Re: HALP!!...(Details for those trying to help me out)...86 GT H20 Temp Low, & Fuel Consumption High--

[jmonetti@us.net (Jonathan Monetti)]

Guys,

I've assembled some of the questions posed regarding my low temp/poor mileage problem in the '86 
CGT...hope this cut&paste helps bring this all together a little better. 

                     ***My answers/remarks/etc. are asterixed

Maybe your "new" thermostat is bad, and your Thermo time switch
really is fine?  THe cold start valve continues to get juice because the car 
really is running way cold.

***Thermostat is opening OK (though I don't know at exactly what temp yet), as the bottom rad 
hose goes very warm/hot to the touch as it should be after the 'stat opens.  

First thing, how are you determining the mpg number you are quoting?

***Like a schmuck, from the trip computer

Second, have you checked the cold start temp sensor?  This is the two-lead
sensor underneath the upper radiator hose where it enters the engine
head.  This may be bad and sending an incorrect "cold running" signal to
the engine control unit.  This will cause the engine to run rich all the
time, producing poor mpg.  

***I checked it with a test lamp, which illuminated when the motor was cranked.  What is the 
correct operation of this sensor?   

Third, have you checked that the idle mixture is set appropriately, and
that your oxygen sensor is functioning?

***No, but will

Are you sure you are running too cool? Do you get good heat from the heater?

***Heater output is just OK, but not *HOT* hot. 

You have already changed most of the cooling system-does the cooling fan ever
come on? (I assume it is not on all the time-that happened to mine when the
fan switch failed.) 

***Cooling fan comes on, yes.  I have read a few posts about the switch being bad, and going 
right to stage three--how do I tell if this is so?  

Make sure the heat range for the radiator cooling fan switch and
thermostat are correct. 

***How? Not sure what is meant here?  

Confirm proper coolant dilution ratio also. 

***Coolant:H20 ratio is correct.  

What is the ambient temp where you are? 

45-50 deg. F day, 20-30 deg. F at night

First you need to confirm that the temp guage is reading correctly... 
they have been known to read bad! 

***VERY EMBARASSING question from me--->...where the Hell is the sensor?  The Bentley, frankly, 
is cryptic and dense.  I simply do not yet have enough time under the hood of this car to know 
what's all what yet.  (Lord, I'm ashamed, and that manual is in NJ!!!)

Now the thermostat.  The biggest thing is making sure its
installed correctly, and its a good German one!

Is installed correctly (arrow pointing down) and is a $25 one straight from the land of beer and 
chocolate ...

Does the radiator fan run long periods of time?

***Depends, what's a long time? Does not run constantly...


THANKS EVERYONE, and thanks in advance for any further advice.  


Jonathan Monetti
'86 Coupe GT, 82k