5.3 with LS6 intake/injectors and COS3 2bar MAFless

[blindawg]

Hello all,

I have a 5.3 with an LS6 intake and injectors on it running COS3 2bar MAFless, and its in an 04 Colorado. I copied over the values for the injector tables from a stock zO6 tune, and the truck runs like crap if I ease into the throttle its not bad, but if I do anymore than ease into it, it is somewhat jerky and lacks power something furious.

before I made the changes stated above, it had the factory truck Injector values in the tables and ran decent, but wasn't at full power. I don't have my WB installed yet, or a log for you guys, but it has to be something simple, right? I'm assuming its running too fat with the LS6 values, and might be a little lean with the truck values, especially at higher RPM beings it is only one value and referenced to vacuum on the truck intake.

Thanks,
Branden

[joecar]

Hi Branden,

Your IFR table is flat (using LS6 manvac=zero cell)...

you might have injectors other than you think.

Post logs of each IFR table (GM.IBPW1/2 and CALC.INJDC1/2).

[blindawg]

Hi joecar,

I'm not sure what you're saying with your first statement. I think I do, but I think you're understaning my first post wrong. (Can't blame ya there. I just re-read it and it's kind of a mess. Lol)

Anyways, I would agree with you about me having mystery injectors, except I pulled this intake and injector setup straight off the 5.3 I had in my s10 to put it on this motor, and have tried running the same calibration as what the s10 ran with and it creates the problem stated above.
I can't log anything right now, but I'll get you a couple logs asap.

Thanks for the help, as always,
Branden

[ProperTuningOG]

Can you share your tune? The pre change 5.3, the LS6 used and the post swap please.

[blindawg]

LS6 File Used-
2004 Chevrolet Corvette Z06 Coupe Manual LS6 5.7 Litre (12592425).ctz

LS6 Injector values-
Silverado COS starting point.ctz

Truck Injector values-
Silverado COS starting point_Truck injector values.ctz

Thanks,
Branden

[ProperTuningOG]

I'll have a look. Where are you located? Can you verify the part numbers on the injectors and the fuel pressure?


Edit - Looking at tune
Is the fuel pressure vacuum referenced?

[blindawg]

North East Kansas.

I need to verify fuel pressure, I was going to do that when I did the logs. Looking like that won't be until tomorrow morning.

No, it's not vacuum ref. It's a returnless, factory car fuel system. If anything I would say my fuel pump is weak because it had a LOT of miles on it, but it runs decent with the truck values so how could that be the problem? (Just thinking out loud.)

Thanks for the help,
Branden

[ProperTuningOG]

I'd verify your pressure and the part numbers on the injectors. Then check the injectors for being plugged. Watch fuel pressure when getting into load.....

Is the engine in the jeep in your pic?

[blindawg]

Injectors should be what I say they are. Only reason I say that with confidence is because it ran fine in my s10 with those values. (Not the truck values) but I'll check for my sanity. Lol.

Nope. That jeep is no longer ours. This is in my 04 colorado.

Thanks,
Branden

[ProperTuningOG]

K. One last question..... Maybe 2.

Whats the reason for the COS3? MAFless the only reason?

Its a manual, right? As in this is original stuff from the colorado minus the intake and injectors.