60lb Inj. Problem

[dewmanshu]

Also, I noticed that your offset table is straight-lined for the different volt levels.

Yeah Pat, returnless systems need to be scaled. Just like your IFR table. At 58psi these inj flow 72.3, so scale from there IMO.

Here is my take on this.

1) Since no one has nailed these inj settings down yet, there is no "right or wrong" as long as the end result is what you want.

2) If your VE was great before the swap, then you shouldn't necessarily need to mess with your VE after the swap (that much) If you enjoy tuning and messing with shit, try other routes.

3) Being returnless, you can log what vacuum kpa you are at in decel and decrease the backside of the inj offset table to accomplish a more lean decel. Yes, it's cheating, but until someone posts a step by step for the way you really tune these guys, I am game for whatever works. (I don't do this, but I have tried it to experiment, worked fine besides they "gray area" between no throttle and throttle)

as redhardsupra knows justin, he's been working on calcs to get the number right, I believe for a whle he was sold (thru calcs) that somewhere in the neighborhood of .53 ( maybe a touch less) was working the best for the offset somewhere near the 13.5 volt row.

I use .48 @ 14volts, .53 @ 13.5volts, .56 @ 13.0volts (I am a return system). I wiped out my pulse adder as well. Yeah I know , I was just experimenting. I actually never finished tuning mine, I had everything working great besides a rich idle (I am dead set against fixing it with the VE) but I have to get thru emissions so I am back in closed loop for now. Which btw, 14.68 all the time now. LMAO, just -10% Idle trims, lol.

[ssnipes]

Here's what I got from the cobaltss.net forums:

"Minimum Pulsewidth - the time it takes the injector to complete one complete cycle to turn on and turn off.
so, 1.14ms + 0.85ms = 1.99ms"

There is also some info there that says the jmin pulsewidt should be around 1.1 for these injectors and the adder used to "progressively ramp off pulse width at a slower pace". I beleave he was actually referring to the short pulse as opposed to the min pw, but I have a PM in to him for clarification.

Also, I noticed that your offset table is straight-lined for the different volt levels. Most that I have seen are done a bit differently. Sorry I cannot give you better info than that, but I am working on it. If I have to take them in for flowtesting and get the numbers that way, I will. I should get them in the mail this week...

SJSchafer and I have been talking about this stuff on another forum. I just tuned into here now. I did exactly what was posted here. problem I ran in to was I was way rich with this setup at 28Map from idle upto 3200RPM (just sitting and revving up motor). after having no or Zero success adjusting VE table it was found that the minimum PW was the problem along with the adder. I set the adder to 0 across the whole table and set the minimum pulse width to GM default of 0.094. then the changes to VE table took effect and the lowest pulse width I saw was 0.9. THis is on the 2.0l LSJ engine found in our COBALT SS supercharged.

hope that helps out.

[ssnipes]

I use .48 @ 14volts, .53 @ 13.5volts, .56 @ 13.0volts (I am a return system). I wiped out my pulse adder as well. Yeah I know , I was just experimenting. I actually never finished tuning mine, I had everything working great besides a rich idle (I am dead set against fixing it with the VE) but I have to get thru emissions so I am back in closed loop for now. Which btw, 14.68 all the time now. LMAO, just -10% Idle trims, lol.

Well I am not wanting this to sound like I am knowledgeable in tuning. I am a beginner tuner. I am just trying to understand your point of view.

Why would you be dead set against changing ve for idle? I have be shown and taught the point of tuning a car is to take the generic tune and get it running better. VETune is necessary to do this. every car will be different. because of the different flow rate of injectors dictates this as well. when you get a matched set of injectors and compare to the exact same product (matched flowed as well) they will be different. Yamaha actually is a good example. they had production tunes according to coded injectors. meaning a tune for yellow injectors, different for red, and again different for green. the matched set was coded according to their specific flow rate. if they fell into a category then these were coded accordingly to get the right tune. What you propose maybe done and would be very cool if you could just do it that way. I would be surprised if you can. either way I am coming up with 14.7 which is the goal. But do tell me more. I am listening. (and not criticizing as I believe there is always more than one way to skin a cat.

[dewmanshu]

I tuned it pretty well on the 42's. Damn well as a matter of fact. I am a "novice" tuner (if that, a "tuner") myself, I unfortunately don't have enough "working knowledge" of the lsx motor, or engine mechanics for that matter. So I am super handicapped. But, it doesn't make much sense to me to change an airflow table that was setup pretty tight (+/- 3 at its worse) just because i changed the injectors. I also said above "(that much)", meaning you'll need to obviously finess in the injectors in some areas, like idle as far as VE goes. I mean if you did mess with VE only, you'd have HUGE decline into idle or incline into the next rpm column. Just doesn't seem effiecient to me. I may be wrong, I only tune my ride a maybe help a few others, so I don't have anywhere near the experience as a lot of you. Just my take, if I ever find real time to mess with them, I'd like to do so through injector tables, not airflow.

(and not criticizing as I believe there is always more than one way to skin a cat)

It's all good, as said, I can use some criticizing, I have no clue what I am doing sometimes. That's the whole fun of it IMO. I've been chasing idling issues on my ride for a year. Found a wire that was burnt last night. Imagine that, a whole year of trying to tune an idle issue, and all it was (or appears) was a f-ing burnt IAC and TPS wire hidden in some wire loom. Ugh.

[dewmanshu]

SJSchafer and I have been talking about this stuff on another forum. I just tuned into here now. I did exactly what was posted here. problem I ran in to was I was way rich with this setup at 28Map from idle upto 3200RPM (just sitting and revving up motor). after having no or Zero success adjusting VE table it was found that the minimum PW was the problem along with the adder. I set the adder to 0 across the whole table and set the minimum pulse width to GM default of 0.094. then the changes to VE table took effect and the lowest pulse width I saw was 0.9. THis is on the 2.0l LSJ engine found in our COBALT SS supercharged.

hope that helps out.

this should help a ton. VE edits (subtracting value) have no effect if you're injectors are just commanded to stay open to much in other tables.

[redhardsupra]

if there was such a thing as tuning commandments, one of them would be 'thou shall not tune a fuel problem with air or spark' (or any other combination of this holy tuning trinity

if you had VE working perfect with a set of injectors for which you have all the data (aka stock), then changing injecotrs should not affect VE. if your new injectors/tuning data changes the behavior, your data are either incomplete or incorrect.

racetronix data seem to have some problems (decimal points in wrong places, wrong units, etc) so don't believe them 100% either.

[03Sierraslt]

Ok here is a copy of a tune with a modified offset table, I guess I messed up and didnt scale mine on a slope like I should have for my fuel system. My AFR has been coming in line fairly good but something still seemed out of whack so to speak. Maybe this will help. Here is the tune tell me what you think.

Dewey what can I do now with my rich decel, I am not sure I follow you. Idle MAP is like 38-40.8kpa and decel it drops into the teens. I see low 11's afr on decel.

[03Sierraslt]

Whoops forgot the tune.

[03Sierraslt]

Does anyone have a good short pulse limit for these? Mine has 3.9 as a short pulse but I see allot of the cobalt guys have 2.0? How do I determine this?

[dewmanshu]

Good luck on determining...eerrrr getting a solid answer on how to figure short pulse adder. (as i said early, I deleted mine LOL).

I am saying your offset table...the slope, when you are in decel you are in the right side of that table. Your vacuum on the far right is 80kpa. (manifold absolute pressure in kpa minus a hundred or just log the PID Engine>Airflow>Manifold Vacuum (metric/kpa). Play with that side of the offset table for decel. I don't necessarily thinks its the right thing to do, but it works great for guys whose decel is clearly over in the 70 to 80kpa vacuum side. The milisec you apply any ounce of throttle it slides the other way and safely brings you back into fueling the correct (or what works) offset values. LOL Just a bandaid probably, but it works on you returnless guys. It works for me too, but I should find the right way since I have the FPR on the rail.

Again, it works cause you are only that far right in that table during decel. Try playing other areas of that table the same way and you throw it all out of whack at the wrong times. Just play with it, you'll see the smallest of values make the biggest difference.

red da man!


PS
That table already has tiny values, don't freak out when you mulitply .51 by .99 (99%) and it deosn't work. LOL Try .98, or .97 or .95.

[03Sierraslt]

Good luck on determining...eerrrr getting a solid answer on how to figure short pulse adder. (as i said early, I deleted mine LOL)

I wasnt refering to the adder, rather the short pulse limit. So what you are saying is in the offset table try playing around with the 80kpa row and lower the values to attempt to achieve a closer to 14.7 value rather then 11.1 that I am at now. Am I understanding you correctly?

[SJSchafer]

SJSchafer and I have been talking about this stuff on another forum. I just tuned into here now. I did exactly what was posted here. problem I ran in to was I was way rich with this setup at 28Map from idle upto 3200RPM (just sitting and revving up motor). after having no or Zero success adjusting VE table it was found that the minimum PW was the problem along with the adder. I set the adder to 0 across the whole table and set the minimum pulse width to GM default of 0.094. then the changes to VE table took effect and the lowest pulse width I saw was 0.9. THis is on the 2.0l LSJ engine found in our COBALT SS supercharged.

hope that helps out.

I very well may be wrong, but I do not believe that they minimum pw and adder are connected. They may be, I am surely (don't call me shirley) no expert. Sometimes I think I am just too anal, because the forums are full of people with tuned 60s, but every one of them went about it a different way and I am just not okay with that. i want someone to say, "this is the formula for calculating the offset table, short pulse limit, min pw and the adder tables, now go do math!".... blah. I even have a book that says that a quick web search can get you the info that you need. HAH!!! I have over 10 hours of internet searching on just the offset tables and nothing! )*^^&$%*BER$&$*^&HT(^R*&^%^&^)*&^*&$!!!!!!!!!!!!

Sorry for the rant. Just had to get it out. What were we talking about again?

[03Sierraslt]

Well after logging KPA, the lowest I hit on decel is 75. At idle in N I am at 65 or so and in gear around 56. The probem I am having now is that idling in gear and in Neutral I am using the 800rpm, 40kpa cell of my VE table. If I get my AFR right in Gear then in N it is about 1pt rich. I played with the offset some more and I think its better but we will see tom. Also something I noticed this eve is when I go into PE or BE after letting up and droping out of boost my AFR continues to go richer for a couple seconds then comes back to 14.7. This is the first I have ran into this, wonder why?

[dewmanshu]

lots of questions, but no real answers until EC_Tune or one of the hero's answers. LOL Until then, here is more of my babble.

SJSchafer oh do I ever feel your pain. I have search and searched. There is a thread in here that I did use as base start, EC_Tune gave some great ideas. But you end doing the same thing as everyone else, finding what works for you. Amazingly, on a HPT forum, you'd think by now someone would of stuck their ugly head in this thread and said, hey dumbass...use "these" numbers. The min and adder aren't connected really. Min inj is the absolute min inj pw. Absolute (adder is already factored in). (okay not really, default is absolute)Short pulse limit is the alarm, when it hits that number it will add to the pw what you describe in the adder table for each of those pw's. Yeah...CRAZY math in there. Serves a great purpose, but that's over my head.

Pat, (03Sierraslt), yeah I know..the limit, again, who knows. People can give good estimated guesses. You are onto what i was saying earlier (that redhard would disagree with good reason as stated) some tweaking will be needed of the ve to get her where you want her. It's the grey area of the decel and idle, where they kinda cross. Get it as close as you can with the offset using idle as your goal not decel so much (in other words, play with decel as much as you want, but as soon as you screw with idle, your going to far left on the offset table). Then with the min inj tables, in the rpm you decel at...lower that bitch. (small parts at a time). It should all eventually fall into place. That's my reference early...cheating by using a little of VE, a lot of offset, and then hit the min inj table at the actual rpm decel problem to get her to play nice.

The inj are bigger, parts are bigger, extra time to shut (lag of fuel in the system). Want it to go away, go back to 1bar and get the MAF back up and running. LOL That's tunable as well, just work on decel and idle for now. Watch lowering those numbers in the offset too much on the left, it'll lean that ve out real fast.

Once you get all that done, go back to closed loop and forget about all the hard work you have done. lol

[dewmanshu]

btw, what formula did you use to get your IFR table. Post it up. I am so unfamiliar with returnless.

[SJSchafer]

I used one of the injector spreadsheets. The values are too big for the ECM with 60s, so we have to reduce them by a percentage to get them where they need to be, then add that percentage to the multiplier to get back to the real numbers.

[redhardsupra]

I used one of the injector spreadsheets. The values are too big for the EMC with 60s, so we have to reduce them by a percentage to get them where they need to be, then add that percentage to the multiplier to get back to the real numbers.

huh? who came up with that award winning solution?

[SJSchafer]

I learned that from ssnipes. I assume that would be the more correct way to go about it rather than what I see most doing, which is tweeking the air tables.

60lb injectors rated at 43.5psi with a rail pressure of 58 psi looks like this:
57.96310254 58.58108618 59.19261829 59.89818191 60.49640153 61.08876329 61.67543598 62.35291123 62.92779943 63.49748297 64.0621007 64.71459559 65.26868533 65.81811063 66.36298734 66.99307595 67.52847271 68.05965787 68.58672927 69.19657194 69.71504837 70.22969722 70.82539451 71.33203285 71.83509806 72.33466468 72.91316651 73.40539662 73.89434793 74.38008509 74.94279948 75.42178463 75.89774699

Our ECMs will only let us go to 63.5, so we divide the values by 1.2. That gives us:

48.30258545 48.81757182 49.32718191 49.91515159 50.41366794 50.90730274 51.39619665 51.96075936 52.43983286 52.91456914 53.38508392 53.92882966 54.3905711 54.84842552 55.30248945 55.82756329 56.27372726 56.71638156 57.15560772 57.66380995 58.09587365 58.52474769 59.0211621 59.44336071 59.86258171 60.27888724 60.76097209 61.17116385 61.57862327 61.98340424 62.4523329 62.85148719 63.24812249

Go to Flowrate modifier VS. Voltage and enter 1.2 accross the board. IFR done.

Again. Thanks ssnipes.

[EC_Tune]

I think what's going to have to happen is someone with an injector flow bench is going to have to flow a couple hundred of these bastard injectors so we know what their range and characteristics are. Until then we're all guessing with the best info we have at hand: NONE>

[dewmanshu]

Until then we're all guessing with the best info we have at hand: NONE>

Thanks for nothing. LOL

The cobalts only go up to 63? UGH.