Does the EGO Control make permanent changes to the VE Table?
 

Hey folks,

I've got a quick question about the MSPNP EGO Control.

I understand what the options do (authorization levels, step sizes, etc.) from all the great posts that are here about it, but I haven't actually found anyone talk about what happens once you turn the car off.

I know that the VEAL has the option to update the ECU, save to the ECU, etc.
But is EGO Control a temporary adjustment?

Or does it adjust the values in the VE table if you're running it.

This will be for my MSPNP for my '94 Miata. The VE table is tuned fairly well by hand, and a bit of additional VEAL on it as well.

Just trying to figure out if anything will be updated permanently if I enable EGO Control with my AEM UEGO.

Thanks!

Yes, EGO is temporary. AFAIK, there are no long term fuel trims as seen in OEM cars.

Thanks Deezums. I'll do my best to keep trimming the VE tables then.

it adjusts zero values. it's just part of the fuel equation. permanently enabling EGO is a smart thing.

^^. There is no way to tune everything perfectly open loop, especially at lower fuel loadings. EGO takes care of those ongoing +/- 2% imperfections, sometimes more with things like heat soak.

Hence Closed Loop idle valve control, and, in the case of EGO, Closed Loop AFR.

more like 10-20% imperfections, condition changes, what-have-yous

I may have understated, but I will be really unhappy if, after I go to a return style fueling, I ever need more than 5%. Perhaps I'm setting myself up for disappointment.

Point is, one can chase his tail re-tuning and re-tuning VE and other parameters, never getting things right, or one can use EGO.

I think we agree on concept.

maybe you and dopple can sit in a corner and cry together?

My EGO is set to 10% on down to idle, I hardly ever see more than 95%/105%.

Perfectly possible.

Deezums. Careful. Unless you have left your tune (wrt VE table and such) untouched for a year (cold, hot, winter gas, summer gas) then you cannot make a definitive statement about the full range needed.

Seems like a bit of a stretch for and ECU without LTFT. Plug a scan tool into a car with a factory ECU and higher milage. You may only see STFT of 5% but look at the long term trim. I don't really start looking for issues until LTFT is up over 10%. In general, late 90's through mid (maybe even late) 2000's won't set fuel trim codes until 15+ LTFT.

Early OBD 2 stuff won't set them at 20%. I've seen a '96 Miata with long term maxed out and no codes. (Not that it is right) Maybe it doesn't have the ability to set a fuel trim code?

So in my opinion, if you only have short term trim, I wouldn't worry too much unless it was pegged in all conditions. If it hits 20% in some conditions, who cares? As long as it runs well.

Wait Scott you run 10-20% EGO?

I've been adding crap to my car all year, tuning in between. It's entirely possible I have no idea what I'm talking about.

I'd be wanting a retune if I got much further than 5% out for long periods in logs since EGO don't run all the time. If I'm not mistaken, Scott doesn't/didn't even run it down in idle. If the rest of the map moves, wouldn't idle?

I can peg 110% on a lean hot restart, though. Doesn't hurt to have it if you don't need it.

I sure wish my CANBUS WB02 module would show up. It's hard to talk 5% when you've got more noise than that in logs...

Hot starts seem to be a different animal altogether. I've only tuned with some out of date injectors but never could get hot start where I was happy. We'll see what I can do with the I.D. 725's I just got. I imagine I will tune it a bit rich for normal idle and let ego pull it back (under non-hot start circumstances), so it's not so far off on not starts. Something I've read about recently and makes good sense.

I suspect (or hope) eventually we will have some sort of hot start map or settings to tune that will take care of the lean hot start issues that some are plague with.

I still suspect OE ecu's are using something for hot starts, just never heard an explanation of what it is.

I slowly rev mine to 3K or so and hold for a sec once the wideband warms up, it seems to balance it right out. I've increased my warm crank and start PW as well, increased the decay a bit so it naturally revs a little longer.

The only problem I have with tuning a rich idle is I'd always stink rich coming to a stoplight or stop sign, which I really didn't care for. EGO is disabled after overrun, and then you have to wait for those steps to correct it back again. It seemed I was trading more time running incorrectly than just limping it off the hot restart.

Hmmm. Good info. Just more for me to try. Props given.

I believe I gave it 15% authority. But never at WOT in boost. Just up to about 5psi or so, so that closed loop was still active in normal driving situations.

if your fuel map is tuned well, who cares how much authority you give it? it helps in those situations where it may need to go above 5%. like a really hot day, or really cold morning and your MAT corrections table isn't tuned well, or you have a slight vacuum leak, or a returnless system where the fuel gets hot...

Great info people. Thanks!