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1G Going crazy looking for boost leak.

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Panchoelkatch

Proven Member
124
5
Jun 4, 2014
Lemoore, California
So far since getting the car, it's been down looking for boost leaks. I rebuilt throttle body due to it having leaks, had some pinholes from my Magnus SMIM, sent it, got it rewelded. Injectors were leaking from the lower seal, so replaced that.

Still, can't hold over 9 LBs, and I hear the dam leak, but just can't pinpoint it to save my life haha. It's coming from somewhere under the intake manifold (So I think). Brake booster doesn't seem to be leaking externally from what I can see.

Is there anyway it's escaping through the crank case? I don't know anymore going a bit crazy.
 
It's very easy and cheap to make a tester. Basically just need a rubber hose cap and tire stem to clamp on the inlet of the turbo and add air pressure. This will let you test the entire pressure side and find your leaks.
 
OP:
  • Are you using soapy water and a spray bottle?
  • What are you trying to pressurize the system to?
  • Are you doing this test on cold, or after warm-up?
Perhaps lift the front end and have someone look under the car to find leaks. An inspection mirror may help as well. It is not uncommon for the PCV to leak pressure into the VC.
 
I was trying to pressurize it to 20 LBS, but will not hold even 9 and loses all pressure in about 15 seconds.

Yes I'm using soapy water in a sprayer, and the test is done cold, haven't started car in weeks.
 
Im assuming you replaced the IM gasket wen you sent it out to be re-welded? Theres also several vacuum lines running down the backside of the IM, if there hasnt been anything deleted yet.
 
Block off your PVC. Even brand new ones from the dealership leak in my own experience over like 8 psi and it can cause headaches when doing a boost leak test. With the PCV leaking air into the valve cover, it basically is leaking air into the crank case.

How many miles does the motor have? An older motor, if valve seats and piston rings are worn can leak some air into the crankcase as well.
 
Finally made a DIY Evap smoke machine, smoked the f***er and found a leak at the brake booster internally. Pinched off the brake booster line and continued my BLT.

Finally got it up to about 20 LBs, but I have a lot of air coming from my cam gears (Where camshafts exit valve cover). I'm doing BLT cold, but it is normal for it too leal this much through there?
 
So the PCV Will essentially go on the nipple located on the top left of my valve cover correct? That nipple is just taped off with tape, just realized that. I also plugged off the nipple located on the middle left of my valve cover (The one that goes to the Oil Catch Can) I Just don't understand how I have so much air going into the valve cover...? I'm starting to believe I'm wasting alot of time on stupid things. I'm wondering if doing a warm BLT will alleviate some of these leaks, since I'll have a proper seal at the piston rings/ Turbo seals.
 
If it wont even hold 9, its a big leak, go buy a pack of smokes, fill that manifold with smoke


How long does your intake system hold pressure during a boost leak test?

ALSO, OP:

what are you using to pressurize the system? hand pump? compressed air from a tank?
 
Yes hose to brake booster needs a check valve. Also are you saying you don't have a pcv hooked up? And just taping off a fitting will not work bro. If it's a nipple get a rubber end cap and zip tie it on. And our cars don't come stock with catch cans. So either explain to us how it's hooked up better or post a pic. you need a pcv or if it's a catch can it needs a check valve. You can't just plug up those breather ports on the valve cover. That's why you have so much air going out the wrong places. You should also have the side port on the valve cover going back into the turbo inlet. Post a pic will help a lot bro. ;)
 
A BLT done after warm up will indeed yield better results. Some turbos though completely functional will leak air during a BLT through the turbo oil return into the crankcase, less when warmed up and essentially none while running/spinning. This usually results in a bubbling noise from the crankcase though so it's pretty obvious, if yours does this, start the BLT after the turbo. Don't forget to make sure your vacuum line going to the BOV sees pressure during the BLT or all your air will just dump out the BOV. Lastly if your wastegate flapper isn't being pulled firmly over the wastegate hole by the actuator and arm, you can leak through that. I had to recently tighten up that arm to lever on the wastegate of mine.
 
How long does your intake system hold pressure during a boost leak test?

ALSO, OP:

what are you using to pressurize the system? hand pump? compressed air from a tank?

The system will hold about 18 LBS, than quickly goes to 10 in about 5 seconds. About 15 seconds after that, it's down to zero. I'm using an air compressor regulated.
Yes hose to brake booster needs a check valve. Also are you saying you don't have a pcv hooked up? And just taping off a fitting will not work bro. If it's a nipple get a rubber end cap and zip tie it on. And our cars don't come stock with catch cans. So either explain to us how it's hooked up better or post a pic. you need a pcv or if it's a catch can it needs a check valve. You can't just plug up those breather ports on the valve cover. That's why you have so much air going out the wrong places. You should also have the side port on the valve cover going back into the turbo inlet. Post a pic will help a lot bro. ;)

Yes I plugged off both nipples on the valve cover with a rubber nipple. Let me get you a pic in a little while.
A BLT done after warm up will indeed yield better results. Some turbos though completely functional will leak air during a BLT through the turbo oil return into the crankcase, less when warmed up and essentially none while running/spinning. This usually results in a bubbling noise from the crankcase though so it's pretty obvious, if yours does this, start the BLT after the turbo. Don't forget to make sure your vacuum line going to the BOV sees pressure during the BLT or all your air will just dump out the BOV. Lastly if your wastegate flapper isn't being pulled firmly over the wastegate hole by the actuator and arm, you can leak through that. I had to recently tighten up that arm to lever on the wastegate of mine.

I definitely have pressure coming to the BOV through that hose that's connected to the IM. Okay I'll try and figure out a way to test after the turbo.


By the way thanks, I'm new to the DSM scene, so I'm just trying to grasp everything and get the best of it. I'm trying to make IFO, at the end of February!
 
Here's how the catch can is set-up. I don't have the breather on it currently. Should there be a PCV Valve somewhere in between the catch can and Valve cover? If so which direction should it be set up for?

I've also verified there's no Check valve anywhere on my brake booster line, could I just buy some sort of universal check valve from an auto store and plug into that hose?
 

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I tried to order the entire booster line, can't find it anywhere. Can I just throw a standard check valve in that brake booster line?

Threw the throttle body back on, and I can't get rid of a stupid leak, that looks like it's coming from the throttle body bolt heads! Things giving me a headache,I'm tryna get it running decent so I can make it to IFO at the end February!
 
I tried to order the entire booster line, can't find it anywhere. Can I just throw a standard check valve in that brake booster line?

Threw the throttle body back on, and I can't get rid of a stupid leak, that looks like it's coming from the throttle body bolt heads! Things giving me a headache,I'm tryna get it running decent so I can make it to IFO at the end February!

Did you get the brake booster line done? Are you sure there isnt a check valve? The valve is inside the hose. You wouldnt be able to see it without taking the hose off. If there isnt one you can buy one and install. With my magnus smim i had problems with the tb bolts leaking air as well. If i remember correctly one of the bolts goes inside the manifold. I had to teflon the bolts to get it to quit. You are spraying soapy water right? What psi do you have the air compressor regulator set for?
 
Did you get the brake booster line done? Are you sure there isnt a check valve? The valve is inside the hose. You wouldnt be able to see it without taking the hose off. If there isnt one you can buy one and install. With my magnus smim i had problems with the tb bolts leaking air as well. If i remember correctly one of the bolts goes inside the manifold. I had to teflon the bolts to get it to quit. You are spraying soapy water right? What psi do you have the air compressor regulator set for?

As of Today, I've removed the brake booster line, and there is no check valve any where in the line. Weird huh? I ordered a couple 3/8 Check valves from USPlastics.com now I'm just waiting for it.

As for the Leaky bolt, I used liquid teflon sealer on all the bolts and lightly RTV'd the gasket. Leak seems to have finally gone away. Yes I'm using soapy water, and I have the regulator set to 35 PSI. I still have alot of air coming through the valve cover, but the car has not been started in several months, I Know Rings work and seal with pressure and heat, so I'm just going put it all together and start the f***er up.

I don't intend to insult you, but I have to ask in the hopes that it helps you: have you rotated the engine so the valves are closed (per post 31 here: http://www.dsmtuners.com/threads/co...cold-starts-slow-spooling-etc.495371/page-2)?

I set it to I believe 30 TDC, so I don't think valves are completely open.
 
OP:
  • Are you using soapy water and a spray bottle?
  • What are you trying to pressurize the system to?
  • Are you doing this test on cold, or after warm-up?
Perhaps lift the front end and have someone look under the car to find leaks. An inspection mirror may help as well. It is not uncommon for the PCV to leak pressure into the VC.
My god thank you so much Was not holding Boost, capped hose going to pcv good to go Thank you
 
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