Honda D Series Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
119 Posts
Discussion Starter #1
So I'm not sure what's going on. But a few days ago I was getting an ECT code 6 and the Coolant temperature readings was bouncing between the correct temp and then just dropping to 150.

So I checked the connector, the wires looked cracked and eroded. So I reconnected new wires on the pigtail connector.

I even tested my new connector with a multimeter to see the resistance and was working. With an old sensor and a hot cup of water as well with the existing sensor in the car. So I am pretty sure the wiring is ok.

Here is the weird thing, in Neptune when the ignition is on but not running. It's reading fine on the data logger, when I fire it up it seems to be stuck at 150.

I am not sure what's causing this, up until a few days ago was having no issues. And when I was tuning I noticed the ECT was fluctuating.
 

·
Registered
Joined
·
119 Posts
Discussion Starter #2
I should note that the code 6 has gone away but still having these issues.

I'm not sure if it's the sensor, the wiring, the ECU or something in Neptune.
 

·
Registered
Joined
·
119 Posts
Discussion Starter #3
Bump.. Someone MUST have had similar symptoms:

1) In Neptune I can get a perfect reading when ignition is on, but not running.
2) As soon as the engine is fired up, the sensor locks out at 150 with rare and intermittent readings of the proper temp.

Is this a ground or sensor issue? Vibration induced? If it were an ECU ground issue wouldn't other sensors like the IAT/TPS/MAP also be wacked?

Please help.
 

·
Meat Popsicle
91 CRX Si
Joined
·
2,936 Posts
Look at the raw voltage output of that sensor in neptune. If you can, read the voltage directly from the sensor with a voltmeter. These two things should tell you whether or not it's the sensor or neptune.
 

·
Registered
Joined
·
236 Posts
That doesn't work for temp sensors, they are just thermistors and don't have a voltage across them. NepTune only reports the temperature value.
 

·
Registered
Joined
·
119 Posts
Discussion Starter #6
Look at the raw voltage output of that sensor in neptune. If you can, read the voltage directly from the sensor with a voltmeter. These two things should tell you whether or not it's the sensor or neptune.
Basically it is resistance based... 0.01 ohms I believe is hot and as it increases it means its colder. Deducing the actual temperature from that I am not sure how it would be done, software controlled.

I am replacing the ECT sensor soon, maybe that will fix it.
 

·
Registered
Joined
·
5,880 Posts
If key/ignition on says correct temp, but running causes it to randomly work, I would find a way to check any shorts in the system.
Seems you have something that is maybe grazing it with engine virbration.

Perhaps you have a wire that is broken inside, but wire jacket itself looks okay.
 

·
Registered
Joined
·
119 Posts
Discussion Starter #8
If key/ignition on says correct temp, but running causes it to randomly work, I would find a way to check any shorts in the system.
Seems you have something that is maybe grazing it with engine virbration.

Perhaps you have a wire that is broken inside, but wire jacket itself looks okay.
Could be, if replacing the sensor doesn't work I'm going to have to run new wires from the sensor to the ECU, that should fix it unless something inside the ECU itself is pooched.
 
1 - 8 of 8 Posts
Top