92GTA

iTrader: (11)

I'm upgrading from 19# injectors to 30# injectors on Tuesday. Bear in mind my engine only needs 19# but I'm installing 30#'s in anticipation of a ProCharger install so for now I need to tune for the 30#'s to work on a 305 that only needs 19#'s. (My stock ones dumped that's why I'm not waiting for the SC'er)

From making a post like this in the past I know I need to change the following:

Injector flow rate
VE tables (Volumetric Efficiency)
PE tables (Power Enrichment)

Any I'm missing considering I'm using the AXXF $8D based code? I know AE is what's affected by the injector flow rate so I know that's covered.

Now my specific questions.

VE: Do I need to start increasing or decreasing the numbers for what I'm doing?

PE: Which PE tables do I need to adjust, I see several. I mean like which PE Vs. --- do I need to change? And also in what direction, and increase or a decrease?

BPW: Is there a variable for this in the AXXF because if there is, I still cannot find it. Only thing even close I see is "Crank Pulse Mult. Vs. Ref Pulses 1-24" Is this right? If it is, then again what direction, do I start increasing or decreasing the numbers?

Now other things that have been suggested in other posts I found doing searches are:

IPW (Injector Pulse Width)
Idle fueling BPC (What does BPC mean?)

Again, are these variables in the AXXF because if they are I also cannot find these. I'm using the "Super_8D_Rev_3-3-04.ecu" file.

Thanks in advance for any help!

TheGreatJ

BPW=base pulse width and is not an actual variable. It's a figure that's calculated by the ECM from the VE tables and various other things (i.e. coolant and air temp tables, etc,) and is then modified by certain subroutines (integrator maybe?) to calculate the total IPW (injector pulse width) which is exactly how long the injectors stay open each time they fire.

At least that's my understanding of it. I may be wrong.

Low C1500

BPW is a constant, then things like VE and PE ratio , and rpm get multiplied with the BPW.

Your injectors have a constant flow rating, so if you go bigger injectors, you need to proportionally decrease only your BPW.

Theres some other stuff like flow characteristics, but you nor I need to worry about that stuff.

If your running 8D code then isn't there just an injector constant?

92GTA

iTrader: (11)

Yes, the "Injector Flow Rate". I already adjusted that to 29.45 from the original 19.76.

If this is so then I can not find where this constant is to change it. I'm using TunerPro RT and the "Super_8D_Rev_3-3-04.ecu" file. I've tried other .ecu files too and also could not find a variable like that. All I can find are tables that mention xxxx Vs. BPW, not an actual constant...

Low C1500

Your injector constant is the BPW, just another name.

Dave_Jones

$8D doesn't have a Base Pulse Constant, like some of the other codes do. So don't bother looking for it.

I would approach things in the following sequence:

1. Set the injector constant. (already done)

2. Do some datalogging, and get as much steady-state (i.e. non-AE, non-PE) data as you can. Adjust the main and extended VE tables accordingly. There is a sticky about 730 part thottle tuning that you should read, if you haven't already.

3. Once you have the VE tables adjusted, then gently ease the car into PE, and adjust the PE tables. For an N/A car, I'd shoot for around 12.8:1 as a starting point, then try slightly richer and leaner, until you find the exact PE AFR your car likes best.

4. Once that's done, work on AE, so that when you crack the throttle open, you have the right amount of fuel to get you into PE. No shortcuts here that I know of, you'll just have to try varying the delta TPS & delta MAP a little at a time, and see what works best. Grumpy has often posted some hints on this, that you should be able to find with a little searching.

Having a WB and an emulator makes all of the above go much faster.

Some folks also tweak cranking fuel to achieve best startup in various weather conditions. Me, I'm not quite that far along yet.

Also note that I've only discussed fueling. As you go through all of this, you'll probably wind up spending some time refining your spark advance too.

Anyway, like a lot of people on this forum, I'm still learning, so anyone with different or better methods, feel free to chime in.

HTH,

92GTA

iTrader: (11)

Thank you!

Now what is the name of the variable for adjusting the fuel during cranking? That was suggested to me since 30#'s are very big for a 305 but I can't find anything resembling that either. I'm guessing it's the "Crank Fuel Delivery Delay vs. MAT" table right?

I'm not going to be able to buy my Zeitronix WB for another few weeks, I was hoping to bore/rebuild my TB and add an APFR first. I also have nothing more than a laptop for data logging and the Burn1 so I guess this will take a while, lol!

I have to smog in January, I hope I have it figured out by then...

EDIT: Since AE is the only thing directly related to the injector flow rate, safe to say that since I'm going to be putting in 32.9% more fuel that I should lower all of my table numbers for PE and VE by 32.9% for starters and go from there?

Actually you know what, where can I get the latest version of VEMaster, like 2.11??? I did a search here and all links are bad or for a really old version which did not support the 730. Nevermind, I found it on Moates.net

Dave_Jones

In $8D, having the correct injector constant will take care of a lot of the other stuff -- so don't jump the gun and go preemptively making any changes to tables, until you have actual test data that indicates that it's needed.

Smog shouldn't be any big deal, if you have a functional catalytic converter, and tune for 14.7 AFR at idle and 2500 RPM. Go in with a fresh oil change, and make sure the engine and cat are fully warmed up. The visual inspection is another matter of course, but I'm sure you're already familiar with that.

Maybe try crank fuel pw vs coolant temp first, which might or might not be defined in the .ecu file you're using. Reading through the ANHT hac will show you what can be adjusted in 8D. Again, no changes without testing the stock settings (w/correct injector constant) first! There was a thread last winter entitled "cold start", or something like that, that had some good discussion.

If your engine is close to stock, the process I outlined shouldn't take that long, since what you'll be doing is more along the lines of fine tuning, rather than starting from square one. Although I recommend it just as soon as you can afford it, you can get by for awhile without the WB, at least until you get to PE tuning. Also, if funds are tight, get a FP gauge and test the output of your stock FPR before buying that AFPR -- if the stocker is providing acceptable fuel pressure, IMHO it's fine. DIY PROM burning capability means not having to tune with fuel pressure, like we did back in the dark ages.

92GTA

iTrader: (11)

Cool. I'll be sure to log before I change anything. Reading the VE tuning post again helped allot.

Yeah my fuel pressure was fine when I checked it the other day so I don't really need an AFPR yet.

Thanks!

Oh, a little off topic, will running rich, like a BLM of 110, ruin the stock NB o2 sensor in 1,000 miles? Because that's what I've been doing for the past for weeks and if I need another sensor before I start tuning it would be nice to know. Also if I install the new injectors, tune, would I need another one since in the begining I was running way rich? I don't know much about o2 sensors other than running too lean will burn them out for sure...

RednGold86Z

iTrader: (1)

When the closed loop has made corrections to the fueling, along with block learn learning those corrections in small blocks, it has found stoichiometry, and is no longer technically running rich. The Calibration and Injector flowrate combination may be rich, but block learn and closed loop have essentially changed it back to stoichiometric. But, there are definite advantages to adjusting the calibration to bring the block learns back up to 128.
The O2 sensor is what the ECU is using to find stoichiometry (14.7:1 A/F in an ideal world). The sensor is fairly resillient to rich and lean. Heat will damage them (retarded timing at high flowrates), along with excessive rich soot or oil or leaded fuel coating them. Thermal shock is also bad, such as dousing a hot sensor with water. Electric shock is also not a good idea.

Dave_Jones

On a side note, something that I find helps keep me from making dumb mistakes, is to avoid describing BLM's as being "rich" or "lean." Instead, I try to think of it strictly as "adding fuel" or "subtracting fuel". I've found that keeping it in those terms helps me avoid making bad assumptions about the fuel mix, especially if there's a sensor malfunction or an air leak.

jonarotz

iTrader: (26)

I just want to chime in, maybe someone in here can help me out. I went from 19lbers to 21 lbers and now I have a huge stumbling hesitation. When I accelerate hard (ie getting on the highway) It is really slow it jerks and stumbles. I don't think that it is an AE problem because it seems to accelerate nicely, It seems to be more of PE problem. Any ideas. Possible fuel pump can not handle extra flow?

RednGold86Z

iTrader: (1)

Jonarotz - AE is in effect only when the TPS is moving, plus a split second more. Once it stops moving, such as when holding it open, the AE decays extremely rapidly. PE is in effect when the throttle is open more than 70% and held there. Is this the way you understand it? If you hold the pedal to the floor is it slow and choking on fuel? Or does it hesitate when the throttle is moving? Switching from 19's to 21-22's is between a 10 and 15% jump which will likely take an already rich stock PE AFR and make it super rich to the point of power loss and stumble as you say it is. Get someone to burn a chip for you quickly - or buy the equipment yourself!

jonarotz

iTrader: (26)

I burn my own chips. It seems fine while the throttle is moving, I can reach a point in the throttle where it starts to stumble hold it steady and it keeps stumbling. If I accelerate harder, push further on the pedal, it keeps stumbling. I have leaned out my PE afr and it seems to get worse, I am running a 305 and right noe my PE AFR is real close to that of a 350. This leads me to beleive that there is something else going on. I would have thought that the bigger injectors would have caused a riccher cond. but it seems that it is actually leaner. I am also not getting any black smoke from the exhaust.

RednGold86Z

iTrader: (1)

Well then, if I were to guess anything, I'd say your fuel pump is shot. Check your pressure under load.

jonarotz

iTrader: (26)

That is the point I am at now. I also suspect my pump to be wasted. It was just very coincidental, that it happened with the new injectors.