60lb Inj. Problem

[SJSchafer]

Does this look right?

Very cool.

[dewmanshu]

DAMMIT, I just typed a bunch of crap and i lost it. I am not typing it again.LOL

DFCO, this thread helped me a ton, but I'd suggest as you know, don't bother until you are happy with the inj's.
http://www.hptuners.com/forum/showthread.php?t=5603

I feel your pain, you can't make the lower vac offset settings lower than the higher vac kpa just to achieve the right afr. Try that histogram and see if it helps you get a better feel for that table. But like SJ says, the pulse adder will keep your progress held back if you are trying to command lower values. SO lower that thing. I wouldn't sweat the rescaling of it too much (yet), I'd delete any values in the short pulse table that are higher than your limit though. Just in case.

I am sure I missed something, I need another cup of coffee.

[03Sierraslt]

DAMMIT, I just typed a bunch of crap and i lost it. I am not typing it again.LOL

DFCO, this thread helped me a ton, but I'd suggest as you know, don't bother until you are happy with the inj's.
http://www.hptuners.com/forum/showthread.php?t=5603

I feel your pain, you can't make the lower vac offset settings lower than the higher vac kpa just to achieve the right afr. Try that histogram and see if it helps you get a better feel for that table. But like SJ says, the pulse adder will keep your progress held back if you are trying to command lower values. SO lower that thing. I wouldn't sweat the rescaling of it too much (yet), I'd delete any values in the short pulse table that are higher than your limit though. Just in case.

I am sure I missed something, I need another cup of coffee.

Ok well he is a question, in Park it will idle with a 1.7 injector msec, however when in gear it jumps to 2.0msec all while using the same VE cell.. So my question is what is making it add the fuel? And how can I keep it from adding as much so that it dont go rich when in gear at idle. As soon as I touch the throttle it comes right back to 14.7.

[03Sierraslt]

IFR table is making it add fuel because of the different VAC, anything else? While I get the whole min pulse etc. Pulse is based off of RPM and it seems to me the VAC is the culprit for the difference. IFR and OFFSET are VAC sensitive so does the answer lie in those tables?

[03Sierraslt]

DAMMIT, I just typed a bunch of crap and i lost it. I am not typing it again.LOL

DFCO, this thread helped me a ton, but I'd suggest as you know, don't bother until you are happy with the inj's.
http://www.hptuners.com/forum/showthread.php?t=5603

I feel your pain, you can't make the lower vac offset settings lower than the higher vac kpa just to achieve the right afr. Try that histogram and see if it helps you get a better feel for that table. But like SJ says, the pulse adder will keep your progress held back if you are trying to command lower values. SO lower that thing. I wouldn't sweat the rescaling of it too much (yet), I'd delete any values in the short pulse table that are higher than your limit though. Just in case.

I am sure I missed something, I need another cup of coffee.

Ok since I cant make the lower VAC settings lower then the higher ones can I at least make them match? Right now the lower VAC settings are higher.

[03Sierraslt]

Just messing around I dropped my in Park idle to 585 so it would put In park idle and in gear Idle in two different VE cells. Sure enough I was able to get it to idle at the afr I wanted in both park and D. I put it back to where it was though because it didnt like the 585 idle. It idled ok but you could tell it was a bit too slow.

[03Sierraslt]

Dewey, My short pulse limit is 3.9 and my short pulse adder table is zero'd out after 3.1 and higher.

[03Sierraslt]

Anyone?

So does lowering the offset value make it leaner or richer?

[SJSchafer]

Anyone?

So does lowering the offset value make it leaner or richer?

Since: offset = injector opening lag - injector closing lag
Then: lowering offset reduces the time that the computer thinks it needs to power the injectors to acheive a specific pulsewidth.

Therefore lowering the offset table = leaner.

[SJSchafer]

The log I just did for Offset says its -17.36 across my whole 14v row.

Wow, that's your AFR error? Are you using a VAC table or a MAP table?

[03Sierraslt]

that was a mistake, I used a different config and I forgot to set it up for my Wideband.

I did make some progress though, as of right now my Drive and park afr's are within like .2afr. I tweaked my IFR table just a hair and tweaked the offset a tad and it seemed to come right in line. I didnt have to change much to get it to make a difference.. Also now I noticed that when I make changes to my VE table there is a much faster response. Before I would add or pull like .5 or so now .1 makes a difference. We will see how it is tom.

[SJSchafer]

that was a mistake, I used a different config and I forgot to set it up for my Wideband.

I did make some progress though, as of right now my Drive and park afr's are within like .2afr. I tweaked my IFR table just a hair and tweaked the offset a tad and it seemed to come right in line. I didnt have to change much to get it to make a difference.. Also now I noticed that when I make changes to my VE table there is a much faster response. Before I would add or pull like .5 or so now .1 makes a difference. We will see how it is tom.

Cool, I am glad you are making progress. If I have learned anything from my tuning session with redhardsupra, it is that you cannot just look at a single bit of data, but you need to look at the relationships between data. I have also learned that it is much much harder to get your tune inline while tuning in SD. If you can tune in MAF, I suggest you do so. MAF already accounts for temperature variations as far as abient ATs are concerned and it is much easier to see the relationships between data. You can tune VE later when you have the other things dialed in.

For example, lets say you are tuning in OLMAF. You notice that although your MAF should be be pretty close, you are seeing consistant trends in your offset vs volts vs VAC/MAP. You tune your offset table. Now let's say, you get your offsets real close and your MAF is looking good, but upon further examination of the data, you see that you are bouncing all over the place in the same MAFcell, but are seeing a trend in your IPW vs AFR error table at low PWs (that's a custom one ). That would be short pulse adder, right? Don't go willy-nilly changing things, because this change or that gives you a result, sort of, but you are still this at that. Start with as many known truths as you can, apply logic towards the inconsistancies by utilizing all the data you can, and the resultant tune will not only work, but it will be correct.

Oh, and I repeat my question, "Wow, that's your AFR error? Are you using a VAC table or a MAP table?" Meaning which offset table are you using in your tune?

[03Sierraslt]

VAC Table, my pcm doesnt have the VAC/MAP option like the cobalts do. I get what you are saying but MAF isnt a option anymore.

Once I setup the new config I used for my wideband my AFR error was like 3%. Becuase I didnt have it setup correctly at first my scanner was reading the default 12.xxx or whatever it is.

[03Sierraslt]

I think I got it sorted out but I seem to be getting some inconsistancies, Ill get the VE damn near where I want it then the next time I drive it it is off again. Even a day later in the same weather conditions. I had hardly any change before with the 44lb injectors. I have my charge bias at 1 and previously this worked great for keeping day to day fueling consistant. Not sure what is going on.

[03Sierraslt]

Any takers?

[03Sierraslt]

Here ya go Dewey.

[SJSchafer]

I can tell you 2 things that are wrong right away. One is your min injector pulse is too high. I guarantee that you go below 1 ms when decelerating. If you are driving a stick, you are also going down below there when pushing in your clutch to shift. Just for a sec or two on that one, but it makes a difference.

The other is your VE. It should be smooth. If it works best when rocky like that, you are making up for something else. Just out of curiosity, where did you get the data for your min pulsewidth and adder tables? You have values all the way up to over 3 ms, but your short pulse limit is at 2 ms.

You have seimens 60 lb injectors, correct? If so your offset table looks a bit off. Have you tuned your offsets?

As far as your AFRs being different from one day to the next - Just a couple of degrees in ambient, intake temp, fuel temp, etc can make a difference when tuning VE.

[03Sierraslt]

If I go any lower with the pulse width the pulse width when I hit decel it goes way lean and wants to stall out. Not sure how lean but my wideband reads as far as 18.0 and it just peggs ----

I know day to day fueling will be slightly different, I didnt just go into SDopen loop when I put these injectors in. I have been runing it for close to a year or so. My point was that prior to running the 60's my day to day fueling differences were very minimial and consistant. I think I found the difference in fueling, on cold starts my Offset is using the 14.5v row and that row is rich. Once warmed up it uses between the 13.5-14v. I did some offset tuning last nite so Ill try it today. How do you really know what you are compensating for, a error in offset or error in VE after all its just reading AFR error%

[SJSchafer]

If I go any lower with the pulse width the pulse width when I hit decel it goes way lean and wants to stall out. Not sure how lean but my wideband reads as far as 18.0 and it just peggs ----

I know day to day fueling will be slightly different, I didnt just go into SDopen loop when I put these injectors in. I have been runing it for close to a year or so. My point was that prior to running the 60's my day to day fueling differences were very minimial and consistant. I think I found the difference in fueling, on cold starts my Offset is using the 14.5v row and that row is rich. Once warmed up it uses between the 13.5-14v. I did some offset tuning last nite so Ill try it today. How do you really know what you are compensating for, a error in offset or error in VE after all its just reading AFR error%

Well if you are going way lean with a lower min PW, you need to find out at which pulsewidths it's going that lean and adjust your short pulse adders accordingly. Large injectors have a problem with precision at short PWs, that's why you tell the injectors, "hey, when we command .65 ms, do me a favor and pulse .665832" (or whatever). Set up a histogram that looks like your adder table with PWs as your axes and logging AFR error. That will tell you how much fueling you need to add where. You will notice in your VE table that you are going lean/rich in the same VE cell, but you are bouncing between different PWs. That is one clue. Hard to do without a proper offset table though.

You never know exactly, but starting with a known good base is a good start. Then on your offset AFR error histogram, you look for trends. Don't copy/paste percent here. Look for trends. It is all harder when VE tuning, which is why I recommended doing all of this in MAF to start and switching to VE when you are good in MAF. Not sure why you don't want to do that. I have attached an excel file that has proven to be a pretty good offset table. The only problem is that it is in MAP. You would need to do some converting for kPa VAC.

[03Sierraslt]

The more I mess with it the more I feel the issues that I am having are related to the offset table. I discovered what I thought were inconsistancies was actually the truck using the 14.5v row of the offset table which was pretty high. Once it warms up and runs for a little bit it uses the 14.v row, I have been looking at alot of offset table and also doing alot of comparing to the offset that was in the truck before. I need to focus on the offset and see where it takes me. I have even got my decel to only drop into the low 14's afr which I am happy with. I just need to figure out this idle in Park vs. Gear issue which I am fairly confident is because of my out of wack offset.