idle issues with '87 4kq, THERE BACK!

[Kneale Brownson]

It isn't unheard of to need a new ISV if cleaning only partially solves the 
problem.


At 07:23 PM 10/23/2000 -0700, Luke Rickert wrote:

>With the archive search engine MIA I am forced to bring up a topic which
>has surely already been well addressed. I apologize.
>
>I sent a message out a couple of weeks back about idle stability
>problems during cold start-up for my '87 4kq.  Since then I have cleaned
>the ISV, checked and replaced both of the temp sensors in the upper
>flange, replaced the O2 sensor, and checked the idle switch.  I cleaned
>the ISV first which partially alleviated the symptoms, the other work
>didn't make any noticible change to the cold idle.  The probelm was
>partially mitigated until Saturday night when I tried to go watch the
>final F1 race, the car returned to the same large oscillations as before
>I did anything. It happenend again last night but today when I went out
>to test it, everything worked as it had after the initial ISV cleaning.
>
>Given that I have the problem at night, when it is cooler than the day I
>suspect a temperature related problem, perhaps the idle position switch.
>I am considering removing the idle switch and seeing if it still works
>after spending some quality time in the freezer. Unfortunately, the
>switch in question does not look like it is going to come out very
>easily, so I would like to be fairly certain that it is guilty before
>removing it.
>
>Are there any theories out there? I am going to go test the switch again
>tonight and see if it works.  I should probably also go pull the
>controller from under the dash and test the ISV, I know that it is
>getting power, but not much else.   One more point, I do get a little
>bit of "dieseling" when I shut down, which according to the manual can
>be caused by a leaking ISV.
>
>thanks for the help
>
>luke
>
>
>---
>Luke Rickert
>www.engr.orst.edu/~rickert
>