EGR valve 56% at idle

[ronniecavs]

Hi all
my c200 cdi failed emissions test, I i scanned with carsoft i980 and had dtc p2511 egr monitoring malfunction
i could see that the egr valve was at 56% while sitting at idle , All information I can find says it should be closed at idle ,I have removed egr and cleaned then refitted and watched it with the end cap off
as soon as I start the engine it opens , and shuts again when engine stopped, so it appears to be working mechanically opening and closing and not stuck
so Im thinking it could be a bad sensor or air leak on on intake and not a bad egr

heres the scan results with engine idling

Rail pressure 320.60 bar

pressure control valve 24.40%

quantity control valve 39%rpm 780

injector quantity 11.66

atmos pressure 1008

air mass 348.80

egr 56%

intake pressure 997

boost pressure 1010

charge pressure position 95%


does this look normal or point to any thing out of whack

any help would be most appreciated

kind regards

Ron

 

[grober]

Need to know the engine/chassis no to determine exactly which EGR system/ technology implemenation we are dealing with. Its a constant source of frustration when folks ask very detailed technical questions about their cars operation after supplying only the bare minimum of information about their own car themselves. I suppose its a natural trap to fall into because as they are there with the car in question in front of them but forget that is not the case for readers of their post. There may well be forum members out there with the exact same model who have experienced the same problem and have your answer but--THEY ARE NOT MIND READERS!!!!!!!!!
In general terms if you accept the function of any EGR is to reduce combustion gas temperature by re-introducing an inert exhaust gas component into the inlet that might suggest that one of the main control inputs for EGR function would be engine temperature related . These systems are complicated an often involve interrelated components. a failure of one of them may lead to uncharacteristic EGR behaviour without it being faulty itself. If for example there's an egr bypass system a failure there might cause the EGR to open prematurely??

 

[ronniecavs]

Hi Graeme
thanks for your quick reply
vin number WDC2030072R121101 i dont have the full engine no with me but its a 646 type engine if thats any help will upload full no later if necessary

cheers Ron

 

[grober]

Your engine number is 64696230076275
CHASSIS MERCEDES C-KLASSE [Car] [CHASSIS] (EUROPA)
INTAKE MANIFOLD MERCEDES C-KLASSE [Car] [CHASSIS] (EUROPA)
unfortunately i don't have access to the mercedes WIS at this time.