> On 11/22/2007 2:46 AM, TE Chea wrote:
> Mine has a manual choke, 1st bought in 12-90.
So, we now know what his car has: a manual choked carburetor with an ECU
that controls the spark advance. Since its now 17 years old, we can assume
there's certainly some wear in the butterfly spindle that's letting air
in.
ie the engine is very likely running lean, hence the combustion
temperature
is elevated. I suppose though that TE Chea will now start complaining that
a
part should not be worn after a mere 17 years...
So, it's not unreasonable to expect that cooling the thermostat region
would
cause the ECU to retard the timing somewhat.
Let's suppose that the hotter lean burn is causing the ECU to set the
timing
at (say) 2 degrees BTDC, whereas the correct fuel-air mix would require
5-8
BTDC, then the engine will not be generating its maximum torque at a given
rev range. Running cooler (or cold) requires a retarded timing setting
from
the ECU, so cooling the thermostat region (and the coolant temperature
sensor) results in the ECU retarding the timing. The question is how far
is
it being retarded. If its back to about 10 BTDC (more or less where it
should be) , then perhaps more torque (or more accurately, the normal
operation torque capability) would be noticed. Reduced exhaust noise?
Excessively retard the timing on any engine and the exhaust noise will
reduce.
Stewart DIBBS
www.pixcl.com/lancerproject
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