I have an 04 silverado with the 5.3 and a maggie 112 radix on top! when i first installed the maggie back in june the truck started normal and seemed perfect but about the last dozen or so times the truck sometimes wont even start on the first crank. I usually notice this when the truck sits for a day or two and then when i go to start the truck, a loud knocking noise seems to be coming from the supercharger. I put my hand on the maggie and had someone start the truck and you can feel the knock as well as hear it. after about 3 secs the trucks idles and runs perfect! any idea what could be cause this? any ideas? all help is appreciated!

 

Knock is normal in the 112 and a rough idle. There are few threads on it here.

 

The first thing I'd say to check is fuel pressure. Then go from there.

 

fuel pressure is 62 psi constant at turnover and throughout idle and full throttle!

Kysilverado ive searched on here for it and came up empty, think you can remember where you might have heard about this or where i can find that thread?

 

https://www.performancetrucks.net/fo...acharger+knock

 

Ok i read the thread about after installing a cam people are noticing a rotor knock, but my engine is completely stock, so why am i experiencing rotor knock? it is definately rotor knock cause you can stick your hand right on the supercharger and feel it when the truck is first turned over, but why am i experiencing this now and not 4 months ago when i first put it on?
anybody have any ideas at all?

 

You might hear a little rotor knock anytime your engine runs a little rough. Whether the "rough" is from a cam or a cold start. It's a little colder out now than it was when you installed it....right? Do you have access to a heated garage? If so, try a not so cold start and see if the noise is still there. I'd bet the knock has more to do with the motor running rough than any problem with the charger. Also bet the charger is not causing the rough running motor.

 

I'm interested in the "hard starting" issue.

 

That's why I mentioned checking the fuel pressure. His pressure sounds good, but he hasn't really given any detailed symptoms of this "hard start." Makes it difficult to help.

 

What about the cranking VE table causing the issue? I believe resupra has a spreadsheet that converts your ve table to cranking ve table..