95 4x4

iTrader: (1)

Injector BPW offset vs battery voltage is their a max value at 11.2 , 12.8 and and 14.4 volts ,when i go over 1000 uSec things go wierd .

pandin

The primary function of the battery volts vs BPW offset is to keep the fuel flow linear when the battery volts change.

For a Ford/Bosch II 24# injector.

14.4 518.81 usec
12.8 671.40 usec
11.2 885.02 usec
6.4 3051.80 usec

The secondary function is to slightly adjust the fuel at idle, to bring BLM's back to 128, without changing the Maf tables.

1000 usec is 1 msec of fuel spray, that is a lot of extra fuel......Idle is around 2 ms. What do your spark plugs say, rich or lean?

What do you mean by "go wierd"? Need more specific info about who, what, where, when, how before the why can be answered.

95 4x4

iTrader: (1)

For starters i'am using the $OD mask with TunerCat and DataMaster for the logging . I have a TPI Vortec 355 cu .in. speed density with roller cam 218/224 and injectors flow matched at 26.76 lbs/hr @ 43.5 psi 3 bar . In TC i had to alter my cylinder volume and injector constant so i would not max out my VE table i no not the right way but it worked . When i put everything back the way it should be i max out the VE table so i increased my injector offset BPW vs battery voltage alittle at a time . What is happening more noticeable at idle it seems like it is double firing my PW all most doubles that is what is weird as it jumps between two cells . No matter how any times i adjust my VE table i always get the same result so i must be maxing out some thing and from what you just said about the values i did some thing wrong . I added an attachment for the table . So for now i go the wrong way and sort things out as i go along . I was thinking of altering the values in BPW multiplier vs battery so i did not have to go so high in the injector offset BPW vs battery values not sure if it works like that .

pandin

Low idle vacuum can give you a false load and cause a rich mixture. You are adding a lot more fuel across the battery table, what do your plugs say about your mixture? Just using numbers to tune without a reality check to the plugs can send you up a long and bumpy tuning road.

If you are maxing out the VE tables then something else is out of balance, find out why first. The VE table should reflect the actual air flow thru the engine.

Maybe one of the SD guys could give you a direction to go to address your maxed VE table.

95 4x4

iTrader: (1)

I have tuned my VE table with a WB in open loop so i no i'am very close then i switched back to closed loop and let the pcm do the fine adjustments . I did a plug reading for curiosity and they look fine . 02 sensor at idle was calibrated with new values using a gas analizer and the same for the road test same results but not as drastic . I now put my injector constant back to the way it should be and i still had to increase my cylinder volume so i can get the fuel ? I have no clue as to where i can correct this , even with all the reading and searching. If this was a MAF set up where would you look in the $OD mask ?

pandin

What do you mean by this "I now put my injector constant back to the way it should be and i still had to increase my cylinder volume so i can get the fuel ?"?

In a Maf setup the air flow reported by the sensor effects the bin injector constant. My new Maf split to difference between the 5 Maf's that I have tried. If the Maf reads more air flow, then the injector constant had to be raised, if it read less air flow, then the constant had to be lowered. The new Maf runs at 128 BLM at cruise with a 24# injector constant, which is off a little because of the 50# fuel pressure.

If your map sensor reading is off, everything will be offset.

The ECM is looking for stock situations and bigger cams (more overlap) tend to have lower vacuum readings which are interpreted as a higher (and false) load. The ECM then adds more fuel to respond to this load causing a richer mixture when not needed. If your injector constant is set too high then the mixture is leaner then the actual and will need an increase to the maf tables or the VE tables to correct.

I wish I had more specific information for you, but I am limited to dealing with Maf only.

Your tuning is very good, but if one of the base constants are off then everything is off.

The reason I say something else is off is because of maxing the VE. Lower the VE and lower the injector constant, then look for an input that is different from a stock setup, Temp, Map, or anything that is not in a normal stock range. The ECM is just a calculator, odd numbers in give odd numbers out.

95 4x4

iTrader: (1)

I always had trouble with my fuel in the upper Map area's so i was cheating with the injector and cylinder constant to get the fuel . So i now have put my injectoer constant back but i still had to increase my cylinder volume to get the fuel in the upper Map area's

95 4x4

iTrader: (1)

Been having a hard time with this post on my third time . Here are some thoughts and maybe some one might catch something .
My PCM has been modded to run in PFI mode using the $OD Mask.
Fuel injectors flow 26.62 lb's @ 43.5 psi
In my TunerCat $OD injector flow rate ( per bank ) is 53.5 so i think it should be set to 107.04 since i have four per side ?
In my TunerPro injector rate ( TBI per Inj ) is 53.5 and injector flow rate ( MPFI V-8 per Inj ) is 27.76 might be conflict ?
So if my constant is set wrong that would explain alot of things and why i run out off fuel ? I no nothing on the PCM mod so could it be set up so i only have to use two injectors for the constant ?

pandin

Have you tried using the PE tables to increase fuel at the upper Map areas?

pandin

On my maf system (TPI), I am running 8, 24# injectors (4 per side) then I would load 24 in the bin injector constant (same number in single and double fire). I believe SD (TPI) works the same way. Total fuel flow would be 192#/hr.

I am not sure about TBI ($OD).

Do a search in TGO on "BUDGET TBI BUILDUP"

95 4x4

iTrader: (1)

pandin i'am gonna start from scratch i think i did alittle to much and got side tracked !! I will change my injector constant along with cylinder volume and injector offset BPW vs battery back to the way they should be . I will re-do my VE tables since this is a big change and collect the data and go from their . Thanks for the help , i will re-post the results and start fresh .

Excellegions

Is there a thread that details for dummies the whole injector pulse ? I want to go bigger injectors on my 3.1 v6 but I don't know what in the bin to modify in order to do so.

93V8S10

The injector flow rate in TunerCat is set-up for TBI and is in lb/hr. When using TC for a PFI set-up you will need to use the lb/hr for two injectors. In other words if you have #29 lb/hr injectors at what ever pressure, 29 + 29 = 58 lb/hr.

The injector flow rate in TunerPro can vary depending upon how the constant is set-up. If you have a constant set-up for V8 PFI, then use that. From the examples you gave above, I assume that you will need to use the flow rate for one injector. Also, check to see if the constant is set-up for lb/hr or Grams per Second.

For more information on Injectors Offset table:
http://www.fullsizechevy.com/forums/...ery-volts.html

95 4x4

iTrader: (1)

Okay that is good news then i do have my constants set right . In TunerPro i have my constants set for lb/hr so that is also set right NICE . I'am half way thru from re-adjusting the VE tables . Thanks nice to get a second opinion .