egr excessive flow
Thread Starter
|
Freshman User
Joined: Oct 2010
Posts: 44
Likes: 0
egr excessive flow
so i got this code on my truck and im not really sure what this exactly means. i did some brief research and i got something with taking off the upper intake and cleaning it out and such. at around 2 thousound rpm it hesitates for a minute than kicks up. im not really sure what to do any suggestions? its a 4.2 6
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
Are you sure it's excessive flow?
What is the code?
It would be P0402 for this failure.
The computer checks the DPFE for flow when the system is supposed to be closed and tight.
If the DPFE detects a pressure drop accross the orface in the metal tube, the EGR maybe leaking past it's seat, diaphram leaking to air, Vacuum Regulator valve stuck open allowing vacuum to lift the EGR off it's seat etc.
The vacuum regulator is a 3 port device. It has a filter in the round cap.
Once it is commanded to open and pass vacuum to the EGR, it has to close again and open that hose to the EGR to let air in for the EGR to close again or the EGR can hang open some amount of time and cause drivability issues.
This type issue can make the motor run rough because it is allowing exhaust gas into the intake when it's not supposed to.
Note, in this case it usually is not the DPFE if there is a drivability issue.
The DPFE is just a sensor to measure pressure drop and report it to the computer in response to a set of test conditons.
Good luck.
What is the code?
It would be P0402 for this failure.
The computer checks the DPFE for flow when the system is supposed to be closed and tight.
If the DPFE detects a pressure drop accross the orface in the metal tube, the EGR maybe leaking past it's seat, diaphram leaking to air, Vacuum Regulator valve stuck open allowing vacuum to lift the EGR off it's seat etc.
The vacuum regulator is a 3 port device. It has a filter in the round cap.
Once it is commanded to open and pass vacuum to the EGR, it has to close again and open that hose to the EGR to let air in for the EGR to close again or the EGR can hang open some amount of time and cause drivability issues.
This type issue can make the motor run rough because it is allowing exhaust gas into the intake when it's not supposed to.
Note, in this case it usually is not the DPFE if there is a drivability issue.
The DPFE is just a sensor to measure pressure drop and report it to the computer in response to a set of test conditons.
Good luck.
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
..Leaking and open are quite different.
..The EGR operation is a controlled function.
..It's not just open or closed.
..The amount of vacuum pull controls the EGR opening against an internal spring tension.
..The rough running is due to the exhaust gas polluting the mixture as well as the ignition timing going advanced and some reduction in fuel that causes the rough running.
..The pipe leading from the drivers side exhaust manifold to the EGR has a small orface internal that will limit the volume of gas that flows plus the exhaust pressure and the intake vacuum pull all have an effect on how much flow at any given time.
..The EGR operation is a controlled function.
..It's not just open or closed.
..The amount of vacuum pull controls the EGR opening against an internal spring tension.
..The rough running is due to the exhaust gas polluting the mixture as well as the ignition timing going advanced and some reduction in fuel that causes the rough running.
..The pipe leading from the drivers side exhaust manifold to the EGR has a small orface internal that will limit the volume of gas that flows plus the exhaust pressure and the intake vacuum pull all have an effect on how much flow at any given time.
