[DML] Re: Idle Problems

["dmc_5180" <dmc_5180@xxxxxxxxx>]

Mike,

I'm confused, why did you have to replace the butterfly assembly? Was the shaft worn at 
the pivot bushings? Normal idle with a properly funtioning ISM is 775+- 50rpm. Are the 
throttle plates fully closed in the Idle position? You have to remove the Ram horn intake 
section to verify. the throttle plates should be fully closed at idle. the ISM controls how 
much air by-passes the throttle plates and controls the idle. Did you split the top and 
bottom of the Air metering unit for some reason?  Is the throttle cable in it's proper 
position down in the groove. I have had the cable pop out of the groove when reving the 
engine by hand at the spool this will prevent the throttle plates from closing and will make 
the engine rev at 2500- 3000 rpm. Just make sure the cable is down in groove where it 
should be. Just a note: any vaccuum leak down stream of the air metering assembly will 
cause a lean condition and idle poorly. 

Dennis

--- In dmcnews@xxxxxxxxxxxxxxx, "Michael & Denise" <luckeys71@xxxx> wrote:
>
> Once again I must ask for the assistance of the experts on the DML as I can't seem to 
solve an idle problem I am having.  Here's the background:I recently replaced the butterfly 
assembly in the air induction and everything seemed to go back together quite nicely.  
Upon starting the car I found that the idle had jumped up to 3000 RPM so I began to 
systematically check the usual suspects.  All of the vacuum lines have been replaced and 
are connected, the brass screws on the assembly are tightened down,  the throttle plates 
seem to be operating normally, the microswitch has been adjusted, and the O rings in the 
air horn have been replaced to make sure they are not faulty.  Furthermore, the idle speed 
motor had previously been removed and tested by Dave Sontos when we were removing 
the air intake and was functioning properly.  When Dave and I were looking at this problem 
last week he found that with the idle speed motor disconnected the idle dropped to 
2000RPM whereas before all of this occurred my idle sat at app.850RPM.  I'm certainly no 
expert on this matter but how could replacing the butterfly assembly cause this mess?  It 
seems most likely to be a vacuum leak somewhere but I'll be darned if I can find the 
source of the trouble.  Does anyone have some thoughts or ideas of what to try next?  My 
neighbors are getting WAY too used to seeing me hunched over the engine compartment 
of my car!
> Thanks,
> Mike
> 
> [Non-text portions of this message have been removed]
>








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