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EGR When Open Increases Idle? (solved)

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Old Feb 2, 2015 | 10:12 PM
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EGR When Open Increases Idle? (solved)

From my reading it seems when I manually activate the EGR valve, the idle should become worse. When I opened my EGR, the idle increased. Am I doing it wrong? I disconnected the tube from the exhaust in order to push up on it.
 
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Old Feb 3, 2015 | 07:32 AM
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Opening the EGR valve at idle makes it an effective vacuum leak therefore the idle RPM will typically increase. What are you trying to repair/resolve?
 
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Old Feb 3, 2015 | 08:23 AM
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No you're not doing it wrong but you do have a problem. Fresh air will cause the idle to increase because it is combustable while exhaust is not combustable so it will cause the idle to get rough or even stall the motor if the valve is opened too much. So with the EGR connected to the exhaust there should be no fresh air getting in, if there is you have a leak in the EGR tube and it needs to be replaced.
 
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Old Feb 3, 2015 | 11:38 AM
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Originally Posted by rla2005
Opening the EGR valve at idle makes it an effective vacuum leak therefore the idle RPM will typically increase. What are you trying to repair/resolve?
A surging idle, horrible exhaust smell, poor gas mileage, and a miss at less than 4k RPM; but mostly the surging idle right now. I haven't finished testing all the sensors but if I'm still stumped when I'm done, I'll start a new thread.

Originally Posted by Conanski
No you're not doing it wrong but you do have a problem. Fresh air will cause the idle to increase because it is combustable while exhaust is not combustable so it will cause the idle to get rough or even stall the motor if the valve is opened too much. So with the EGR connected to the exhaust there should be no fresh air getting in, if there is you have a leak in the EGR tube and it needs to be replaced.
That made the light bulb turn on, thank you. Of course, that makes sense. The test was performed with the EGR tube disconnected because I don't know of any other way to manually activate the EGR valve without a vacuum pump (something I don't have). I'm guessing if it had a leak, I'd hear it? I hear no leak.

Thank you both!
 
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Old Feb 3, 2015 | 01:11 PM
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Originally Posted by DesertZuki

That made the light bulb turn on, thank you. Of course, that makes sense. The test was performed with the EGR tube disconnected because I don't know of any other way to manually activate the EGR valve without a vacuum pump (something I don't have). I'm guessing if it had a leak, I'd hear it? I hear no leak.

Thank you both!
Unless the leak is massive you will never hear it. If you want to open the EGR for troubleshooting purposes run a a piece of vacuum line to the manifold vacuum tree, start the truck then momentarily connect both ends of the line (EGR + manifold). The EGR should open 100%. No vacuum pump required.
 
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Old Feb 3, 2015 | 03:24 PM
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^ That's just a bit of brilliance. Thanks.
 
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Old Feb 3, 2015 | 05:33 PM
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All you need is a straw with your lips wrapped around it to create enough vacuum to open the EGR valve. Now that's lovin your Ford!!!!!
 
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