EGR vaccum
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Member
Joined: Mar 2006
Posts: 50
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From: Apopka, FL
EGR vaccum
does anybody know how many psi's of vaccum the eqr should be getting under normal acceleration? i recently discovered that a hole had rusted its way into the "coffee can" vaccum reserve (go figure), i replaced it with a pickle jar and some apoxy (which is holding up fine) but i put a vaccum gauge on the green vaccum line that supplies the EGR from the EVR (i think its called, it regulates the vaccum to the EGR), newayz i drove it around and it only put out bout 3.5 psi at max under normal acceleration, which does not seem like much to me.
thanx.
thanx.
Senior Member
Joined: Oct 2002
Posts: 7,295
Likes: 125
From: St. Louis (Out in the woods)
There should NOT be vacuum on the EGR valve during acceleration. EGR is only commanded during steady state cruising.
Check the input drive (low side) of the EVR solenoid. When EGR is commanded, you should see an EGR vacuum proportional to the EVR drive duty cycle.
Steve
Check the input drive (low side) of the EVR solenoid. When EGR is commanded, you should see an EGR vacuum proportional to the EVR drive duty cycle.
Steve
Senior Member
Joined: Jul 2004
Posts: 6,200
Likes: 39
From: Easton, Pa.
If you teed into the line between the EVR and EGR and done a drive test, you should have saw vacuum only in lite throttle cruise range rpm/speed mostly in 3rd or OD.
The vacuum level measured would normally be in the 3 to 5 inch range and would depend on how much throttle opening is applied since the TB/ load dictates the intake vacuum level at any given time.
If you went wide open throttle it would drop to zero because the PCM would have closed it again.
This is a good way to see absolute EGR function as far as the vacuum action goes because the EVR has to let air back into the EGR once it has been opened, for it to release when it is supposed to otherwise you would get drivability problems from an full time locked open EGR. Vacuum at any other time means the EVR is stuck open as well as the EGR. This would normally set a code and a CEL light.
You can see this as a troubleshooting method for operation but won't tell you much about a plugged port or much about the DPFE except by association, specific code and elimination logic.
Iv'e done this exersise of test and elimination when a 401 code appeared before spending on a new DPFE and it was the fault.
There is a more to all this but will stop here.
The vacuum level measured would normally be in the 3 to 5 inch range and would depend on how much throttle opening is applied since the TB/ load dictates the intake vacuum level at any given time.
If you went wide open throttle it would drop to zero because the PCM would have closed it again.
This is a good way to see absolute EGR function as far as the vacuum action goes because the EVR has to let air back into the EGR once it has been opened, for it to release when it is supposed to otherwise you would get drivability problems from an full time locked open EGR. Vacuum at any other time means the EVR is stuck open as well as the EGR. This would normally set a code and a CEL light.
You can see this as a troubleshooting method for operation but won't tell you much about a plugged port or much about the DPFE except by association, specific code and elimination logic.
Iv'e done this exersise of test and elimination when a 401 code appeared before spending on a new DPFE and it was the fault.
There is a more to all this but will stop here.
