Low Boost After Boost Elbow Install

[Andyba20]

Just trying to track down the issue efficiently, if anybody has a good/better/best place to start. Did a boost leak test last week, found a few leaks, tightened some clamps, leaks gone. Threaded in a new boost elbow. Before, with leaks, I was seeing about 18-19psi max. Now I can’t get to 10psi. Set screw is turned all the way in. Bleed orifice does seem to be constantly bleeding air,  but I’m not sure if that’s by design or not. It’s the adjustable boost elbow from DAP.

[Threadzy]

Possibly your wastegate is partially stuck open. I’ve had that happen to me with my old HX35.  EGT’s were high and no power. 

[dieselautopower]

The bleed orifice is supposed to leak some air.  Is the adjustable screw still in the elbow?

 

Did you adjust anything else?

[Andyba20]

I haven’t noticed any higher egt’s (been watching) but it’s definitely a dud right now. Wish these things would happen when it’s warm outside. 

[Andyba20]

23 hours ago, Threadzy said:

Possibly your wastegate is partially stuck open. I’ve had that happen to me with my old HX35.  EGT’s were high and no power. 

How did you remedy your stuck wastegate? 

[Threadzy]

4 minutes ago, Andyba20 said:

How did you remedy your stuck wastegate? 

Took it apart and rebuilt it. That’s when I saw it wasn’t closed all the way. I cleaned everything up real good. Ran it for a bit longer till I put together the hybrid I have now.  It’s on my brother in laws truck now. He hasn’t had any issues. What I also did to both turbos was drilled the waste gate port to 7/8” I believe. I’d have to look at the drill bit. And drilled through to the other port for better flow at higher boost levels. 

[Andyba20]

I was hoping you’d say a little PB Blaster and a couple taps from a hammer. Here we go.

[Threadzy]

I think the flapper inside the exhaust housing on mine was  seized up. Try moving the diaphragm arm back-and-forth with some pliers and see if you get movement. 

[Andyba20]

Alright still trying to chase this one down. I set my compressor to 25psi, removed the boost hose from the boost elbow, and ran my blow gun into the hose/actuator. The actuator arm did move, but I didn’t hear any air. If the wg was stuck open, or sticking open intermittently, wouldn’t I hear some air moving?  Went back and triple checked for leaks, and found a small leak at one of the fuel filter housing bolts, and a small leak at the boost bolt. All is tight now. Everything else is normal, just can’t get more than 8-9psi immediately after the adjustable boost elbow was installed. Can anybody think of what mechanically could have happened from installing the elbow that would result in this sudden issue? I’ll replace/upgrade whatever it needs, I just don’t know where the problem is yet. Only other thing I can think to add is on my first test drive after I installed the elbow, I was seeing 18-19psi like normal, went back and tightened the adjuster screw, then went for another run and that’s when the boost dropped. 

[IBMobile]

Try this, remove the hose from the wastegate actuator, block off the hose, and take the truck out and do a few hard launches.  You should see 28-30PSI.  If still low boost, then waste gate problem, if good boost then problem with boost elbow.

[Andyba20]

Thank you, great idea. I’ll give it a try. 

[Andyba20]

Did your test @IBMobile and still nothing over 6 psi. Looks like I get to remove the turbo. 

[Mopar1973Man]

Be aware if the wastegate is frozen be careful trying to free it up. Make sure to spray plenty of PB blaster, WD-40, or similar to get some lube down the shaft into the cast iron housing. Might even consider heating the cast body to expand the metal a bit and allow the spray lube to creep into the shaft more. Then carefully with a hammer tap a few strokes on the gate or arm and work it back and forth slowly. If its not moving just soak more lube and let it soak for time. Wastegate sticking only occurs when people drive so mellow that they never build enough boost to get the gate open at least once in awhile. Then the carbon and rust build up till it sticks, typically in the closed position. At least my two trucks see enough boost to open the wastegate at least once a week, yes I mat the throttle and let them eat once in awhile. 

[Andyba20]

Is it possible that I drove mellow for so long that when I added the boost elbow and got enough pressure to open the gate it stuck open or partially open? I’ve tried everything I can think of besides removing the turbo and digging in. 

[Mopar1973Man]

Very possible, I've seen several here locally and free a couple too. Kind of like a Kenworth with Cummins 6BT I worked on the owner wanted me to free the exhaust brake vane. Good luck it was so froze up because the previous owner never used it. There wasn't anything I could do to free the exhaust brake. Again you have to work all these components on a regular schedule other than that when it sits idle too long it just seizes up and then the fight is on. 

[wil440]

I picked up 2 exhaust brakes for the Cummins 5.9 for I think £100, one is brand new but hadn't got an actuating cylinder the other is an old one and it's seized solid, this has a cylinder but the rod is bent due to the shaft being seized, and also the cylinder is seized too

 

Like you say "use it or lose it"

[Mopar1973Man]

7 hours ago, wil440 said:

Like you say "use it or lose it"

 

Confirmed what I'm saying... Yup You gotta stand on the throttle once in awhile to shake things up and make that mighty Cummins use it all. Like freeway on ramp stand on that throttle for the what 1/8 to 1/4 mile and let it eat. Like myself I use a full range of throttle on my trucks like two days ago I was using Thor (2006) and on my way home I would down shift when its clear and the stand the throttle to about 80 to 85 MPH and then back out back to cruising speed of 65 MPH. I can drive in such a manner that I never bring boost above 10 to 15 PSI on either Beast or Thor and never work that wastegate, being I typically drive with economy in mind. Att the same time I know I got to work that wastegate now and then. Hmmm... Maybe that why Beast (2002) never had a wastegate issue. The previous owner of Thor (2006) was well kind of rough on it. But didn't take care of the failed wastegate solenoid and the P0243 code now I can reach the P0234 over boost code so I might have to check mine ot be sure it not stuck either as @AH64IDsuggested in my other thread. 

[Andyba20]

This seems like an odd place for a leak (intake horn). And it must be tiny bc I looked with a magnifying glass and couldn’t find it. It’s on the left side. The right side bubbles on the other pic are bubbles that blew over from the left. Any suggestions on the best way to fix it? Or just buy a new one? At first I thought it was air getting by the bolt, so I torqued at and checked again-still got bubbles. Then rtv’d the bolt head and tried again-still got bubbles. 

[Silverwolf2691]

Seems like the aluminum cracked, hairline fracture.. That wouldn't be enough to drop your boost that much though..

 

Intake horn is up to you. Marginal performance benefits going after market, but does look better in the engine compartment 

Edited January 31, 2022 by Silverwolf2691

[Andyba20]

Any reason not to try some high heat JB weld there?