boost leak tester

[jms19delta]

I made a boost leak tester today and tried to check for leaks...but when I pressurize the system....my boost gauge doesn't move and I hear no leaks. I can hear the air going in but thats it.

I tried putting the tester on ic piping, then directly on the turbo...same outcome.
Modified by jms19delta at 2:57 PM 7/23/2009

[Vkoslak]

How are you pressurizing the system?

Every time I've had a leak test done there was a gauge on the tester itself.

Got pics of your setup?

Kingsport, nice. I'm probably going to be headed to Bristol around Labor day.

[jms19delta]

Ill take pix of what I am using a little later...about to head to the gym

Good ol Bristol....what you headed up here for?

[Vkoslak]

I have family there. I actually went to Battle H.S. a LONG time ago.

[jms19delta]

here is what I am using....

[Vkoslak]

Did you seal up the hoses from the recirc valve? I would put that stuff back on and add air pressure where the MAF normally is.

[jms19delta]

the maf would pretty much be right where I had it hooked up. What recirc valve? My bov vents to the atmosphere. I have tried putting the tester on the turbo (like above), I tried putting it on the ic pipe right off the turbo and I have tried putting on the ic pipe by the throttle body. I can hear air flowing through the ic pipes when I use my stethoscope. But I can never hear a leak anywhere. I am ready to rule out a boost leak. I have to be losing vacuum from somewhere. I have tried uping the idle with the screw on the manifold and no matter how much I turn it in either direction the idle does not change (unless I close it all the way then it dies). I unplugged the aac valve and nothing changed, unplugged the tps and nothing happened. The car revs fine, just doesnt do well under load. Could this be related to running so rich? If so, why would it all of a sudden start acting up?

[240daveTX]

maybe your sensor died

[rb25drag]

First off I would Put that tester on the IC pipe and not the turbo.

2nd I hope when you are adding pressure you got the Throttle wide open. Otherwise your going to Bend the Throttle body butterfly.

I think this is why your not seeing any boost on ur gauge. also What type of gauge you running? Does it show Neg vacuum also? If so what does it read at idle?

Also Sounds like ur AIC is bad.

As your testing ur pipe make sure your spraying soapy water around the couplings and looking for leaks. You dont have to just hear air. You will be surprised of what will show up that you cannot hear.

Also make sure you spray ur BOV. Mine leaked internally that I never knew about until I tested it with soap.

Its also Nice to have another hand helping you. Good luck!!

[jms19delta]

I have tried everything except holding the throttle open and soapy water. When I had a dsm, I did a boost leak check and the throttle was closed but I still had movement in my gauge. I am using a autometer gauge, its a 30-0-20 gauge so it reads vacuum. When I last ran the car, it was pulling about 13in of vacuum. I have a very steep driveway and the car wouldnt make it up to the top without wanting to die. I am going to talk to a friend of mine who is very good with rb's tomorrow. I am thankful for the help you gys have given me. I pulled the aac valve off and cleaned it as good as I would my weapon (I'm in the army). Maybe that will help.

[910bluebird]

this is really stupid question , but i assume you have blocked off the exhaust?? . be gentle this is my first post

[Fibre guy]

Did you try the fuel injector insulators, they let a lot of air by without any sound. Most leaks can't be heard with just your ears. Did you try using a mechanics stethoscope?Just some places that leaked on mine that might help:-The bolts on the back of the compressor housing (high temp silicon fix)-Compressor housing seal ring (tighten bolts)-boost gauge inside the car-Fuel pressure regulator-AAC valve hose that comes off of the IACV

[jms19delta]

Yes I use a mechanics stethoscope. This is really irritating! I dont see how I could be missing a leak. I am losing vacuum somewhere! The highest vacuum I have pulled in the last few days is 13.

[Coolwhip]

in case it wasen't thought of...

If you are using an electric boost gauge (rather than mechanical) you'll need the ignition key on for the stepper motor to provide the signal.

Sorry if this was performed already, just didn't see it mentioned.

GL

[jms19delta]

thanks for the info, but I am using a mech gauge.

BTW CoolWhip, I ordered a power steering line from you....works perfect! Thanks!

[gawdzilla]

double check your timing belt. sounds like your timing belt may be off a notch. that or you have bent valves.

you are doing the test right. you do not need to open the throttle and you do not need to seal off the exhaust.

listen at your exhaust and if the air is coming through there, you have a mechanical issue. bent valves or timing belt off/adjustable cam gear slipped imo.

[rb25det250sx]

assuming the motor is a Rb since its in the Rb section, i was leaking BAD from my turbo elbow. fixed it. but im still loosing boost somewhere. anyways i found out my BOV was leaking. thats fixed, but im still losing boost. sorry for the thread jack.

to check and see if you have bent/burnt valves do a leak down test... check IC piping to.

[Fibre guy]

My RB pulls about 20Hg at the boost gauge and with my liquid filled vacuum gauge I have for vacuum bagging carbon fiber I get 23Hg.Before I fixed all the leaks I was getting about 11ish. Did you check the Injector insulators yet?

[240daveTX]

mine is running 20 vacuum at stock idle. check all your vacuum lines

[jms19delta]

haven't checked the insulators yet....work owns my life. Ill get to it tomorrow.

[Fibre guy]

If it is the insulators you have 3 options... 1. you can buy for 3.10 each at the dealer.2. You can try silicone and hope it seals right.3. Or you can get the generic USD ones for a 1996 maxima.

[mott6904]

I vacuum leak is not the only thing to cause low vacuum. It could be mechanical timing, ignition timing, bad maf, dirty IAC or not correctly adjusted. it really could be a bunch of different things. Is the idle low, is it missing out, does it have any running issues. Have you recently changed anything and it started after that?

[Conrad 2NR]

Thread is nearly a year old BUT couldn't it have been that the vent-to-air blow off valve was slowly leaking what ever air was put in before pressure could've actually been held in the circuit?