Enabling Alternator Charging - L83 Swap on Hotrod

[turabo87]

Hi folks,

I'm trying to enable alternator charging on what is essentially a hotrod with an L83 swap from a 2017 Silverado. Alternator is currently not charging at all. To my knowledge, vehicle doesn't have the BCM nor CCM (only PCM and TCM) and the alternator wiring has been simplified (I don't have exact details yet on the wiring but I can confirm later). Are there any particular alternator charging settings that can be done in the PCM to try to enable alternator charging full power, full time?

PS: Confirmed from the shop that did the swap, there is no BCM and the two pins of the alternator plug are wired factory to PCM, but the PCM is still looking for the amp meter on ground (amp meter has been removed) to calculate power draw and regulate voltage, so I'm looking for a way to force the alternator to run all the time with full power without the use of this amp meter.

[grandam75]

As far as I know there are no settings that will make the ecm control the alternator if the other systems are not present.
You can disconnect the 2 wire connector from alternator and it should charge about 13.6v as a failsafe mode.
If you want more voltage, get a pwm generator and connect directly to the alternator.

[rs6]

I have been told that there is a "Fuel Economy Mode" in the ECM, that if turned on will prevent charging without seeing inputs from the BCM getting it's own inputs from the factory dash. If you can find the "Fuel Economy Mode" and turn it off, that's the place to start. I have the same problem and trying to figure it out too. Just got my MVI2+ a few hours ago so I have no idea where that mode is in the ECM

[rs6]

BTW - mine is a 2017 GM also, two-wire on an L5P Duramax.

[rs6]

one more thing - I pulled the alternator and took it to O'Reilly's to bench test it. (had to show them how to do it ,but..). It tested just fine, internal regulator and total charge.

[CamHaro]

I enabled one by changing to an LS1 style regulator, it is a total hack but it works ok

[TheMechanic]

I enabled one by changing to an LS1 style regulator, it is a total hack but it works ok

You should post how you did that.

[rs6]

OP:

I just bought one of these. http://www.usalternators.com/gm-pcm/

Autotech engineering makes one also. You basically need a PWM pulse at 5amp 180ohm, duty cycle is what controls it. Right now our alternators are not getting the pulse from the BCM. About 80% fixed duty cycle should put you at 14.5 V or so. I bought the fixed cycle as I don't need another knob in the cab and I don't anticipate needing more voltage.

Hope this helps!

[rs6]

Link to Autotech:

https://autotechengineeringusa.com/P..._Plug_Adapters

[rs6]

Still looking for someone who can post how to get to "Fuel Economy Mode" using HP Tuners software and MVI2+

[rs6]

correction MPVI2+

[kevin87turbot]

Just go to System>General and Fuel System Min Voltage and adjust as necessary. Stock is typically 10.5V.

[rs6]

Just go to System>General and Fuel System Min Voltage and adjust as necessary. Stock is typically 10.5V.

Thank you - is this in Scanner or Editor? And this will adjust alternator output, not fuel system voltage right? It has been a pain to get the L5P pressure exactly where it likes it.

[kevin87turbot]

It's in the Editor.

[rs6]

Thank you!

[CamHaro]

Attachment 113761

First, I wouldn?t reccomend anyone to do it, I had to do it because when the OEM alt failed we had no immediate source to either replace or repair it, basically I took a delphi alt apart, removed the regulator assembly and wired it to the LT4 alt. I had no previous experience building or repairing alternators but you only need to spot the places where to run the wires, there is only 4 wires to run, these are the Field(rotor), Stator(external coils), ground to the alt body and B+ which is directly to the diode plate, It is worth mentioning that I did (and anyone willing to try should) the initial testing with the alt on the car and the alt output isolated to a separate batterry in order to check for a voltage runaway situation, wich fortunately I didn?t have, just a perfect 14.2v output. Of course you should mount the reg assembly remotely, not like in the pic, that was on a race day hurry situation, which is already been "correctly" relocated.

[rpmextreme]

This should work for the E92 as well. EZCANBUS Alternator Control module

[rs6]

OP:

I just bought one of these. http://www.usalternators.com/gm-pcm/

Autotech engineering makes one also. You basically need a PWM pulse at 5amp 180ohm, duty cycle is what controls it. Right now our alternators are not getting the pulse from the BCM. About 80% fixed duty cycle should put you at 14.5 V or so. I bought the fixed cycle as I don't need another knob in the cab and I don't anticipate needing more voltage.

Hope this helps!

Turns out I did not need this, but cannot return it because I tossed the original box. It's for sale for $100 plus shipping. 50% off for whoever needs it.