I have a 89 740 nontubro with a check engine light on, I checked the codes and it saidf that I have a probelm with coolant temp signal I replaced the sensor and the guage and it still g9iving the same code . Place help

 

Did you erase the code?

 

Yes I reset the codes and it it came back on after about 5 minutes

 

Check the wiring harness. It might be falling apart.

 

Will this cause the engine to be hard to start after it warmed up , I have to step on the gas in order to start, once it starts, the car run fine

 

Yes it can cause that as well.

 

This car is driving me up a wall, but I refuse to give up, I just changed the speed sensor for the flywheel, and it ran better for a few days, now it act like the air mass sensor is bad replaced it still the same, now it will start than stall, if I keep trying to start it while pumping the gas paddle it may keep runnig, is this cause by the computer , and the check engine light came back on ( codes 123-224 ) sorry if this a bit much, but I can't afford to take it in to a repair shop

 

Codes are Coolant temp sensor.

How old is the coolant temp sensor?

 

just changed it last week and the check engine came back on

 

What about the wiring harness?

 

It seems to be in tack there are no cracks in the insulation and the connectors seem to be tight, wish I had a wiring diagram or if anyone known where to check on the big plug to the coolant temp sensor, then I could check it with my meter.

 

Look at the color wire at the sensor then trace back to the plug and ohm it and see what happens.

 

Is your car an 8 valve or 16 valve engine? I can get you a schematic but I need to know which engine you have first.

Dale

 

Here's some info that might help concerning the sensor with an 8 valve engine. I'm not sure if the resistance values are different with the 16 valve engine but will certainly look to see if you have that engine. This is the sensor that supplies temp. values to the ECU not the gauge. This sensor is a 2 wire sensor whereas the one supplying values to the gauge is a single wire sensor. From what you've said I'm guessing you replaced the wrong sensor, which is the one that supplies information to the gauge.

Coolant Temperature Sensor


At 14 deg. F. (-10 deg C) 8260 - 10560 ohms

At 32 deg. F. (0 deg. C.) 5800 - 6000 ohms

At 104 deg. F. (40 deg. C.) 1050 - 1200 ohms

At 176 deg. F. (80 deg. C.) 290 - 364 ohms