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Erratic CLT readings on a new sensor
Posted: Fri Mar 21, 2008 6:17 pm
by yarin
I'm getting very erratic CLT numbers on my air cooled type IV motor. I thought it was the cylinder head temp sensor, so I changed it. Problem still exists. After a certain period of running time, the CLT bounces up and down. Eventually it sits at 180.1F, and occasionally returns. I tested the new sensor off the car, outputs looks good up to 350F. Is there any reason why the reading would drop to exactly 180.1F? This is an issue since at 180F my warm up enrichment kicks in and dumps more fuel in. The sensor is calibrated properly, what could the issue be?
I could try to connect the sensor to the air temp channel, reprogram and see if the channel is bad... any other thoughts?
MS II v.3.0, code ver 2.6
Stock single wire head temp sensor.
Posted: Fri Mar 21, 2008 6:38 pm
by yarin
see .png of megalogviewer. Check the logs, very strange. the signal sits at 180.1 for minutes at a time.
Posted: Sat Mar 22, 2008 5:05 pm
by yarin
Took a look at my thermistor file, appears that there are no entires above 346F in the table. So, any temp above 346 will return 180F as seen in table below. I tried entering in temp values above 300F, but the application won't let me. Any suggestions?
//-- Type = 0 (CTS) --
//-- Bias = 2490.0 --
//-- --
//-- Resistance tInput tComputed --
//-- ------------ ----------------- --------- --
//-- 4179.0 ohm 279.8K ( 44.0F) 44.0 --
//-- 317.0 ohm 355.9K ( 181.0F) 181.0 --
//-- 68.0 ohm 422.0K ( 300.0F) 300.0
#ifndef GCC_BUILD
#pragma ROM_VAR CLT_ROM
#endif
const int cltfactor_table[1024] EEPROM_ATTR = {
// ADC Volts Temp Ohms
1800, // 0 0.00 180.0 0.0
1800, // 1 0.00 180.0 2.4
1800, // 2 0.01 180.0 4.9
1800, // 3 0.01 180.0 7.3
1800, // 4 0.02 180.0 9.8
1800, // 5 0.02 180.0 12.2
1800, // 6 0.03 180.0 14.7
1800, // 7 0.03 180.0 17.2
1800, // 8 0.04 180.0 19.6
1800, // 9 0.04 180.0 22.1
1800, // 10 0.05 180.0 24.6
1800, // 11 0.05 180.0 27.1
1800, // 12 0.06 180.0 29.6
1800, // 13 0.06 180.0 32.0
1800, // 14 0.07 180.0 34.5
1800, // 15 0.07 180.0 37.1
1800, // 16 0.08 180.0 39.6
3460, // 17 0.08 346.0 42.1
3401, // 18 0.09 340.1 44.6
3347, // 19 0.09 334.7 47.1