LC-2 shared power and ground - noisy?

[turbogrill]

Hi,

 

The new LC-2 wideband controller only have 1 ground instead of 2 (previous had 1 for sensor and 1 for power). They list it as a feature

 

However this feature creates a little headache for me. With my current Megasquirt installation I can't find a good grounding strategy:

 

- Ground at Megasquirt sensor ground. This COULD be a good option but I am not sure how much noise there is on the Wideband ground? It's fine if it's just a constant extra 3A for a few seconds during startup. But if there is a lot of noise here it will mess up everything.

 

- Ground at Megasquirt power ground. The voltage drop over the megasquirt ground cable can be anywhere between 0 - 0.3v depending on injector pulse widths and other stuff. This corresponds to up to 0.5 AFR inaccuracy

 

- Shorten the Megasquirt ground cable. The MS ground cable is now 30 inches, if the above doesn't work I could shorten it.

 

LC-2 manual doesn't say much detail about this. Manual only mentions a 3A current draw and has a simple grounding scheme.

[Eman911]

A couple of Alfa guys have had Megasquirt issues caused by O2 sensor grounds that were not at the same grounding point as the Megasquirt.

[mhr650]

I put a single point ground stud on the ECU mounting plate, you can see it in the first picture. I run a 10 gage wire from the chassis ground and a second 10 gage wire to the engine and then ground everything to the same point. You can see I have 2 LC2 controllers, one for the front rotor and one for the rear rotor, they work great and with Tuner Studio Ultra I could use both sensors to individually auto tune each rotor. I only used the sensor ground for the actual sensors, nothing else.

 

 

 

[turbogrill]

I will probably do something like that. Eliminates any grounding issue I guess!