CAC effects on mpg

Last week I had a dyno done on the truck. It came back fine on hp & blow by, but the truck was only making 18 lbs of boost. I thought it might be the VGT, but we also pressure tested the CAC & hose to the turbo. Sure enough the hose had a massive leak and we also found a leak coming from the actual CAC. I had the hose replaced, but wasn't able to replace the CAC because if time constants and having to remove the radiator. I noticed my mpg went up a little just changing the hose, but will a leaking CAC cause additional loss of mpg's?

 

It's leaking from one of the front seems. Enough that when you pressorize the system, you can feel the air coming out by the front bumper.

I have a Mack and 2 of the mounts are blocked by the frame, so we actually need to lift the radiator up to unbolt it from the radiator, so we don't actually have to completely remove the radiator, just lift it up about 10-12 inches.

 

When we tested both the CAC & hose it was completely draining 40 psi in 10 secs. I don't know what the drop is on CAC only, but I know it's more then 5 psi in 30 sec. I'm having it done next Tuesday, so we'll see if I finally fixed my low mpg problem.

 

I hope your right!!!! I've been chasing this problem for 8 months. Oil temps keep running hotter then they should be. It's not so bad in the winter, but when it gets over 70 out my oil temps are way hotter then they should be.

 

Update, truck went into shop today to have the CAC replaced and the VGT inspected. I'm leaving out tomorrow to do my regular run from Chicago to st Louis. Hopefully it'll start running better and the mpg's come up some more. I've come up about .4-.6 mpg from just changing the hose & clamp and that was driving loaded both ways through TN. (Eagle pass and the gorge)

 

Another update. CAC and house to turbo was done. Tasted the VGT and had full range and it's still getting bad fuel millage, (although it did come up about .5 mpg, so not all bad) so.............. I'm getting the ecm reprogrammed next week. We're convinced the guy who programmed my ecm when I had my dpf issues, just deleted about everything he could and set the turbo to a fixed setting.