turbo 4.8 tahoe needs help

[bigmike]

to anyone that might want to help!! 2007 tahoe 4.8 2wd
Recently bought a project truck. I didn't buy or install the parts but i got the truck with receipts and pics for a pretty decent deal. the truck had 300k on it with a bad lifter before motor was pulled to rebuild. full rebuild all new bearings pistons rings block and crank went to the machine shop not 100% on exactly what the did with the block i think just hone and cam bearings polished the crank stock rods. btr stage 4 truck cam v2 with springs ls7 lifters the heads were gone through all new valves. then what i think is a ebay truck turbo kit was installed. aem wideband and boost gauge in the truck. I just installed a qfs 340 fuel pump and converted to a regulated return fuel system referenced off the manifold. welded in a stainless -6 jic on the passenger side of the rail that goes to the return. while the rail was out i pulled stock injectors, decapped cleaned and flow tested them. they all looked good within 1-2% excellent spray pattern. I am a pretty good mechanic with yrs of experience welding and fabricating experience from building custom metal boats. Im also fairly tech savy. ordered the mpvi3 with 2 credits been doing a ton of research on tuning watching hrs of videos on youtube and from what i can tell so far its going to take me months if not years before i am where id like to be skill and knowledge wise on tuning. Id rather learn to tune and be able to continue to make changes than pay someone else a whole bunch of money and they might not even nail a perfect tune.
The truck will start and run. i havent tried to drive it at all just in fear of doing damage from the tune being so far off. I think the previous owner also did something with the tune but had no idea what they were doing so i dont know what may have been changed already just to get the thing to idle. Ran way better with the decapped injectors but now the idle is super fat wants to stall. Any how im not looking for this thing to make gobs of power or be super fast just want to get it driving as good as possible low boost maby 5 psi? Can i get away with the stock map sensor?
pulled the tune on the truck last night attached it. any help/advice would be greatly appreciated.

[blindsquirrel]

Well first off you have hacked-up injectors that now flow something like 75-80lb-hr but the ECM still thinks they are 29.4lb. And neither the flow rate or offset tables have been changed over to suit a referenced regulator.

If you decide to keep the junk injectors, the tune will have to be scaled. Your early ECM has a hard limit of 63lb-hr.

[blindsquirrel]

This is on a Gen 3, but everything about the decapped injectors still applies, so it'll save a bunch of retyping the same stuff over again if you just read through this:
https://forum.hptuners.com/showthrea...wap-won-t-fire

[bigmike]

I am not opposed to buying injectors if thats what makes all the difference?. What would you recommend? No way the stock capped injectors would have worked anyway right? Should i get a 2 bar map sensor too? Im trying to stay budget friendly but ill spend the money where its needed. Just didnt want to waste money buying the wrong injectors. I really appreciate the help. Guys around my area are super tight lip unless your paying.

[blindsquirrel]

What's your realistic HP goal? Like, something you wouldn't be upset about not being able to exceed?

Did you read the thread I linked?

[bigmike]

Yes. read a bunch more too i understand the parameters are all out of wack making it pretty much not tunable down low. Im not worried about power at all. Big truck old 4l60 just want it to sound good and be as drivable as possible. 5-550 hp is more than enough. Im sure im going to be into the trans before long. No head studs. id like drop in injectors. Modifying the rail height is easy enough but id rather not cut into the injector wires.
So maby 60 pound injectors?

[blindsquirrel]

https://www.ebay.com/itm/274424906026

51lb/hr from a L96 truck. I can convert the late E38 injector data over to your early E38 if you decide to go that route.

This part number is the only one you can get that cheap and not get offshore fakes. It's just a happy coincidence that it happened to be the one part number that'll support ~650 HP.

[bigmike]

Awesome thats alot better than the 600 for fuel injector clinic. Are those injectors slightly shorter? Do they require any modification to the rail or can you run them as is?

[bigmike]

https://www.psiconversion.com/tech/l..._injector.html

nevermind. found this pretty helpfull

[bigmike]

Injectors will be here friday. What do i need to do in the tune to make the regulated return work? Is it worth hooking up the pro link to log afr?

[blindsquirrel]

Flash this file (it's yours with only injector data updated), set the regulator to 58psi either with engine running and vacuum hose to reg removed, or key on engine off.

tahoe how i got it 1 - 12613412 58psi referenced.hpt

[LS ROB]

https://www.ebay.com/itm/274424906026

51lb/hr from a L96 truck. I can convert the late E38 injector data over to your early E38 if you decide to go that route.

This part number is the only one you can get that cheap and not get offshore fakes. It's just a happy coincidence that it happened to be the one part number that'll support ~650 HP.

That for a whole set!? hmm.. wonder if these would work in the ls7? Where can i find dimensions on these? google?

[blindsquirrel]

delphi.jpg

https://www.rockauto.com/en/moreinfo.php?pk=1887186
https://www.gmpartsdirect.com/oem-pa...embly-12613412

[blindsquirrel]

Use this lower o-ring to adapt them to the bigger LS3/7 manifold: https://www.mcmaster.com/9262K994/

They are slightly taller. Might need a spacer under the rail to raise it up. Just depends how far down into the hole the injector can go.

Clips: https://www.rockauto.com/en/moreinfo.php?pk=438100 (yes, that price is for all 8 in one bag)

[LS ROB]

Use this lower o-ring to adapt them to the bigger LS3/7 manifold: https://www.mcmaster.com/9262K994/

They are slightly taller. Might need a spacer under the rail to raise it up. Just depends how far down into the hole the injector can go.

Clips: https://www.rockauto.com/en/moreinfo.php?pk=438100 (yes, that price is for all 8 in one bag)

Incredible. I'm going to grab a set. I appreciate that info brother!

[LS ROB]

https://www.mcmaster.com/9262K994/

^^ These guys got their crap together! Ordered that stuff shortly after you posted the links. I noticed when I ordered I got an email confirmation that says "we shipped your item." I thought, yeah.. just the normal shipping jargon. Man, 9-930am next morning I had a pack of o-rings setn on the front porch! LOL

[blindsquirrel]

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!').

[eighty6gt]

I discovered mcmaster at an old job, they seem to accomplish the impossible.

I should order some of those injectors.... I have 8.1 31's/34's and am worried they aren't in good shape. Thanks for the link.

[gtstorey]

Grainger can be useful to. Not quite the selection of MC, but if you have a local branch you can get it shipped there for free.

[Bigbeave1]

blindsquirrel not to hijack the thread but im in the same boat 5.3 turbo swap wondering what injector data i needed for the ebay injectors i also got a set new to tuning what would i need to copy and paste to switch from stock 5.3 injectors to the upgrade ones?