EGR System Inputs

[mrbythatmuch]

From the service manual 11-128
The EGR System is designed to reduce oxides of nitrogen emissions (NOx) by recirculating exhaust gas through the EGR valve and the intake
manifold into the combustion chambers. It is composed of the EGR valve, CVC valve, EGR control solenoid valve, PGM-FI ECU and
various sensors.
The ECU contains memories for ideal EG R valve lifts for varying operating conditions. The EG R valve lift sensor detects the amount of EG R
valve lift and sends the information to the ECU. The ECU then compares it with the ideal EGR valve lift which is determined by signals
sent from the other sensors. If there is any difference between the two, the ECU cuts current to the EGR control solenoid valve to reduce
vacuum applied to the EG R valve.


So I think this may be why I'm not passing smog since I'm not getting enough vacuum pressure to the EGR Valve. Does any one know what the
"various sensors" are?
Does the ECU really "reduce" the EGR control solenoid command if the lift is not where it should be? I would have expected it to use the lift sensor on the EGR valve as feedback to dec or inc the signal command to the EGR solenoid. Why would the manual say it will always result in reducing the vacuum.

 

[Briank]

If your egr valve does not move correctly it your ecu will through a cell/mil. You can read the manual all day long and infer what ever you want. The manual has typos and things that were lost in translation. The EGR valve system is a very simple system that just works. I there is a problem with the plumbing being clogged or disconnected you will have Nox issues but no CEL.