Hondata

I was using AEM EMS and a full set of AEM gauges. When I did a kswap on my EG6, I moved to HONDATA KPRO but still have my AEM gauges (fuel press, oil press, oil temp, water temp and UEGO).

Im getting a lot of noise using 0-5v analog output from them to the analog input ports on kpro. Even on ports that Im not using, I can see some voltage fluctuating (0.01-0.03v very fast at kmanager). When I turn off my stock o2 (disconnect cable), the noise seems to be lower (some gauges seems to stop fluctuating voltage at analog inputs). I already changed the 12v input from hybrid-racing conversion cable from ECU to battery.

My question is, AEM gauges have a serial output, can I use all hooked up at digital input in kpro?

tks

Possibly, it depends on the gauge model. Unfortunately AEM does not multiplex the serial streams like PLX, so you're limited to one input as far as I know.

However, if the voltage fluctuation improves without the o2 sensor this is a fairly clear indication that the o2 heater current is moving the ground, so it should be fairly easy to correct by removing and cleaning all the grounds.

I will review all my grounds (trans, head cover and block). Today I did a new one at my block near the alternator. I did one from kpro frame to battery - . All gauges are grounded at battery - and from there to chassis. Its interesting that stock sensors (map, tps, iat) are ok, but analog inputs are fluctuating. Im uploading a simple datalog to show that. Even if I disconnect all inputs, the noise is there...

Do not add extra grounds - they just make ground loops, which makes the problem worse.

Jumper one of the analog inputs straight to the analog ground and see what the noise level is like. If there is still noise then the problem could be the ECU internal power supply or the KPro itself.

I have one in trans, one in head cover. The engine harness is grouding on head cover too.
ok I will do that tonight. The noise should be 0 only on that input or all of them ?

I did the jumper from analog ground to an0 1 2 and so on.... The noise stopped...

You can also use a 1.5V battery to give a signal to try and narrow it down. Also use a multimeter to measure between the battery negative and gauge ground to check for bad grounds.

Will do that.. between AN0 and Analog ground right? I double checked all grounds, seems to be ok. Checked resistance between battery - and chassis, 0.000 ohms. Checked from analog ground and 0.001 . I also tried to check gauges output (0-5v) and voltage seems ok (but I dunno if the multimeter has enough reading velocity to show that noise).

How about adding a ceramic capacitor 0.1uF at AN0 and analog ground ? AN1 and so on.. ?

Measuring resistance is not accurate enough to be useful. You need to measure voltage with the engine running between the battery negative and any other ground. There should be less than 0.01V.

Adding a capacitor will smooth out the inputs.

I added the capacitors between ANx inputs and ground, nothing happens.

My ground at head cover is outputting 0.000v and at my trans 0.016v