Erratic EGR valve

[grosser panzer]

Hi all.
My e320cdi was running really roughly recently after my mrs filled up with Shell V power diesel. It then went in to limp mode. I stopped and restarted and the car was fine for about a mile and then went into limp mode again, this happened continuously. I lifted the bonnet and removed the plastic engine cover and with the engine idling I could hear a scratching sound from the right side of the turbo. This turns out to be the egr valve which seemed to be actuating. After some effort I removed the valve which was sooted up as was the bore it sits in but nothing more than I would have expected. I cleaned it and replaced it with the plastic end cover removed. Now the car starts and runs for a few seconds then the egr valve actuates up and down continuously. Every time the valve opens the engine can be heard responding so its basically hunting. The turbo actuator was repaired a year or so ago so I'm hoping its not related, the actuator also moves when the engine starts, revs and turns off. The back end of the egr valve has a plastic cap with the electrical connections inside. There is also what looks like a magnetic ring on the shaft which has cracked into pieces. So questions are:

• Is this EGR valve continuous on/off cycle a sign of something?
• Is the EGR valve at fault or is it being commanded to operate due to something else on the car?
• Has anyone else had a fault caused by using V power diesel or is that coincidence?

If the EGR valve was cheap I would just replace it as a matter of course but local dealer tells me that service exchange is currently unavailable and a new valve is £418+VAT.

Also due to people getting back to normal working etc no garage can book the car in for 6 weeks (looks like good times for garages!)

Any help much appreciated

 

[Fez7]

Sorry, I can't help with the EGR fault apart from recommending it be replaced or even deleted and remapped if you want to go down that route but I purely run my car on Shell V Power diesel for its extra cleaning properties so that won't be the cause of the problem.

What's your current mileage? What diesel do you normally use, standard Shell/BP etc or supermarket?

 

[Gazwould]

Fez I can save you lots of money !

 

[grober]

DETERMINE the EGR part no and then cast your replacement net a bit wider than the MB PARTS COUNTER by searching on the net?

 

[Gazwould]

As in the non Mercedes branded but Mercedes OEM Wahler may be cheaper for an identical replacement .

 

[TeddyRuxpin]

Try cleaning it as (at least) a stop gap?

Buy a can of EGR cleaner, and you can also carefully pry off the plastic taps to reveal the actuator. Make sure it moves freely and possibly even add a little dab of oil on the mechanism.

This was mine 12-18 months after the previous cleaning (I didn’t take the plastic off last time though). Pretty good condition.

If you take the plastic off (be careful with the tabs) you’ll be able to push the mechanism to see if the valve opens easily/smoothly or if it’s stuck.

I’ve read that sometimes the valve seems fine but is still broken, but it’s worth a go as it’s already out!

 

[TeddyRuxpin]

Also get a new gasket and the turquoise o-ring!

 

[grosser panzer]

Thanks for the replies. I did clean the valve prior to refitting and I did manually actuate the valve and it seems to operate ok. With the black plastic cover removed it is possible to see the valve opening and closing, I would say the actuation is ok and so I am thinking either the fault lies with some other part of the system which is then commanding the valve to open and close or the feedback from the valve is at fault as the magnet ring on the back side of the unit is cracked (sorry I didnt take a photo).

I did get a part number from the existing unit which is A642 140. When I spoke to the main dealer they said they needed more digits. They must have identified the part then from the vin but without the other digits I am not confident about buying one from the internet incase its not the right part.

The car has now done 160k miles. It has a full service history and has been well looked after. It has a few war wounds here and there but otherwise drives great and the interior is like new. I want to keep this car for as long as I can!

Any further help welcome!

 

[grosser panzer]

I took the car to my local independent who are great. They agreed the EGR was faulty and quoted a new replacement. That was fitted and straight away the car was different. 1st journey after installing the new EGR and something wasnt right. Car drives ok but occasionally when accelerating as engine speed is around 1500rpm a jerk can be felt. I wondered if this was related to the EGR valve and so I removed the end cover of the EGR valve to reveal the actuator. I then fitted a camera under the bonnet and drove the car. While driving I watched the valve expecting it to slowly modulate open and closed which it did but occasionally it goes really erratic and snaps fully open and closed instantly. In those moments the engine note changes and the loss of power can be felt.

So the valve should be ok as it is new. I am guessing something else is providing a signal which is causing the valve to respond. Could that be exhaust dpf sensor, turbo actuator or gearbox electronics? Any ideas on what I can check or test or insight into how this system works much appreciated.

Thanks