Xcal3?
 

Are there any possiblities when using xcal3 canned tunes and a cai of running lean? From 97-03? 04-08?

Lars

Lars, I know your question is really directed at Bill, but don't you think that any tune written for a stock setup is going to have problems when faced with a non-stock intake? There's no way a canned tune programmer can recognize the presence of a "different" MAF sensor environment.

- Jack

Jack that kinda is what I am getting at with this question. That canned tunes no matter who the mfg is cannot account for a cai. Right?

Lars

I honestly can't see how they could, Lars - but, of course, there's only one real expert here, and it's not me. :o

- Jack

Correct, gentlemen. Canned is canned, no matter how you slice 'em.

The only reason I proposed this question is the problems sml175 on f150online was having. Then I asked if he had a cai, the answer was no? Now here's the next one, can a canned tune be to lean? Or be to conservative? Or is there more info that is not forth coming?

Lars

Canned tunes most certainly can be too lean. Obviously, it depends on how the files were tuned. In general, closed loop shouldn't present much of a problem since load is relatively low. Open loop, on the other hand, is where serious damage can occur. If the open loop tables are too lean, bad things happen.

On the other foot, I guess you could make an overly conservative file. We generally call those "Stock" though. ;)

Ok the year of his truck is a 2008. One more variable to throw into the pot.

Lars

Forgive me if I dig into far into proprietary areas. Now, Bill when the developement of canned tunes was done at edge, wasn't their some safety proticals established or parameters? Wouldn't you guys test the extremes either way?

Now wouldn't sct do the samething with the xcal3?
It seems like a stable unit to operate?

Shoot! Another thought. Would a ffv interfere any with the canned tune being lean?

Lars

Yes, when testing vehicles we pushed them to the ragged edge (no pun intended). We know where power can still be made with both aggressive timing and fuel modifications and we always back down a bit to leave room for error.

Many things can affect performance including temperature, humidity, fuel quality, fuel octane, ethanol content, and others... and that's not even getting into the bolt-on stuff.

It has been my experience that SCT and Superchips tend to run a bit more aggressive on their canned tuning, which I believe stems from their desire to have good marketing HP numbers. This means that there is less tolerance for environmental changes or mechanical modifications.

Hope this helps.

I was wondering the same thing when I saw that posted over there. Glad to hear the answer about it from Bill also :thumbs up yellow:

The rest of the story!
 

Like Paul Harvey used to say "and now the rest of the story".

Turns out sml175's problem began at the stock program level added a tuner to make it better???

The stock program was the culprit not the hand held. Kinda felt like Jack and Bill for awhile not getting all the info up front is kinda frustrating.

Lars

It IS frustrating when you're blundering around in the dark, isn't it?

But, all this discussion has brought up a question that has been in the back of my mind for a while. I guess this is to the Mad Doctor too.

If a lean problem is seen in "open loop", i.e., WOT (in most cases), would increasing the WOT fuel have any beneficial effect? I guess what I'm asking here is does an increase in WOT fuel uniformly lower the A/F ratio across the open loop table? Or, does it just somehow make more fuel (if needed) potentially available, maybe at or near max rpm?

Open loop doesn't always have to occur at WOT. There are functions that control open loop based on a number of different factors, most particularly load.

The WOT multiplier controls how far the fuel adjustment can go in order to achieve desired AFR for peak torque. This is more of a limiter in the sense that it won't allow any fuel adjustment beyond a certain point. Outside of that, the main fuel tables are what offer final adjustment of open loop fuel while the MAF sensor provides the air mass values to the PCM so the PCM can have a base to maintain the target AFR of 14.64:1 in closed loop. Short and long term fuel trims take care of everything else.

I knew Open Loop didn't mean just WOT, but I guess I WAS confusing the two when I talked about WOT fuel, wasn't I? Sorry bout that!

Isn't there a limit of some sort on the possible adjustment available in the Closed Loop fuel trims? In other words, if things are badly out of adjustment, it may not be possible to achieve the desired A/F ratio? I seem to remember reading this somewhere.

- Jack

There is an allowable range for the PCM to adjust fuel trims. If trims venture beyond those limits, the CEL sets. In general, it's +/- 25%.