M278/M157 direct injection tables. Any info, tips

[Globois550]

Looking for some info or pointers on messing with injectors slope, inj pulse multi, opening delay, split injection. If anyone wants to chime in I know it?s hard to get help or information on here.

[outlaw_50]

Looking for some info or pointers on messing with injectors slope, inj pulse multi, opening delay, split injection. If anyone wants to chime in I know it?s hard to get help or information on here.

Inj Pulse Multi - is what you play with for fuel quantity

[chevota]

I'll add a bump for this one because I have the same questions. Like what does Inj Slope do, exactly? Plus all the other stuff Globois asked.
I'd also love to know how the ecu decides how much fuel to add from cold start to closed loop, spark timing too. I can set these to something that should be what I want, or at least not move, but they do whatever they want until closed loop.
Same question for throttle position after start. What decides this because it certainly isn't what I asked.

Fyi I have WinOLS finally, just need to spend a year of my life learning how to use it and start fixing some of this crap.

[chevota]

To answer what I do know, which isn't much, is the Inj Pulse Width seems to merely adjust your fuel trim window. Basically the ECU can only adj by so much so you want to move that adjustment window so it has enough room to adjust for any lean conditions.
Lets say you turned your Inj PW way down and it caused your trims to read +25 & +30 to compensate for it, now you are at your limit and the ecu cannot add more fuel if you go leaner. If you set it so trims are ~0 & 0 then you have equal room available for the ecu to make adjustments, richer or leaner. So regardless of what your trims are, as long as you don't run out of trim you're fine. Most people adjust so it's reading 0 & 0, but mine can't stay on zero to save it's life and will adj from ~ -5 to +20 all the time. You car/ecu probably work normally so you'll have much better luck, but I'd shoot for 0 or neg #'s so you have more room to add fuel should you need it. for example I thought about that with E85. Let's say someone added a full tank of E85 and did nothing to compensate for it. I'd imagine the trims would be way up there in their effort to make it work, which leaves little room for error. If set so you're normally reading -20 or -30 then you have much more room for such an event. I can't imagine an issue where it needs to pull a lot of fuel so running out of -#'s seems harmless.

Mine has gone as far as 25 STFT and 30 LTFT, which for reasons I can't explain, but that's how I know their limits. I've not only hit them, but did so without it actually adding that much more fuel. I think it was adding like 10% more fuel, so either it's hozed or those trim #'s do not represent %, but I'm pretty sure it's just hozed in my car.
Normal driving my trims are all over the place by about 30, so mine will never hover ~0 like people here are able to do, but it is able to adjust it's heart out and so far not run out of adjustment (during normal use), which is all that matters.

The other stuff you asked about I don't know, but would assume split is two pulses of fuel instead of one. Who knows why, maybe simply because they can, but I doubt it helps. I suppose maybe if actuated just right at low rpm it could net better mpg, maybe, and probably net better emissions. A short burn followed by a short burn under light load, or maybe look at as a long flamethrower burn vs a one big fast one, would no doubt keep NOx down? Then I suppose you could run a leaner mix? Just guessing here but that's my guess.
The opening delay seems self explanatory and there will be a perfect opening time for each pulse of fuel, but my guess is it's likely already set to ideal. All I can say is try it and see what happens, but my guess is nothing you can tell and probably there to dial in the best emissions. I'm sure there is an ideal timing to get the best burn, and again best temps for CO & NOx.
Not much help because what you said is true, very little info for Benz, even less for our engines. I've been struggling since February and made over 100 tunes so far. A lot of stuff in the program is incorrect or doesn't work, so throw that in with no info and you have a long road ahead. I believe most people give up and pay someone or do minimal mods and call it good. I'm not wired that way, I see it as a challenge, maybe OCD too, to figure it all out and squeeze out every bit of power. So far it's like deciphering a dead language. I think I could make a dissertation from this experience, even if incorrect nobody could contest it.

[Globois550]

Inj Pulse Multi - is what you play with for fuel quantity

Okay thanks. This is one I?ve had issues with no matter if I add or subtract car seems to run like crap

[Globois550]

To answer what I do know, which isn't much, is the Inj Pulse Width seems to merely adjust your fuel trim window. Basically the ECU can only adj by so much so you want to move that adjustment window so it has enough room to adjust for any lean conditions.
Lets say you turned your Inj PW way down and it caused your trims to read +25 & +30 to compensate for it, now you are at your limit and the ecu cannot add more fuel if you go leaner. If you set it so trims are ~0 & 0 then you have equal room available for the ecu to make adjustments, richer or leaner. So regardless of what your trims are, as long as you don't run out of trim you're fine. Most people adjust so it's reading 0 & 0, but mine can't stay on zero to save it's life and will adj from ~ -5 to +20 all the time. You car/ecu probably work normally so you'll have much better luck, but I'd shoot for 0 or neg #'s so you have more room to add fuel should you need it. for example I thought about that with E85. Let's say someone added a full tank of E85 and did nothing to compensate for it. I'd imagine the trims would be way up there in their effort to make it work, which leaves little room for error. If set so you're normally reading -20 or -30 then you have much more room for such an event. I can't imagine an issue where it needs to pull a lot of fuel so running out of -#'s seems harmless.

Mine has gone as far as 25 STFT and 30 LTFT, which for reasons I can't explain, but that's how I know their limits. I've not only hit them, but did so without it actually adding that much more fuel. I think it was adding like 10% more fuel, so either it's hozed or those trim #'s do not represent %, but I'm pretty sure it's just hozed in my car.
Normal driving my trims are all over the place by about 30, so mine will never hover ~0 like people here are able to do, but it is able to adjust it's heart out and so far not run out of adjustment (during normal use), which is all that matters.

The other stuff you asked about I don't know, but would assume split is two pulses of fuel instead of one. Who knows why, maybe simply because they can, but I doubt it helps. I suppose maybe if actuated just right at low rpm it could net better mpg, maybe, and probably net better emissions. A short burn followed by a short burn under light load, or maybe look at as a long flamethrower burn vs a one big fast one, would no doubt keep NOx down? Then I suppose you could run a leaner mix? Just guessing here but that's my guess.
The opening delay seems self explanatory and there will be a perfect opening time for each pulse of fuel, but my guess is it's likely already set to ideal. All I can say is try it and see what happens, but my guess is nothing you can tell and probably there to dial in the best emissions. I'm sure there is an ideal timing to get the best burn, and again best temps for CO & NOx.
Not much help because what you said is true, very little info for Benz, even less for our engines. I've been struggling since February and made over 100 tunes so far. A lot of stuff in the program is incorrect or doesn't work, so throw that in with no info and you have a long road ahead. I believe most people give up and pay someone or do minimal mods and call it good. I'm not wired that way, I see it as a challenge, maybe OCD too, to figure it all out and squeeze out every bit of power. So far it's like deciphering a dead language. I think I could make a dissertation from this experience, even if incorrect nobody could contest it.

Thanks for that info. It helped much. Right now I?m trying to figure out why I?ve added fuel to the fuel rail and fuel pump but feel no real difference I know there?s one little fuel table I?m missing. It?s just a headache. Like you said I have so many tunes saves and only 1 or 2 is usable

And tbh there?s a lot of info on our cars. Our cars are just a big profit to some people so instead of giving pointers they?ll rather charge ppl a arm and a leg. I seen our engines make very good power with no mods. From what I?ve heard watching a tuner on YouTube, is that there?s even a way to stop peak boost from falling off. But then again there?s no one sharing info. Idk I guess I just have To leave my comfort zone and mess with everything until I see benefits.

I?ll try to share everything I learn and find out about these engines eventually

[chevota]

Post the best tune and a run on it so I can see, and notes on what youre having issues with at what time stamp

[Schnell]

Okay thanks. This is one I?ve had issues with no matter if I add or subtract car seems to run like crap

By how much are you changing the values?

[clifftoo]

I agree with outlaw. I can give some examples of 550 vs 63 vs tuned

[Schnell]

Inj slope changes fuel quantity throughout the operating range; inj pulse multi changes quantity in specific areas. So if your long term trims are 8-12% positive at various engine RPM, you could add 10% to slope and then fine tune with pulse multiplier to get everything near 0. Like a gain and offset... Or you could do it all in the pulse multiplier table. But I think the intended purpose of that table is fine tuning, with inj slope used for coarse tuning.

[Globois550]

By how much are you changing the values?

Not by much being that I wasn?t sure what it did so for an example a cell that is maybe 0.985 I changed to 1.000, my buddy was in the car with me he also felt the power loss mid range.
Not sure if I need to add fuel from somewhere else to compensate or what but it was driving me crazy so now I?m back to stock values
Also wondering if it has something to do with injector slope I notice that the amg tune I?m referencing is .01800000 and mine is at .01546875 not sure if less = more, or more = less

[Globois550]

Inj slope changes fuel quantity throughout the operating range; inj pulse multi changes quantity in specific areas. So if your long term trims are 8-12% positive at various engine RPM, you could add 10% to slope and then fine tune with pulse multiplier to get everything near 0. Like a gain and offset... Or you could do it all in the pulse multiplier table. But I think the intended purpose of that table is fine tuning, with inj slope used for coarse tuning.

I read this after my response thank you this helps a lot. It?s greatly appreciated.

[Schnell]

Not by much being that I wasn?t sure what it did so for an example a cell that is maybe 0.985 I changed to 1.000, my buddy was in the car with me he also felt the power loss mid range.
Not sure if I need to add fuel from somewhere else to compensate or what but it was driving me crazy so now I?m back to stock values
Also wondering if it has something to do with injector slope I notice that the amg tune I?m referencing is .01800000 and mine is at .01546875 not sure if less = more, or more = less

Are you making these adjustments to correct fuel trims?

More = more for both inj slope and the pw multiplier table.

[chevota]

Instead of using the Pulse Width chart to adjust fuel trims from positive trim #'s to 0, I figured I'd try using Inj Slope. What a massive mistake that was!
I read, although hard to find, that lowering the Slope # will increase fuel flow. Apparently the slope # represents what the injector can flow so telling the ecu it flows less, it will increase pulse width to compensate, which is what I wanted. I wanted ~13% more fuel so I changed the slope from the oem 0.01669792, to 0.0147.
I mentioned in a previous post here that 30 was a far as LTFT can go, because in the past both mine went there are stopped. I was wrong. With the 0.0147 slope they went past 60! So I changed the slope # in the other direction to .019 and my trims dropped to ~20. Still not right but substantially better than the 0.0147.
So I re-read what the internet says and again people say you lower the slope # to get more fuel delivered, which lowers positive trim #'s.
Wth?
Fyi I never got the thing to run right with slope tinkering, and the % change to the slope # does not give anything close to what I want in fuel trim adjustment, so I went back to using the pulse width chart and multiplying all the #'s in all the cells x 1.13. So now I'm back to normal. But lets say I did want slope to work, or say I didn't have a pulse width chart to play with? What am I supposed to do?

So in clear English, if the oem slope # is, for example, 0.010, and you set it to 0.011, what happens?
Or if your slope is the same example of 0.010 and your trims consistently read 10, what would you adjust slope to?

I also discovered that when STFT peg at 25 for either too long or maybe by too far, they go to 0 and the car basically loses control of fuel delivery. By that I mean it no longer adjusts to a lambda of 1.00 or whatever and went rich. It still idled fine, but see the attached pix. Note the lambda, ignore the MAP which I made a mistake on when playing with the charts. It's reading MAP minus Ambient. But see the trims & lambda.

LTFT 64.jpg

[Schnell]

So I re-read what the internet says and again people say you lower the slope # to get more fuel delivered, which lowers positive trim #'s.
Wth?

So in clear English, if the oem slope # is, for example, 0.010, and you set it to 0.011, what happens?
Or if your slope is the same example of 0.010 and your trims consistently read 10, what would you adjust slope to?

Increased slope = more fuel.

If you change slope from .010 to .011, you are adding 10% fuel. But remember there is something wrong with your car, so your results may not be the expected results. Also you need to give the car time to adapt when you change fueling, for the trims to settle.

[chevota]

Thanks Schnell I tried it again, put the Inj pulse width to oem and bumped slope by the same %. Fail. Idle was hunting all over the place, stft pegged 25, then zeroed out and went super lean. Sigh... I tried running it and restarting over and over thinking maybe it needed to adapt, but no change. The only difference is this time ltft never compensated. It moved around but stayed + - 5 or so. I went back to pulse width, and a minute in closed loop to adjust and it's back to normal.

[Schnell]

Oh and if your STFT maxed out, you probably have lambda sensor error code(s) which need to be cleared or trims may stay wonky.

[chevota]

I did but they go away on restart.