RE: 86 4ksq rev limiter

["Buchholz, Steven" <Steven.Buchholz@kla-tencor.com>]

>
>   after following the threads for a bit i understand that 
> there is also
> a sensor for coolant
>  mixture...could this be the cause????

... if the light flashes after the car is started, then yes, your coolant
may be a bit low or the switch in the overflow tank is bad ...
> 
>      next (related?) question:::
>        the car starts instantly and runs smoothly and flawlessly and
> pulls hard until approx.
>     5075 rpm according to the tach. at this point the engine 
> cuts out(it
> is definitely some
>   kind of rev limiter in my opinion/experiences)

... this situation happens more often than I would expect.  It turns out
that the fuel pump relay actually controls the rev limit function.
Unfortunately the fuel pump relay doesn't know whether you have a 4 cylinder
or a 5 cylinder engine, so if someone inadvertently replaced the fuel pump
relay with one from a 4-cyl car, your red line will be reduced to 80%.  If
you take 6500 and multiply by 0.8 you'll find that you get something very
close to 5075 ...

Get a fuel pump relay from a 5-cyl 4000 or Coupe GT and you'll be back up to
the redline you expect ...

>    so many questions.....
>     next::: the console rotary dial for the diff locks: pos #1 light
> comes on (yaayyy!!)
>               how can i tell if diff is ACTUALLY locked ????

If the diff is locked and you make a sharp turn you will know that the diff
is locked!  The rear diff is much more noticeable than the center, but you
should be able to notice each.  

>                          the car idles smoothly at 1000 rpm(should be
> 800) after hooking up
>                          vacuum line,car now idles at 1150 or so.....
>                          idle also seems to vary,sometimes 
> 1150 or 1000
> or 1500 or 900
>                           or etc etc  it can be different 
> every time you
> stop at a light.....

The car has an idle stabilizer valve.  It may be that the one on your car is
sticking a bit and allowing the idle to go a bit high.  Another possibility
is one that I just dealt with on my '85 4kSQ ... and that was that the idle
speed adjust screw in the throttle body was loose (or was loosened by the PO
because the car would stall due to a bad ISV).  I tightened the screw, and
all of a sudden the car would stall sometimes when coming to a stop.
Dropped in another ISV and we're back on the road!

>                                       problem::: clutch engages about
> 1/2 inch off of being buried
>                                                       in the
> carpet!!!!! clutch travel is all over and done
>                                                       in the next 2
> inches......

My suspicion is that a PO got the wrong part for the clutch M/C.  The 4kQ
has a very long arm that reaches from the firewall to the clutch pedal,
while other cars have the M/C mounted inside the car, so they have a much
shorter linkage.  I'd recommend that you see if you can find a similar car
to see if you can see a difference.  I suppose that I could take a picture
of my car with the digital camera if you'd like and e-mail a pix to you if
you thought that would help ...

HTH!
Steve Buchholz
San Jose, CA (USA)