Archived No Boost

[surfbeetle]

I pulled a long grade with my 12valve towing my fifth wheel. Normally my boost is 30 psi. Now it barely hits 10psi. My exhaust never went over 1300 degrees pre turbo. I checked the intercooler boots & the guage connections. When looking at the front left of the engine where the head meets the block, I can see what think is a light colored gasket.



What are the symptom of a blown head gasket or pulled head studs? The truck still seems to have good power but not as snappy as it was before. Anyone know what Cummins Cal Pacific would charge to fix a head gasket?



Thanks, I'm stressing about this.

 

[GAmes]

My first thought was the turbo is binding. Have you checked it? If it is stock I believe a lot of use in the 30 psi range will shorten it's life.

 

[surfbeetle]

I will check it. The turbo is the original. It would sure be easy if that was the problem.

 

[CBeeman]

Try presure testing your intake. Make a fixture to connect to the turbo inlet and but 10-15psi of air presure in it. What year truck is this? Is the exhaust system stock?

 

[surfbeetle]

It's a California '95 truck. The exhaust is 4" with a straight thru muffler. I plan to make the pressure adapter tomorrow.

 

[RON'S RAM]

Do you have an exhaust brake? I lost power & boost and found the problem to be a broken retaining ring inside the exhaust brake. The brake was about 70% closed.

 

[surfbeetle]

Thanks to all who replied. I was out on a camping trip when this happened and was using my phone to post online. I kept it brief, typing a post on a phone is a kind of a pain. I did what CBeeman suggested, I pressure tested the system with a end of a plunger that I put an air chuck onto. My problem was the hose for the boost guage sprung a leak. I cut the hose down and reattached it. I will be getting new hose this week that hopefully will last a bit longer. My boost is back to 30 psi. Looking back it makes sense why the truck still seem to run okay with minimal smoke in the exhaust and what appeared to be no boost as the guage was not reading correctly.

 

[GAmes]

I've run my boost hose thru hard plastic tubing like I used on my air-horn. It has worked very well.