Krpo BAT voltage issue

[Tehdango]

I want to reference from this post:
viewtopic.php?t=6156&sid=015f5d7dbc4545 ... 5dabe52e5a

You told him to check the voltages from the battery posts to A2 and A4 so thats what I did.

From Battery Pos to A2 = .22
From Battery Neg to A4 = .03

From Battery Pos to A4 = 13.70 Stable
From Battery Neg to A2 = 14 Stable

All readings are stable despite kpro showing from 11/12 to 13.70 erratically.

My BAT seems to be all over the place sometimes down to 11.70 but never goes higher than 13.70. I have test from battery positive post to every ground in my car and they all show 14 volts while running. Please tell me there is something I am missing because this is driving me crazy.

I have included a datalog so you can see how wild my BAT voltage is in kpro.

[Tehdango]

I tested several more times and here are the results

From batt neg to A2 and A3 I get 14
From batt pos to A2 and A3 I get .03

From batt neg to A4 and A5 I get .07
From batt pos to A4 and A5 I get 14

It seems as if the issue is within the ECU or kpro itself. Is there a way I can test inside the ecu for voltage to confirm?

[Spunkster]

You would have to trace through the wiring harness and see where the voltage is dropping.

[Tehdango]

I am testing from the battery to the ECU plugs. There is no drop.

[Tehdango]

If I am testing from the battery to the ecu plugs and it shows the same voltage the alt is putting out does that not mean the ecu is getting full voltage? Also, none of the voltages I have tested are unstable. Why would the kpro show such an unstable voltage reading?

[Spunkster]

Are you measuring with a multimeter that reacts quickly while it is running and seeing these voltage fluctuations?

[Tehdango]

When I measure the ecu pins with my multimeter from the battery I get 14.03/14.02 so it is able to show minor changes quickly. The issue is my multimeter never drops below 14 volts while testing any wire including the ecu plugs but the kpro shows readings from as low as 11.60 to only ever as high as 13.7.

[Tehdango]

Is there other places I should be testing voltages that align with how the kpro reads them?

[Spunkster]

It only reports the voltages it is seeing. Maybe your multimeter does not read fast enough to see them

[Tehdango]

What mulitmeter would I need to satisfy this? I have been dealing with this for years, since day 1 of getting my ecu back and been through several alternators and batteries with absolutely 0 change. I have tested every single piece of wire in my vehicle and they always come back as 14+ volts and extremely stable.

[Tehdango]

Lets say my multimeter is actually not reading fast enough. When I measure the ecu pins with the car off I get 12.5 volts while the kpro shows a stable 11.70 volts. What sense does that make?

[Spunkster]

What aftermarket parts does your vehicle have?

[Tehdango]

Thats a pretty broad question. Anything specific you are thinking?

Its a stock k24 turbo. The main relay is powered with a dedicated line right off the battery with an inline fuse. Its a hybrid racing universal harness. I use an aem 30-4110 O2 and I removed the relay for the OEM O2 in the conversion harness since I don't need to power that plug. I tried plugging the relay back in but it made no difference. I have the aem O2 wired to analog 1. All gauges are powered from their own dedicated circuit. I've gone through great legnth to isolate the power the ecu is getting to ensure its not an issue with the OEM wiring. My fuel pump is also powered by its own dedicated line off the battery with an inline fuse.

The only real aftermarket things I have are the turbo, radiator, TB and a couple sensors like the map and tps.

[Spunkster]

Have you tried your ECU on a known working vehicle?

[Tehdango]

I don't know anyone around me to plug mine into. I'm at the point where I would ship mine to you and when you plug it in to a known working vehicle and mine still doesn't work we can finally move forward. Its been years and I'm not keen on just buying another $1500 ecu to test with.