GEN3 Tuning Injector Data

[rwilson2510]

I have a P01 Computer i am using on a 2000 Iron LS Block. The engine was rebuilt with a 4" stroke crank with 10.3:1 compression. 363CI stroker. Now with that said I am using the 799 heads with the TBSS Intake. I decided to use the 36lb/hr injectors EV6 Plug that came with the TBSS Manifold, Also I am running the corvette 58psi filter regulator with the no return style fuel rail. I believe they are the Chevy Delphi 36lb injectors stock I can get the numbers off the injectors. Now when I try to start and put 36.4 in the box for Injector flow rate vs kpa she barely runs. When i set it back to the 24.7 as seen in the attached photo I can get her to idle. My question is where is a good starting point for the Injector Flow Rate Vs Kpa, Short Pulse adder and Offset vs. volts vs. VAC tables. I would like to not have to change the fuel system. If I have to I will. I will add a higher flow regulator set it got 58 PSI for the max pressure and run a vacuum line to it. Also attached is the tune file I am using.

[kevin87turbot]

Your tune is Tunerlocked. You'll have to unlock it for us to review it.

Once you do that, let us know the part number of the injectors, along with which MAP sensor that you're using as well as the cam specs.

[rwilson2510]

The Cam I am running is a BTR STAGE 2 TRUCK CAM V2 - BTR31218110 SPECS: 212/218 .553/.553 111+0. The Map sensor is the stock MAP sensor off a 2000 Sliverado. The MAF sensor is a Stock Card style I got off a later model and adapted. I did this because i am running a 92mm throttle body DBC. and my intake tube is a 4". Also how do I go about unlocking the tune? The injector I believe I am using is a PN 12613411

[blindsquirrel]

Is it a 'TBSS intake' & the stock injectors that came off an actual Trailblazer 5.3/6.0, or are you using the term 'TBSS intake' as internet shorthand for 'that bigger boxy intake from any Gen4 cathedral port truck that was first used on the TBSS'?

[rwilson2510]

I am using the TBSS intake. I believe it came off a 2007 TBSS. The injectors I know are the GM 36lb

[blindsquirrel]

Then they are not any injectors that came in an actual TBSS. All the GMT360 variants with a V8 used the same 29.4lb injector. None of them were flex fuel.

[rwilson2510]

The PN on the injector I am using is 12613411

[rwilson2510]

I reuploaded the unlocked file

[blindsquirrel]

screenshot.19-08-2022 11.59.55.png

[rwilson2510]

What the heck there is no remote tuning

[blindsquirrel]

Try doing a fresh read of the PCM and save as a new filename.

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2002 P01 12613411.hpt

screenshot.19-08-2022 12.10.08.png

Open your file, open this file as Compare.

Go to View Comparison Log.

Go to Engine > Fuel > General, right click on Injector Control, select Copy Over Selected Differences. (if you accidentally hit Copy Over All Differences it'll copy EVERYTHING different in the whole file, even though you'd right-clicked on that one item)

Save your file with a new name so you have a before/after.

[rwilson2510]

Thanks for the help. I will try this today and let you know. So i noticed the injector flow rate vs KPA is a lot higher than 36. Is there a reason? Also When i got it somewhat idling with the 27lb.hr value my LTFT and STFT were going to the max why is that?

[blindsquirrel]

You have a 'returnless', non-vacuum-referenced fuel system?

With a non-referenced regulator like the file is set up for, the injector flow rate increases when vacuum sucks harder on the injector outlet. At WOT it's spraying into near-atmospheric pressure so the flow is less, but this number is what's meant when someone states a flow rate in lb/hr.

I'm not even going to bother with anything about why it does a certain thing when it's got the wrong injector data in it. It does weird shit because it's being lied to.

[rwilson2510]

Thankyou sir for assisting. As i was getting ready to spend some money on a regulator as well as a different filter and go to a referenced regulator basically hooking up a vacuum line to the regulator.

[blindsquirrel]

Referenced regulator can still be beneficial, especially when boosted. Huge giant injectors can sometimes have a dirty idle because the PW can't go low enough and remain stable; referenced regulator reduces fuel pressure during high vacuum and can allow more reasonable PW. And when boosted, raising the fuel pressure above what it does with a static regulator can let the injectors support more power than they would otherwise. The way it works is that increasing manifold pressure (less vacuum, or boost above atmospheric) has the same impact on injector flow as reducing supply pressure by the same amount - with a fixed regulator 20psi boost is the same IFR-wise as cutting fuel pressure by 20psi. If fuel pressure is always the same relative to manifold pressure then the injectors flow the same at 20psi boost as they do at 15" of vacuum.

[rwilson2510]

I added in two more Files. Basically the 1st read. The second file is where I am at today before the injector adjustments. So the back story was this PCM and engine was originally a 4.8l Ls out of a 2000 Sliverado. I had rebuilt the engine with a 4" stroke crank with 3.780" pistons with 10.3: compression. Then I added the 799 heads. Then the BTR Stage 2 Truck Cam. On top of all that is a TBSS Intake manifold with a 92mm Throttle body. Then I did 4" intake with a welded in slot for the card style Mass air meter off a later model. the MAP sensor is off a 2002 Sliverado it is new ACDelco brand. Also I added in a 255lph Fuel pump with the corvette regulator filter. What I did in the tune was change it to 6.0l because the motor is now a 363ci stroker. I am having issues with starting and idling so i can do the idle tuning. So with that said 1st Start V01 is the tune file I can use to get it to start and idle the STFT and the LTFT go right to 25% My wideband is reading 14.6-14.9. But i cant get it to run with the settings you sent. I am open to ideas. the injectors i am using as stated before are EV6 12613411. I am getting close to say screw it and remove the corvette filter regulator and install a different regulator with a vacuum port. I am open to ideas to help this not being so painful

[blindsquirrel]

What is the actual fuel pressure as measured with a mechanical gauge?

[rwilson2510]

58 psi

[5FDP]

Still can't view the files.

[blindsquirrel]

58 psi

Then changing to a different style regulator, and changing injector data to suit, will not solve this particular problem.