Pressure Testing Air Intake System

[boonsur]

A while back, someone posted a way to pressurize the intake system to check for leaks. I could not find the link.



I have a really bad whistling/howling sound at higher boost. It is not a normal turbo sound, but more like a stereo grounding problem sound coming from the engine. I'm wondering if one of the sensors (IAT/MAP) isn't tightened properly, or one of the hoses has a small hole/slit in it (I have checked and double checked all the connection and clamps - all appear to be O. K. )



I'm thinking of a plate, with a rubber boot that fits over the turbo intake, with a NPT to connect a regulated air supply. Or could I cap off the intake, and pressurize by using the port where you would connect a boost gauge. (Where is this port?). (If it works out, I could pass my test rig around to anyone wanting to give it a try).



Would this hurt anything in the turbo and/or manifold?

 

[WyoJim]

PVC pipe cap

Since no one has responded yet I'll take a crack at your question.



I remember the thread you are talking about and it boiled down to finding the proper size PVC pipe end cap and installing a tire valve stem in the end of it. Then take the hose off the turbo, slide the cap in the hose, tighten the clamp and pump 30lbs of air into it. Every leak should sing you a tune. Soapy water would help find the small ones.

 

[JohnB]

The way I do it is to block the intake snorkel with a towel, start engine (it should pull the filter minder down) and then spray ether at all the joints. Any leaks will suck in the ether and slightly speed up the engine. Any point that blows out under presure will suck in under suction. This always worked for me.

 

[Evan A. Beck]

We have had this system at ourt shop for a couple years... A customer of ours made us some fitting out of aluminum, with a fitting on them for an air hose connection. We fasten it to the front of the turbo, and then connect regulated air pressure, and turn it up to 25-30 psi. We then use some soapy water in a spray bottle, and squirt it on all the intake connections. I would say that AT LEAST 75% of the trucks that come in here have some kind of boost leak.