Gen 3 5.3 idle tuning help

[justinphillip414]

Did full engine build, 11:1 compression, ss2 cam, full 3"
Exhaust, tbss intake, 92 mm throttle body. Tons of other crap... I went cheap on my TB, it was junk off Amazon, anyway got my truck email tuned, it ran great... till it started getting cold outside. Idled like trash, rpms shot up when you put it in gear, cold weather cold start initial start up started at 1100 RPM for a few seconds and then it would slowly start climbing almost all the way to 2000 RPM.
Went out and bought a good throttle body with IAC and TPS. Readjusted my IAC counts and TPS voltage, To where it is about 60-70 almost hot idle and TPS voltage is at .45.
But now something else feels off if I blip the throttle the idle dumps down and then recovers. And it's also smelling like raw fuel now at idle
Can somebody please walk me through what I can adjust it's already been tuned I feel like it just needs idle tuning redone?

[gametech]

You need to include a tune and log, or all we can do is speculate on what "may" be going on.

[ns158sl]

Why is this so hard to comprehend for new "tooners". Can't really help without a tune and a log.

Also, what injectors, MAF installed or not, fuel pressure regulator style along with pressure?

[blindsquirrel]

Hold your phone next to the car (make sure NFC is enabled).

[justinphillip414]

I apologize I wasn't expecting such a fast response I've never been on this forum page before, wasn't 100% sure there was somebody who could work with me through all this I'll be home here in just a minute and I'll go do a data log and upload my stock file and my latest tune file along with all my build information

[justinphillip414]

Why is this so hard to comprehend for new "tooners". Can't really help without a tune and a log.

Also, what injectors, MAF installed or not, fuel pressure regulator style along with pressure?

engine build 5.3l with .30 over 2cc dome pistons on stock stroke
.040 head gaskets
~ 862 heads-stock flow- calculated CR is 11:to 1
~ Camshaft specs: 228/230 .585/.585 on a 112 lsa
~ TBSS style intake manifold with 92mm throttle body drive by cable
~ Injector specs: same injectors from 2010 silverado 2500 6.0,
flow rate @ 43.5 psi (42 lbs/hr) - solenoid resistance/ impedance12.5 ohms)
3 BAR dead/latency time ( 0.6957 ms at 14 volts)
~ Adjustable fuel pressure regulator
~ Stock temp thermostat
~ Ls7 mass air flow sensor
~ 4 inch intake tube with open air filter
~ 1" 7/8 long tube headers with 3 inch collectors and 3 inch all the way out


my aeromotive fpr is set at 43.5 rail pressure and the vacuum port regulator is being utilized.
I know my injector data is saying 42lb/hr but data shows its running at 49lb, not sure what the deal is with that.

[justinphillip414]

this is the last log file before i swapped my TB

[gtstorey]

Injector part number?

[justinphillip414]

gm part # 12613412

it has 2 different flow rates , i assumed if i set my regulator pressure @ 43.5 i would achieve 42lb/hr but i guess regardless its going to stay close to 50lb/hr

[justinphillip414]

just went and did a current log file see attached

[SiriusC1024]

With reg vacuum line unplugged it should be 58psi. That's the setting. When the vacuum is reconnected it'll vary.

Data is wrong.
https://forum.hptuners.com/showthrea...l=1#post803270

With that vacuum-referenced reg use the 0kPa column for all columns of IFR and Offset.

After setting that up correctly start worrying more about VE. The idle tuning comes after that.

[justinphillip414]

okay so basically, my injectors are not 42lb, theyre 50lb, so i need to cap the ports and turn the pressure up to 58?

[justinphillip414]

then make all my columns match the 0kpa column?

[SiriusC1024]

okay so basically, my injectors are not 42lb, theyre 50lb, so i need to cap the ports and turn the pressure up to 58?

Don't leave it capped. Unplugged is to set 58. Reconnect vacuum after.

[justinphillip414]

So I've been going down the rabbit hole tonight on this forum page and I realized something. I have a Gen 3 motor and I'm using I guess Gen 4 injectors so I realize all my injector data is off. Is there a reference I can use for my injector data so I can go back and change it?
I'm also using returnless, as well as deadheading the regulator.
I have the 50lb 12613412 injectors

[SiriusC1024]

Gen III data for those injectors is in that link I posted....

For deadhead yes cap off the vacuum ports. Set to 58psi. The data will scale along the vacuum kPa axis. Instructions in that file if that's not clear.

[blindsquirrel]

Do not cap off the nipple on the regulator, that chamber above the diaphragm cannot be sealed off, must be able to see ambient air ('referenced to atmosphere'). Just plug the hose that went to it.

[SiriusC1024]

That's right.

[Alvin]

Getting the injector data is going to be critical on this first. A rich idle is going to have stability issues so be patient with the idle until the tune comes around.

Your IAT needs to be calibrated if you are using the LS7 MAF for IAT also. I made my own calibration table using a hot plate/ice and a bench computer. The table works off of 0-100% over a bias resistor built inside the ecm that I couldn't find documentation about. If you need I can add this to your file.

Also, these have BRAF hard limits.. usually around 28 -32 g/s. So you might need to set this up to where desired airflow doesn't match with a VE or MAF airflow just to keep the IAC within limits. You can tell when you've exceeded this limit cause the IAC will actually drive to 0 if you go too high.

[blindsquirrel]

a bias resistor built inside the ecm that I couldn't find documentation about

In an E38 it's 10.6Kohms. Measure from the IAT signal to a 5vref, there's no other components in the circuit that get in the way of just measuring it. The one I checked has the same reading to either 5V1 or 5V2.

I assume a Gen 3 PCM would have the same arrangement inside (except for only having a single 5V rail).