caliswangin916

iTrader: (3)

i've been doing a lot of reading the past 2 days on ls1tech and hptuners but have yet to figure out how to tune my injectors. i have a 2000 ss a4. all stock to the best of my knowledge with free air mod.
i have 36lb lucas blue rings. i changed the IFR according to redhardsupra 's spreadsheet that ranges from 43-47. car runs fine at idle and WOT but at any point that i take my foot off the gas and decelerate, the afr will dip. say i cruise at 45 and taking my foot of the gas will drop my afr from 14.6 down to the 11's, 10,s and even 9's. afr will catch right back up to 14.6 when i give it light throttle. from a WOT to 80 and letting off dropped my afr below 9's.
everything else looks like a stock tune under the engine tab.

i've looked at the repository but nothing for 36lb injectors and the other size injectors bins seem to conflict as to what changes and direction i need to go. i've flashed calibrated about 10 times but no luck. i'm not sure what i'm not catching. i'm think it's a combination of changes that i haven't made?

i've tried the ifr, dfco, transient fuel, and minimum injector pulse.

i will also be running a dry NOS kit with the 50 or 100 bhp shot. i was getting a 12.5 afr before the injectors and would like to be within the range of 12.0-12.5 afr with these injectors. thanks ahead for any help you can give me.

below is my bin with only the ifr tuned for the injectors and a scan.

jimmyblue

iTrader: (11)

I'd reduce the minimum injector pulse width if you see
that's the value you're hitting on decel. Roughly
scale it by the flow value, (IFRold/IFRnew) as a start.

The injector offset may be different as well, from stock,
and contribute to short-pulse-width errors. But good
luck finding any useful data there.

GuitsBoy

iTrader: (4)

I dont have my software in front of me right now, but IIRC theres a minimum transient fueling miligrams setting that was around .047 stock on my car. I lowered it to around .038 if I recall. Play around, but remember that first .0xx and dont accidentally enter .xx. Also, a little bit goes a long way.

caliswangin916

iTrader: (3)

i read you're post about that. i tried going to .40, .38, .20, .01, and .005, they didn't seem to be letting me get into dfco. i've been tweeking the map entry and exit points at .045(stock 00 ss) and it's at least getting me to go dfco when the points are set at 30 entry and 40 exit. stock was set at 18 and 28.
i tried 25-32 and a a transient min of .040 and looking at the scan now, it looks good, but i don't remember liking how it was driving. i'm going to try that tune again tomorrow with .045 transient.

muncie21

iTrader: (14)

like Jimmy mentioned, take a look at pulse width and min. injector opening time.

caliswangin916

iTrader: (3)

leaving transient fuel at .045 and lowering the minimum injector pulse to .790(old irf/newifr X 1.277(stock inj pulse min.) or lowering the minimum injector pulse min and defalut injector pulse min to .790 was giving to me more knock retard(2-4*) when lightly accelerating after a decel. i'm not sure if it's acceptable amounts but looks like kr is occurring more often than my other logs prior to the injectors being installed. i am also noticing what seems like some very light backfire on decel. but overall afr is much more consistent with the stock injectors and tune.

i moved my dfco points to what i like and am fine in that area.(i think-as long as dfco doesn't affect other fueling commands). engine breaking was nice but i'm going to pass on it.

can someone please tell me what injector pulse minimum, default injector pulse, and transient fuel minimum are for and how the work together or don't work together. does upping the units increase or decrease fuel? what overrides what and when?
i've ran over 30 tunes now and need to get back to spraying my car without breaking something.

jimmyblue

iTrader: (11)

As I understand it your airflow and the fueling target first
are used to make a delivered fuel mass, then translated to
a pulse width via the IFR table. To this is added the injector
offset value (dead time in the mechanicals) so that the
electrical pulse width delivers the desired mechanical /
fluid shot. Offset affects low-airflow, low fuel delivery, a
lot potentially; offsets can be on the order of the "real"
(desired) pulse width.

After all this there's a backstop, minimum pulse value.
If you calculated less, too bad, here's your double cheese
anyway.

I think you were maybe bumping up against the miniumum
and now that it's relieved your trims will creep to match
the new fuel delivery. So too you may get leaner actual
fueling and KR (pull some timing if fuel is good now). But
I'd wait for the trimming to settle out before chasing it
too hard.

SSpdDmon

iTrader: (10)

I follow what you're saying regarding the minimum/defualt minimum (commanded) pulse width tables where in our cars, you can't have a commanded pulse width less than 1.277 miliseconds (in stock form). However, the question remains....how do we know, or even, how do we find the minimum pulse width performance of the injector we just installed??? IMO, this table should be set in accordance with the injector's performance to tell the PCM, "Hey...if you command a PW less than this many miliseconds, these injectors are going to f*** up." But the problem is, nobody seems to know where to find this information.

Looking back at the small pulse width adjustment table, I would think this means that nearly 1/3 of it is not used (0-1.216ms). It also shows how the stock 28lb injectors might start to show problems with PW's at ~3.7ms.

What this means to me is, going to a bigger injector is going to require a shorter-than-stock commanded PW at certain points (idle & decel). So, changing that 1.277 minimum commanded threshold will be required at some point. Also, I would think the performance as seen in the pulse with adjustment table is going to be different for a different injector. But unless you know where the injector starts to go south and how fast it takes the f***-up plunge (yes, that's a technical term) , how do you know which way to adjust that table - especially when there are other fueling variables in the equation (like MAF and VE)?

jimmyblue

iTrader: (11)

Well, that's the trouble - zero quantitative data for all the
non-stock injectors (other than, if you can find the GM
vehicle that used it and extract the tables from the tune
file). That's one reason to prefer Delphi / Bosch OE part
types, even though I've seen nothing there yet - at least
"it could happen".

I'd like to know vehicle apps that used the Delphi 32, 36,
42#ers (I have a set of 32# and 36# sitting around) and
dig for tune files to see what can be found....

Otherwise it's a full science project on a short science
budget & even less free time.

caliswangin916

iTrader: (3)

just realized(i think) that my attachments don't show up here. her's a link to hptuners that should enable a download of my scan and tune.
TUNE
http://www.hptuners.com/forum/attach...5&d=1172454225

SCAN
http://www.hptuners.com/forum/attach...6&d=1172454251

i've since been running an IFR of 43-47 and a min injector pulse of .790. seems to be the best tune so far but i'm getting kr more often than stock and the car seems to be slower. going to change my plugs later today.

edfiero

ok, so I know I'm not answering your question, but why are you giving your self a headache by tuning up 36lb injectors when your car is all stock. These injectors are currently not needed, and won't give you any additional power. I say pull them out and put them on the shelf until you have other supporting mods to make use of the additional fuel.

tici

iTrader: (1)

I have #36 Bosch injectors, an additional fuel pump (T-Rex) and during decel I see an AFR of 12.5 - 13 (I think it's not too low).
My IFR is not calculated but it's the result of scanning for LTFT + STFT aiming at 0% correction... maybe it's just your IFR curve that is just too low @ low map values.

UKDriver

I've just fitted Accel 36lb injectors. Was told by them that the injector offset was 0.8 at 13.5 mV

Running the stock 26lb injectors my inj milli seconds in fuel trim cell 21 (Is this at DFCO?) is 0.45, ie when no fuel is flowing. For Accels this seems to be about 0.49 but still some work to do on these.

SSpdDmon

iTrader: (10)

Did you mean 0.8 miliseconds at 13.5V? If so, that's nearly double of what is in my Injector Offset table at 13.5V. The stock offset for decel is .46ms at 13.5V, which would match what you say above.

UKDriver

I was surprised it was that high - but yes, 0.8 msec

SSpdDmon

iTrader: (10)

I wonder how it changes as the voltage increases/decreases? That way, we could tell if the delta was linear or not.

Anyone have any of this info for the SVO injectors (like the 30-lbers)???

caliswangin916

iTrader: (3)

i'm still having a problem tuning these injectors.
i got my afr to not go to the 9's and 8's by setting my min inj pulse at .790, but i still hit the 10's sometimes and am mostly in the 11's. when i dropped my min inj default down 5%, i was getting back into the 9's on decel.
i sometimes get up to 7* kr at light accel from a decel when maps are roughly 60-80 and and going 40-60mph. afr is showing 14.3-14.6 during this.
when i get kr, my ltft are positive with bank1=6 and bank2=3. there isn't any noticeable noise at engine that concerns me.
i've been playing with the min inj pulse, default inj pulse, and irf tables but still can't rid of the kr.
often, i throw a tune in and drive for 15-20 minutes and change tune if i'm not getting any good results.is there a learn time for the pcm to use the new tunes i put in?
most of the tunes that i've tried don't have any drivability problems but the scanner is telling me things are off.
thanks jimmyblue and everyone else for your help.
tici and ukdriver, can you send or post your tune for me?

SSpdDmon

iTrader: (10)

With every injector setting back to stock (except the correct IFR for your injectors), did you try increasing the injector pulse width (offset) vs. voltage table by .25 miliseconds for 12+ volts (or something along those lines)? After reading what UKD wrote, this is where my 'gut' told me to try first.

SSpdDmon

iTrader: (10)

I might be onto something here. If you compare a '99 26lb injector vs voltage table to an '02 28lb table, there's a difference of .05~.14ms in the car's normal operating range.

tici

iTrader: (1)

I have an LS1Edit file... if you only need the IFR curve I can put it on a Excel sheet.
Email address?