turbo 4.8 tahoe needs help

[Bigbeave1]

McMaster-Carr is like Amazon, but for people who build cool stuff. And without all the 'sponsored listings' and animated 3rd-party banner ads and endless upselling and cult recruitment ('Join Prime - pay us a yearly fee and we'll stop delaying your orders!').

this is the base tune ive been working on for first start up on the gen3 5.3 haven't got injectors delivered yet mind taking a look?
Speed Density Base turbo tune.hpt

[blindsquirrel]

What's your fuel pressure? What type fuel system?

[Bigbeave1]

What's your fuel pressure? What type fuel system?

Currently have stock truck intake and fuel rails with a 255lph holly sniper pump but will be upgraded to the 450 lph running a return line but I believe I'll need to add a boost referenced regulator I will bump the fuel pressure up to what ever would work the best for my setup running 93 pump gas

[blindsquirrel]

A little bit of a red flag goes up whenever I see the phrase 'upgrade injectors' used as I've only seen that applied to offshore copyfakes, which will have actual specs unrelated to the real part numbers they are allegedly based on.

If they are real actual 12613412s, here you go

P59 12613412 58psi returnless.hpt
P59 12613412 58psi base return-style.hpt

[Bigbeave1]

A little bit of a red flag goes up whenever I see the phrase 'upgrade injectors' used as I've only seen that applied to offshore copyfakes, which will have actual specs unrelated to the real part numbers they are allegedly based on.

If they are real actual 12613412s, here you go

P59 12613412 58psi returnless.hpt
P59 12613412 58psi base return-style.hpt

i ordered from the link you posted from ebay i will be running a return line off the regulator .should i flash with your updated tune for the first start up ?

[Bigbeave1]

Thank you

[blindsquirrel]

i will be running a return line off the regulator .

It does not matter if there is an external path from the regulator back to the tank. What matters is if there is a vacuum/manifold reference line going to the regulator. If you have an aftermarket inline or rail-mounted adjustable regulator, but no reference hose going to it, then it uses data just like a 'returnless' system, because the fuel pressure stays fixed no matter what's happening in the intake manifold.

However, once there is a vacuum/boost line going to the regulator, then the fuel pressure rises when manifold pressure rises and fuel pressure drops when manifold pressure drops, so the pressure across the injector is always the same, so the flow rate (and Offset) is always the same.

should i flash with your updated tune for the first start up ?

NO! Copy in injector data only, into YOUR file! That is just a random sample file with the injector data in it.

screenshot.03-11-2022 12.11.15.png

Copy only the ones in green.

[Bigbeave1]

It does not matter if there is an external path from the regulator back to the tank. What matters is if there is a vacuum/manifold reference line going to the regulator. If you have an aftermarket inline or rail-mounted adjustable regulator, but no reference hose going to it, then it uses data just like a 'returnless' system, because the fuel pressure stays fixed no matter what's happening in the intake manifold.

However, once there is a vacuum/boost line going to the regulator, then the fuel pressure rises when manifold pressure rises and fuel pressure drops when manifold pressure drops, so the pressure across the injector is always the same, so the flow rate (and Offset) is always the same.




NO! Copy in injector data only, into YOUR file! That is just a random sample file with the injector data in it.

screenshot.03-11-2022 12.11.15.png

Copy only the ones in green.

ok thanks

[Bigbeave1]

im assuming i also have to copy the cranking Fuel specs also they are in green

[blindsquirrel]

Green in that picture I posted, not green when you open it as a compare with your file. There will be TONS of differences, basically in every tab, from that injector data sample file and your file.

[blindsquirrel]

[ECM] 12311 - Injector Flow Rate vs. KPA VAC
[ECM] 12315 - Minimum Injector Pulsewidth
[ECM] 12310 - Injector Offset vs. Battery Voltage vs. KPA VAC
[ECM] 12314 - Short Pulse Adder

[Bigbeave1]

thanks again