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4KQ Idle Gossip...
As some of you know, I have an '84 4KQ (most problems eliminated...the
fumigator is almost finished). Now here's a new one:
Starting the car cold, the idle is unstabilized. It fluctuates between
650-1000 rpm over an approx. 4-second interval:
vroom......vroom.....vrooom. After the coolant heats up, it stabilizes
and acts like its normal self. During the fluctuating period, if you blip
the throttle, the engine RPMs drop back very quickly and dip well below
1k before the wheezing engine recovers and goes on gasping for breath.
During the normal (non-fluctuating) period, the RPMs are regulated, and
gracefully float back to about 950, never falling below that. I can hear
the ISV doing its thing during this time.
This also occurs for about 30 seconds after you've shut the engine off
while hot and then restarted it. Then it stabilizes again and runs fine.
The car is CIS-E with an ISV and electronically-regulated fuel mixture.
Also, when it is cold, it seems to be running rich. Lots of gas smell
from the tailpipe. What's happened? Is the oxygen sensor gone and the
system having trouble in open-loop mode? Is there some kind of
thermo-time switch on this car that affects the FI system? She...used to
BTW has someone posted a message about how to properly clean the ISV?
Thanks in advance,