92 300CE-24 high idle issue
03-13-2024, 11:50 PM
#26
Junior Member
Thread Starter
CEL is Check Engine Light. Sometimes referred to O2 sensor signal.
Yeah the O2 sensor output is no good. Change it to see if you can get the expected signal.
If you are still getting timing error from the ECU that is not good.
When you say you are getting a timing error, what is this like. Is that the 16 pin connector diagnostic port?
Can you give details? Is it possible you are misinterpreting this?
- Cheers!
Yeah the O2 sensor output is no good. Change it to see if you can get the expected signal.
If you are still getting timing error from the ECU that is not good.
When you say you are getting a timing error, what is this like. Is that the 16 pin connector diagnostic port?
Can you give details? Is it possible you are misinterpreting this?
- Cheers!
Cheers!
03-14-2024, 12:03 AM
#27
Junior Member
Thread Starter
CPS signal value to CIS ECU
As said, with all the combinations of 2 different MASs, 2 EZLs and 2 CIS ECUs, I kept getting CPS error from the diagnostic port while the techno meter that shares the same signal source is showing the correct rpm. I decided to check if CPS signal is reaching the CIS ECU. I disconnected the ECU and started the engine, measured the AC voltage signal between pin 27 and ground. The result is shown in the following Youtube video. Seems that CPS signal is being relayed to ECU through the EZL and the MAS. However, I wonder if the signal value is proper
Cheers!
Cheers!
03-14-2024, 12:07 PM
#28
Super Member
Your Fluke meter has Hz/Duty cycle capability. Can you also take a video of that signal in duty cycle and Hz mode.
It should be an even fraction or multiple of your engine speed and not jump around.
With the primitive OBD signals of the time, the ECU generally has a set range it expects for any monitoring signal like this.
So for this signal I assume if the frequency is less than or more than a set window for a certain period of time it will throw an error code.
This is the case for temp sensors, altimeters, TPS, AFM pot, etc, etc. I assume it is the same for the CPS unless......
In the early models the Crank Position Sensor and and the CAM position sensor sensors are NOT compared to each other.
In an '89 model for example the CAM position sensor does not go the the EZL or ECU, it is just dangling for a mechanic to diagnose with equipment.
How is this in your model year? Does the CAM position sensor go anywhere other than the X11 socket?
It should be an even fraction or multiple of your engine speed and not jump around.
With the primitive OBD signals of the time, the ECU generally has a set range it expects for any monitoring signal like this.
So for this signal I assume if the frequency is less than or more than a set window for a certain period of time it will throw an error code.
This is the case for temp sensors, altimeters, TPS, AFM pot, etc, etc. I assume it is the same for the CPS unless......
In the early models the Crank Position Sensor and and the CAM position sensor sensors are NOT compared to each other.
In an '89 model for example the CAM position sensor does not go the the EZL or ECU, it is just dangling for a mechanic to diagnose with equipment.
How is this in your model year? Does the CAM position sensor go anywhere other than the X11 socket?
03-16-2024, 11:28 PM
#29
Junior Member
Thread Starter
Your Fluke meter has Hz/Duty cycle capability. Can you also take a video of that signal in duty cycle and Hz mode.
It should be an even fraction or multiple of your engine speed and not jump around.
With the primitive OBD signals of the time, the ECU generally has a set range it expects for any monitoring signal like this.
So for this signal I assume if the frequency is less than or more than a set window for a certain period of time it will throw an error code.
This is the case for temp sensors, altimeters, TPS, AFM pot, etc, etc. I assume it is the same for the CPS unless......
In the early models the Crank Position Sensor and and the CAM position sensor sensors are NOT compared to each other.
In an '89 model for example the CAM position sensor does not go the the EZL or ECU, it is just dangling for a mechanic to diagnose with equipment.
How is this in your model year? Does the CAM position sensor go anywhere other than the X11 socket?
The cam sensor also sends signal to the EZL. I checked the continuity between it and the EZL, continuity is fine and the sensor is a new one too.
It should be an even fraction or multiple of your engine speed and not jump around.
With the primitive OBD signals of the time, the ECU generally has a set range it expects for any monitoring signal like this.
So for this signal I assume if the frequency is less than or more than a set window for a certain period of time it will throw an error code.
This is the case for temp sensors, altimeters, TPS, AFM pot, etc, etc. I assume it is the same for the CPS unless......
In the early models the Crank Position Sensor and and the CAM position sensor sensors are NOT compared to each other.
In an '89 model for example the CAM position sensor does not go the the EZL or ECU, it is just dangling for a mechanic to diagnose with equipment.
How is this in your model year? Does the CAM position sensor go anywhere other than the X11 socket?
The cam sensor also sends signal to the EZL. I checked the continuity between it and the EZL, continuity is fine and the sensor is a new one too.
Cheers!
03-17-2024, 03:35 AM
#30
Super Member
OK, so your EZL receives both the CPS and the CAM sensor and you measured both for resistance value I assume.
How do you believe a CPS or CAM sensor error makes it way to the ECU from the EZL?
How do you believe a CPS or CAM sensor error makes it way to the ECU from the EZL?
05-24-2024, 11:45 AM
#31
Super Member
Seems you carried this diagnosys over the BW forum. I refuse to participate there any longer even though I used to be a moderator.
I would look into your knock sensor next instead of going around in circles with all the things you have already diagnosed. I think it has been a few weeks since you moved over there.
Since the knock sensor has something to do with timing there is a good chance it maybe at fault.
I know next to nothing about how the knock sensors work but read up on that.
- Cheers!
I would look into your knock sensor next instead of going around in circles with all the things you have already diagnosed. I think it has been a few weeks since you moved over there.
Since the knock sensor has something to do with timing there is a good chance it maybe at fault.
I know next to nothing about how the knock sensors work but read up on that.
- Cheers!
