Can Manual Egr Valve Have A Fault Code

[S&M Inc]

Evening all,

My 2003 C5 2.0 HDi has been playing up, lack of power, lost 10mpg of the urban average, lots of black smoke out the exhaust etc.

 

Local garage diagnosed faulty MAF from the error code.

I replaced the MAF no change.

 

Having studied the forum I've disconnected the vacuum pipe from the maual EGR valve and this have improved.

 

There's no cable at the EGR so would it have an error code?

The vacuum pipe has suction present at tickover, could this mean the control valve's goosed?

 

Many thanks

[mechcanico lee]

Bad diagnosis there from the garage just because theres a fault code for the air mass doesnt mean its at fault .

 

Egr fault codes on non potentiometer type egr valves use the difference in the mass air flow when the egr is open or closed to work out if the egr is working for instance .......... engine at idle mass air flow reading egr closed could be 100 kg/h open egr valve it can roughly half reading to bout 50 kg/h .

 

The diagnosic process of the ecm knows that there should be a change in air mass reading when egr is open or closed in your case if the egr valve is permanently open it could see this as an air mass fault and flag a fault code for air mass.

 

There should be vaccum there at the pipe at idle but normally after a few mins the vac goes off , try holding the revs up quite high see if the vavc is there then (egr tends to work at light throttle loads and goes off at bigger throttle openings )

 

If the vac is always there you could have a solenoid fault (trace the vac tube back it will go to the solenoid ) its worth trying leaving the pipe plugged and see if you get the man. light coming up ,engines better without it anyhow

[S&M Inc]

Many thanks Lee.

 

Any further advice on the following would be greatly appreciated

 

I disconnected the vacuum hose from the EGR last week. I'm no longer running on kangaroo diesel or creating my own smoke screen but my average mpg remains at 31 (was 39 Urban)

 

The hose seems to have constant suction which suggests to me the Solenoid Valve is goosed but as it's not correctly connected I'm at a loss to understand how this could be.

 

I disconnected the MAF plug and the car ran worse so I'm assuming the original MAF was faulty.

 

Thanks again.

[mechcanico lee]

Un plugging the air mass plug isnt definative in knowing if its duff ......it just puts a default value in the ecm allowing the car to be driven in a limp value , if the new air mass didnt improve your fault you can presume it wasnt that what was your fault .

 

If you say there is always vac on the pipe it could be a duff solenoid or the solenoid is constantly switched or the vac pipes are mixed up somehow .

 

If the egr has been held constantly open for a long time it could be coked up with the black death , take it off and throughly clean it and make sure the valve is seating properly.

 

When you said it goes better since removing the vac pipe did you plug the end of the pipe also , if the solenoid is duff you will lose vaccum in the other circuits e.g manifold butterfly and turbo wastegate control .

[qman3428]

You could try fitting a blanking plate between the egr and the manifold, that eliminates the egr from the system and I have found gives a lot more power and performance. Bought mine for my 4x4 from the Mitsubishi owners club but you may find one on Ebay. If you decide to make your own you can use the egr gasket as a template for the outside and holes for bolts but make the plate at least 3mm thick to stand the heat (dont use a coke tin as damage will result)

[S&M Inc]

My thanks for the advice received.

 

I've decided to try blanking off the EGR Valve and have ordered a blanking plate.

 

I was unable to remove the EGR valve as I couldn't figure out how the collar between the intercooler and the valve is released.

 

Any ideas please?

 

Thanks