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Old Aug 7, 2020 | 11:22 AM
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Default EGR test

What is the best way to test EGR on 1980, 350?
Getting a bad idle when in park. Going to start there.

Last edited by nickster2213; Aug 7, 2020 at 11:25 AM.
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Old Aug 7, 2020 | 03:50 PM
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take it off.. see if you can see heavy build up and or blow through it.

personally block it off..79 had 4 different ones!! not all tests make sense on vacuum bypass ones..

slide 14 and 25

https://www.corvetteforum.com/forums...x-power-2.html

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Old Aug 7, 2020 | 09:28 PM
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I took mine off and tested it with a hand vacuum pump. The pump has a gauge and if it’s good it holds pressure. I think amazon has this tool.

Many people just disconnect this valve but I cleaned my valve with carb cleaner. I have all the pollution control items in original condition as is the car.

Last edited by Proactive_Solutions; Aug 7, 2020 at 09:29 PM.
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Old Aug 7, 2020 | 10:50 PM
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Originally Posted by Proactive_Solutions
I took mine off and tested it with a hand vacuum pump. The pump has a gauge and if it’s good it holds pressure. I think amazon has this tool.

Many people just disconnect this valve but I cleaned my valve with carb cleaner. I have all the pollution control items in original condition as is the car.
Nope..depends on what type egr you have..some dont hold vacuum and are fine ..see my thread how i learned...

remove it

Last edited by interpon; Aug 9, 2020 at 03:40 PM.
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Old Aug 9, 2020 | 02:38 PM
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Remove the EGR valve and operate it manually. It should move freely. If not, replace. If it seems OK then clean both the pintle and the seat as deposits will cause a leak and bad idle. The valve should be fully closed at idle and deceleration.
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Old Aug 10, 2020 | 03:11 AM
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Move the vacuum advance on the distributor from a ported vacuum source to a manifold vacuum source on the carburetor. My 80 would barely idle when I accidentally swapped the port.

If you take the EGR off to test it, block it off with a plate.

Last edited by Bikespace; Aug 10, 2020 at 03:12 AM.
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Old Aug 10, 2020 | 07:32 AM
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I agree with Bikespace, if you are removing the EGR the idle will lower if you live the distributor advance to the manifold port. I have also found this to be true.

Last edited by Proactive_Solutions; Aug 10, 2020 at 07:32 AM.
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Old Aug 10, 2020 | 08:45 AM
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Originally Posted by Proactive_Solutions
I agree with Bikespace, if you are removing the EGR the idle will lower if you live the distributor advance to the manifold port. I have also found this to be true.
on my 79 the distributor advance on carb is in fact manifold..they made some weird tweaks even in same year different models.. like l82 mechanical timing already all in @2000
manual auto also makes difference.. and what was on the shelf for EGR valves and designs..at build time..

i think other than not sealing with crap.. they are pretty bullet proof

Last edited by interpon; Aug 10, 2020 at 08:47 AM.
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Old Aug 10, 2020 | 10:02 AM
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You guys are convincing me in closing it up. I am always in favor of lowering the idle to save the transmission bump when putting in gear.
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