jarno

Hi all, been a long time since i ever posted anything here. But i have a quick question you fellas might know.

If ego control is turned on in MS/TS but you cut the power to the wideband or cut the signal wire to the ecu. Will the megasquit be so intelligent to resort to soley the map? Or will it try to correct for low signal? (Full rich or full lean, dunno which is which)

Past 10 years ive always used the tuned map because the widebands tend to die ever so often and that makes the car undrivable. Due to an even so slightly drifted fuel map (just some spots in cruise region) id like to drive with ego control on now. If im at an event id like to be able to resort to base map and turn ego control off without a laptop in case the wideband sensor decides to **** the bed.

Kr

Jarno

curly

iTrader: (25)

Unplug it and see what the AFR goes to. Usually it's full rich. On MS3, you can set a min/max AFR, so assuming it goes to 8.X when unplugged, set your min AFR to 9.0 and it won't correct anything richer than 9.0.

On MS2, you're fucked. You'd have to go in and manually disable EGO, it only has coolant min, RPM min, TPS max, and MAP min/max.

jarno

Thanks for your quick reply, that makes total sense, and saves me alot of time messing with the wiring. I have an MS2, and indeed am missing these options. Guess ill just bring the old computer box with me on events then i guess.

sixshooter

iTrader: (12)

I don't trust the sensors not to die and lean out the mixture. Once the car is tuned I don't even need the sensor. I never used the EGO adjusting feature for those reasons.

jarno

ye so thats what i did last 10 years, been tuned several times but experimenting with EGO on got me to notice that cruising (up to 0.65kpa) the AFRs are way better with EGO control on. Differences are probably non-significant, but as my tune drifted a little bit (only on the lower kpa) EGO on is better for me at this point then off, getting a retune at this point is also not worth the money (had one 5 months ago).


Something that got me thinking for MS2 users. Rather then driving home when you are in a pickle with a bogging car due to a dead wideband. Its probably better to unplug the coolant temp sensor. the car will go full rich (WUE). And will turn the ego control off, as you are fooling the MS to thinking the car is not up to temp. Assuming the MS will go to max cold on sensor reading when unplugged.
That got me thinking again. What if you set a 0 degree kelvin setting in WUE to have 100% WUE which will in turn turn off you EGO as it doesnt work up to X coolant temp but the WUE will be 0.

In any case it should be possible to fab some dummy sensor to put on the coolant temp sensor plug tricking the ecu in thinking its at a certain temperature. Where ego control is not active. I might test this and let you know.
Example: Ego control starts at 80degree, WUE ends at 70 degree. If you match the resistance of the sensor to what it is at 75 degree and put that in a dummy. You have no WUE and No EGO control without needing a laptop lol.

None of this is tested, its purely a hypotheses at this point.

douginjenison

iTrader: (1)

Interesting idea, thats pretty creative! How much do you have Ego authority set to for various kpa's? I have zero exp w MS2, and a different ecu- but i love having ego on full time. I do have a gauge with trim% tho too. Do you just keep a spare o2 sensor with you? Or do you get a slowly drifting o2 thats hard to notice?

jarno

I have the auth set relatively high at 15% mainly because ms2 for some reason has very hard times with afrs at idle. I used to only use ego control for idle. No i dont keep a spare, when they go they realy go, they start jumping from full lean to full rich in an instant when just cruising on the highway. I think i have a video somewhere

jarno

Found it

curly

iTrader: (25)

You could also say that it would save you from a lean condition if some other system failed, like injectors or fuel pump.

If your wideband is failing frequently enough to warrant not using it, it's either an install or hardware issue.

Edit: To back this up, I've tuned enduro miatas, looked at logs of "pro" tuners on motecs and others, and oh, every single OE car that tracks, none of them disable widebands on track.

jarno

Up to what kPa level do you normally recommend set the ego control to be on?

Fireindc

iTrader: (13)

I think in the days of ms1/ms2 it was pretty common to not use EGO at WOT for the reasons Six mentioned. However, in the days of ms3 (or better) you get an EGO authority table, and you can give it substantially less authority under WOT and high load areas so even if something goes haywire it couldn't lean things out too much.

curly

iTrader: (25)

Yup, what he said. I usually give it +5% fuel control above 5psi of boost, maybe a little less in the negative, like -3%. Ms2 is frustrating that it’s +\- a single number for any map level unless you turn it off completely above a certain MAP.

I also enjoy using Link’s long term trim table, which looks at constant EGO control and starts adding it into the
“permanent” long term table like any modern OBD2 car. You can then go through and multiply the main fuel table by the LTT table, eventually leaving you with a “perfect” fuel table that EGO only does minor corrections to.

jarno

Maybe the big conclusion i draw from this post is that i should upgrade ecu after 10 years of MS2

curly

iTrader: (25)

MS2 was actually released in 2005, 19 years ago. Although the pnp unit you probably have wasn't released until ~2012(?)

source: https://en.wikipedia.org/wiki/MegaSquirt

jarno

Very well possible, bought mine in 2014. Got the pnp mslabs unit from Reverant