mhorn0817

I have a 02 Sierra, supposed to have a 180 amp alt but I never verified. When my Efans kick on it seems like there is a huge shock to the truck and it's like e everything dies for a quick second. What cause this and what can I do to fix it

N20zuki

Are you using a relay to control the fans? What fans are they?

Atomic

iTrader: (42)

You can stagger the fans so they both don't kick on at the same time. Other than that it may be a weak battery or alternator?

That a stock alt? Gm never made a 180.

BlueTexan24

Mine does the same thing, especially if I turn the ac on and they both kick on. A bigger alternater is the solution I would think cause after the initial shock it's about normal, but it feels like it sucks about 100hp out of the motor when they first come on for the ac. I've got like a 105 amp alternator I'm pretty sure. It's a stock replacement for 99 and it's too small.

Atomic

iTrader: (42)

Yea you need a bigger alternator. When I did Evans with my 105 I could literally kill the engine if I turned them on at idle. Even when driving it made weird issues. The 145amp alt fixed it.

03sierraslt

iTrader: (22)

Also- injector offset table incorrect and or too little running airflow in tune.

BlueTexan24

Atomic, where did you get your 145 amp alternator? Did you just rebuild it with better internals?

Atomic

iTrader: (42)

Its actually a factory 145amp one from an 07 or something. I dont believe there were any factory 1wire-4connector ones that will drop in. You have to replace the regulator, which isnt hard, but is about $45.

You can upgrade the stator while you are in there if you want to for more output. I think the details are in my build thread in my sig if you search that thread you should find it.

bobfig

just get one that is from 04 or older and it will have the 4 pin connector that the older trucks used. in 05 they changed to the 2 pin where the pcm controls it.

GMCtrk

iTrader: (27)

I'm curious if the oem fan harness/relays have a ramp built into then because my efan operation is seamless. You never know they've come on unless you hear them.