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C6 2.7 Stuck EGR Valve -- any easy fix ? |
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onthecut
 
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  Member No: #2793
Location: West Mids |
I have the £ sign on on the dash and the Lexia says it's the rear EGR valve stuck at 19% (or at least that's my interpretation of what it says). I'm not bothered from a functional point of view as I have blanked the EGR pipes, but the lamp is irritating, especially as amazingly it seems to be the only fault listed. I have read the excellent 'sticky' post on replacing the valve and having just spent a couple of weeks grovelling about the car and am not much minded to start again, straight away. I wondered therefore if there is any fix for this, just to get the light off that doesn't require the big effort ? How exactly does it measure the valve position; does the physical valve stick or is it an electrical / control issue ? I see some places advertise EGR removal from the whole electronic system -- anyone tried this ? Mike. |
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gmerry
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   Member No: #21
Location: Scotland |
Hi Mike, as you have guessed, there are two options:- 1/Software EGR delete etc 2/Replace the EGR Valve. regards G |
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David Hallworth
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   Member No: #90
Location: Glasgow |
NFC Autocare in Thornton Clevelys do a lot of work with C6's and offer a remapping service where they can disable the EGR valve. The owner has done this to his own C6 and I know of two customers (Trainman on here is one of them) cars that have also been done and they've had no problems. Economy goes up considerably too as it's not changing gear as much due to having more torque. I believe the cost of the service is around £150. Another thing I'd have done whilst you car is on the ramp is a gearbox oil change if you've not already had it done. Regards David. |
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onthecut
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Member No: #2793
Location: West Mids |
David, thanks for the recommendation -- it's always so much better when you know people have had first hand good experience of a service provider. Gearbox oil change -- oh yes ! First drain was like molasses coming out; second still very grimy; the third, which I did yesterday still much dirtier than I would like to see but a big improvement on the previous two. Will be doing another drain when I do an oil change in about 3000 miles. Given it's such a relatively simple job, why it wasn't routine is beyond me. The other auto we run in the house is a GM 'box of similar mileage which I do a drain on once a year and the fluid comes out like new, so it's quite disappointing to see the state of the fluid in this C6 box. Fortunately, the box seems to work OK, so hopefully got to it in time. Mike. |
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onthecut
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Member No: #2793
Location: West Mids |
Booked in with them tomorrow, so we'll see how it goes. Mike. |
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Cisco
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 Member No: #1429
Location: Glasgow |
Mike, Very interested to hear how you get on. My egr system is ok but, based on all the reports of improved overall performance, blanking and deletion seems like the way to go, especially after looking at the exhaust crud deposited in the inlet chamber. ATB Frank |
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e3steve
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 Member No: #1163
Location: Warsash, Hants & Palma de Mallorca, Spain |
So blanking and deletion seems the way to go? I'm not entirely convinced on this one, because it makes the car not the same car it was produced as. However, I'm listening... Aside: I keep my EGRs as clear as I can by only using Shell V-Power Nitro+ or BP Ultimate Diesel and by regularly (every 2-3k miles) squirting Wynns EGR cleaner into the induction duct. Premium diesel pays dividends; I've proved that to myself! |
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onthecut
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Member No: #2793
Location: West Mids |
Nice day at the seaside yesterday and EGR issue all disappeared. Excellent, friendly service. I really haven't driven the car far enough before having this done to make any comment on pre / post remap performance, but what was impressive was the 41 mpg on the way up, sometimes doing 71 mph, followed by the same mpg on the way back when probably a good quarter of the journey was stop start, 10 or 20 mph stuff. As far as the ethics of EGR removal goes, I have no qualms at all. Every vehicle I have had with EGR has had the same grimy intake tract and I simply don't believe ultimately it's any good for the engine. If you gathered a year's worth of EGR deposits in a bottle and handed it to someone to pour in their engine, anyone with mechanical sympathy would laugh. I appreciate that EGR cleaning fluid may keep the intake visually clean, but as it only acts presumably to shift the visual grime, it's all still going through the engine. Mike. |
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321dave
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Member No: #614
Location: Dublin |
Unfortunately we don't have premium diesel available here in Ireland. But I believe it is pretty standard fuel quality, and a few outlets here sell the fuel with a recommendation now from the AA and mention additives added to the fuel. |
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e3steve
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Member No: #1163
Location: Warsash, Hants & Palma de Mallorca, Spain |
onthecut wrote ... Good thought, Mike. Premium diesel does prevent the c r a p from being produced; low sulphur and, therefore, greatly-reduced soot! I have the engine evidence to prove it...Nice day at the seaside yesterday and EGR issue all disappeared. Excellent, friendly service. I really haven't driven the car far enough before having this done to make any comment on pre / post remap performance, but what was impressive was the 41 mpg on the way up, sometimes doing 71 mph, followed by the same mpg on the way back when probably a good quarter of the journey was stop start, 10 or 20 mph stuff. As far as the ethics of EGR removal goes, I have no qualms at all. Every vehicle I have had with EGR has had the same grimy intake tract and I simply don't believe ultimately it's any good for the engine. If you gathered a year's worth of EGR deposits in a bottle and handed it to someone to pour in their engine, anyone with mechanical sympathy would laugh. I appreciate that EGR cleaning fluid may keep the intake visually clean, but as it only acts presumably to shift the visual grime, it's all still going through the engine. Mike. |
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onthecut
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Member No: #2793
Location: West Mids |
300 odd mile round trip yesterday, following the remap. Steady motorway / good A road cruise to South Wales; up and down the Valleys a bit, steady run across the M4, proper blast up the A449 / M50 and then a lot of crawling and stop start up the M5. Overall mpg -- 41 according to the trip computer. For the size of car and engine, plus the fact it's auto that seems to me to be pretty good. However ! The remap extinguished the £ lamp on the dash and this stayed out'til past Swansea. Getting on the M4 and giving it some stick uphill, suddenly the dreaded 'anti pollution fault' and lamp back on. Lamp remained on for the first and second restart, but was out again on the third start. All fine from Swansea to Monmouth. At Monmouth, back on pulling away from the lights. This morning, still on first and second starts; out on the third. Presently out. Plugged the Lexia in and I now have a different range of messages. The pre- remap one about the EGR valve being stuck open is now replaced by 'EGR valve blocked' (which is fair enough, as I have physically blocked both of them). Must admit though, I thought the remap bit removed all reference to the EGR system ? Other main message was front turbo over pressure. There were also several very random faults logged, which I am guessing may be generated in the course of the remap. Haven't had time to look at any real time data on what the turbos are doing, but I am curious where the individual turbo pressure measurement is taken. So far, I have only seen one pressure device and that's smack on top of the common intake housing. Mike. |
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David Hallworth
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Member No: #90
Location: Glasgow |
That's very unusual but it does sound like something isn't quite right in the map. Might be worth giving Leo a quick phone and seeing if he's got any ideas. David. |
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onthecut
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Member No: #2793
Location: West Mids |
I have just come across a different thread on here, describing my new symptoms pretty spot on and attributable to differences in turbo boost pressure, with the lamp then going out after 3 - 5 restarts if the condition has not persisted. When I got the car I soon found the rear turbo pressure hose was split and looking at the oil sprayed about, had been for a while. I am now wondering (and hoping) that perhaps one or other of the wastegate controllers has become lazy due to pressure loss at the split and now I have been giving the car a bit of proper exercise isn't moving as far or as freely as it should ? I will give it a week or two and a few more miles to see how we go. The last C5 I bought , with a variable vane turbo (yes, I know they are a different thing) had spent time doing no more the potter round town and over the first few months definitely came to life with proper use. Two things I'm definitely happy about after having it in loads of pieces are that the cooling system has gone back together spot on, as has the replacement oil pump assembly (OK - I get the picture - I needn't have done that bit.  )Mike. |
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speedfix
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 Member No: #1043
Location: south west |
[NFC Autocare in Thornton Clevelys do a lot of work with C6's and offer a remapping service where they can disable the EGR valve.] Imo many C6 cars that have had EGR valves blanked off will be scrapped when the DVSA and DFT get their act together and start testing them for the MOT with the gas anilizer that may well have data link connections picking up rpm temp feeds etc etc. To get these cars returned to run as they are intended will need remapping back to original speck after replacement EGR valves etc. Strong words to DVSA at last from the Founder and Director of clean air in London. Simon Birkett, Founder and Director of Clean Air in London — 10/11/2016 [Dear DVSA and DfT Your lack of enforcement and reliance on a 'visual check' test for the 'original fitment of (CATs and) DPFs' is covering-up the industrial scale removal of factory-fitted abatement equipment and associated activity across the UK. For example, you must also check, enforce and stop people tampering, removing or modifying OBD units e.g. remapping and ECU delete. You are both complicit in the widespread bypassing of fundamental public health protections.] NOx is deadly the EGR valve dosn't just remove a small amount of NOx it removes alot of which diesel engines produce a lot of. The EGR valves are not opperating all the time just as the temp reaches 2,500F. IMO the EGR valves when working correctly make the engine more efficent and does not effect power and makes the engine last longer. Reported improvements after mapping etc are compared with fauty running EGR systems not systems that are working as the manufactures vehicles left the factory. 25000-30000 deaths related to NOx gas exposure not good for the younger generation! |
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gmerry
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Member No: #21
Location: Scotland |
Whilst I generally agree with Speedfix's sentiment, there are a few things I'd like to add to:- 1/ EGR is a very flawed method of controlling NOx emissions from a Diesel engine, causing significant reduction in Specific Fuel Consumption and not being effective at cold engine and full throttle conditions (even when new) 2/ SCR is really the only way forward hence the adoption across the Euro fleet with Euro6 3/ London has specific issues, these do not affect semi rural parts of the country where I live, so my own behaviour / ethics reflect the local issue as well. 4/ London could easily extend and enforce a no diesel zone, at least no diesels older the Euro 6, into the Congestion Charging zone if they had the political will, rather than inflicting a solution which is not warranted in non Metropolitan areas. 5/ Not sure if the 2500F temperature referred to is a modelled temperature: certainly no control system I know of is capable of measuring and acting on a presumed in cylinder combustion peak temperature (nothing to do with combustion chamber temperature) 6/ DVLS could take immediate steps to ensure that engine MIL light is a MOT failure (it has been explained on this forum that it isn't) 7/ No technology currently exists for routine measurement of diesel exhaust gas composition - hence reliance on outdated "on the governor limit" testing for smoke emissions. regards G |
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