Anyone know the correct temp sensor values for 1990 B230FT with LH-Jetronic 2.4 fuel injection? I got the 1990 MOTOR book from the library and it shows 1k at 176F and 10k at 68F. This is considerably different than the 2.2 system which is about 300R at 180F and 2k at 68F.

Thanks, Joe

The values you list from the MOTOR book are for the Motronic ignition system. The resistance versus temperature chart for the LH 2.4 coolant temperature sensor is identical to that for the LH 2.2. The LH 2.4 sensor is actually two parallel sensors in one. One for the LH 2.4, the other for the EZK, with a common internal ground.

2.2 and 2.4 systems are different: this is from the latest unpublished edition of the FAQ:

[Don Foster:] With the control unit connected, connect a voltmeter across LH ECU terminals 13 and 5 (ground), turn

the ignition switch ON.

At 68F (20C) the voltage should be 2.0 +/-.5v volts.

At 104F(40C) the voltage should be 1.2 +/- .3volts

At 176F (80C) the voltage should be .5 +/- .2volts.

The resistance values between pins 13 and 5 or between pins on the sensor are (by eye from the chart):

32F (0C)-- about 6000 ohms within a range of +/- 10%

68F(20C) -- about 2300 ohms "

104F(40C) -- about 1300 ohms "

140F(60C) -- about 600 ohms "

176F(80C) -- about 300 ohms "

212F -- about 190 ohms "

[Response 2: Steve Ringlee] ECT resistance "cold" should be around 6k ohms at 32 degrees F (0 deg

C), 2300 at 68 degrees F (20 C), and 200 at 212 F (100 C). However, try checking your ECT wiring:

Between pins 13 and 5 at the LH ECU (with sensor DISconnected) resistance should be infinite. Voltage

with the ignition ON and sensor connected, measured between pins 13 and 5, should be:

0 C=around 3 volts +/-.5v

20C=around 2 volts +/- .5v

100C=around .3 volt +/- .1v

If these aren't correct, check the connections in the ECT wiring harness. Check engine ground

connections at the intake manifold. If the voltage is zero, your ECU is at fault.

The resistance versus temperature charts for the coolant temperature sensor for the LH 2.2 and LH 2.4 are identical. The only difference between the sensors is the LH 2.2 sensor is a single sensor with its ground connection made to the intake manifold. The LH 2.4 coolant temperature sensor is actually two sensors (one for the LH 2.4 and the other for the EZK ignition) in one unit, both internally grounded. My 90 B230FT is currently running the LH 2.4 sensor on the LH 2.2 system on the 87 745T. I will send you an old e-mail dealing with this. As with the LH 2.2 system; at 14 degrees F, 8,260 to 10,560 ohms; at 68 degrees, 2,280 to 2,720 ohms; at 176 degrees F, 290 to 364 ohms.