bowtieman81

iTrader: (35)

Background story is a I used to have the serial version of HPtuners and used it with success in conjunction with my LC-1 wideband.

Now, I have just upgraded to the MPVI Pro setup. I am having a problem with getting HPtuners to read the correct a/f ratio. I am getting a/f ratios consistently around 16-16.5:1. Now, I did not change any of the setttings in HPtuners, but I went back and checked them anyway. Everything in the scanner was correct. So, I figure it is the LC-1 acting up. I reprogrammed the LC-1, updated the firmware, and even borrowed a different O2 sensor from a friend. Still the same problem.

So, either HPtuners is messed up or the LC-1 is. So I get my trust voltmeter out and investigate. After everything is warmed up, the voltage coming out of the LC-1 is ~3.0 V. My LC-1 is set to read a/f ratios between 10 and 18 on a 0-5V scale. So, a reading of 3.0V at idle is right about where it should be.

Next I hook up the voltmeter to the wires I have running into the cabin. They are reporting the same 3.0V. So, the correct signal is being sent to the EIO. Now, I hook everything up and read the voltage at the EIO. It is reading 3.8-3.9 V

Can anybody help me understand what is going on? I seems I have a voltage offset, but this offset seems massive. I have heard of 0.1 offsets, but not almost 1 V.

Also, this setup is not different at all from before the MPVI upgrade. Before the upgrade I had no voltage offset issue at all.

jimmyblue

iTrader: (11)

First off try looking at the raw voltage of all 4 inputs.
One (not sure which) is the "canned" LM-1 / LC-1 and
the others, if you connect to them, won't work with
the LC-1 selected PID. This isn't especially clear in the
docs but you can probably drill down to it.

Then, just for yucks, put your voltmeter beween the
MPVI-Pro ground screw and the LC-1 ground lead
with them not hooked to each other but operating
normally, independently. The ground difference you
see, may be small or not; if not, you want to tighten
that up.

bowtieman81

iTrader: (35)

Jimmy, thanks for your input. I checked the EIO inputs 1-4 and it got some weird results. When I first checked them all I would get about 2.5 V for all 4. But, after going back a second time and checking them I got about 15 mV on all of them

I am not sure what this means.

I also checked the EIO ground compared to the LC-1 ground as you suggested and saw ~25 mV difference.

Is it possible I have something wrong with my EIO?

Gold Phoenix

iTrader: (1)

Have you recalibrated it lately? I would try that first. I would also check the settings on the controller module of the LC1

bowtieman81

iTrader: (35)

Yep, recalibrated the LC-1. Also checked the settings on it several times. This time the the problem does not lie with the LC-1. How do I know? Well, I hooked my voltmeter up to the leads of the LC-1 outputs (without being plugged into the EIO) and the LC-1 outputs the voltages it is supposed to. My LC-1 is working perfectly. The problem lies in HPtuners EIO some where.

I would post this up on the hptuners forum, but for some reason my account wont allow me to post anything at the moment.

Steel Chicken

iTrader: (3)

The HPTuners scanner needs to be configured to read the voltages correctly. Cant remember how to do it, let me see if I can find the thread.

http://www.hptuners.com/forum/showthread.php?t=5059

http://www.hptuners.com/forum/showthread.php?t=11018