I got my truck put back together and went for a drive, I did not beat on it just incase something was still wrong. Since my last test drive I have pinned the crank pulley, replaced the FPR, Changed Headers and installed my boost gauge and fuel pressure gauge. My boost gauge is still reading 3psi? My fuel pressure gauge is 53psi @ idle, maximum of 63psi while driving around. I also scanned my truck while driving around and I do not get any KR while driving around except for when i got into the throttle a little bit more and then the KR went up to about 6 or so? https://www.performancetrucks.net/fo...ad.php?t=344673 I pulled up an old scan from last year before I installed the Heads, Cam, and Radix and I was also showing about 6 or 7 deg. of KR at that time aswell. I think the cause of the KR is from a lean condition so hopefully when I get the wideband installed Jesse can get my tune fixed. If anybody else has any ideas of what might be the cause of the KR or the low boost I would appreciate some advice. I am getting closer but I am not quite there yet. Hopefully Blownchevy can chime in about the low boost issue.

 

I was thinking about something, Stock Radix makes 7psi, 3.1 pulley adds about 2psi so I should have about 9psi if I had a stock truck which I dont. How much boost does the Stage 2 Heads, GT2-3 Cam, Airaid Intake, LT Headers, and no Cats take away from showing on the boost gauge? Maybe 3psi is all it is showing because of the free flowing exhaust that I have? Let me know what you think.

 

wack a 2.9 pulley on it, easy to do and easy enough to compare boost levels.
you'll probably need a belt to go with it.
most of the 6.0 guys are running 2.9s.
would be some quick troubleshooting and save alot of grief trying to find other sources of your low boost.
you are probably right about your exhaust's affect on your boost levels.
dave

 

two things
1. did you swap to a newer PCM? the older ones had problems with unexplainable KR. Did you adjust your knock sensors for the cam?

2. Have you checked and rechecked your manifold bolts? Do you have the bypass installed correctly?
How does it feel?? there could be a kink in the boost gauge vacuum line. What does it show for vacuum at idle?

 

I did swap to a 02 pcm, whether or not Jesse used the 02 program to tune my truck is another question. I do not know if he adjusted the knock sensor for the cam but I was having KR problems last year before the cam was installed. My truck feels strong and I cannot hear any audible knock so I dont know. I also do not hear any whine from the radix which is weird, that could be from the lound exhaust? The bypass was installed from the factory so I hope it is installed correctly. I will have to get back with you about the vaccum reading @ idle. I will also recheck the manifold bolts again just incase. Thanks.

 

Am I reading this right? You still have 5.3 right? I don't think 3psi is possible even with the most of free flowing anything. Maybe tons of restriction in your intake and open headers. Stuck bypass. Something is wrong. This is a new radix install?

Tried Mechanical boost gauge for testing purposes? Like Green asks, what's your vaccum at idle? If it's way off then more than likely you are just getting a wrong reading. However...not being able to here the radix scream at WOT would bother me.

 

I didn't notice any boost drop with a header install, free flow cats, and Corsa cat back. I dropped about 1.5 to 2 psi when I installed a reverse split cam.

 

Yes I still have a 5.3L and yes this is a Brand New Radix install, I currently have an Autometer mechanical boost gauge that is reading a maximum of 3psi? I am going to check my friends boost gauge to see if for some reason mine is broken, but that still does not explain the lack of the Radix whine? Yea it bugs me to that I can't hear the Radix scream when I get on it. How do I check the Bypass to see if it is stuck? The boost gauge climbs up to 3psi and then is stuck there. I know it is probably something simple, I just need to find it.

 

Check your bypass valve on the Radix and see if it is stuck open. There is a silver shaft that comes out the back of it that opens and closes with the vacuum of the engine. With the truck idling the valve should be open, when you shut off the truck it should close. If you have someone help you, you can watch it as the truck shuts down and you should be able to see it close. You can also have your helper rev up the truck (WOT only, if you rev it slowly you won't see any boost) and you keep an eye on the bypass valve to see if it moves at all.

 

I will find out if my bypass is stuck, also I will check the vaccum @ idle when I get home from work. Thanks, Brad