EGR valve
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Senior User
Joined: Jan 2008
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From: Issaquah, WA
EGR valve
On a '85 302 FI, I can hear my EGR valve flapping when the engine is around 2000 rpm. I am sure thats what is going on because I took the sensor off the top of it, and held a screw driver on it and it stopped. My question is what controls that valve? The electronic component is a position sensor, so what should be stopping that from flapping? I can't see anything wrong with the valve itself. The spring seems fine, etc.
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Joined: Jan 2001
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From: Virginia
The valve is controlled by vacuum, and there is a solenoid that turns the vacuum on and off. The solenoid is turned on and off by the engine computer.
There where several variations of this control system, but I believe that is the one you have. You may want to pull some codes, and see if you have an egr sensor errors. If the feedback sensor is bad, it can confuse the computer.
There where several variations of this control system, but I believe that is the one you have. You may want to pull some codes, and see if you have an egr sensor errors. If the feedback sensor is bad, it can confuse the computer.
Thread Starter
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Senior User
Joined: Jan 2008
Posts: 105
Likes: 1
From: Issaquah, WA
So swapped out O2 sensor. I don't get any codes for the KeyOn test.
The valve makes a chattering sound around 2k rpm. The vacuum line from the valve to the solenoid seems to be a perfect shape. Is there a way to better diagnose this? The valve & solenoid are pretty expensive, so I'd rather not just start swapping in new parts. Has anyone else experienced this?
It doesn't seem to effect the engine much, but it sounds pretty weird going down the road with the engine chattering away!
The valve makes a chattering sound around 2k rpm. The vacuum line from the valve to the solenoid seems to be a perfect shape. Is there a way to better diagnose this? The valve & solenoid are pretty expensive, so I'd rather not just start swapping in new parts. Has anyone else experienced this?
It doesn't seem to effect the engine much, but it sounds pretty weird going down the road with the engine chattering away!
Moderator
Joined: Jan 2001
Posts: 56,980
Likes: 2,735
From: Virginia
Unplug the solenoid. If the chattering goes away, then at least you know the computer is causing the chattering, since it controls the solenoid.
If the computer is causing it, it may be getting bad info from the position sensor on the egr valve. If have never messed with one, but if you could unplug the sensor, and then put a ohmmeter on it, and slowly move the sensor or the egr valve open and closed, you could see if the ohms of the sensor where nice and smooth, or all chopped up and jerky.
If the computer is causing it, it may be getting bad info from the position sensor on the egr valve. If have never messed with one, but if you could unplug the sensor, and then put a ohmmeter on it, and slowly move the sensor or the egr valve open and closed, you could see if the ohms of the sensor where nice and smooth, or all chopped up and jerky.
