Mechman billet 240 alternator problems

[jus1975]

I have a 2004 GMC sierra.  Has anyone installed a Mechman Alternator.  Im having messages on the dash for no battery charging.  But its charging.  The message is not all the time.  comes and goes.  Ive changed the 12 volt feed location.  didnt fix it.

Also Im getting a service brake booster message.  

Mechman is very helpful but cant fix the problem.  They said its just a ghost code.  nothing can be done.  But I cant leave it alone and I can never get it inspected.   

 

Anyone figured it out

Thanks

 

 

[richard wysong]

Sounds like a defective alternator or a bad ground

[kickass audio]

when you say you changed the 12v feed location, are you using an external regulator for the voltage or are you using the factory voltage regulator on the engine harness? Did you do the big-3 upgrade as well?

 

I've run mechman alternators in 3 of my vehicles and only had one outright die from a bad bearing, all the other ones are perfect. Mechman did goof up on the alternator I bought for my 2014 silverado and the rear of the alt has a rear facing stud for the +12v bolt instead of a side facing bolt so it was super close to hitting the valve cover. That same alternator because of GM's fuel economy mode would spike over 15v when I first start the truck when it's below 40 degrees outside and the HVAC system would shut down with the voltage being so high and after about a minute of the engine running it would run like normal and the voltage would never get higher than 14.6v. I will see how my 2023 likes the same upgraded alternator with the start/stop engine.

 

What I would start with is if you get a battery light on the dash and the voltage is reading fine the entire time then maybe you have a wiring problem with the 4 pin connector going into the alternator. I would talk to Mechman and ask them what you need to do for tricking the truck that the alternator is fine and keep the light off. On the newer 2 pin harnesses you just need to jump the 2 pins together and it will keep the battery light disabled but you in turn need an external voltage regulator for the alternator to turn on and set the output voltage.