  I do a quick check of the Right Header which appears to NOT be turning colors at this point. FYI I was in a rather dark building at the time so it was fairly easy to see the heat GLOW.  Well I've never had this happen before. and As the header starts turning very RED rather quickly , I Shut it down immediately.  While the engine was shutting, down I hear a woooof sound in the exhaust, almost like I flame igniting.  The exhaust header quickly turns back to normal color. I wait about a minute then start the engine again. Idle is steady at 1700.   The scary part for me was the Left exhaust appearing to be much hotter than the right.  Again I did not notice the Right side turning color as the left did.  This is a STAGE I exhaust.  both sides are independent each with a CAT.  I thought about the possibility of maybe a plugged CAT but I'm not so sure about that.  Any thoughts of what may have caused my idle to increase like that?
> 
> 
> Dennis
>




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