View Single Post
Old 04-05-2012, 02:58 PM   #13 (permalink)
steffen707
Master EcoModder
 
Join Date: Oct 2009
Location: Midwest
Posts: 337
Thanks: 4
Thanked 37 Times in 21 Posts
Quote:
Originally Posted by jonEmetro View Post
In theory the EGR does improve mileage by partially filling the cylinders with exhaust which is inert. Less oxygen means less gasoline burnt. This also means we have to open the throttle a little more to get the same power thus reducing pumping losses.

Attach a vacuum gauge to the vacuum hose going to the EGR valve and drive using less than half throttle and see if the vacuum solenoid is providing vacuum to the valve. The ECM will need to see warm coolant temp, vehicle speed & proper MAP sensor voltage before it will activate the solenoid.
I have tried exactly what you said and there is no vacuum.

I've even driven the car with the vacuum pump hooked to the egr to manually actuate it myself and it certainly does put exhaust into the engine. if i put enough vacuum to the EGR it will choke the motor off enough that it shuts off. So I know the EGR can work, but doesn't seem to ever get actuated by the ecu.

Could it be the car never gets up to high enough temp? And yes i've driven 4 hours straight with the car on the highway, so it "should" have gotten up to temp before.
  Reply With Quote