Very cool. :cheers:Quote:
Originally Posted by 03Sierraslt
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Very cool. :cheers:Quote:
Originally Posted by 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.Quote:
Originally Posted by dewmanshu
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?
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.Quote:
Originally Posted by dewmanshu
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.
Dewey, My short pulse limit is 3.9 and my short pulse adder table is zero'd out after 3.1 and higher.
Anyone?
So does lowering the offset value make it leaner or richer?
Since: offset = injector opening lag - injector closing lagQuote:
Originally Posted by 03Sierraslt
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.
Wow, that's your AFR error? Are you using a VAC table or a MAP table?Quote:
Originally Posted by 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.
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.Quote:
Originally Posted by 03Sierraslt
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?
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.
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.
Any takers?
Here ya go Dewey.
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.
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.Quote:
Originally Posted by 03Sierraslt
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.
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.
I think I may have got it, I will get into what I changed when I confirm its good. So far it is, the real test will be to see what it does tom.
I agree. That's why I sent you an offset table. LOL. You just have to convert my kPa MAP to your kPa VAC and put the numbers in the appropriate spots. This offset table has been confirmed to work well on 2 vehicles with siemens 60lbers.Quote:
Originally Posted by 03Sierraslt
Update: I will have a VAC offset table shortly that actually works better than the MAP one I posted before. This is because, although they are based on the same theory, on closer inspection, the VAC table was modeled more realistically. Once I am done, i should be able to convert it to MAP or VAC depending on people's needs. :)
I would be interested in seeing this VAC offset table as I am going from 44lb Multecs to 60# Mototrons when I install my 2.8L Kenne Bell this weekend and will eventually be putting the 60# in my wife's '06 Cobalt when I do the pulley swap.
I have an offset table that I believe is very good right now. I will be ready to release it once I am done with the adder table. It is close now and should be ready by the end of the weekend.Quote:
Originally Posted by BigKID
Also, if the 60s are flow matched, I can get you a map that will work even better if you let me know the rates.
Very interested in this also. I bought a set of flow matched 60's from Racetronix.. They came in individual ziploc baggies with no documentation, not even a box.:mad:Quote:
Originally Posted by SJSchafer
That bites. If they flow matched them, they should at least send you a peice of paper showing the results. Mine where an average of 62.5 or something like that. If they don't give you the specs, how do you really know they're flow matched? :eek:Quote:
Originally Posted by blown3qtr
EXACTLY! :rant:
A lot of good info here... I have been reading along just for infomation on how to fine tune my 8.1L truck injectors as the stock settings I got from an 02 pcm got it close, but not quite right.
Here is some interesting information that I stumbled on today.
http://www.yawpower.com/injectordeadtimesarticle.html
http://www.yawpower.com/injectordynamics.html
Nice stumble! I wish I could pull out my injectors and send them!! Unfortunately, i need to drive my car. :doh:Quote:
Originally Posted by truckmann
Let me know if you can find some more info about this. He is correct in what he says, which is why I have been spending all the time I have been spending on this.
I can't even imagine the fun you guys must be having with the 60#ers. I'm not that thrilled about the afr numbers I am seeing after installing my MultecII 8.1L truck injectors. I copied the injector tables from a 2002 file and it runs ok, but my afr is no where near as stable as it was with the stock injectors. After all the looking I'm starting to think that as nice as it would be to drop in new injectors, plug in the new numbers and have it run just like it did with the old injectors, is next to impossible. For me anyway it all stems from trusting that the stock numbers in the injector tables are "correct" when in fact how do we know that they are any better than just "good enough"? Then to make it all work they map out a VE table and depend on the maf and O2's to compensate for the rest.
So far I haven't even been able to get anyone to look at my tune/log and even tell me that I'm just stupid, lost, out of my mind or something. I guess I just don't seem to know how to ask for help. I know people have been swapping to larger injectors for years now and it seems that there is very little information out there on getting them tuned the right way. It's almost like it is a big secret....:shrug:
Ok enough of my rant guess I'm just a little amazed at how little info seems to be available on this stuff.:banghead:
That's because nobody really knows the right numbers. I have over 100 hours now on just my fuel tables and they are damn close (or at least they seem to be), but i am still working on them. I would gladly pay someone to test my injectors and get me the right offset table numbers. Everything else would be cake from there. Unfortunately, I can't be without my car that long.Quote:
Originally Posted by truckmann
Ya I know what you mean. I figured I would just be able to copy the numbers from a stock tune file that used the same injectors I put in but no luck. Either GM doesn't really know the right numbers or maybe the 8.1L trucks run on a different fuel pressure or something because the numbers they use don't work quite right on my 5.3L I had to up the IFR from 29.95 to 30.63 to get the afr's close although they are still unstable. I don't think I'm ready to start messing with the offset table yet.
Does a return fuel system vs. a returnless system have any effect on what the Offset table should be??? Keeping in mind that the return system is regulated at the rail and the returnless is regulated at the pump.
The reason I ask is from looking at Offset tables from a 2002 and a 2004 Silverado 8.1l they are drastically different and I want to understand why.
Nope, the offset table should not be different. It is an injector stat. 14 volts@ 0 kPa is the same whether returnless or return.Quote:
Originally Posted by truckmann
The fact that those 2 are different is not a surprise. There are 2 versions of the stage 2 tune for SC Cobalts and the offset tables are different, as are the flowrates, VE, MAF, etc... Same car, same injectors... GM can be goofy sometimes, i guess.
Well at least I'm not completely confused then cause that is what I thought.
Darn those little GM tuning gremlins who are making my life difficult...:doh:
Damn! That is a good find. It's got me thinkin. But, it sucks to have to spend an additional $280 on top of $400 injectors just to get the right calibrations. I dunno My buddy's gonna be buyin some 60's for his 408 I'm building, maybe I'll give these guys a call.Quote:
Originally Posted by truckmann
You would think if they have already tested a bunch of injectors that they may already have decent data. The way I see it is that while every injector is going to be a little different, the difference between them should be very very small. After someone has tested a fair number of injectors and averaged the data then testing a few hundred more and adding them to the data will make little difference. So the question is; if they already have the data that we need will they be willing to let go of that data without sending them injectors? I was thinking if I just had one injector to send in for testing it should give a reasonable idea of the offset numbers needed, instead of guessing.
We are on the same page.:cheers:
Any update with your progress, 03sierra?
Removed information, as it was not correct.
Greg Banish (eficalibrator on here) does have the correct data for using the Siemens Deka injectors on your GM, including ALL the correct data for using ANY Ford Racing injector on your GM. Please see here:
http://www.hptuners.com/forum/showthread.php?t=22788
Read the whole thread. The DVD is on pre-sale at www.summitracing.com right now! You can see it here:
http://www.summitracing.com/parts/SME-DVD-1/