Temp Gauge Accuracy

[Patrick Norris]

I tried searching but there are so many threads with the work temp or coolant it is insane.

I just got a 91 sho and I have been replacing sensors and doing repairs that are long past due from previous owners. But I am still having issues with the coolant gauge. When I got the car it would never move past the blue line so I figured the thermostat was open so I checked and sure enough it was failed open so I changed it. The gauge registers alittle high but not even close to the L. So I searched and found mention to the ECT. I replaced that and it is higher but now only at the L never between the AL. Is this ok? Is the gauge just old or out of calibration or do I still have a problem. Also would air trapped in the system affect the reading because with all the messing around with different things I haven't been able to get the system 100% air free.

 

[advocate]

Turn your EATC off and go for a good drive. I found this same issue that you have even after replacing everything. With the EATC turned off the needle went to half way on the guage. I think it has to do with the auto setting on the EATC - it likes to use the a/c compressor it seems which keeps the needle from moving as the fans would be running all the time keeping the car cool.

I found that leaving the EATC on auto after a run down the track is great for cooling the car down

 

[SHOZ123]

With the EATC in a mode that will use the compressor (any setting but floor or vent) and at speeds under 40 mph and at temps above ~235F the fans will be on.

 

[Patrick Norris]

Turn your EATC off and go for a good drive. I found this same issue that you have even after replacing everything. With the EATC turned off the needle went to half way on the guage. I think it has to do with the auto setting on the EATC - it likes to use the a/c compressor it seems which keeps the needle from moving as the fans would be running all the time keeping the car cool.

I found that leaving the EATC on auto after a run down the track is great for cooling the car down

I don't have eatc and I have had the climate controls on off all week with the same results.

But good tip anyways.

 

[yamahaSHO]

Are you sure you replaced the ECT? Some replace the gauge sensor thinking it is the ECT. The stock guages are not known for being accurate. On mine, the needle points at the "M" when around 210 degrees. I have another temp gauge... After having the seperate gauge and seeing what the stock gauge does... I could trust it... at least mine anyway.

 

[NBSHO]

Hi, For some reason after my trans was rebuilt my temp guage started working better....hmmmmm ???

 

[Axianator]

I'm with Jason on this one. Most of the dash temp gauges are pretty accurate when they have a working sender feeding them voltage and you can reference a specific temperature to a certain point on the gauge.

As for fan kick on temps, the factory setting for the Gen 1 MTX is 216F on and 192F off.

 

[Axianator]

Hi, For some reason after my trans was rebuilt my temp guage started working better....hmmmmm ???

Perhaps your rebuilder routed your tranny cooler lines straight to your external tranny cooler and bypass the radiator completely?

 

[Patrick Norris]

I'm with Jason on this one. Most of the dash temp gauges are pretty accurate when they have a working sender feeding them voltage and you can reference a specific temperature to a certain point on the gauge.

As for fan kick on temps, the factory setting for the Gen 1 MTX is 216F on and 192F off.

Well the gauge is consistant just not as high as everyone says. I was in a drivethru today and the temp was at the L and I heard the fans come on then it went down to just below it. I am thinking it is just out of calibration or I need a new dash sender.

 

[Slo-Sho]

The single wire dash sender is adajacent to the upper radiator hose housing and cost a little over $1 at AZ last time I bought one.

 

[Axianator]

Well the gauge is consistant just not as high as everyone says. I was in a drivethru today and the temp was at the L and I heard the fans come on then it went down to just below it. I am thinking it is just out of calibration or I need a new dash sender.

While it is very well possible that the dash sender may need replacing, don't forget that adding loads to the electrical system can and will affect the reading of your dash temp gauge. Just something to think about.

 

[SHOZ123]

Quite frankly as long as it is working and there is a swing with the temp change what difference does it make. What temp is your L anyway?

 

[Patrick Norris]

Quite frankly as long as it is working and there is a swing with the temp change what difference does it make. What temp is your L anyway?

I don't know how much L is worth. I was going to buy a infared thermometer but they cost too much.

 

[projectSHO89]

I don't know how much L is worth. I was going to buy a infared thermometer but they cost too much.

$59.99 at Sears (price went up $10!). Craftsman Club starts today, so take an extra 10% off.

That little gadget is cool to play with. You will have fun with it if you get one.

http://www.sears.com/sr/javasr/product.do?BV_UseBVCookie=Yes&vertical=TOOL&pid=03482327000

Steve

 

[autobahnsho]

I had no idea what you guys are talking about before last week.

But I had a leak start from the theromstat housing. I struggled w/ broken studs/ retapping, etc.. and got it fixed today.

I unplugged the sensor sender on accident, although I THINK the fans and a/c were still working ok. (I turned the heater on to check because the dash gauge was dead.)

Although I re-used the same t-stat it registers up in the M range, where sometimes it would get in the O range before the fans would kick on. I don't know what is different, but something's changed...

Sorry my rambling here isn't helpful, I have no clue what the point of my post is.