Cooland Temp read "LO" on dash
Thread Starter
Heel & Toe
Joined: Mar 2005
Posts: 18
Likes: 0
Cooland Temp read "LO" on dash
On MY 1992 LT1 my coolant temp was reading 142 on the dash all of the time and I got a code 15 so I changed the coolant temp sensor
. When I changed it I drained the radiator but forgot that it still had antifreeze in the top of block and got it all over the front of the engine bay. Now the dash temp reads "LO" all of the time and the car didn't run for awhile so I let it dry for a few days. Now it still runs very rough and the "LO" temp is still there.
. When I changed it I drained the radiator but forgot that it still had antifreeze in the top of block and got it all over the front of the engine bay. Now the dash temp reads "LO" all of the time and the car didn't run for awhile so I let it dry for a few days. Now it still runs very rough and the "LO" temp is still there.
Race Director
Joined: Apr 2000
Posts: 15,344
Likes: 4,009
From: Texas
Pull the plug from the CTS. Check the terminals for signs of corrosion. Also makes sure the pins on the CTS are ok. Frankly, it sounds like the new CTS is bad which is not an uncommon problem with some of the low cost replacements.
You can also pull the CTS connector off the CTS and see if you get a DTC 14. If you do, then you know the ECM is seeing a signal and the wiring is ok. If you don't get a DTC 14, you may have a wiring issue. Check for 5v at the sensor connector and also verify the ground.
Regarding the rough running....if you poured coolant all over the front of the engine, you also drenched the Optispark. Rough running is a typical symptom. Sometimes if you run the engine long enough, it'll dry out. Other times, if you remove the cap from the Optispark, you can dry it out / clean it up (including the optical sensor itself) and it'll be fine. Other times you have to replace it.
You can also pull the CTS connector off the CTS and see if you get a DTC 14. If you do, then you know the ECM is seeing a signal and the wiring is ok. If you don't get a DTC 14, you may have a wiring issue. Check for 5v at the sensor connector and also verify the ground.
Regarding the rough running....if you poured coolant all over the front of the engine, you also drenched the Optispark. Rough running is a typical symptom. Sometimes if you run the engine long enough, it'll dry out. Other times, if you remove the cap from the Optispark, you can dry it out / clean it up (including the optical sensor itself) and it'll be fine. Other times you have to replace it.
Thread Starter
Heel & Toe
Joined: Mar 2005
Posts: 18
Likes: 0
Pull the plug from the CTS. Check the terminals for signs of corrosion. Also makes sure the pins on the CTS are ok. Frankly, it sounds like the new CTS is bad which is not an uncommon problem with some of the low cost replacements.
You can also pull the CTS connector off the CTS and see if you get a DTC 14. If you do, then you know the ECM is seeing a signal and the wiring is ok. If you don't get a DTC 14, you may have a wiring issue. Check for 5v at the sensor connector and also verify the ground.
Regarding the rough running....if you poured coolant all over the front of the engine, you also drenched the Optispark. Rough running is a typical symptom. Sometimes if you run the engine long enough, it'll dry out. Other times, if you remove the cap from the Optispark, you can dry it out / clean it up (including the optical sensor itself) and it'll be fine. Other times you have to replace it.
You can also pull the CTS connector off the CTS and see if you get a DTC 14. If you do, then you know the ECM is seeing a signal and the wiring is ok. If you don't get a DTC 14, you may have a wiring issue. Check for 5v at the sensor connector and also verify the ground.
Regarding the rough running....if you poured coolant all over the front of the engine, you also drenched the Optispark. Rough running is a typical symptom. Sometimes if you run the engine long enough, it'll dry out. Other times, if you remove the cap from the Optispark, you can dry it out / clean it up (including the optical sensor itself) and it'll be fine. Other times you have to replace it.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
The temperature displayed on the dash comes from a different temperature sensor in the passenger side head between spark plugs #6 and #8.
The CTS on the front of the engine goes to the ECM.
The CTS on the front of the engine goes to the ECM.
