Question about EGR/Vacuum leak/ Smoke test

Discussion in '1994 - 1995 Specific Tech' started by GTA_V6_Mustang, Mar 29, 2008.


  1. GTA_V6_Mustang

    GTA_V6_Mustang Active Member

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    Im sure you guys who work at dealers and so forth are familiar with the evaporative emissions smoke machine finding EVAP leaks. Now that can also be used to check for vacuum leaks. Well I check my car and sure enough I found a vacuum leak at the PCV valve to valve cover grommet. It was a nice leak, the PCV valve wasnt seating correctly with the VC grommet. Anyway I took care of that now no more leaks at all from there and I have no leaks at all from any vacuum lines or anything now however I did notice one thing the smoke would come out from the EGR valve itself. You know the like holes around it where you can see like the orange or something diaphragm. is that normal? Or am I pulling in unmetered air threw the EGR Valve.
     
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  2. GTA_V6_Mustang

    GTA_V6_Mustang Active Member

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    Bump.... Anyone?
     
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  3. HISSIN50

    HISSIN50 "How long does it take to get help in here? SN Certified Technician

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    Should not be normal. I'd pull the EGR valve and inspect it. See if you can deadhead one port on the EGR valve and connect smoke/air compressor to the other side and redo the test.

    Alternatively, use a vac pump on the EGR nipple and see how fast the reading drops (a sign of a bad diaphram).

    Do be careful with any testing. EGR diaphrams dont like a lot of vacuum (i.e. connecting direct manifold vac can really slam the valve open).

    Good luck.
     
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  4. R.J.

    R.J. Member

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    +1 for putting a vac pump on the EGR and see if it holds pressure. Also any time you have or think you have a vac leak try spraying starter fluid on the suspect area with the car running. When the starter fluid gets sucked into the leak, the car will idle up.
     
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  5. GTA_V6_Mustang

    GTA_V6_Mustang Active Member

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    Ok well I put vacuum to the fitting on the egr and it moves the little orange diaphragm just fine and holds 19inhg just fine. However I believe nothing should come out of there when doing the smoke test. So I am afraid that I might be sucking in unmetered air threw there near and at WOT
     
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  6. GTA_V6_Mustang

    GTA_V6_Mustang Active Member

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  7. R.J.

    R.J. Member

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    Try spraying where you think you have a leak with starter fluid! You will know if it is sucking in unmetered air, trust me!
     
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  8. GTA_V6_Mustang

    GTA_V6_Mustang Active Member

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    Good point I keep forgetting to try that. LMAO Tomorrow I will do it.
     
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  9. GTA_V6_Mustang

    GTA_V6_Mustang Active Member

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    Well tried starting the car (cold) and sprayed some throttle body cleaner on the EGR and idle did not change at all. I pulled the vacuum line at the valve and noticed no vacuum at it at all. I assume that vacuum to there is controlled by some soleniod and only activated under driving conditions?. I am at a loss here. I am almost sure I have a vacuum leak, and almost positive that its coming from the only spot where I had smoke escape from during my check for leaks. But I cant verify it.
     
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  10. Chythar

    Chythar Well-Known Member

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    The EGR only opens at part throttle, when you're maintaining speed. It's closed at WOT and at idle, as I understand. No offense, but are you absolutely sure the smoke came from the EGR, and not from somewhere below it?
     
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  11. GTA_V6_Mustang

    GTA_V6_Mustang Active Member

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    LMAO no offense taken. And yea I know its on off idle but not at WOT. And yes it is comming from the EGR I checked multiple times, I can take video and show u guys also if youd like. I might just take the egr off to see if i see any damage internal to it, just something thats been bugging me though.
     
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  12. HISSIN50

    HISSIN50 "How long does it take to get help in here? SN Certified Technician

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    You got good info above. It doesnt work at idle or WOT, so you really need to check its function while viewing PIDs on a test drive. That said, you can inspect the solenoid and the lines to and from it. It's in the passenger fenderwell.

    I'd definitely remove the EGR valve and have a look at it. It takes but 2 mins to remove it. Be careful with carb cleaner around it but I do douche the passageway and clean it with a bore brush.

    If you get a new aftermarket gasket, it probably wont fit right. I've been having to cut them to make the ports line up.
     
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