First time user looking for advice on 2013 Gen3 6.2 runs hot and no power

[Chorst]

Good day everyone,
I just purchased the HP tuner kit with pro feature package and I'm getting started with a 2013 Yukon Denali, 6.2 that is running hot and low power.
I'm doing a lot of reading...just looking for advice, because it looks to have multiple problems and I don't want to make it worse before it gets better cause it's on the edge with the temp.
It's had the DOD delete about 3 years ago with paid for tune from local machine shop, ran fine but recently running hot and no power.

2013 GMC 6.2
Speed Density - 2 bar:
OS:1250239

Speed density air mode not applied
Manifold vacuum boost not applied
TCS patch not applied
Vats1 patch enabled
Vats2 patch enabled
starter fault checks enabled


I've attached 2 scans and the tune, no changes made yet.
I do not have a wideband sensor, I hope to buy one tonight, because it looks like that's the way to go.

Some things I noticed was:
the Voltage is dropping into the 12V range sometimes
MAF looks low
IAT gets high
ECT gets high
sometimes I think the fans are not running at full speed, even when it's hot. just by the sound they make.
I'll probably start with calibrating the MAF tonight, if I can do it without the wideband.

Thanks in advance - Any help would be greatly appreciated.

[Lakegoat]

Looking at your short term fuel trims, I don't think you have any need to disturb the MAF settings.
My '13 runs about 210 degrees all the time---normal for a stock setup. If you think it is too hot, check the radiator cap and maybe change out the thermostat if you want to see cooler numbers. What size tires do you have on that rig
I see on the second log it is running about 220---230 degrees. I still wouldn't suspect MAF calcs. Make sure your radiator hose isn't sucking closed also.

[blindsquirrel]

"Recently running hot and no power" is not a tune issue, it's a physical issue.

Does it still have cats, and are you sure they aren't getting restricted?

[Chorst]

I didn't think about the cats getting plugged.
any ideas on troubleshooting this, maybe take the O2 sensor out and get a back pressure reading?
The fans don't seem to be running on high speed all the time. You can hear when they when they kick into high gear, very loud and makes a difference.
intermittent for sure, and the voltage shouldn't go from above 14 to 12 should it?. I may change out the high speed fan relay in the fuse box. and/or use scanner to see what it's telling the fans to do.

[Chorst]

I'll check the hoses.
Seems to be generating a lot of heat. the IAT goes up when not moving and it's pushing a lot of heat out of the radiator.
The MAF just seems to run down on the lower end of the scale, just didnt look normal, but IDK what normal is.

[Chorst]

Found broken vacuum hose fitting from passenger side valve cover to intake.
So it is sucking a little air, not much. Gonna try and replace tomorrow.
and replace fan relays.
Do I need to worry about that voltage dropping down to 12V?

[Chorst]

Stock tires.

[Chorst]

Was goiing to try and buy a wide band O2 sensor tonight...
Any advice on which one to get for the MPVI2+; they also have a LSU 4.2.
I have the cable to wire it into. Jsut need to pick a sensor.

will probably order this one.

MSD Ignition 2267 - MSD Power Grid Wide Band Oxygen Sensors
Oxygen Sensors, Replacement, Wideband, LSU 4.9, Each

Part Number: MSD-2267

[blindsquirrel]

It has a module that turns the alternator off under certain conditions. I don't have access to service info for that year but I am nearly 100% certain there will be an info-only TSB for owners complaining about voltage fluctuates on its own, voltage reads low, etc, and advising this is normal operation.

From the 2009 Silverado manual:

Voltmeter Fluctuation Condition

Some customers may comment that the voltmeter is fluctuating between 12 and 14 volts on their full size pickup or utility vehicle. Starting with the 2005 model year, light duty full size pickups and utilities are equipped with a new Regulated Voltage Control (RVC) system. This system reduces the targeted output of the generator to 12.6-13.1 volts when in "Fuel Economy Mode" to improve fuel economy. The generator may exit "Fuel Economy Mode" if additional voltage is required. This will cause the voltmeter to fluctuate between 12 and 14 volts as opposed to non-regulated systems that usually maintain a more consistent reading of 14 volts. This fluctuation with the RVC system is normal system operation and NO repairs should be attempted.

[blindsquirrel]

Was goiing to try and buy a wide band O2 sensor tonight...
Any advice on which one to get for the MPVI2+; they also have a LSU 4.2.
I have the cable to wire it into. Jsut need to pick a sensor.

will probably order this one.

MSD Ignition 2267 - MSD Power Grid Wide Band Oxygen Sensors
Oxygen Sensors, Replacement, Wideband, LSU 4.9, Each

Part Number: MSD-2267

AEM 30-0334 - it piggybacks onto the OBD connector and feeds data straight into VCM Scanner for logging.

[Chorst]

It has a module that turns the alternator off under certain conditions. I don't have access to service info for that year but I am nearly 100% certain there will be an info-only TSB for owners complaining about voltage fluctuates on its own, voltage reads low, etc, and advising this is normal operation.

From the 2009 Silverado manual:

Thanks. Good information; is there any way to turn the regulator on and off?

[Chorst]

I have the prolink+ cable so guess It will wire up to it. HP tuners didn't list one.

[blindsquirrel]

Thanks. Good information; is there any way to turn the regulator on and off?

Sure, just trade in the truck for an older model from back before they started using that system.

It's doing what it is supposed to do, and it does a lot of more sophisticated stuff than turn the alternator off sometimes. There are some settings in the tune file at System > General but I suggest you get yourself access to the service manuals and read up on how it works before deciding to make any changes.

Battery Sulfation Mode
The BCM will enter this mode when the interpreted generator output voltage is less than 13.2 volts for 45 minutes. When this condition exists the BCM will enter Charge Mode for 2-3 minutes. The BCM will then determine which mode to enter depending on voltage requirements.

Charge Mode
The BCM will enter Charge Mode when ever one of the following conditions are met.
? The wipers are ON for more than 3 seconds.
? The GMLAN Climate Control Voltage Boost Mode Request is true, as sensed by the HVAC control head. High speed cooling fan, rear defogger and HVAC high speed blower operation can cause the BCM to enter the Charge Mode.
? The estimated battery temperature is less than 0?C (32?F).
? Battery state of charge is less than 80 percent.
? Vehicle speed is greater than 145 km/h (90 mph)
? Current sensor fault exists
? System voltage was determined to be below 12.56 volts
? Tow/Haul mode is enabled

When any one of these conditions is met, the system will set targeted generator output voltage to a charging voltage between 13.9-15.5 volts, depending on the battery state of charge and estimated battery temperature.

Fuel Economy Mode
The BCM will enter Fuel Economy Mode when the ambient air temperature is at least 0?C (32?F) but less than or equal to 80?C (176?F), the calculated battery current is less than 15 amps and greater than -8 amps, and the battery state of charge (SOC) is greater than or equal to 80 percent. Its targeted generator output voltage is the open circuit voltage of the battery and can be between 12.5-13.1 volts. The BCM will exit this mode and enter Charge Mode when any of the conditions described above are present.

Headlamp Mode
The BCM will enter Headlamp Mode when the headlamps are ON. Voltage will be regulated between 13.9-14.5 volts

Start Up Mode
When the engine is started the BCM sets a targeted generator output voltage of 14.3 volts for 30 seconds.

Voltage Reduction Mode
The BCM will enter Voltage Reduction Mode when the calculated battery temperature is above 0?C (32?F). The calculated battery current is less than 1 amp and greater than -7 amps, and the generator field duty cycle is less than 99 percent. Its targeted generator output voltage is 13 volts. The BCM will exit this mode once the criteria are met for Charge Mode.

[Chorst]

Thanks for the help. I?m gonna get back on it tonight. Been doing a lot of reading. Lots of good info on here.

[Chorst]

Thanks. I won?t dwell on the voltage any more. I just don?t remember it dropping down that low and I swear the oil press gauge dips when this happens.
I?m replacing those fan relays. I think the high speed is not always coming on.

[Chorst]

Thanks. I?ll look it up.
I have this cable that came with the + scanner but the one you described sounds like the ticket.