Zazexom

Hi All,
My car failed smog yesterday due to engine running very rich.
It ran fine with power and no black smoke.
But I can smell the fume when at idle..
I am suspecting the coolant sensor?



I have 4 sensors on the thermostat housing.
Which one should I replace ? or just replace all four ?


Thanks.

dolucasi

I doubt it. Measure your duty cycle instead after it warms up, The ECU is probably reporting another fault condition thru the duty cycle.

- Cheers!

Zazexom

IGN ON/ENG OFF
3-2 : 6.1
6-2 : 12.2

ENG COLD
3-2 : 7.0
6-2 : 14.1

ENG HOT
3-2 : 7.0
6-2 : 13.83

ENG REV 2500
6-2 : 13.91
3-2: 7.03

dolucasi

IGN OFF/ENG OFF
3-2 : 6.1
6-2 : 12.2
Dolucasi>> Strike one:This is 50%. It should be 70% (non california, or 85% california cars). I believe this is telling you there is something wrong with the O2 sensor or the wiring to it. Do you have a check engine light on?

ENG COLD
3-2 : 7.0
6-2 : 12.2
Dolucasi>> I believe you have a typo here. 6-2 better be 13.5-14.0V when running cold

ENG HOT
3-2 : 7.0
6-2 : 13.83
Dolucasi>> ECU is just outputting an error code with 50% duty cycle which is again an O2 sensor or wiring error

ENG REV 2500
6-2 : 13.91
3-2: 7.03
Dolucasi>> Same here, the ECU is still outputting an O2 error.

If ignition on/ engine off was outputting 70% or 85% there was an outside chance it could be the temp sensor not letting the ECU know engine reached operating temp but not with the 50% error code in the beginning.

You can measure the temp sensor for resistance for ease of mind but the arrow is pointing in another direction I'm afraid.

- Cheers!

Zazexom

I just recently replaced a brandew O2 sensor.
I will take a look to see if the wire is intact.

Thanks,

Zazexom

BTW which on is the temp sensor ? The orange with two pins ?

Zazexom

ENG COLD
3-2 : 7.0
6-2 : 14.1

Thanks!

dolucasi

Sorry, I can't help you there because I do not have your model or knowledge of your model specifics.

I assume you know how to test the O2 sensor, you should also test that. If it is new definitely check the wiring, particularly if you decided to cut corners and use a universal sensor you had to spice in. but even if it is the model specific sensor there could be something wrong there.

- Cheers!

dolucasi

Great! This looks correct now. - Cheers!