How to properly wire the LM-2 to MPVI Pro

Anyone who has the LM-2, knows that it is a pain for getting it to work with HPT. The voltage floats all over the place, and never stays the same. Other times it will vary with respect to lambda, creating a non-linear output that you can't correct for.

Well, there is a solution to this problem that I've been using for a while; ground the output.
This works, because with the LM-2, Innovate made the unit able to output differential signals. Due to the nature of this design, the negative side of the output is not grounded within the unit, even when ground is the reference. By correcting this externally, we get rid of the float.

When you hook up your LM-2 to the MPVI, hook it up as follows;
Pin 1 on EIO - lime green (analog1+) of LM-2
Pin 5 on EIO - yellow (analog1-) of LM-2 AND to a good ground source.

http://www.hptuners.com/forum/attach...1&d=1272039555

Now, what I have done on my personal unit; I opened up the power plug-in, and soldered a 22ga wire from to the ground side, and ran it to the interface. I feel this is the optimal location to ground to as the LM-2 is grounded at this source, so the output signal should be as well.... plus it's easy to disconnect.

Note, that this fix might work for other widebands that seem to be floating, as well. Make sure to verify before tying this, that the negative signal of your system can be grounded without damaging the wideband unit.

I use an LC-1, and I have mine wired so that the ground for the main power source is also connected to the signal ground (and consequently pin 5 on the interface). I never have float or inconsistency from vehicle to vehicle. I also pull power straight from the battery.

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Originally Posted by DSteck

I use an LC-1, and I have mine wired so that the ground for the main power source is also connected to the signal ground (and consequently pin 5 on the interface). I never have float or inconsistency from vehicle to vehicle. I also pull power straight from the battery.

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My LC-1 is also wired that way.
The thing about the LC-1, is that it is internally referenced grounded... so there usually is no worry about it floating around on you.
Most issues with that system, come from bad grounds, or bad power sources.

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Originally Posted by omega_5

My LC-1 is also wired that way.
The thing about the LC-1, is that it is internally referenced grounded... so there usually is no worry about it floating around on you.
Most issues with that system, come from bad grounds, or bad power sources.

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I'll have to try this - mine has nasty float. Tightening up the AFR range helped - and I'd be happy with my LM-2 if this corrected it.

So let me get this straight, you want to ground the analog 1 - wire from the wideband with the ground going to pin 5 on mpvi pro? Does this also apply to the lc1? If so maybe that is why my hp tuners readings always vary from the lc1 gauge readings. I currently only have the 1 wire going to input 1 from my lc-1

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Originally Posted by TheBuMan78

So let me get this straight, you want to ground the analog 1 - wire from the wideband with the ground going to pin 5 on mpvi pro? Does this also apply to the lc1? If so maybe that is why my hp tuners readings always vary from the lc1 gauge readings. I currently only have the 1 wire going to input 1 from my lc-1

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This really only applies to the LM-2, as the LC-1 is internally grounded this way, and only has one output (an analog + wire).
On an LC-1, it is still important to properly ground the device, though.... you will want to wire it with your analog + going to pin 1, and run a good ground to pin 5.

This is enough to make your head spin:confused:

I am new to HP tuners so go slow and use small words, lol.

I have a LC-1 I am trying to hook up for the first time. With all that I have read on here and on Innovate's site, I have 3 grounds for the LC-1, system (white), heater (blue) and analog output (green). I have a 09 G8 so I ran the wires through the firewall and used a mounting stud for the dash to the firewall as a ground for the blue wire and used the stud for the brake booster to the firewall for the green adn white wire. Now I was going to run pin #5 ground to the same location but I'm having second thoughts?????

Should I run the green LC-1 wire to pin #5 adn then run another wire out to the engine compartment and ground it to the neg battery terminal on the drivers fender or should I ground it to a ground wire on the OBD diagnostic port? Where should I ground this wire???????

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Originally Posted by DrBoost

I have a LC-1 I am trying to hook up for the first time. With all that I have read on here and on Innovate's site, I have 3 grounds for the LC-1, system (white), heater (blue) and analog output (green). I have a 09 G8 so I ran the wires through the firewall and used a mounting stud for the dash to the firewall as a ground for the blue wire and used the stud for the brake booster to the firewall for the green adn white wire. Now I was going to run pin #5 ground to the same location but I'm having second thoughts?????

Should I run the green LC-1 wire to pin #5 adn then run another wire out to the engine compartment and ground it to the neg battery terminal on the drivers fender or should I ground it to a ground wire on the OBD diagnostic port? Where should I ground this wire???????

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Right... I forgot that Innovate made a 7-wire LC-1.

For the case of those with this 7-wire system, you would wire it like the LM-2; ground the white, blue and green wire of the LC-1, and pin 5 of the MPVI all at the same position. From there use either the yellow or brown wire with the appropriate MPVI input pin.

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Originally Posted by omega_5

Right... I forgot that Innovate made a 7-wire LC-1.

For the case of those with this 7-wire system, you would wire it like the LM-2; ground the white, blue and green wire of the LC-1, and pin 5 of the MPVI all at the same position. From there use either the yellow or brown wire with the appropriate MPVI input pin.

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Thanks that is exactly what I did. In addition I ran a ground wire from the negative battery lug under the hood which I believe is a ground location for the PCM.

the biggest problem with the Innovate Devices is the Grounding
get your main power and ground from the battery, use a relay to turn on the device when the ignition is on.

Take your analog positive wire to the EIO Pins 1,2,3 or 4
take your analog negative to pin 5 and to the battery ground...

extremely important with innovate devices..take all of the grounds to the main grounding point, even if they have to hit another spot first, run a wire to teh same ground point as the main power source for your device

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Originally Posted by soundengineer

the biggest problem with the Innovate Devices is the Grounding
get your main power and ground from the battery, use a relay to turn on the device when the ignition is on.

Take your analog positive wire to the EIO Pins 1,2,3 or 4
take your analog negative to pin 5 and to the battery ground...

extremely important with innovate devices..take all of the grounds to the main grounding point, even if they have to hit another spot first, run a wire to teh same ground point as the main power source for your device

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I grounded everything to the same spot with the exception of the blue heater wire ground. The LC1 instructions said NOT to ground this wire with the green and yellow to avoid ground interference. Everything seems to working well.

I like to ground everything to the neg bat terminal too. I haven't even seen the battery in my G8 yet I think it is in the trunk somewhere:) I'm pretty sure the ground lug up front is either tied directly to the neg battery terminal OR at lease to the PCM ground. Anyone know for sure?
Thanks for the help.

the innovate guys are idiots when it comes to electrical design...

take my advise.. take ALL grounds to the battery..including the blue heater wire.

remember.. what I do for a living..depends on proper electrical wiring and proper grounding... if I dont ground things properly in my work, people get hurt or even die....

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Originally Posted by soundengineer

the innovate guys are idiots when it comes to electrical design...

take my advise.. take ALL grounds to the battery..including the blue heater wire.

remember.. what I do for a living..depends on proper electrical wiring and proper grounding... if I dont ground things properly in my work, people get hurt or even die....

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I wasn't doubting your advice and appreciate the info. BTW what do you do for a living, sounds interesting?

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Originally Posted by DrBoost

I wasn't doubting your advice and appreciate the info. BTW what do you do for a living, sounds interesting?

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I work on the road as a touring Audio Engineer, RF Engineer and Systems Tech..

which makes me ask what happens if I do NOT GROUND the interface? last time I tried hooking up my LM2, I just hooked up the positive wire, and the + and - without any chassis ground.

Could not get a signal on hptuners, was that my problem?

No ground = no completed circuit = no signal

I wired up my LM2 today. To many FKing wires, but I got it working.
Im not sure if I did it right. I have several wires stuffed into 5 and one in 1

anyone have a good picture

Im a full point off from my LM2 reading and my HPT scanner.

I tried several differant off set voltage, but none many a differance.

How do I get the LM2 and the HPT to match :doh:

wow! i only have the lime green hook to 1 and the yellow to 5 on the EIO interface. i got it to read pretty closes to the LM2 guage. the problem i'm having is in the hundreds it jumps around alot. Example if my guage is reading 14.7 on the LM-2. My scanner would rapidly read something like 14.9-14.5. I am useing the cig. lighter for power and ground. I do compare my STFT to my wideband error % and they are a little off. Example -2 and 2.

Just ordered a new LM-2. Surely there are more people that have it working 100% than just the few in this thread. Really that many issues?

The LM2 manual says to make sure to ground the -