ok i know this has been covered from many diff areas but i havent found anything like this. i have recently put an obd 1 h22 in a 94 accord lx. everything is fine except something is screwy with the ECT sensor. when hooked to the scanner the temp says 246 always even when the car is stone cold. as you can imagine this makes the cold start bad. it runs rough until it warms up. i cannot figure out why its stuck at 246. i tried new sensors, bled the cooling system and checked all of my wiring. everything is ok. there is also no check engine light either. i read the voltage from the IAT and ECT sensors on the scanner should match but they dont. the IAT is 3.08 volts which is in spec but the ECT is .08 volts meaning it thinks its hot. if anyone can help it would be great ive been searching all day. thanks

 

oh yeah the gauge is working properly too.

 

anyone? heh i got one upset customer

 

bump

 

Try disconnecting the sensor and check if you get a check engine light. If you don't then you probably have a short in the signal wire.

brian g

 

thanks a lot man ill give it a try

 

Also there are 2 sensors for Coolant Temp....one goes to the guage other goes to the ECU....so just cuz the guage reads right doesn't mean the ECU will be seeing the right voltage.

 

yes it is the two sensor type. i know the ecu is seeing the wrong thing. the ecu sees 246 constantly. i was just saying that the gauge is working fine

 

now if i unplug any connector it doesnt throw a check engine light. for example i unplugged the map sensor which was wiring i didnt touch and it didnt throw a CEL. the same thing with the O2 and ECT. do you think i could have a bad ECU? im not sure but i think its a jdm h22 also if that matters. it came from hmotorsonline.

 

Okay, so check your wiring from the ECU To that sensor, and check that the proper voltage is at the sensor, and that it has teh proper resistance when hot and cold.....

It's all in the factory service manual how to diagnose your problem...I suggest you pick one up.

 

Is there a bulb in the instrument cluster for the MIL? Does it come on when you first turn the ignition on?

brian g

 

Did you switch the two wires at A6 and A11? These are not related to TA sensor, but they are related to rough idle. What wires did you add to your harness?

brian g

 

hey i figured it out. it turns out i had the plug for the ECT and purge solenoid crossed. they are the same plug unfortunatly. anyway i switched them and it fixed the cold start prob but then created a surge. i played with the idle a little and got it better but every now and then the idle drops to like 200 rpms and almost stalls but then it comes back up and its fine. it also threw an insufficient egr lift code so maybe this has something to do with it. thanks for all of the suggestions. ill keep you posted on when i fix it. thanks a lot

 

Switch the wires that control the O2 heater and the EGR lift solenoid. I believe they are A6 and A11.

brian g

 

already done