Battery voltage low, jagged and falls at WOT

[DonMizzi]

Hi, I would ask for help on the voltage detected from my KPro v4.
It's installed on Civic eg + K20A2 and harness K-Tuned, ECU Pra, KManager 4.1.5

As seen in the chart below, the voltage always fluctuates of about 0.5 volts (the graph is all jagged).
If I use a multimeter on battery (or stereo connector) I do not see these fluctuations.

Also, when car is in full throttle the voltage drops significantly (even in this case other 0.5 volts circa)

Finally, while at the stereo connector there is the same battery voltage (engine on) 14.4 Volt, KPro detects a voltage between 14.0 and 13.6 volts circa (at idle)



I would like to ask a few questions:

- What are the positive and ground pin used from KPro to detect the voltage (ECU PRA)?

- Is it normal the oscillation of 0.5 volts in the logs of the voltage?

- What may be due the drop voltage when going at full throttle?

Thank you very much for helping

[Spunkster]

Without the calibration and datalogs showing the issue it is impossible to speculate what is happening.

[DonMizzi]

Thanks for reply.

I attach calibration and datalog

[Spunkster]

This sounds like a wiring problem that is causing this. Have you contacted the company that made the harness to see if they have any ideas what in the harness may be causing this?

Has the battery been relocated?

You multimeter may not be fast enough to se the voltage changes.

[DonMizzi]

thanks, battery has not been relocated.

I also think is a wiring problem. I'm investigating to find the cause.

So I wanted to know the pin from which the KPro obtained voltage.
Are pin 2-3 for positive and 4-5 for ground in the Connector A?

Also, you confirmed that both the jagged, the voltage difference respect to the stereo connector, and the voltage drop at WOT are not normal.

If anyone has had similar experiences and can indicate me some point of harness to be controlled, I would be grateful

thanks
regards

[Spunkster]

So I wanted to know the pin from which the KPro obtained voltage.
Are pin 2-3 for positive and 4-5 for ground in the Connector A?

That is correct.

[DonMizzi]

One question: can I exclude alternator and battery as causes of the problems?

Or some of my anomalies may also be due to one of these two components?

Thanks

[Spunkster]

I wouldn't rule them out completely, but wiring is the most likely cause.

[DonMizzi]

A little update, I solved fluctuations, changing the source of wideband controller.

Voltage drop at WOT is yet present, but soon, I will check the diameter of the main wire and ground

For source of wideband controller (techedge 2j9), before I used positive and GND of ECU (A2-A4), now I use battery GND and positive from stereo connector, and fluctuation has disappeared.

Why do I say this?

Since I have a problem with the closed loop on PRA (P0132 O2 Sensor voltage high), I would understand if my wideband controller may be defective.

Or if you can suggest something to check on my ECU wiring.

The output of the controller is as follows AFR = (V * 2) + 9, and seems to work well. By measuring with the tester, I have values ranging from 0 to 5 V
Only a note, with 5.0V output, datalog measures 18.8 AFR in Kmanager

thanks
Don

[MarkyMark203]

Did that solve your problem?

Can you provide pictures of where you wired the wife and? 8' also having the same exact issue and recently installed an AEM wideband.

[DonMizzi]

I have yet some strange behaviour.

This winter I'll try to check my wirings, size and connections

I don't understand what particular problem do you mean, I have more then one problem.
I tried to use always direct GND from chassis for wideband controller

[MarkyMark203]

IMG_1672.JPG

My problem was a bad cabin harness. We rewired the entire car with a new Bussmann fuse box and all new Tefzel wire