Custom 07 Tahoe, Charging System Issues

[smmperformance]

Hey Guys. We are working with a unique project and would like to resolve our charging system issues. The vehicle is a 2007 Tahoe LTZ SUV with a GM LS7 7.0L engine and GM 4L80E transmission.

First of all, see our most recent attached tune file...

We have had the OEM 07 Tahoe PCM & TCM flashed with a new VIN for a vehicle with a 4L80E transmission, for proper operation.

We are having another issue with the charging system on the vehicle, ever since the computers were flashed & the tune was altered for the new 4L80E transmission. The "Service Charging System" error message randomly pops up on the display at times, during starting or driving.

I appreciate everyone's help... Please advise.

[smmperformance]

No help able to be provided? Please advise.

[WarWagon]

The 2007 has the alternator kick out and system monitor for the battery discharge. See the big device on the battery cable? I bet the hot rod engine alternator is not compatible with the shutdown commands for a Tahoe. So system says battery full, conserve fuel and cut out the alternator... It continues to run and hence the message.

[smmperformance]

I actually have a large amp Stinger alternator, so it is not OEM.
What do you suggest?

[WarWagon]

I actually have a large amp Stinger alternator, so it is not OEM.
What do you suggest?

I do not know where this is activated in the computer. However there is a way to get it to work. It does require a way to shut down the alternator via a special connection to it or a special alternator.

Just start with the simple stuff for a test.
Swap in a Tahoe 07 Alternator. You may have to re-clock it.
Make sure the factory current monitor is on the battery cable.

First charge the battery so the system will activate quickly.
Then keep electrical loads low/off.
Start and run engine maybe even drive at a steady freeway speed above 60 so fans don't kick on.
It should work indicated by the voltage suddenly dropping off.
(This is a heart attack giving drop on the volt gauge, aka alternator just failed, when you are in the middle of Route 166 out of cell phone range and not enough reserve bat power to get cell phone range.)
As the battery discharges the system will kick in the alternator again. Or if you turn on the headlights or other high load for a time.

If the alternator will not fit: (Or if it does and the test works
Ask Stinger if they have a high amp unit that will work with this 'system'.
Check the Chevy repair book at a dealer (Maybe where you got the crate engine?) for all components that this system uses as there may be more than the two listed devices used for it. This will also give you any special wire connections to the alternator and testing for this error message you get.

The high amp output is irrelevant because at a given voltage/temp a battery will only take so much current. So you will not peg the battery cable readings.