86 5KTQS High Idle Problem (and others)

[Haydn Taylor]

G'Day all

First post to this list and hoping somebody has seen my problem previousely
as it's driving me insane!

I have a 1986 5KTQS that I bought from friends about a year ago, since then
I have been steadily working my way through all of its issues (too many to
list, but getting significantly fewer).


Towards the end of last winter I noticed the idle speed creeping up, then
spring came and the problem seemed to dissapear. As the outside air temp has
begun to decrease again the idle problem has returned. The car now starts up
from cold with a normal(ish) idle of about 1200rpm, as the motor warms this
builds to approx 2000rpm. When I then drive and stop again, the idle is at
about 2200rpm, it then hunts up to approx 2600rpm, then after approx 5
seconds drops back to 2200rpm, this cycle then continues, after a couple of
minutes the idle will sometimes fall back to about 1800.the thing that is
really getting me confused is that if I slip the clutch to bring the engine
down to say 800rpm, sometimes when I fully depress the clutch again the idle
will stay down at 1000, and other times it will go back to it's hunting game
up at 2200.

I have noticed the problem is noticably worse on cold days.

I have also noticed a puff of white smoke on startup that is getting worse,
and a drop in fuel economy - making me think about leaking injectors (I
bought a new set at the weekend but have not fitted them yet)

My only other thoughts for the cause are
A. Oxygen Sensor dying,
B. Temperature sensor somewhere not functioning correctly,
C. Vacuum leak somewhere.

finally the only other thing I have moticed that is odd and sort of relates
to the heater controls. with the heater set to 'econ' the idle is a little
lower (1800 ish), and with it on max, the AC clutch kicks in for about 2
second duration every 10 to 15 seconds, and the idle is even higher.

Any thoughts on this would be greatly apprecated before I start tearing the
thing down again next weekend.

Yours most sincerely

Haydn




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