Couple weeks ago I installed a new compressor wheel and up pipes, gutted the ebpv. I've already got plenum inserts, t bolt clamps, and riffraff boots. Yesterday I was dragging a trailer home, first time towing since the new wheel and up pipes. At first I was very impressed, I couldn't make the egt's go above 1150 on hills. As the drive went on I had to back out of the pedal quite a bit on hills to keep the temps down, was boosting around 10 in the trouble areas. I figured that a boot was leaking or coming off, and since those aren't fun to adjust on a hot engine, we took it easy and made it home. Today I hooked up the boost detector and sprayed everything down with soap and I can't find any leaks... To make matters worse I can't build any boost! 2psi, can get a few more if I crank the regulator way up. I can't for the life of me figure out where the air is going. I can tell that some is going out the tailpipe, as I remember that is normal. Some comes out of the ccv, again normal, and the gauge doesn't change if I hold my hand over the ccv, although the pressure does buildup in the crankcase some. I've sprayed soapy water everywhere, listened to everything as well as I can, and felt everywhere I can think of and can't feel air escaping. I verified that the wastegate is working properly and have now unhooked the red line to it. I'm at a loss for what to check next, short of a dunk tank I don't know how to figure out where the air is escaping!

 

You were testing for leak past the CCV tube right?

 

Yep I sure was

 

Subscribing... Been chasing low boost for 6-1/2yrs, lol. Can't get anymore than 11psi/16 with redline capped

 

Did you check around your intake plenums and the boots between the spider and the intake?

 

Wow, I'm hoping to figure this out sooner than that! I boost tested just a week ago and everything was great then, was showing 20 psi on the gauge with no leaks. After installing the compressor wheel I was boosting over 25 pretty easily and setting a code and the light, so I put the Riffraff overboost code regulator on, at this point it's not like I need it anymore.

 

Yeah I sprayed quite a bit of simple green around today, everywhere I could reach with the spray, and followed up with hands feeling for air movement.

 

I ask if the procedure for testing boost leaks is being properly applied: CCV completely out of the picture - air applied to the turbo inlet without the neck to the air intake.

 

Yep, 1 section of hose from the turbo to the boost tester, which eliminates the ccv and allows some air out of the ccv. Same way I've always done it, including on this very truck a week ago with great results...

 

If you are not seeing any leaks in the CAC/boost system, what about leaks in the exhaust system at the manifold, manifold-up pipes, up pipes-collector, collector-turbine, you get the picture.

You are losing pressure somewhere, and since the exhaust drives the boost you may be losing boost before it is even being built. I think you can hook up a compressor to your tail pipe and with about 20 PSI test the exhaust system for leaks.

 

Safety wire your waste gate shut and plug your actuator feed (red line). See if anything improves and report back.

 

tried both yesterday

 

Do you have an EGT gauge? If so what is it reading? How is the truck running? Are blowing a lot of black smoke?

 

So where are you reading your boost from? You don't think the code regulator could be causing it do you? I don't use a regulator so I'm not really familiar with how they are set up. But that seems to be the only thing that's changed since your boost went away.

 

Yes I have an EGT gauge, as I described in the first post it's running hot. Truck is starting and running fine. I didn't specifically look for black smoke, I normally notice it if it's there.

I keep on thinking this scenario over in my mind, i've wondered if the turbo isn't making boost, but then I remember that I can't even build boost with the leak detector. I did discover after I put it back together that my ts chip was turned down from where I normally run it, which could explain lower boost, but then egt's should be lower, and then of course that doesn't explain why I can't built boost with the leak detector.