RE: [DML] Re: Not passing emissions (high idle)

["IN2TIME" <Specialty@xxxxxxxxxxx>]

I think David and I have simply agreed to disagree on the throttle return
problem/solution related to high idle. The problem with the throttle plates
not closing fully and not actuating the idle speed micro-switch is that the
throttle plate return spring (located just below the idle stop screw) isn't
doing its job. As Elvis pointed out, this may be related to dirt, shaft
wear. It can also be from weakening of the throttle plate return spring. The
result is that the micro-switch doesn't close - which prevents the idle
speed circuit from actuating, and also prevents the throttle plates from
closing properly. 

 

The solution David recommends does work, and is easier than mine, but it
uses the throttle spool spring via the "quadrant link" to simply assist the
throttle plate return spring. To do this you "push" all of the slack out of
the quadrant link to force the throttle closed. Then, when you step on the
gas pedal, you have to pull all of that slack back out of the quadrant
linkage before the throttle opens and the car accelerates. As you release
the gas pedal, the throttle stops moving when the screw hits the
micro-switch, and then (when you close up the quadrant link slack) it gets
pushed the rest of the way closed by the throttle spool spring. 

 

To actually fix the root problem, you need to clean, lubricate, and probably
tighten (or replace?) throttle plate return spring. Elvis mentioned
"readjusting/bending the spring" - which may be enough to overcome the
problem. I prefer to take an extra full turn on the spring. Admittedly, this
is not an easy procedure, but the result is that the problem goes away
completely, and you have the much better "feel' of immediate throttle
response. Since (with my solution) you can also "pull" the extra slack out
of the quadrant linkage, you have instant on-throttle and off-throttle
response. You also prevent the possibility of the slack preventing you from
getting to full throttle (imagine getting more power for free). 

 

Try it, you'll like it.

 

Gary

IN2TIME

 

 



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