wideband logging

[kevinodb1]

Hi Eds, thanks for the response.

The LM-2 Has two analogue out wires though, Green+ and Yellow- and according to the manual can also be setup as a differential input with an extra earth. 3 different diagrams shown.

When I measured the Green to earth, it was over 7 Volts at 20.9 AFR.

The Green is the one that should be connected to the Grey/Red wire as you have stated, but that is a port expecting to see 5V MAX....

Hence my concern!

Its possible that connecting the Yellow wire to the Ref Ground-the black wire is all that is required, the differential across the two is less than 5 Volts, but I do not know that is correct for sure.

The 3RD Grey wire not being used at all.

The LM-2 has this two wire system, the MTX has a 1 wire system so may be slightly different again.

As Steveo and some others have done it I was hoping one of them could chime in and confirm what to do.

The 92/93 ECM's are very rare now and are expensive so I would rather not damage the input port by making an assumption I am not confident with.

Once its finally working I will post back here for others to know the exact things to do...

Cheers
Kevin

[steveo]

you are overthinking it
+ to + and - to - (- being the ac pressure connector ground)
try measuring with your meter in parallel once it's connected this way and you'll see the voltage normalizes to ~5v when AFR is maxed out

[kevinodb1]

Hi Steveo

Thanks for the reply.

Appreciate it.

Indeed I may be overthinking.....just being cautious! I will hook it up during the week then and report back.

Cheers
Kevin

[kevinodb1]

Ok Folks

I have now got it working, thanks Steveo for your input.

Here are the results for my 1992 Corvette Manual, for a first 3 gears run.

Also included is the wiring diagram and formula for PSI to AFR if your logger cannot be made to adjust from PSI.

Many cheers for the festive season.

Kevin

[Terminal_Crazy]

Fyi the ‘95 z28 has an adder table for the ac pressure.
Even zeroed out, turning the heater to an ac activation causes the iac to open.
I think this could just be response to the vacuum drop from thedoor opening but not certain.
Never found anything that stopped it.

Hth
Mitch