daveturnbull Posted September 10, 2018 Share Posted September 10, 2018 Another off topic thread from me, but I figure most engines work the same so.... For a while now my Volvo 2.0d (d4204t engine) has, on a mildly cold day, had a really rough idle until the engine is properly warm. Not just coolant warm, but block warm. A bit of research suggested that this might be due to the EGR valve being stuck open. It's done 185k miles now so no big surprise if some components are less than fresh. I parked it in the workshop and started pulling bits off, expecting to find the EGR full of gunk. It wasn't, just a little soot, and nothing that would cause restricted movement. I cleaned up all of the soot and had a closer look at how it all worked. On the end of the solenoid there is an armature with a wheel that rolls up and down a slot, operating the valve. In the slot the wheel runs, a tiny tiny ridge has worn, meaning that if you release the tension on the spring slowly, it sticks just before the valve is fully closed. At the 'valve open' end of the slot, the guide pin that holds the wheel also rubs a little on the arm as it twists, again I suspect due to wear. Fully closed position. Where it sticks a little before fully closed. I'm guessing that the movement should be super smooth, so I've ordered a new valve in the hope it fixes the issue. I know little about EGR valves, don't have one on the Land Rover, so am I correct is thinking... Cold engine = EGR closed, warm engine = EGR open That tiny little gap is enough to cause the engine to run a lumpy as my wife's gravy Blanking them off on a modern engine is less than ideal Quote Link to comment Share on other sites More sharing options...
geoffbeaumont Posted September 10, 2018 Share Posted September 10, 2018 Hopefully it wasn't as spendy as some - our old Honda Civic (2003 plate) had a sticky EGR, which still played up intermittently after being cleaned twice (once by a garage, once by me). Other than the engine management light coming on intermittently it was more inclined to smoke under heavy acceleration (family bus, so that wasn't very often) when the light was on, but it ran fine and didn't use more fuel. The car was old and Honda wanted £500 for a new valve, so it stayed that way... Quote Link to comment Share on other sites More sharing options...
daveturnbull Posted September 10, 2018 Author Share Posted September 10, 2018 They seem to range from £60 for an unbranded one up to about £300 for a genuine one. I've managed to find a Delphi branded one (same as the current one) for £100 so that seemed the sensible choice. Annoying really as I can see exactly what the problem is, but you can't get just those bits new, only a complete assembly. They are probably the cheapest bits of the whole thing too. Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted September 10, 2018 Share Posted September 10, 2018 (edited) If it's sticking at one bit can you smooth it off a bit, see if it will go over? We had a picasso, the first owner did 3 years of pottering around, very low mileage and low speed, then my wife give it another year of the same as she was on maternity leave. The car still ran but with an engine management light on. We cleaned it but couldn't get it to work properly so took it to a garage. They fitted a new one and had to recalibrate it to the car so I can only assume there is more than just 'open' and 'closed', the car must be able to set how open it is, like a pwm valve or whatever. The only one I've had blanked off was on a Fiat Bravo, it would go into limp home on hard acceleration which was great when overtaking. Blanking off was the cheaper fix I was offered, I can't remember if they had to do an ECU fiddle or not? I believe older ones were vacuum operated rather than electronic. They're usually fully closed when cold. They have recently changed the MOT rules on EGR and DPF blanking, I don't know if they will apply to your car as it depends on age but check before you decide to do it. Edited September 10, 2018 by Cynic-al Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted September 11, 2018 Share Posted September 11, 2018 (edited) The 4204T is a Ford PSA DW10 engine that is also used in the S Max, Kuga, Mondeo .......... PUG 307, 407, 607, 308, & 508 .......... citreon, Fiat, & Suzuki have also used it in some models. Basically it is a good engine with smooth power delivery and known for longevity My Volvo V70 uses this engine and is now on 160K and on a recent run to France was still returning an average of 54mpg (fully loaded and crusing at 75mph) ......................... The EGR failure is a common fault and on the volvo application the only answer is to change it. Volvo use a pressure sensing system, so if you blank the EGR it will bring on the engine management light (which is now an MOT failure) ................. on the Ford / Pug applications the EGR can be blanked as they did not use pressure sensing. Mine went faulty at about 130K and I sourced an OEM valve from a third party supplier which was about £120. The symptoms are as you describe ............ rough idle that is also sometimes faster than normal. Also it will blow a good amount of smoke when you give it a boot full............No codes are usually shown but an OBDII check using 'Torque' showed me that the EGR failed the setup test (this shows that it wasnt closing quick enough or it was staying partly open) Changing the valve is a challenge ..................... it is at the back of the block and hidden underneath it is a 5mm Allen screw thay can only be undone by feel .......... a lot of people break off the bottom lug from the valve and then remove the bolt. You also need to clean all the pipework feeding the valve and then you are good to go fo another 100K + .............................. If you havent already done so, It will also pay you to change the inlet hose from the intercooler to the throttle body as at high milages these tend to develop tiny leaks at the throttle body end ........... a new pipe is £98 ............. you will know when its past it best as good burst of right foot will push it into limp mode and you also get a 'Pending boost pressure' code. Edited September 11, 2018 by Bull Bar Cowboy Quote Link to comment Share on other sites More sharing options...
daveturnbull Posted September 12, 2018 Author Share Posted September 12, 2018 21 hours ago, Bull Bar Cowboy said: Changing the valve is a challenge I did a bit of reading about this before attempting the job, as you do, and this seemed to be the general consensus, however I must admit I found it quite easy. Must be all those hours spent working on badly designed fiddly rusted solid Land Rover bits. I've also removed and cleaned the Valve to manifold pipe and the throttle body. I had the manifold off a while back to do the gasket and scraped a good amount of gunk out of there too. New valve is on order, due to be delivered Thursday so with any luck I should be driving it again Friday. The next job on this one, which I am not looking forward to, is changing the fuel filter head. I get the occasional air bubble entering in the line at this point which causes a very slight miss occasionally at idle. It not so much a problem, just annoying. Quote Link to comment Share on other sites More sharing options...
daveturnbull Posted September 12, 2018 Author Share Posted September 12, 2018 Well the new valve turned up this afternoon, so I've got it fitted and had a quick run round the block. All seems well but I'll have to wait for a cold(ish) morning to see if it has fixed the rough idle issue. Quote Link to comment Share on other sites More sharing options...
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