[12VRattler]

I have a 96 dodge 2500 4x4 with a manual. Ever since I bought it a couple months ago it has seemed to have some power issues. I put guages on it this weekend and found that I have low boost. I can only pull 14 psi full throttle and it takes about 1/2 mile of full throttle to build that much. At cruise no matter the speed my gauge reads 0 psi boost, and upon romping on it, it takes a quite a while to build boost. I have read alot talking about boost leaks and such and built a test cap to pump up the air charging system and found a couple leaks but they seem to be very small.
The leaks I found are
wastegate actuator ruptured (capped of line)
intercooler boots have very small pinholes
I also hear air going down the exhaust just a slight bit. I pumped it up both with the intake horn hooked to the engine and with it capped off. I have sprayed everything liberally with soap water and am having a helluva time finding a leak that amounts to much. My exhaust is wide open, no restrictions and no intake restrictions, new filter. Any suggestions? I cannot find ANY leaks that amount to anything but the air is leaking out fast but I cannot hear it, and I can normally pick up leaks.

 

[stupid_productions]

Let's not forget that even a little leak contributes to big problems. That being said, it does still seem like more than a few little leaks being your problem.
Do you have a EGT or Fuel pressure gauge hooked up as well? If so, what readings you getting there? Low boost may be due to low drive pressure, from low fuel pressure.
Is your truck blowing black smoke like crazy when it's slowly building boost?
A boost leak usually won't take a while to build/spool up as it's gonna spool as quick as normal, just not give it all to the engine.... causing excessive black smoke.
Can you hold the boost pressure steady with the throttle... or does it always drop down fast - this would be a leak probably... unless it's low fuel pressure again.

 

[12VRattler]

I have a temporary fuel guage hooked up, I was getting 15 psi at idle and 25 at about 2000 rpm. I clamped the return line and it shot up to 60 psi so I have an overflow valve on order that is supposed to be here on tuesday. I have not changed the prefilter strainer out, although I do have the assembly. I do also have a new fuel filter on it with under 1500 miles. I didn't know having low fuel pressure could cause low boost pressure. How is that so? My EGT guage hits about 1000 F and stays there. Driving normally just about 1/4 throttle up to 60, I see 0 boost. If I hit WOT I slowly build boost up to about 12 psi and as soon as I let off the throttle it drops back to 0 psi. I spend hours on it today and all I can find is some small pinholes on that intercooler boot that isn't much. I know I have low fuel pressure but I didn't know that would affect my boost pressure.

 

[stupid_productions]

Nah, your fuel pressure is not low enough to affect boost. The reason I say fuel press can affect boost is because without the fuel going through the engine and out to the turbo... the drive pressure for the turbo isn't there. Would take really low fuel pressure though, like barely running pressure.
Running hot, cuz you're getting no air... maybe your wastegate is sticking open or just opening at the wrong times...
Seems weird that a few pinholes would make it lose pressure that fast.
Try check that wastegate... if it's sticking open... or mostly open that would create issues building boost but somewhat allow it, and would lose boost fast. I think.

 

[12VRattler]

I ended up pulling the wastegate actuator off of the truck because it was leaking so bad, I knew it was shot anyway.How do I know if the wastegate is sticking open? Wouldn't I have heard it when I aired up the system?

 

[12VRattler]

This has been very very frustrating, I have went through probably a gallon or more of soapy water and have not found any more leaks, and cannot even hear anything. But non wastegated I should be able to hit 30 pretty easy from what I read and I struggle to hit 12 but yet I cannot find anything leaking. BUT I do hear a woosh after I let off the throttle in 2nd or 3rd but do not hear the same sound in nuetral just revving it.

 

[ykdave]

You would only know its stuck after the actuator is removed and you can see if the arm is moving.

I suppose the WG could be stuck open, that would cause these symptoms. But its pretty uncommon to see the WG stuck open, if anything they usually get stuck.

You wont build any boost in neutral and just revving it, you need to load the engine to build boost.

Your fuel pressure is decent, but you may as well replace the overflow valve if you have one on the way.

Check out that prefilter screen, a lack of fuel isnt going to help at all!

 

[stupid_productions]

I'm really not sure how you'd check the wastegate. Have you pulled the front intake tube off the turbo... how's it look in there? Maybe the turbo is hard to spin.
Might have to wait till someone else chimes in, with a little more experience on this kind of topic.

 

[12VRattler]

I had the intake tube off when I was pressurizing the system and took a good look at the turbo. I had no side to side play or front to back. There was no scarring on the outside like it was dragging in any way. It seemed to freewheel fine and not be dragging in anyway.

 

[12VRattler]

And on the wastegate, I removed the actuator and have about 30 degrees of motion on the piece that the actuator hooked to.

 

[stupid_productions]

Hmmm, I could be mistaken but I'm thinking it should move more than 30*. Again, I'm not very experienced with how the turbo/wastegate works, just my guess.

 

[12VRattler]

Yea I am at a pretty big loss here, I think if my wastegate was stuck open that I would hear it hissing loudly when I pressurized the system.

 

[Stump Jumper]

30-45* sounds about right it dose not move far. If I am reading right you have been driving with the wastegate actuator off? If so that is why you are not making boost the wate gate is always open it needs the actuator to hold it shut.

 

[Stump Jumper]

Yea I am at a pretty big loss here, I think if my wastegate was stuck open that I would hear it hissing loudly when I pressurized the system.

nope wastegate is on the other side of the intake pressure.

 

[ykdave]

^^

Yup, wastegate vents the exhaust. Opens a bypass hole in the turbine housing which allows exhaust to bypass the turbine wheel, thus controlling turbo speed/boost

 

[12VRattler]

Now this is making sense! I removed the actuator because the diaphram in it was ruptured and leaking. So I capped the line and removed it to better get a look at it. I am getting roughly 30 degrees of movement out of the lever that the actuator hooks to. After I took it off today I didn't notice any difference in how the truck acted. Prior to today it had been on the truck.

 

[12VRattler]

Another quick questiion, in what position is the wastegate actuator arm shut? The actuator was holding it right in the middle on my truck. I didn't know which was open and shut, so I would guess right in the middle is gonna be open and leaking boost, and since I have the actuator off now its gonna act the same because the pressure will push that valve open and let the pressure bleed out.

 

[Stump Jumper]

Another quick questiion, in what position is the wastegate actuator arm shut? The actuator was holding it right in the middle on my truck. I didn't know which was open and shut, so I would guess right in the middle is gonna be open and leaking boost, and since I have the actuator off now its gonna act the same because the pressure will push that valve open and let the pressure bleed out.

you got it get the gate closed and you whould be set to go

I am tryin to remamber how it looks on the truck......... closed is pulling the waste gate twoatds the actuator.

 

[12VRattler]

Thanks for your late night persistance guys!! I ended up getting it fixed first thing this morning.My wastegate was stuck partially open...Now I am getting 32 lbs of boost with the wastegate plugged!!

 

[rossboss]

put the waste gate actuator back on ,the spring pressure holds it shut . boost opens it . make sure the actuator line is plugged. what condition is the turbo in , maybe you should pull it and check it out?!