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ECT vs. Temp Guage

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Old Jan 5, 2006 | 10:03 AM
  #1  
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Default ECT vs. Temp Guage

I bought a Diablo programmer and while viewing live data it says my ECT is (example) 170 (have a 160 thermostat installed) however my temp guage in the car says 210.

Is the ECT tied to the coolant temp in the radiator and the cars temp guage tied to the head temp?

Also, when adjusting my setting for the fans on/off is that based on the ECT or the cars temp guage?

I know...alot of questions but this is my first LS1 and and I feel like I'm learning cars all over again
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Old Jan 5, 2006 | 11:04 AM
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The gauge is a hoax, just to make you think you've
got one. It relation to reality is pretty loose.
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Old Jan 5, 2006 | 11:49 AM
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The coolant temp in the PCM (ECT) is what all the pcm parameters are based off of. It should be pretty damn close to the actual engine temp unless there is some fault with the coolant temp sensor.
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Old Jan 5, 2006 | 03:05 PM
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It depends on what year your car is. Only 1998 Models had a real temp gauge in the gauge cluster, 1999-2002 had what is termed as an Idiot gauge. If functions just like and idiot light, but instead of turning on a light, it moves a needle to three different positions (cold (below 160), warm (range between 170-220), hot (anything over 220)). If you have a newer model, then do not base any temp reading from your gauge cluster, rather use a scanner to check the true temp of the engine ... the ECT is/should be the engine/coolant temp.
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Old Jan 5, 2006 | 03:34 PM
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Originally Posted by Flame Throwing SS
It depends on what year your car is. Only 1998 Models had a real temp gauge in the gauge cluster, 1999-2002 had what is termed as an Idiot gauge. If functions just like and idiot light, but instead of turning on a light, it moves a needle to three different positions (cold (below 160), warm (range between 170-220), hot (anything over 220)). If you have a newer model, then do not base any temp reading from your gauge cluster, rather use a scanner to check the true temp of the engine ... the ECT is/should be the engine/coolant temp.

Could I use the temprature sending unit from a 98 in my 2000 to make the guage work properly or should I just disreguard it all togather and get a aftermarket mechanical guage and hook it up to the head?

BTW thanks everyone for your help...
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Old Jan 5, 2006 | 03:52 PM
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nope...

98s = 3 wire temp sensor... 1 to PCM, other direct to gauge
99+= 2 wire.. no wire to gauge ... it's accurate to the PCM (if you use a data scanner it's accurate) but it gets dummied down somewhere between the PCM and the needle

if you want an accurate temp gauge that bad, easiest would prolly be to install an autometer coolant temp gauge... I think you can install it on the passenger side head (both heads have a spot for a temp sender I believe)
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Old Jan 5, 2006 | 04:02 PM
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Originally Posted by horist
nope...

98s = 3 wire temp sensor... 1 to PCM, other direct to gauge
99+= 2 wire.. no wire to gauge ... it's accurate to the PCM (if you use a data scanner it's accurate) but it gets dummied down somewhere between the PCM and the needle

if you want an accurate temp gauge that bad, easiest would prolly be to install an autometer coolant temp gauge... I think you can install it on the passenger side head (both heads have a spot for a temp sender I believe)

So is it correct to say that the head temp is the same as the ECT? Sorry, a bit old school here and I like to know whats goin on with the motor. Is the same true for the oil pressure guage (that it is a dummy guage as well)?
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Old Jan 5, 2006 | 04:15 PM
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oil pressure is a real gauge... on F-Body's there's no PCM feed... it goes straight to the gauge cluster

I think that the coolant sensor plugs into one of the cooling passages in the head ... so it measures the Engine Coolant Temp not necessarily the cylinder head temperature
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Old Jan 5, 2006 | 04:21 PM
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Perfect, thanks again for your help...
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Old Jan 6, 2006 | 02:52 AM
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See this link for sample schematic diagram showing temp and oil guages:
https://ls1tech.com/forums/showthrea...ighlight=gauge
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