KATOOM

If you look at my profile you will see what little I have done and I get around 28-30psi boost. Well I just returned from pulling the TT around and I couldnt get any more than 25psi? ??? It was in the 40's/50's outside, raining, and 300 to 6000 ft. elevation. EGT's looked normal. Why would I all of a sudden loose 3-5psi of boost? Would fuel do this? Power seemed good and I just changed the fuel filter. How would I check for leaks, if I should possibly have one, since there is no boost sitting still? Could the air filter have anything to do with it since it was raining? This is the first time I pulled since I removed the snorkle from the airbox. Could I have been pulling in moisture to block flow? O yea, I forgot to say that the turbo didnt seem to be spooling as fast as usual either. It normally just jumps right up there. Please let me know if this is a normal thing. I plan on getting a aFe real soon and I was wondering if boost would increase or just spool faster? Thanks for any info!!!

BigBlue

Check the intercooler hose clamps. They may have wiggled lose. Are you using a turnbuckle to clamp off your wastegate? If so, try and see if maybe it came loose. Also, the air is thinner up there so it's not compressing it as much. Boost is a measure of restriction.

KATOOM

I checked all hose connections and even cleaned the dirty IAT. No gains > I dont know how to check the MAP and I even removed the air cleaner for one pass (no gains). I dont get it. I'm stumped. What about the lift pump? I would think I would see a lose in power if that was the case?! I dont want to chaulk this up as another unexplained Cummins problem. >

mac1

Check your boost elbow. I have seen small particals get caught in the bleed orfice and cause a lack of boost. Also check your wastegate pot. Apply 10-20 psi of air pressure to it and see if it leaks. <br><br>Hope it helps<br><br><br>

KATOOM

Hey mac1, I dont understand why either of those would cause a lact of boost. Both of those problems would lead to more boost. Maybe I'm wrong. ???

AlpineRAM

Katoom, this would lead to a lack of boost because if the small orifice that leads to the open air is plugged the wastegate sees all the pressure instead of just a part. <br>Another factor is if the wastegate does not move freely it may be stuck in the open position. Hence more lag and less boost.<br><br>HTH<br><br>AlpineRAM

KATOOM

Still I dont understand because the brass elbow you get with the EZ has a SMALLER hole in it. Are we talking about the same thing? So if the hole was totally plugged then the wastegate would not open at all right? How do I check to see if the wastegate is opening or closing all the way?

Battering Ram

Kattom, he is talking about the orfice that bleeds to the open air... if it is plugged it cannot bleed the air off. If no air is bled off, it's like having a regular boost elbow.

Scotty

Check your coolant overflow bottle.<br>Is it empty or low? If so, top it up and pull the trailer again.<br>If low or empty again...look at the head gasket. I doubt thats it though.<br>

ChiefW4

Check the torque on the intake manifold bolts. If you have not found the problem anywhere else, you may have blow an intake manifold gasket.

KATOOM

I think that I have a fuel problem not a air leak. I am going to have the fuel pressure tested and get a FP guage. I think it is fuel related for a few reasons. The turbo spooles to about 20 psi then has to work to get to 25 psi...My EGT's are normal and if I had a boost leak they would have been higher than normal, especialy while towing...and I know this sounds silly but when I free rev the motor I still get and hold 2-3 psi and I still get 7-8 psi at 70 mph. That was normal before and wouldn't boost levels be low across the board? If they are low at WOT then that would indicate fuel? The only thing is I dont have any surging that I feel yet. I am going to change the fuel filter again. Maybe I got a bogus one. I will let everyone know if any results.

KATOOM

Sorry but I STILL dont understand what bleed hole!!! ??? Please try to explain what you are talking about better. I know I must seem like an idiot right know but I just dont get why anything plugging the boost elbow (the little brass one I got from EZ, right?) would hamper boost. It should increase boost or why would they give me one with a smaller hole??? Are you saying that the air goes in the turbo through the elbow not out the elbow from the turbo? Plus what torque are the manifold bolts supposed to be?

Turbobob

The little bleed hole in the boost elbow bleeds off pressure to the wastgate actuator &quot;fooling&quot; the actuator into seeing less boost pressure than is actually there. If this hole becomes plugged, the actuator sees full boost pressure from the turbo, and opens the wastegate to bleed off excess boost. Hope this helps clear things up. ;D

Scotty

Pressure test your intercooler too.

KATOOM

Ok, So if I remove the hose off the elbow then the wastegate will think there is full boost??? I am under the impression that the boost from the turbo blow out the elbow hole into the wastegate pot and opens the wastegate at a certain amount of boost. Replacing the elbow with the new one (smaller hole) allows less air to pass and show the pot less boost which in turn leaves the wastegate closed more so I get more boost? Am I right? Why do guys put things like .22 shells in the hose? Thanks for your patience.