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Quick question: What's a good way to hunt down a boost leak?

2K views 12 replies 7 participants last post by  Jeffrey Watts 
#1 ·
I've got a boost leak somewhere, and I can't find it. What are some good hunting tactics?
 
#2 ·
Could you give a little more information like what's happening, are you losing some boost that's noticeable but not really bad? Or is it bad and you are barely getting any? But I mean first one is pretty simple just check your boots around all piping for cracks, leaks or a lot of wear and tear
 
#3 · (Edited)
I would start looking at boots for cracks
clamps for tightness.
from there check your y pipe for cracks
04 you should have the metal cac pipe so that shouldnt be an issue.
after that it gets ugly manifold bolts and gaskets
leaks in the intercooler
turbo itself
ok not that bad but i forgot to mention that earlier :doh:
 
#4 ·
Google "how to build a boost leak tester"
 
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#5 · (Edited)
Along with above, you can buy a rubber cap and hose clamp set at most Ace Hardware that'll fit over the intake connection to the turbo. Drill a hole, stick a Schrader in there, and use rubber glue to affix. Mount and charge to 20psi with a compressor. Listen. ...or push smoke in there if you can get your hands on a smoke machine for a visual.

Good luck.

Edited to add...
Just saw @sbluke55 's post above. I swear that wasn't there when I started typing this. Lol.
 
#6 ·
#7 ·
Turbo is new, boots are new, Y-pipe is new.

Way down on power, (Lots of turbo noise, though) Blowing black smoke as thick as cotton candy.

This is the 2nd test drive. I've blown off the plastic CAC tube under the air filter, and the aluminum CAC tube where it goes into the boot at the turbo end. All clamps have been tightened since then.

Best I've been able to get is 15-20 PSI, I think.
 
#8 ·
stock intercooler? if so I am betting the end tank separated from the core like mine did.
 
#9 ·
Yup. Stock intercooler.
 
#10 ·
yea id guess you cracked an end tank, I separated mine on the passenger side closer to the top, you could see where it split and the rubber seal had been pushed out. If you build a pressure tester you will find it for sure as thats how i found out where my leak was.
 
#11 ·
first thing would be to pull the air filter off the turbo and make sure the turbo spins freely and there is not any excessive play.

Exhaust leaks are a big problem. Bigger turbos will usually make leaks worse. Check the ypipe bellows and the ypipe to turbo connection. Those are very common. An easy way to check it would be to have someone stick the truck in drive, hold the brake, and give it some gas. Push the pedal as hard as you can without causing the truck to move. Look for any smoke coming out from behind the turbo. If you see any smoke then you need to find and fix the leak. It is best to be running a race tune and just MASH the throttle, then when the tire are about to spin let off and try again. You want to product black smoke if possible because it is easier to see.

Boost leaks are also a big problem. The most common areas are the boots on the charge pipe, plastic ends on the intercooler, and the plastic hot side charge pipe on the drivers side. If you have a plastic charge pipe on your drivers side then replace it ASAP. They will not hold up under high boost. You can check for boost leaks in the same way as an exhaust leak. MAKE SURE THE TRUCK IS COLD. Have someone stick the truck in drive, hold the brake, and give it some gas. Push the pedal as hard as you can without causing the truck to move. Use your hand to follow the lines from the turbo to the intercooler and then from the intercooler to the intake manifold. Feel for any leaks. Some people use soapy water too. Another option is a boost leak detector from dieselsite. Here is a link

http://www.dieselsite.com/dieselsiteturboboostleakdetector-4.aspx



Pull and check all of the following sensors. Use your programmer to make sure they are reading right.

MAP sensor located on passenger side by the air box. Make sure the tube going from the sensor to the motor is not cracked. Make sure the tube and sensor are clean and not plugged.

MAF sensor is located between the air filter and turbo. make sure it is clean and plugged in.

EBP sensor is located off the exhaust manifold on the drivers side. There is a tube going from the exhaust manifold to the sensor. It is very common to clog and have issues. Clean out the tube and make sure the sensor is not clogged.

IAT sensor is connected to the top of the intake manifold near the fuel bowl. Pull it out and make sure it is clean. It is very common to get covered in crap. Clean it and make sure it is connected right.

Baro sensor is located under the dashboard. Make sure it is plugged in and reading right.

VGT solenoid. The vgt wire/pigtail are very common to have cracks, slices, and breaks in it, especially right where it plugs into the solenoid. Double check everything to make sure it is working right. An easy way to check and see if it is working right is while the truck is running. plug and unplug the sensor. You should be able to hear the exhaust sound changing when you do that.



These don't relate directly to boost but it is still a good thing to check. They can really hurt performance.
ICP sensor
IPR
FICM (make sure voltage is good)
 
#12 ·
Can a comment be stickied? ...'cause ^^^ that right there deserves some stickying!
 
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#13 ·
Yup. Charlie came through with good info. I've been warned about the plastic tube on the hot side, specifically the bellows where it goes into the CAC.
 
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