I installed a new cam in my truck and noticed yesterday that while having the truck tuned, the maggie makes a brief knocking noise at low rpm's intermittently, then goes away when rpm's go up (around 900). The maggie was installed last year new with only a few thousand miles on it since. I did find a post here that stated " If your cam is causing a slightly rough idle the blower gears will knock together. You can raise you idle or increase idle to spark to help smooth it out." I copied the thread below. My new cam specs are in my sig below. It didn't make this noise with the ZO6 cam, but then, this is a larger cam. Also, why would having a custom tune void the maggie warranty???

https://www.performancetrucks.net/fo...arger+knocking

 

Normal. Gear drive in the front snout not liking a cam hit. Mine has done it since day one and the somewhat rough idle on cold starts.

 

Did you do anything to compinsate for the noise, like turn up the idle? How long have you had your maggie?

 

A custom tune will void the Maggie warranty because you are no longer running the Magnuson tune.....one that is proven safe and CARB legal.

I agree the little intermittent knock at idle is pretty if your idle speed is low.

 

So magnachargers are not made for modified turcks??? What was the point in me buying one then. Does procharger or others also void their warranty when installing their chargers on a modified truck?

 

Well, time for me to get back to work. I will chime in later to see what you all have to say more on this matter. Thanks again for your time and advise.

 

Whoa, slow down cowboy.

if you modify the tune how can anyone other than the person modifying the tune say that that new tune will not cause damage?

Will GM cover your truck's engine if you pull out the stocker and put in a 408?

 

Point taken. It sounds like, with some research of other post, that this is a common problem after installing a bigger cam. I take it then, not to worry about it? Just do as the posted link and mabye turn up the idle or change spark tables at idle?

 

the knock could also be coming from the idler tensioner. mine does the same thing after i put my cam in and idle at it makes a knocking sound

 

I called magnuson and the guy I spoke to said that it didn't sound normal and he doesn't see how a cam swap would cause it to knock at low rpm's. He told me to call back in a half hour and talk with David.