Author Topic: DynoJet: 800mV voltage drop when Autotune pro plugged in?  (Read 438 times)

0 Members and 1 Guest are viewing this topic.

Online jjdalynh

  • Full Member
  • Posts: 222
  • Country: us
800mV voltage drop when Autotune pro plugged in?
« on: September 05, 2017, 09:10:01 AM »
2003 RG, PV1 connected.  When the autotune pro module is connected engine running the PV is reporting 13.3 V.  Without its 14.1-2 (at idle).  Voltmeter in fairing at battery report 14.1-2 volts with it plugged in also.    Is this cause for concern?   My issue is that when it's not running, the voltage is dropping below 12V and until the o2 are heated and start reading, it's going into the 10s (according to the PV B+ reading).  What's going on here?

Online jjdalynh

  • Full Member
  • Posts: 222
  • Country: us
Re: 800mV voltage drop when Autotune pro plugged in?
« Reply #1 on: September 05, 2017, 01:19:08 PM »
It appears (response from Dynojet) is that there's an expected voltage drop as the AT module draws current for heating the O2 sensors.  Fuel Moto provides a Deutsch Y connector to connect the PV and he AT module to the diagnostic port in order to provide power to the AT.  Looks like I need to make a new connection to the brake light circuit (following the recommendations of DJ), moving to the other circuit allows the ECM to see the full voltage.   Several times I've had programming not start due to low B+ reading at the ECM, and one time had a block program failure.  This should alleviate that issue.

Offline upnorthbiker

  • Full Member
  • Posts: 68
Re: 800mV voltage drop when Autotune pro plugged in?
« Reply #2 on: January 01, 2018, 01:35:27 PM »
Hi, I'm running PV1 with Autotune pro on a 2014 Vrod. I have the Dynojet wiring harness supplied by Dynojet which takes power from the diognostic connector.
I have the bike plugged into a battery tender when parked. Still I se a low volts on the battery display on the PV1 as you did. Occasionally, when I start The bike, it cuts out at the point the Widebands show they are sampling on the PV1 display. Bike starts instantly but then cuts out after a few seconds. If I rev the bike  up it does not stall.
Could this be a similar issue that you had and do you think I should wire a separate power supply, maybe from a spare fuse, to the AT pro box.
I appreciate any input.
Jeff

Online rbabos

  • Full Member
  • Posts: 13243
  • Country: ca
Re: 800mV voltage drop when Autotune pro plugged in?
« Reply #3 on: January 02, 2018, 06:18:12 AM »
My PV1 also shows about .4 volts low in the display and logging on my vrod compared to an actual VOM check, both on Battery or charging volts. Always has since new and never changes. I think I asked once but never got a response as to why.
Ron

Online jjdalynh

  • Full Member
  • Posts: 222
  • Country: us
Re: 800mV voltage drop when Autotune pro plugged in?
« Reply #4 on: June 19, 2018, 10:50:17 AM »
heh, just noticed that this was replied to earlier this year.  i have not made a new connection yet to see if this is a solution.  my PV1 still shows 13.2.  kinda a pain now because i've added an oil cooler which draws some fan power when hot.  i usually only program when the bike is cool and the radio is off (so the map isn't drawing anything either). 

Online jjdalynh

  • Full Member
  • Posts: 222
  • Country: us
Re: 800mV voltage drop when Autotune pro plugged in?
« Reply #5 on: June 21, 2018, 06:38:30 AM »
unplugged the power from the AT Pro module from the Y connector from DJ and connected it to the accessory plug under the seat.  NOTE: YOU NEED TO REPIN THE CONNECTOR FROM THE AT PRO TO PINS 1 FOR THE RED POWER WIRE AND PIN 4 FOR THE BLK GND WIRE!  This will take power from the blue wire on accessory port. 

So, after doing this the battery power was showing 13.5V.  i wasn't hearing the WBO2 circuit (or whatever it is) switching on every few seconds and seeing the B+ voltage on PV dropping as a result. 

BUT!  one troubling thing was that i could now see that the AFR for the rear was reading way lean now!   i'd been making some small changes after dataloging lately using MLV from rides i'd been taking and the rear VE had been trending downwards.  i've bumped them back up down low again and will report back with some datalog results today. 

Online jjdalynh

  • Full Member
  • Posts: 222
  • Country: us
Re: 800mV voltage drop when Autotune pro plugged in?
« Reply #6 on: June 21, 2018, 09:28:49 AM »
looks like a bad O2 sensor.  open air calibration has front at 478.x and rear still bouncing around at 16.x.   swapped and readings follow sensors.  sigh.  wonder how long this has been going on.