Re: '83 tqc

[Robert Houk - WorkGroup Server Firmware <Robert.Houk@East.Sun.COM>]

   i have been reading the manual for my tqc, and see all of the warnings
   about not letting the coupe idle after it is started.  well, i live in

er, uh, what warnings are these?

You have an actual "manual".

Written documentation?

That's cheating, ya know . . .

   north dakota, and am wondering how good it is to not let it warm up when
   it is 25 below zero.  any suggestions, or experience with this, and what
   i should do about it.

Experience with warming up an UrQ? Yup, I've got that . . .

The basic problem (that *I* have encountered...) is that the warmup
cycle is basically "static" in nature. There is a mechanical fuel
enrichment (pseudo-timed-thermal) via the "Control Pressure Regulator,
and a mechanical quasi-choke (well, more of an anti-choke, actually)
via the "Aux Air Valve" to admit extra air/fuel. Finally there is an
electronic (ECU-controlled) fuel enrichment based on block temperature.

The former two you can sorta tune for one specific "warmup" curve,
hoping it works OK for the rest of the times... What I do on mine is
to crank the aux air valve open all the way for winter usage (seldom
drops below -10F, more commonly +20F), then about halfway closed for
summer usage. By cranking it all the way open, it maximizes cold idle
warm up RPMs, almost running smoothly; drawback is if I immediately
drive off, the engine warms up faster (natch), and there is an interval
(a minute or two) where the idle is way too fast (1400-1600) until the
aux air valve has itself warmed up (and shut off, leaving sole air
control to the throttle valve).

The ECU control (in *my* opinion) behaves wierdly in two regards.
First, it has a radical leaning-out period (around 90F block temp),
which always caused my UrQ to run rough for 15 seconds or so, just
before it goes into full closed-loop operation (substantially worse
with the Schrick cam, which definitely likes a richer cold mixture!)
Second, I think it goes closed-loop just a little too soon. Neither
problem is much of a problem where it doesn't get cold outside (or
inside...), but when it drops substantially below freezing, the
cold-engine warmup charactistics of the stock UrQ are fair to poor...
(as related to letting it "idle" to warm up; if you just get in and
drive off, no problems, other than freezing to death).

I've reprogrammed my ECU to have a slightly higher cold enrichment
level, to not do the radical lean-out cycle, and to extend the warmup
cycle longer (to around 120F block temp, maybe half a minute (?) longer
cycle). In addition, I adjust the static mixture to just slightly
rich (45% Freq Valve duty cycle, fully warmed up), so that the cold-
engine warmup enrichment is slightly richer. Coupled with cranking the
Aux air valve wide open, I have no troubles with engine warmup in the
coldest that New England can throw at the car (well, other than keeping
the **^^&$&ing battery going). Details of my changes are available on
my UrQ page http://www.tiac.net/users/rdh/http/Urq (and note the
capital "U").

Good Luck!

					-RDH