Alright I have tried everything I know but leak test. Ichanged the boost line on my guage out 3 times now. Had it hooked to the map line and now the Y intake. I get a max of 8psi on the boost guage at WOT with the superchips on the highest level. Get about 2 psi boost going down the road at 80mph. I disconnected the waste gate and plugged the line and still get the same boost numbers. Everytime I changed the boost line I still got the same numbers. I pull the boost line off from the back of the guage and drive and I dont feel much of any boost comming out. If the turbo was bad how do I check it. I plan on using air condition leak soap today to see if there are any leaks in the lines. When I pull off the intake tubes and just run it allot of white exhaust is comming through them. Its not clean air comming through. Could that be a leak in the turbo or ??. I dont know what to look at now so any help would be great. When I get on the throttle I do have quite a bit of black smoke but nothing that I would think was to much with a bad turbo. Im going to make sure there isnt a leak in the intercooler today also. But I would think it would have to be a pretty big leak in order to cause that much of a drop in boost. I can see the turbo spinning and no weird noises from it. Anywhere I can look would be great. My guages are autometer and my truck is a early 99 model.

 

Double check your inner cooler boots all four of them to ensure they do not have a leak or crack in them.

Fire Rooster

 

Would they leak just sitting at idle or do I have to hit the throttle? Im checking all of them in about 45 minutes when my bro brings over some more AC leak soap. Its easier to use this type of soap cause it bubbles and stays on the pieces longer.

 

Just got it tested. NO leaks. We did some tests though. We pulled the intake tube off right before the y intake into the engine. We reved the engine and it was pumpin a substaintial amount of air. We couldnt hold our hand over the tube to stop the pressure. So im pretty sure its over 8lbs of pressure comming out of there. So im back to the guage again. I plan on getting another guage from Autometer and checking it out. I know I checked it other ways but that is the only thing left that it could be. My question is feeling the amount of air comming out would the turbo go up to 20lbs+/- just by reving the engine.

 

Yeah I would blame the gauge then it sounds as if your turbo is fine.

Fire Rooster

 

Sounds like the gauge to me too. You said you changed the line 3 times was there any damage to the lines when you removed them. How do you have the line run? The tubes are very fragile and even something that looks like minor damage on the line may be causing your problem.

 

Ran the line from the Y intake tube throught the whole in the fire wall by the brake booster, up into the mounting pod. I checked and checked and checked the lines over and over. I pulled them out blew air through them and not one kink. I personally dont think there is a problem with the guage but I have checked everything. I can still put the compressor on 20psi and roughly 20 psi comes up on the guage when I pull the line off the Y intake. What I need to know is how to check the turbo for blowby in it. Lets say there is blowby at higher RPMs the air from the turbo is just comming back out through the intake. Let me know if this is possible.
Thanks

 

line could be plugged somewhere before it even gets to the vaccum line. check the MAP line that you are teed into.

Fire Rooster

 

At first I T'ed into the Map line and was getting 0 on the guage. Now Im tapped into the Y pipe right after the turbo. Im doing one last thing today. Getting 1/8" copper tubing and try running it that way. My other question is a blown turbo would be making tons of noise correct? Could it be a seal on the turbo causing this cause nothing leaks on the turbo. Could it be a bad wheel on the turbo? I just hate to pull a turbo and find out that wasnt the problem with the wheel. At idle when I put my hand over the Y pipe I can stop the flow of air and it comes back out the intake side. Im wondering at higher RPMS if there is blowby on the turbo. I imagine a worn compressor wheel would cause that but im no turbo guru. I tried my hand over one of the boost tubes at higher RPM's and couldnt stop it but that still doesnt tell me if Im getting enought boost. I did notice the amount of air right after the turbo was higher than after the intercooler. Could it be a plugged intercooler. I bought this truck used and it was VERY dusty from Texas. Let me know

 

You are driving it right???, cause you will not get any boost reading without the truck moving. Sitting still it will read 0 lbs boost no matter how hard you mash on the GO pedal

 

I get 8psi at WOT cruisin down the road. I just couldnt understand why you would get 0 psi on the boost guage also while reving it up. There is allot of air rollin through those boost tubes just sittin there revin the engine. I figured some amount of pressure would be built up in the tubes. That aside I still have a problem with the 8psi max boost at WOT while movin. If there is blowby in the turbo I could see that causing a very low boost as the air is blowing back into the air intake tube or through the bearings. I hope its not the turbo cause thats something I dont want to have to have rebuilt.

I borrowed this from another site.

Turbo
Problems connected to the turbo should also be among the first issues to be checked if you experience power loss.

Is the turbo providing the engine with pressurized air? Get the turbo pressure checked to see if it is OK. Wear might give too much blowby through the turbo bearings, thus pressure is lowered
ALSO THIS>
The turbo is controlled by a wastegate actuator, which might be at fault. A boost check will provide an answer to this.

 

if you were having an internal turbo failure i suspect youd be hearing it. Almost like a loud screech. there are a few things that can cause this problem. !st thing i would do is recheck all lines and piping and make sure they are good. Then take a hand held pump (like u use to air up a football preferably w/ a gauge) and connect to the wastegate and manually pump it up to see if the wastegate diaphram isnt opening too soon. Check your exhaust for any blockages. Also make sure you are getting adequate fuel pressure. Low fuel pressure = low power= low turbo boost.

 

Alright second guage installed and guess what 8psi of boost at WOT driving down the road. Installed new fuel filter and checked for any restriction in the exhaust. I have a 3.5 downpipe and 4" out from there. I get plenty of exhaust comming out of the tailpipe. Ran the truck with the air filter intake tube totally removed and still got 8psi of boost. Checked the waste gate and lever moves but takes quite a bit of force to open it up. So that seems fine. I checked for leaks and none.

What could it be??????????????????????
Could it be a cloged intercooler?
Could it be something internal on the engine that is bad?
Could there be an exhaust leak that is not evident unless under a load?
Any help would be appreciated.

 

did you try with the wasegate disabled?

 

Rosa you said you pulled the line at the intake and hooked it to a compressor and they pretty much showed the same pressure? Maybe the compression fitting your using is leaking. Is it the same fitting you used when you had it tee'd into the MAP? Turbos need a load to build boost. If the truck is not moving there is no load.