Re: Fast Idle 87 5ktq

[Kneale Brownson <knotnook@traverse.com>]

When I followed Scott M's advice to replace the switch with the newer
design (using the newer one that had been put on my parts car sometime
back), I got the high idle you describe, Doyt.  I repositioned the switch
slightly a couple times and got to the 750-800 idle.

Kneale Brownson


At 09:21 AM 11/1/99 -0500, Doyt W. Echelberger wrote:
>This 87 5ktq at 160k idles at 2,000 RPMs after warmup. It starts fine,
>idles cold at about 1,200, and then RPMs keep climbing as it warms up.
>When warm, I can turn the idle screw down to 'closed'(from a setting of
>about 1/4 turn) and it doesn't affect anything. 
>
>After it warms up, I can get it to idle at 750 very smoothly by
>disconnecting the electricals of the ISV. It continues to idle at 750 if I
>then reconnect the ISV electricals. This puzzles me and is why I elected to
>post to the list.
>
>The same day this fast idle appeared, I had followed Scott Mockry's advice
>about resoldering the internal connections of my throttle switch. I did the
>work and replaced the switch and set its position by rotating it
>counterclockwise until the microswitch clicked, and then locking it there.
>
>I suspect that the fast idle is a result of the positioning of the throttle
>switch, but I thought I'd confirm this hypothesis by consulting with the
>list before tampering with all those components. Resoldering the throttle
>switch noticeably improved acceleration response, so Scott was right on
>when he said ALL the old throttle switches are probably running with
>fractured and inconsistently working internal connections. One of my
>connections was totally covered with brown crusty stuff, which probably
>indicated longstanding problems. The other 3 looked pretty clean, but I
>resoldered them anyhow.
>
>OK, there it is.  Replies and speculation appreciated. About all I can
>think of is to fiddle with the throttle switch rotation, and clean the ISV.
>
>Doyt Echelberger
>87 5kcstq