2004 Avalanche

[F540HD]

Any suggestions to keep the ECU happy on a high amp alternator setup on an 04 Avalanche? Once the ECU sees excessive load it turns the alternator off and doesn't restart until the key is cycled. Unplugging the alternator while in this condition will yeild 13.5 volts and bring the amps up but turns on the battery light on data center.

Mistake, it's a 2006.

Edited May 27, 2010 by F540HD

[MECHMAN]

A 2004 avalanche does not have a PCM controlled regulator.

Also, if you unplug the alternator, there is no way for the regulator to recieve power, which means the alternator cannot function when it is unplugged. The ECM will not be bothered by a high output alternator.

If you already have a high output alt on the vehicle, they may have used the wrong regulator, or the belt could be slipping, which would explain why you can turn the vehicle off (belt regains it's grip) and start it back up again and have it charge.

[F540HD]

I'm incorrect on year, it's an 06. It did this with the original regulator as well as two replacements. The regulator has a B+ and a stator signal internally. It will not self excite but will remain charging if unplugged. I was quite suprised to see it start charging upon unplugging. The belt has great coverage and is new. The pulley doesn't over heat so I'm sure it is not slipping plus the unplugging making it charge says slipping isn't the problem.

Sorry about the year model mistake. I've been dealing with this truck for 4 months now.

[Guest DC Power Rob]

On an '06 Avalanche with RVC, the PCM is not shutting it off from EXCESS load, it's shutting it off from a perceived LACK of load. I've never, ever seen a GM PCM shut off an alternator because it was charging too much, ever. The current clamp on that truck should be on the ground side and if you re-did all the cables there may just not be enough current flowing through the clamp to make the PCM see a need to keep the alternator on. The way the RVC system is setup, the PCM takes a combination of current flow and battery voltage to determine at what rate the alternator charges and adjusts the PWM signal to the L terminal on the regulator. If you have a good scope or DMM you can watch the PWM on the L terminal to see what the PCM is telling the alt to do based on the duty cycle of that signal. Try disconnecting any additional grounds you ran and re-check it, my guess is that it will charge just fine. Most all GM vehicles with RVC (2 pin) regulators I have seen will self excite and go into default mode and charge at it's default setpoint which is 13.8, not 13.5v. Rob

[F540HD]

When I say excess load I don't mean an overcharge situation but a high amp load. If you don't use the stereo you can't get the problem to happen even with everything the truck came with at maximum draw. Start turning up the 15,000 watt system though and if the truck is cold you get about 20 minutes but if it's been using the system and already tripped a couple of times you may only get 3 minutes before it's no charge time. Before it goes to no charge the voltage drops to 12.8 for about 30 seconds then begins dropping toward 11 quickly. Killing the stereo and other loads brings voltage back to 12.3 or so but not higher and no amperage showing on power wire from alternator. Unplug the regulator and voltage comes up, might hit 13.8 at alternator but battery shows 13.5-13.6 volts.

Alldata and Transpo say the regulator is controlled by the ECU.

I was hoping somebody had found an easy way around this. I haven't added extra grounds but I can't say the stereo installer didn't. I'll call him tomorrow and ask.

By the way, this alternator makes 324 amps @ 13.2 volts. The main power wire from alternator to starter / alternator block was upgraded but the factory wire from there to battery is intact.

Edited May 30, 2010 by F540HD

[Guest DC Power Rob]

When I say excess load I don't mean an overcharge situation but a high amp load. If you don't use the stereo you can't get the problem to happen even with everything the truck came with at maximum draw. Start turning up the 15,000 watt system though and if the truck is cold you get about 20 minutes but if it's been using the system and already tripped a couple of times you may only get 3 minutes before it's no charge time. Before it goes to no charge the voltage drops to 12.8 for about 30 seconds then begins dropping toward 11 quickly. Killing the stereo and other loads brings voltage back to 12.3 or so but not higher and no amperage showing on power wire from alternator. Unplug the regulator and voltage comes up, might hit 13.8 at alternator but battery shows 13.5-13.6 volts.

Alldata and Transpo say the regulator is controlled by the ECU.

I was hoping somebody had found an easy way around this. I haven't added extra grounds but I can't say the stereo installer didn't. I'll call him tomorrow and ask.

By the way, this alternator makes 324 amps @ 13.2 volts. The main power wire from alternator to starter / alternator block was upgraded but the factory wire from there to battery is intact.

You could have a bunch of things happening to it, none of which you can really dig into without a scope or a DMM with a scope.. If I'm reading right, your running a 300+ amp alternator on basically stock wiring which in it's own right is a big enough no-no, but on this truck depending on where your pulling the runs for the stereo if your running 300 amps into the battery through the inductive amp clamp thats on theses trucks the PCM may just be shutting the alt off. Like I said though, the only way to know is to scope the L wire at the alternator to see if the PCM is shutting the alt off, or if the PCM is telling the alt to charge and it's not which indicates an alternator problem. I wont even speculate as to who built the alternator, but if it's got an aftermarket regulator in it and not OEM, the alt itself could very well be the problem. There is not ONE one single aftermarket manufacturer of voltage regulators in existence that is not an OEM manufacturer who builds regulators that are 100% compliant on these newer systems, not ONE.

I would really recommend redoing all of your power and grounds and make sure they're all done **correctly** and re-checking again, but if that fails your going to need to find someone local that is capable of troubleshooting a system like this, or have the alt checked out, or both.

Speaking strictly logically, (and not trying to be a d*ck) what I really dont know is why your only running one, 300 amp alternator on a 15Kw system?? Being that your only gaining at best 160 amps over what the stock alt will do after what the truck needs for itself and giving you about 2k watts of charging capability on a 15kw system?? That leaves you so underpowered for your system it's not even funny. I'm really confused on that one especially when its so easy to run duals on these GM's.

[treossi]

i just learned something

[F540HD]

Speaking strictly logically, (and not trying to be a d*ck) what I really dont know is why your only running one, 300 amp alternator on a 15Kw system?? Being that your only gaining at best 160 amps over what the stock alt will do after what the truck needs for itself and giving you about 2k watts of charging capability on a 15kw system?? That leaves you so underpowered for your system it's not even funny. I'm really confused on that one especially when its so easy to run duals on these GM's.

When it comes to dealing with the public you can make recommendations but the customer won't always go for it. Many don't mind paying thousands of dollars for amps and woofers but nickels and dimes for the charging system. It was hard to get this customer to even get this alternator and 1 decent battery. We suggested a dual setup and at least 2 batteries.