EGR Valve and Boost Leak Question

[habitatguy187]

I've tried searching and reading up about egr valves, but haven't found exactly what I'm looking for. So my questions are;

1. Where does the exhaust enter the egr valve? It's not through the vacuum line right?

2. If it's not through the vacuum line (because I have my lines capped off) could a bad egr valve dump boost into the exhaust causing a boost leak?

I ask this because I have had a boost leak forever (or symptoms exactly like a boost leak) and I can hear air around my TB but I know it's not my IM gasket, I changed my TB shaft seals, brake boost check valve is ok. Over the past 4 months I've used gallons of soapy water, leak finder for AC units, and even a fog machine. There is no air escaping my system to the atmosphere, so I'm wondering if it can go out the egr into the exhaust?

Thanks

 

[95blackGsTurbo]

The EGR valve only opens during cruising or when the motor is in vacuum to recirculate exhaust gas through a port on the back of the head that goes to the intake manifold to help with a/f ratio's during cruising. If the valve is stuck open it can cause some drive ability problems. Should not cause a boost leak per say. The easiest and most common thing to do is to remove the EGR valve all together and use a block off plate. This will cure any issue's that you might be having.

 

[habitatguy187]

recirculate exhaust gas through a port on the back of the head that goes to the intake manifold. If the valve is stuck open it can cause some drive ability problems. Should not cause a boost leak per say.

How would it not be a boost leak? If it was stuck open couldn't it build pressure in the IM and send it through the exhaust port of the head and out the exhaust manifold?

 

[95blackGsTurbo]

How would it not be a boost leak? If it was stuck open couldn't it build pressure in the IM and send it through the exhaust port of the head and out the exhaust manifold?

Which would in turn spool the turbo and suck in more air. Take the EGR valve off and see if it is stuck open or opens when you apply vacuum to it.

 

[romeen]

Yes, it is possible to have a leaky EGR valve that will release boost directly into the exhaust stream. The port for the EGR is located in the #4 exhaust port of the head. If you remove the exhaust manifold you can see a small opening in the lateral wall (passenger side) of the #4 port.

You may be able to listen at the #4 runner of the exhaust manifold using a stethoscope while doing a boost leak test to see if that is where the air is leaking. Otherwise, the only way to be absolutely certain is to remove the exhaust manifold.

http://www.dsmtuners.com/forums/tun...694-boost-leak-test-question.html#post1803609

 

[habitatguy187]

Yes, it is possible to have a leaky EGR valve that will release boost directly into the exhaust stream. The port for the EGR is located in the #4 exhaust port of the head. If you remove the exhaust manifold you can see a small opening in the lateral wall (passenger side) of the #4 port.

You may be able to listen at the #4 runner of the exhaust manifold using a stethoscope while doing a boost leak test to see if that is where the air is leaking. Otherwise, the only way to be absolutely certain is to remove the exhaust manifold.

http://www.dsmtuners.com/forums/tun...694-boost-leak-test-question.html#post1803609

Thank you so very much that's exactly what I was looking for.

 

[habitatguy187]

So I blocked off my egr valve and my vac and idle dropped 1hg, but I'm still hitting fuel cut. This is really getting on my nerves. I've had this problem since I bought the car, and I've thought that I had fixed it so many times, but it keeps eluding me. So far I have,

1. Done AT LEAST 12 boost leak tests, more I'm sure.
2. Replaced BOV
3. Replaced TB shaft seals
4. Replaced FPR
5. Replaced fuel pump
6. Replaced injectors
7. Replaced fuel filter
8. Used so much soapy water, AC leak finder, and even a fog machine
9. Blocked off EGR

It's SO FRUSTRATING I've checked every single part of the intake tract 50 times and can't find anything, and yes I checked my brake boost line. This thing is killing me, I almost just want to sell my car and buy another one.

 

[nytescion]

I used an egr block off plate on mine and it leaked. I have to use an egr gasket with ultra grey silicone on both side and put a little on the bolt threads that sealed it up. also a friend of mine had a similar problem too it was his intake manifold that was warped. we used brake cleaner to spray around while the car was running. it raised the idle when the vapor/fluid was sucked in. We have a spare one lying around and bolted it up. Problem fixed....