[guillotineFI]

Anyone using Innovate LM-2 with RPM signal from Coil?
I'm getting good AFR data. But the RPM signal is not good - working ok at lower RPMs and cruising - then cutting out at high RPMs and then back in intermittently. It would be great to get good clean RPM data!
Has anyone had experience with it?

 

[alfaparticle]

I have experience with cleaning up the coil signal to work with a Zeitroniox ZT-2. Tach filter for Zeitronix ZT2

 

[guillotineFI]

Thanks Ed!
I do remember seeing this, and was looking for it this morning, but couldn't find it.
I'm imagining it's a similar issue with the "dirty" signal from the ignition.
I'm not much with electronics. But, I can follow your diagram if I can find the parts. I'll start looking for the parts and give it a try.

 

[alfaparticle]

I can build you one. I think that I have all of the parts on hand.
PM or email me.

 

[guillotineFI]

That would be awesome!

 

[FlyingBanana]

This seems to be a commercial version of the circuitry Ed has built (i.e. a signal conditioner) Tachometer signal conditioner -559- GBP35.00

 

[alfaparticle]

It is fancier than mine as it appears to use active devices. Mine is passive with just 3 wires. I played around with active circuits and never got them to work consistently but in retrospect it may have been due to incorrect grounding. I probably still have one or two lying around but the simple one now works well.

 

[guillotineFI]

I saw another one as well: Tachometer Signal Filter
But, there is not a lot of information on it from the supplier, and I don't know much about electronics to know myself if it could cause harm to the LM-2 if connected. The fact that it draws on a power supply, rather than being passive, left me unsure about it??

It looks like there are two versions, the one above and an HEI version: HEI Tachometer Signal Filter

 

[alfaparticle]

My circuit has a zener diode to protect against damaging voltages but I would not recommend connecting anything to the coil of a CD ignition. I wonder how they define "High Energy Ignition"

 

[guillotineFI]

Hey Ed,
I'm running a 123 Distributor with MSD Blaster 8222 0.7 Ohm Coil with 0.6 Ohm Ballast resistor. This should be ok with your circuit right? I think it's similar to your ignition, but with LM2 instead Zeitronix AFR.

 

[alfaparticle]

Hey Ed,
I'm running a 123 Distributor with MSD Blaster 8222 0.7 Ohm Coil with 0.6 Ohm Ballast resistor. This should be ok with your circuit right? I think it's similar to your ignition, but with LM2 instead Zeitronix AFR.

Exactly right. Just make sure that you ground it to the engine.

 

[guillotineFI]

Exactly right. Just make sure that you ground it to the engine.

Yes. I did already connect the LM2 ground to the engine - at the front cover near the distributor. I'll use the same location for the ground to the filter.