bad egr valve or solenoid
December 5th, 2011, 06:12 PM
#1
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bad egr valve or solenoid
My question is i'm not sure if my egr valve is operating. I definitely have vacuum to it, when revving the engine above idle. The diaphram does not move up when revving the engine. I manually lifted it and the engine did stumble so i assume the passages aren't totally blocked? IF the vacuum is reaching the valve but it won't cause the diaphram to open is the valve itself bad? I would appreciate any help
December 5th, 2011, 06:27 PM
#2
In general, if you have vacuum at the valve and there is no bypass or relief vent in the system the valve would be bad. If you have a hand held vacuum pump you can test it. The diaphram on the valve may have a leak. If the solenoid is before the valve it lets vacuum to the valve or no vacuum to the valve. The old EGR's were simple and worked thru a temp sensing vacuum switch. The newer ones are pretty complicated/involved.
December 5th, 2011, 06:29 PM
#3
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It's an 83 with the 307. There is basically no cat (it's hollowed out). Could that cause a sufficient drop in exhaust backpressure that would not allow the egr valve to open. I've read it needs some amount of exhaust backpressure to operate and the regulate how far the diaphram opens
December 5th, 2011, 06:34 PM
#5
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Location: Plano, TX
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Welcome! (There's beginning to be quite a few of us Robs here... 
)
Solenoid is fine. Sounds like the internal EGR valve port in the shaft may be clogged or the bleed valve stuck open. Remove the valve and you can find out. This is a funky valve...
Here is the manual page describing it - I assume you have the 5.0...
A hollowed out cat could cause it to not have enough pressure, but check out the valve itself, first.
)Solenoid is fine. Sounds like the internal EGR valve port in the shaft may be clogged or the bleed valve stuck open. Remove the valve and you can find out. This is a funky valve...
Here is the manual page describing it - I assume you have the 5.0...
A hollowed out cat could cause it to not have enough pressure, but check out the valve itself, first.
December 5th, 2011, 06:37 PM
#6
Connoisseur d'Junque
Join Date: Sep 2010
Location: The Hudson Valley
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I'd just get a new valve - $22.79 at RockAuto.
- Eric
edit: but if Rob says so, then maybe it IS right...
December 5th, 2011, 06:41 PM
#7
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Thanks for your help. I had the valve off the manifold a while ago, there was some carbon but it wasn't bad and i cleaned what i could. the diaphram moves but i'm not sure if it should be easier to push open as i don't have a good valve to compare to, even tried going to parts store to compare but no one seemed to have it in stock w/o ordering
December 5th, 2011, 07:23 PM
#9
^^ Well chances are you're not getting an ACDelco at Rock, so don't bother with the part number on the EGR itself.
Really sound like to me that it's broken, unable to open under vacuum, so I say get a new one, or a used one at the junkyard if your planing to removing emissions althogether
Really sound like to me that it's broken, unable to open under vacuum, so I say get a new one, or a used one at the junkyard if your planing to removing emissions althogether
December 6th, 2011, 05:34 AM
#10
Seasoned beater pilot.
Join Date: Jan 2007
Location: Chicago
Posts: 5,468
The valve should squish open pretty easily when pushing it open with both thumbs.
Should feel about the same pressure as it would take to smoosh in a beer can in the center with both thumbs.
Should feel about the same pressure as it would take to smoosh in a beer can in the center with both thumbs.
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