injector math

[k1500]

First, some important information. ECM 16197427-BJLF, Current bin and definition should be attached. Running MAP. Mask id changed to AA, cylinder volume changed to 47.87ci. Fuel pressure key on engine off approx. 28psi. Fuel pressure drops off to 0 in seconds. 7.4l throttle body with injector flow rate of 916cc/min at 14.7 psi per. Guesstimation of the fuel pump is Walbro 50psi 27lph free flow. Im trying to get the fueling in the ball park for idle so that I can zero the mechanical timing, she's spraying a whole lot of fuel at idle right now. Pressure regulator is adjustable. I guess what I think I need is a good line on the math that will enable me to calculate and set injector constants and pulse width. Any help would be appreciated. Also, when I hit enter to type this I don't get a new paragraph, so I hope it turns out easy to read.IM

[EagleMark]

To get a new paragraph, carraige return...

Top of the page, Settings, then scroll down on left for General Settings, then look for

Message Editor Interface:
Enhanced Interface - Full WYSIWYG Editing
Basic Editor - A simple text box
Standard Editor - Extra formatting controls

Choose Standard or Basic.

Need some more information on your engine build, estimated HP and injector size to figure out what your doing?

Other info like why you changed Mask ID to AA? That is only needed for Emulation.

Here's the official GearHead-EFI.com TBI caculater spreadsheet that will help with all your calibrated settings your trying to get.

[k1500]

HP is probably going to be around 400 or more. 383ci, TB 50mm.

I don't have nominal injector size, injectors flow 916cc/min at 1 bar(87lb) according to test report.

Current static fuel pressure(key on engine off) 28#, so looks like 1200cc/min(120lb) per injector, according to witchunter's calculator.

Mask ID changed to AA to prevent checksum error in emulation.

I am very new to this and failed to do some things properly.
I should have started trying to tune with my stock motor, but that's no longer an option.
I should have checked for vacuum leaks better before I tried to fire it the first time, its good now.
I should have came to this forum much earlier, lots of good info.

While trying to use the calculator/spreadsheets the white cells appear to be protected. I'll need to figure that out.

My plan while emulating is not to change parameters while running but to change, start, run, log, shutdown, change. Instead of run, burn, run, burn ect.

I have a few more things to double check before I try to fire again, after which I will change the oil again.

I changed it after the second fire and run(<45sec) and found a couple of small metal shavings about the size and shape of a small fingernail clipping. Along with a small amount of sludgy particulates.

If I find more metal after the next fire(it'll be awhile). I'm sure I will have plenty of time to study up on tuning while I tear it down to find out what I tore up.
Not looking forward to that.

I will continue to study the information available on this site and others, and hope I can get this figured out. Thank you for taking the time to reply.

[EagleMark]

Are you cutting the oil filter open and unwrapping all the filter materiel to look for metal too?

While trying to use the calculator/spreadsheets the white cells appear to be protected. I'll need to figure that out.

Just checked the one I uploaded for you and White cells are the only ones you need to fill in and they are not protected!

All other cells are so people don't change what is not supposed to change. As in notes that say "Fill in white cells only!"

Protection can be turned off, it is not password protected, nothing to hide, no secrets. Protection was just to keep people in White Cells!

[k1500]

Cool, I will just turn off protection and be careful.

Just cut the filter open. Very fine metallic particles suspended in the remaining oil at bottom. A few very small flecks in the element.

I'm having some trouble with my MAP and knock sensors.

In TP5 knock shows an error in malfunctions list, but will count the knocks when I tap the block next to it. 98.3 KOhms, 5VDC supply in range.

In TP5 dash map shows consistent 89KPA, while plugged in I get a good voltage range back probing while applying varying amounts of vacuum to sensor. Should i expect to see the dash value change as the other monitors do?

I think I will stick with the issues I've already mentioned in order to keep focused and to keep from sounding too needy. :)

[EagleMark]

Post a data log and your ADX and I'll look at it. Yes MAP KPA should more with voltage... or is there a MAP Baro too? Is your MAP sensor vacuum hose connected to center port, rear of TBI between fuel lines? Make sue it is good hard line or thick rubber that will not collapse.

Knock sensor has to match knock module in Memcal?

[k1500]

I don't understand "is there a MAP Baro too". I have only the one MAP, Line is connected in the proper port, Ill toss some hose clamps on to be sure line is good.

Map was tested during emulation while monitoring, Key on/engine OFF. I back probed the sensor, set the lap top on the dash and sucked on the vacuum hose while watching both my meter and the TP dash. Meter showed range, TP dash did not show range on map or baro. Not sure what to make of it.

Thanks, ADX is up, I will get the logs up after I do the arithmetic on the fueling and get another oil filter in a few days.

[k1500]

deleted

[EagleMark]

Looks like MAP is working fine, with engine off it's 89 but then there's no vacuum, when running it's 25.

But idling at 2300 RPM is an issue? Constant 4* knock retard and no knock counts along with Knock Error code needs to be addressed.

That a monster amount of fuel to tune!

[k1500]

It appears having the correct knock sensor helps.
No counts but error and retard are gone.

Idle is way high, I'm trying to figure out how to tell it to calm down.
Ill start by dropping about 8lbs of fuel pressure, and finding a way to tell it its getting more air than it thinks with the larger TB

[EagleMark]

What kind of injectors are these? Pictures? Specs? There are no 87 pound injectors so lets try and figure out what you have. Even 74 lb/hr BB injectors only need 20 PSI for that HP.

How are you going 3-4 MPH at 2400 RPM?

Might as well post up cam specs and the rest of the motor build if we are going to get you started?

O2 sensor never goes Closed Loop? Is it hooked up?

[Six_Shooter]

Wrong knock sensor will cause an automatic amount of "knock retard" to be applied to the timing. A disconnected knock sensor does the same. The only reason it doesn't happen at idle, is because there is an RPM threshold that needs to be crossed before knock sensor is enabled. This RPM varies from code to code, but is usually above 1200 RPM.

Also don't get fooled by assembly lube. Many times assembly lube in oil will look a lot like a metallic fleck, suspended in the oil. The metal shavings are something to be concerned with. They could possibly be from the machining process, and just didn't get cleaned out when the block was tanked.

[b1500]

Had to take a little hiatus. While I was busy with life I forgot both the password and email for my k1500 account and most of my records are MIA. The original computer i was tuning with was destroyed(five kids).

So I'm back to square -1. I've got a email out to summit for order history which should help.

What I know I've got is AFR 1040 head with 65cc chambers, 383 with I think 5cc dished pistons, if I recall my desired compression ratio was around 9.5.

Intake is a edlebrock dual plane spread bore with a 50mm tbi. Injectors came with throttle body from tbiparts.com. flow rate was around 913cc/min at 14psi. Fuel reg is adjustable and set to 13lbs running.

Cold idle is rich, no smoke but o2 voltage is near .940.