High Idle Puzzle
Fleet Mechanic
Joined: Aug 2015
Posts: 1,840
Likes: 367
From: Candy Mountain
Not to say you can't have a ruptured EGR diaphragm or that it wouldn't be a problem. Just that it wouldn't cause a high idle.
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Mountain Pass
Joined: Mar 2018
Posts: 208
Likes: 1
From: Oregon
I doubt that is the core problem. The diaphragm would only leak when the EGR control solenoid is in the on position which only occurs during a few conditions, ie not puttering around town or stationary idling. When the control solenoid is in the off position it vents to atmosphere, ie a controlled vacuum leak.
Not to say you can't have a ruptured EGR diaphragm or that it wouldn't be a problem. Just that it wouldn't cause a high idle.
Not to say you can't have a ruptured EGR diaphragm or that it wouldn't be a problem. Just that it wouldn't cause a high idle.
Fleet Mechanic
Joined: Aug 2015
Posts: 1,840
Likes: 367
From: Candy Mountain
What you need to determine is if it is not moving because the diaphragm is ruptured in the EGR valve (not the most likely scenario) or if the vacuum signal is too weak or intermittent to move the diaphragm (given your symptoms a much more likely scenario, and it better fits an intermittent CEL activation) because of an up stream vacuum leak. It is also possible for the EGR valve to become frozen from carbon buildup.
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Mountain Pass
Joined: Mar 2018
Posts: 208
Likes: 1
From: Oregon
This may be a dumb question, but where do i get new vacuum hose lines? i looked up some on rock auto and AZ, but only got specific ones. is there not a general tubing i can use and cut? i've never worked with the vacuum system before
Fleet Mechanic
Joined: Aug 2015
Posts: 1,840
Likes: 367
From: Candy Mountain
I use bulk rubber hose. I prefer Gates EEC/PCV/Fuel hose for vacuum lines. They make it in various sizes, which you will need. It is not rated for high pressure so it has "not for EFI" all over it, but it is perfect for under hood vacuum lines. Available from various places, box stores like Orielly's and online retailers. I have found that the Gates stuff lasts longer they anything else I have used.
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Mountain Pass
Joined: Mar 2018
Posts: 208
Likes: 1
From: Oregon
how many feet should i order? is 5/32 the right diamter for the 5.0 302 v8?
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Mountain Pass
Joined: Mar 2018
Posts: 208
Likes: 1
From: Oregon
ok. done a bit of research and thought i would share this post from another forum. it talks about a full replacement of vacuum lines for the 5,0 302 v8
Rubber Vacuum System Replacement (5.0\5.8 EFI) - Ford Truck Club Forum
Rubber Vacuum System Replacement (5.0\5.8 EFI) - Ford Truck Club Forum
Cargo Master
Joined: Jun 2013
Posts: 3,182
Likes: 15
From: Somewhere n North America
ok. done a bit of research and thought i would share this post from another forum. it talks about a full replacement of vacuum lines for the 5,0 302 v8
Rubber Vacuum System Replacement (5.0\5.8 EFI) - Ford Truck Club Forum
Rubber Vacuum System Replacement (5.0\5.8 EFI) - Ford Truck Club Forum
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