relation between engine temp and running rich…

bigcletus94

Registered User
I posted a thread recently about how bad my fuel economy has become and I have a theory about it. Correct me if I am wrong, but the cooler a car runs it also will run much richer, using more gas. With the lower temp thermostat and my adjustable thermostat, the temp needle rarely gets past the C in the gauge.

Also being winter, I am using my heater almost all the time. Doesn't the heater run the fan when it is on too?

My main question is where is a good position on the gauge for the needle to rest at? Or better yet, at what point on the gauge does the temperature become dangerous or overheat?

On a side note, can the color of the motor oil determine if the car is running rich? I told my friend that my oil gets black soon after changing it and he said that it is an indication of a rich condition. On my Mustang, the oil stays nice and clean up until I change it. Thanks for any input.
 
I was woundering the same thing my self I have a 180Tsta. and an EEC tuner turning my rad fan on at 190. My car has no cooling problems at all. Now when ever I go WOT my car puts out a black cloud no idea why since the A/F is 12.7:1.
I'm still lost off the reason why it does lets hope we can find out why.
 
my 89 doesnt seem to run rich with 180 thermostat it mostly runs and adjusts from the oxygen sensor, the oxygen sensor has a heater in it . it starts working in about 5 minutes as soon as it reaches 600 degrees i can see it working with my air fuel ratio guage . it may run rich until computer learns to lean it out . it could take a few days for it to adjust and learn new settings but you should have more power too
 
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It might be possible that your running cold enough that you don't get to closed loop. That would explain bad mileage, but I'm not sure where the threshold is.
 
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