EGR Valve Spring Too Weak?

 

Asking this as at idle EGR quantity is sometimes high EGR (actual) above 400 mg/str while specified is 240 mg/str. A blip on the throttle often takes actual down to match specified.

 

EGR valve thoroughly cleaned and seating well.

Have checked EGR valve actuation with a hand operated vacuum pump

New solenoid valve block

Vacuum pump producing 27inHg vacuum

No vacuum leaks

New MAF sensor

New MAP sensor

New turbo (actuation also tested with hand operated vacuum pump)

 

What I am wondering now is if the EGR spring has weakened and is not strong enough to hold it properly shut.

 

This is not a problem I see being discussed often, but is mentioned in some sources as a possible EGR problem. Is it something which our cars are prone to?

 

Engine 1.9 PD BXE

 

Thanks

 

I guess the only way to check is to try manually/digitally (i.e. with a finger) opening the valve from below, with the feed pipe disconnected.  Trouble is you'd need a known good one to compare with in terms of how much movement if any you can generate with a calibrated finger poke.

 

I've got a spare EGR somewhere (off an ASZ I think), doubt it's quite the same as yours but the fundamentals might be similar (maybe same vac diaphragm size, same return spring)? I can have a play later if I can find it.

 

My recollections of helping an Octavia-owner friend clean his out was that it was really hard to move it with finger pressure.  Can you remember trying this on yours when you were cleaning?

Thanks Wino

 

Took the plunge late on last night and ordered a new EGR valve from Darkside Developments.

 

Unfortunately did not try pushing valve open by hand when I took it out, only used manually operated vacuum pump to open it. The more I think on it the more I doubt that it is the problem though.

EGR valve tested, started to open at 11 inHg  and fully open at 21 inHg, which sounds reasonable to me (in the absence of any specification), I will however compare this with the new one when it arrives.

Oh well new EGR valve arrived today, pretty hard to open by hand right enough.

Vacuum tested and it started to open at 11.5 inHg, fully open at 19 inHg

So very little difference unfortunately.

 

Might try a bit more investigation of the anti shudder valve as there isn't much left.