New feature idea: EGO diagnostic switch

Shad Laws · Post by **Shad Laws** » Mon Feb 04, 2008 11:05 pm

Hello-

Is it possible to make an option in the EGO Control setup that requires one of the digital inputs to be switched for EGO Control to work? In other words, if the signal is one way, continue like normal; but if it's the other, disable EGO Control (and, therefore, Automatic Mixture Control). Here's my thinking...

With EGO control and automatic mixture control, it's pretty important that the oxygen sensor be functioning well. OEMs know this and have a bunch of diagnostics built up to enable the engine to know if the sensor is going bad, and have a mode to run in that doesn't require the sensor (but gets a little worse emissions). Currently, the MegaSquirt has none.

A lot of us use the Innovate LC-1, which has two outputs. We only need one for the signal. The other one can be setup to only put out low voltages during normal operation and 5V if there are errors or during warmup. If this was used as a switch to turn off and on EGO control, then we'd be assured that EGO control wouldn't push the engine the wrong way when the sensor isn't working.

Just a thought

. Whatcha think?

Take care,
Shad

Post by **muythaibxr** » Tue Feb 05, 2008 8:58 am

We don't have automatic mixture control in ms2/extra, so that feature is probably not necessary.

Ken

ptownsin · Post by **ptownsin** » Fri Feb 15, 2008 8:38 am

Shad,

I was thinking along those lines a while back.
As a test I added one of the inputs to the first if statement in ms2_extra_ego.c and as expected I could swich closed loop on and off.

Was that what you meant?

It worked as I had hoped. when in the off position the EGO correction went straight back to 0 in megatune.

Paul.

Shad Laws · Post by **Shad Laws** » Sat Feb 16, 2008 12:03 pm

Hey Paul-

Yep, that's exactly what I was thinking of. I took a peek at the code as you suggested, and you're right: it's not that hard to add the feature. Once I get the newest beta version actually running on my car (right now, only v1.0.2 works), I'll likely add this and see how it goes...

Thanks!

Take care,
Shad

Pimp_daddy_Patty · Post by **Pimp_daddy_Patty** » Sat Feb 16, 2008 5:22 pm

I had a similar problem when my wideband o2 crapped out on me. It defaulted to a 14.7:1 output, but i guess the ms still saw it as .01 too lean and it started running pig rich, to the point where it would stall.