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    Mpg significantly down after egr replacement

    My VW Golf is one of the 'emissions scandal' affected vehicles, still without a fix. A couple of months ago it went into 'limp mode' and a new egr unit was diagnosed as the solution. This was carried out and fixed the fault, however since then the mpg is noticeably lower and I am refueling more often. E.g. motorway driving would usually show 65-70mpg, but is now at 49-55mpg. I am going to ring VW to get it checked out, but wonder if anyone has had a similar problem or knows what's likely to be the cause of this issue?

    Many thanks in advance

    18 Comments

    Clean the fuel injectors, check the oxygen sensor ? Treat with a good fuel additive? Tyre pressures I guess.....clutching at straws mate could be a number of things

    Original Poster

    paulj765

    Clean the fuel injectors, check the oxygen sensor ? Treat with a good … Clean the fuel injectors, check the oxygen sensor ? Treat with a good fuel additive? Tyre pressures I guess.....clutching at straws mate could be a number of things



    Thanks for your reply. The drop was immediately after the egr replacement, so wondering if it could be that the unit wasn't sealed in properly or something related to the engine having to be taken out and refitted... (looking for some info to use before I take it back in to VW). Thanks again

    A lot of people including me have put in an egr blanking plate that stops all the dirty sooty exhaust fumes being recirculated in to the engine this improves performance and mpg.

    Original Poster

    robbarraclough18

    A lot of people including me have put in an egr blanking plate that stops … A lot of people including me have put in an egr blanking plate that stops all the dirty sooty exhaust fumes being recirculated in to the engine this improves performance and mpg.



    Interesting idea, but doesn't that then mean all the dirty exhaust fumes go straight into the environment, thus making the car very polluting...?

    Reburning your soot still makes your car dirty and pollutant.blocking off your egr valve must be better for the environment if you are getting better mpg.

    Mermoo

    Interesting idea, but doesn't that then mean all the dirty exhaust fumes … Interesting idea, but doesn't that then mean all the dirty exhaust fumes go straight into the environment, thus making the car very polluting...?



    It's done to reduce nitrogen oxides (NOx) emitted into the air.

    The air mass sensor may not be reading correctly as it maybe still compensating for the restricted flow of the old EGR valve and pulling in excess air and thus fuel.
    Try removing the plug to the sensor. Turn the ignition to the on position. Turn back to off then reconnect the sensor. Now see if your MPG improves.

    Are you sure it's not because the cooler weather?, It can reduce the fuel economy, has your driving style changed?, are you using A/C more than you were before?. They may have disconnected the battery when replacing the EGR and reset the trip computer.

    If you cap the the egr you'll probably get an engine management light on, so might need it remapping which will help improve mpg anyway!.

    Or you could just ignore the eml, Because the egr is new you could just disconnect the the cable to the egr.

    With the egr being new it shouldn't effect the mpg too much and in theory might actually improve it a little as it recirculates the gases to be reburnt.

    The problem is after so long things get really dirty, everything gets caked in carbon which basically suffocates the engine along with the turbo and exhaust etc.. so has the opposite effect more so with town driving.

    Capping/Disabling the egr will most definitely improve engine smoothness and there will be much less carbon build up.

    Are you sure VW haven't done "The emissions fix"?, I'd guess that might reduce economy, I'd also avoid having it done has it will most certainly have a negative effect. Unless you care about trees.

    Original Poster

    GAVINLEWISHUKD

    It's done to reduce nitrogen oxides (NOx) emitted into the air.The air … It's done to reduce nitrogen oxides (NOx) emitted into the air.The air mass sensor may not be reading correctly as it maybe still compensating for the restricted flow of the old EGR valve and pulling in excess air and thus fuel. Try removing the plug to the sensor. Turn the ignition to the on position. Turn back to off then reconnect the sensor. Now see if your MPG improves.



    Thanks-I will try this and report back.

    Original Poster

    shauneco

    Are you sure it's not because the cooler weather?, It can reduce the fuel … Are you sure it's not because the cooler weather?, It can reduce the fuel economy, has your driving style changed?, are you using A/C more than you were before?. They may have disconnected the battery when replacing the EGR and reset the trip computer. If you cap the the egr you'll probably get an engine management light on, so might need it remapping which will help improve mpg anyway!.Or you could just ignore the eml, Because the egr is new you could just disconnect the the cable to the egr. With the egr being new it shouldn't effect the mpg too much and in theory might actually improve it a little as it recirculates the gases to be reburnt.The problem is after so long things get really dirty, everything gets caked in carbon which basically suffocates the engine along with the turbo and exhaust etc.. so has the opposite effect more so with town driving.Capping/Disabling the egr will most definitely improve engine smoothness and there will be much less carbon build up.Are you sure VW haven't done "The emissions fix"?, I'd guess that might reduce economy, I'd also avoid having it done has it will most certainly have a negative effect. Unless you care about trees.



    I've been driving the car for 6 years - same journeys and have taken into account the cooler weather. I never use a/c, so can't be that.

    I was thinking they might have done something so that when the 'fix' is released I wouldn't notice...

    Original Poster

    Further info:

    Interestingly shorter journeys seem to get better mpg than motorway driving. I have just done a 7 min journey, average speed 18mph, cold start and got 61mpg. This morning did 20min on motorway, average speed 40mph, not gone over 65mph and got 53mpg.

    The car is running at 2200rpm in 5th gear at 60mph-does this sound high?

    Thanks
    Edited by: "Mermoo" 3rd Dec 2016

    Mermoo

    Further info:Interestingly shorter journeys seem to get better mpg than … Further info:Interestingly shorter journeys seem to get better mpg than motorway driving. I have just done a 7 min journey, average speed 18mph, cold start and got 61mpg. This morning did 20min on motorway, average speed 40mph, not gone over 65mph and got 53mpg. The car is running at 2200rpm in 5th gear at 60mph-does this sound high?Thanks



    Not particularly, Are you going by what the cars trip computer is displaying? or by real life mpg?. It's only a guide, maybe there is a faulty sensor, perhaps they might have disturbed one when replacing the egr?. For example a temp sensor, if the cars temperature is low then it'll probably give you a false reading like you're seeing. Fuel mixture might also be incorrect etc..

    Original Poster

    shauneco

    Not particularly, Are you going by what the cars trip computer is … Not particularly, Are you going by what the cars trip computer is displaying? or by real life mpg?. It's only a guide, maybe there is a faulty sensor, perhaps they might have disturbed one when replacing the egr?. For example a temp sensor, if the cars temperature is low then it'll probably give you a false reading like you're seeing. Fuel mixture might also be incorrect etc..



    The rpm seem a bit higher than normal in 5th. I'm going by the trip computer and also the fuel gauge/miles remaining and it is definitely using more fuel than previously. Prior to the egr being replaced my town driving would show around 49mpg and motorway always 62mpg+ in cold weather. Maybe it is a faulty sensor-I will put that to VW next week. Thanks

    Mermoo

    The rpm seem a bit higher than normal in 5th. I'm going by the trip … The rpm seem a bit higher than normal in 5th. I'm going by the trip computer and also the fuel gauge/miles remaining and it is definitely using more fuel than previously. Prior to the egr being replaced my town driving would show around 49mpg and motorway always 62mpg+ in cold weather. Maybe it is a faulty sensor-I will put that to VW next week. Thanks


    You're welcome, Clearly somethings not right, Hope you get it sorted.

    The only way your rpm to mph ratio in 5th gear can change is bigger or smaller wheels, slipping clutch or gearbox change but I don't think they would have done that when they fitted the egr.

    Mermoo

    Further info:Interestingly shorter journeys seem to get better mpg than … Further info:Interestingly shorter journeys seem to get better mpg than motorway driving. I have just done a 7 min journey, average speed 18mph, cold start and got 61mpg. This morning did 20min on motorway, average speed 40mph, not gone over 65mph and got 53mpg. The car is running at 2200rpm in 5th gear at 60mph-does this sound high?Thanks



    you didn't get 61mpg, you got that displayed on the screen, even the manuals for the car will say this is just an estimate.

    you need to do a few cycles through a full tank and work out the real MPG figure

    shauneco

    Are you sure it's not because the cooler weather?, It can reduce the fuel … Are you sure it's not because the cooler weather?, It can reduce the fuel economy, has your driving style changed?, are you using A/C more than you were before?. They may have disconnected the battery when replacing the EGR and reset the trip computer. If you cap the the egr you'll probably get an engine management light on, so might need it remapping which will help improve mpg anyway!.Or you could just ignore the eml, Because the egr is new you could just disconnect the the cable to the egr. With the egr being new it shouldn't effect the mpg too much and in theory might actually improve it a little as it recirculates the gases to be reburnt.The problem is after so long things get really dirty, everything gets caked in carbon which basically suffocates the engine along with the turbo and exhaust etc.. so has the opposite effect more so with town driving.Capping/Disabling the egr will most definitely improve engine smoothness and there will be much less carbon build up.Are you sure VW haven't done "The emissions fix"?, I'd guess that might reduce economy, I'd also avoid having it done has it will most certainly have a negative effect. Unless you care about trees.



    ​I think along similar lines it's probably he weather aswell. the lowest I use to get for my toyota corolla verso was around 22mpg but in last few weeks it's gone down to about 15 mpg that did involve a lot more local trips but I still recon it should have been abit more if the wether was warmer.

    have u had the oil changed sometimes differnet oils can reduce mpg by upto 10mpg for these diesel cars espicciely the passats

    Original Poster

    shauneco

    Are you sure it's not because the cooler weather?, It can reduce the … Are you sure it's not because the cooler weather?, It can reduce the fuel economy, has your driving style changed?, are you using A/C more than you were before?. They may have disconnected the battery when replacing the EGR and reset the trip computer. If you cap the the egr you'll probably get an engine management light on, so might need it remapping which will help improve mpg anyway!.Or you could just ignore the eml, Because the egr is new you could just disconnect the the cable to the egr. With the egr being new it shouldn't effect the mpg too much and in theory might actually improve it a little as it recirculates the gases to be reburnt.The problem is after so long things get really dirty, everything gets caked in carbon which basically suffocates the engine along with the turbo and exhaust etc.. so has the opposite effect more so with town driving.Capping/Disabling the egr will most definitely improve engine smoothness and there will be much less carbon build up.Are you sure VW haven't done "The emissions fix"?, I'd guess that might reduce economy, I'd also avoid having it done has it will most certainly have a negative effect. Unless you care about trees.

    muddassarsardar

    have u had the oil changed sometimes differnet oils can reduce mpg by … have u had the oil changed sometimes differnet oils can reduce mpg by upto 10mpg for these diesel cars espicciely the passats





    It doesn't make sense that short town driving is consistently showing higher mpg than lengthy motorway driving though.

    The car has been regularly serviced by VW, with an oil change in September and no noticeable drop in mpg. The egr was changed in late October and the mpg have been down since then.
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