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Had a quick word with a mechanic concerning my poor fuel economy and an EGR fault code and he suggested "deleting" the egr- not strictly legal but would likely improve fuel economy/performance? Any anecdotes to share? Or just try cleaning/replacing the egr valve first as it maybe stuck/bad? Just replaced battery so hoping may solve. (has stopped economy mode and esp light coming on which is a good start..)
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In reply to magma:
using my friend's driving as a test (same 1.6 hdi engine), she got just over 40mpg over a few 60mile trips with my Citroen C4 GP yet she's just recorded an admirable 55+ with her Peugeot 308..
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In reply to magma:
If you delete the EGR remember never to complain about any environmental issues again.
It's there for a reason, people who delete it are part of the problem, it's not really a solution to anything.
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In reply to magma:
How many miles per year do you do in your diesel?
In reply to magma:
I would find a new mechanic, someone who will actually fix things rather than shortcut with dubious practices
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In reply to Andrew Lodge:
it's there for a reason, (marginal reduction of nox at startup?), but if it's not working properly it's worse than useless/deleting..
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In reply to magma:
A working EGR has an insignificant impact on mpg.
It will reduce it a tiny but, as it's cooling cylinder temperatures, and displacing oxygen, you don't quite get as thorough combustion, but I don't believe you would notice the difference in mpg.
If it's stuck open, and the EGR allows too much exhaust gas into the cylinder (some can pass a lot through, not sure about yours) then under higher loads, you could be running rich and basically throwing fuel down your exhaust unburnt.
Not sure where the EGR only working on start-up comes from. They are effective mainly under partial throttle (not that your diesel uses a throttle in the conventional sense, but you know what I mean). At full throttle, they close off so they don't impact performance when you want full power.
A new EGR is about £120 (you can get cheap aftermarket ones for £30 but no idea if these are a waste of money or not). Since a blanking kit will cost something, the work to fit is similar to an EGR, may as well just get an new EGR and be done with it.
If it's the EGR motor that's gone, as the code suggests it's likely something else (injector?) that's causing the fuel efficiency issue.
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In reply to magma:
Would this count as an engine modification that you’d need to declare to your insurers so as not to invalidate your insurance?
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In reply to magma:
The suggestion to delete it, feels a bit like putting black paint over a warning light to "fix" the problem.
If you think there's only a few miles left in the vehicle and you want to use it a little longer, then delete away. But if you think the vehicle is worth fixing...
Edit: and clean your injectors!
Post edited at 06:59
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In reply to magma: Maybe buy some alcohol and give your mass airflow sensor a clean. We have a 2005 diesel and I’ve just replaced the turbo to keep it going for a few more years until we go electric or similar and the fuel economy has jumped. We try and avoid short journeys at all costs as they are not great for diesel engines especially modern ones.
Good luck
Toby
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In reply to Blue Straggler:
> Would this count as an engine modification that you’d need to declare to your insurers so as not to invalidate your insurance?
It's illegal so it would absolutely invalidate your insurance, if found
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In reply to magma:
No idea how similar the compared vehicles actually are but a reported 40 vs 55mpg is a reasonably significant difference, probably big enough to indicate a real phenomenon. Assuming similar vehicles, loads, conditions and usage, also assuming they run the same electronics so the dash/metering can be ignored I'd check the basics like tyres and brakes before messing with the engine.
Speed, wind, hills, bendy or wet roads, soft or threadbare tyres, draggy brakes, gearbox, aircon and heavy loads can all make a noticeable impact on economy and a big one cumulatively.
If your EGR might be broken get it properly diagnosed then if necessary fixed or cleaned.
jk
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In reply to jkarran:
got as far as the EGR fixing bolts. think they're puny torx 27 and someone seems to have had a go at removing as can't get any torque. luckily seems to be enough access for drilling/bolt extractor, or would you suggest something else?
In reply to magma:
hammer and chisel at an angle to get them turning.
In reply to magma:
> got as far as the EGR fixing bolts. think they're puny torx 27 and someone seems to have had a go at removing as can't get any torque. luckily seems to be enough access for drilling/bolt extractor, or would you suggest something else?
T27 is what, M3, M4 at most? If you cut the heads off, will you ever get the threaded portion out? Are they really rounded or clogged with crud? Drilling M3 screws out without a mill will be a nightmare, they'll be way tougher than the body they're in, even getting the heads off with a drill won't go that smoothly, they're usually pretty tough.
Obviously penetrating oil, some axial smacks to break any stiction. I can't see a spiral screw extractor working at that scale but could be wrong. Assuming you can't turn the heads with pliers or mole grips? If you're sure they're already trashed see if you can pound in the next size up hex/torx driver or even a flat if it fits across lobes. Or you could cut a slot for a flat bit. If there is space to get the angles you could try knocking them round with a sharp chisel/punch. Or you could weld a screw on.
Also, does it actually have to come off, are you sure it's not working? All of it?
jk
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In reply to magma:
I'd just look carefully first, a lot of EGR's (Beemers, Fiats, McCormick are ones I know) are installed with Torx TR (Tamper Resistant) commonly called Torx with a pin as there is a central pin to prevent a normal bit engaging fully. You'll find them on power tools, domestic appliances and stuff you aren't supposed to open. The bits are commonly available, just look for a hole in them.
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In reply to jimtitt:
thanks jim, didn't know about them. no, they're defo normal torx. just ordered a damaged torx removal set to try first - some sort of hybrid of torx and screw extractor..
In reply to jkarran:
> does it actually have to come off, are you sure it's not working?
PO0490 error (possibly due to failing battery- now replaced)
if it's stuck then some sort of vacuum gizmo may release it, but perhaps easier to remove and inspect/test/replace?
Post edited at 20:53
In reply to ianstevens:
> It's illegal so it would absolutely invalidate your insurance, if found
yes, was surprised the mechanic suggested it, but said it would be cheaper than replacing it (~£300 for delete). that's when i decided to do it myself- easy access on the DV6C engine- and a new one is only £60. just the pesky bolts. will need reprogramming tho?
Post edited at 21:18
In reply to magma:
Have you checked your tyre pressures recently?
In reply to wintertree:
tyres slightly overflated, new air/fuel filter. i'd like to give the engine a good thrash (meant to clear the soot/increase mpg if car has been used conservatively) but not sure of the timing belt..
Post edited at 22:27
In reply to magma:
Once you have removed it you can clean it and put it back on. Nylon bristle brush, carb cleaner, oven cleaner for the stuborn hard to reach places, rinse and repeat. Half an hour elbow grease and ideally new gaskets is all it takes.
Chances are the cooler is also blocked which takes a fair bit longer to do. I should know as i have to do it at least one a year.... (Thanks Volvo you useless clueless gits)
In reply to magma:
You’re welcome
In reply to Mr Lopez:
It's almost certainly the EGR motor that's gone based on the code.
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In reply to magma:
> yes, was surprised the mechanic suggested it, but said it would be cheaper than replacing it (~£300 for delete). that's when i decided to do it myself- easy access on the DV6C engine- and a new one is only £60. just the pesky bolts. will need reprogramming tho?
Your mechanic is a cowboy. Go to someone that doesn't recommend illegal modifications.
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In reply to magma:
> PO0490 error (possibly due to failing battery- now replaced)
Since it's putting up a fight, clear the error, leave it alone for a while see what happens.
jk
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In reply:
this is a really good explanation of the EGR valve and delete..
youtube.com/watch?v=Bnpj4eIo6nI&
wonder how many people are driving around with high fuel consumpion due to bad ERG valves/MAF etc. don't think MOT emission tests would detect..
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In reply to montyjohn:
Not necessarily. 0490 indicates that the voltage measured indicating the valve position is higher than the expected value that should be received from the commanded position. I.e. the valve is not opening/closing as directed.
I get 'control circuit high' codes when it's time to remove and unclog my manifold/swirl flaps and egr
In reply to Blue Straggler:
> You’re welcome
my pleasure not sure how many MOT stations/insurance claims are going to go routing around behind the engine.. anyway, i'm determined to keep things legal. Thanks for your concern
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In reply to Mr Lopez:
> Not necessarily. 0490 indicates that the voltage measured indicating the valve position is higher than the expected value that should be received from the commanded position. I.e. the valve is not opening/closing as directed.
> I get 'control circuit high' codes when it's time to remove and unclog my manifold/swirl flaps and egr
thanks. my circuit high code was in conjuction with cylinder 1 contribution balance. low mpg would suggest stuck open? hoped a new battery could provide enough voltage to get it moving, but prob not. error codes have not returned tho. there's a resistance test you can do without removing?
In reply to Toby_W:
> Maybe buy some alcohol and give your mass airflow sensor a clean.
thanks. will try that as well. electrical contact spray should do? although no MAF error codes..
In reply to jkarran:
> Since it's putting up a fight, clear the error, leave it alone for a while see what happens.
> jk
^ This.
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In reply to magma:
Not really. The voltage referred to by the code comes from a potentiometer within the body. The valve/stem has a wiper that sweeps up and down on the potentiometer as it moves open/closed. Nothing to do with how much 'power' the battery provides.
Depending what software you are using, you can read the 'valve position' and 'commanded position' and play around with the throttle see what happens and if you see any changes or.patterns. With more advanced software you can command the egr yourself to diagnose.
If your software allows you to read egr flow that's another way to figure out if it's moving, open, closed, or stuck somewhere in between. Playing with the throttle it should be commanded open in neutral with light throttle with a cold engine and should be closed if you touch nothing after start
In reply to Ridge:
i did get 43 on a hypermiling 10 mile journey from cold over some hills. need to do a longer journey myself really, but going from friend's driving over 60mile, fuel consumption seems to be about 20% up compared with peugeot 308sw with same engine, so something is up.. best get it sorted soon to save the earth?..
Post edited at 15:25
In reply to Mr Lopez:
i thought you'd be able to test in situ by applying a voltage and listening for something moving?
In reply to magma:
Don't fall down the emissions conspiracy rabbit hole and just fix what's actually broken on the car. If you're concerned about exactly how the engine is running get a reader that'll show you live sensor data and you can review it for any anomalies that might not trigger an individual error code.
also 1.6 HDI isn't a specific engine if you want to compare expected figures between your car and your friends try these (or correct the years):
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In reply:
I'm just about here with bolts removed so just a matter of twisting/pulling it out. unfortuately my attempt with a crowbar has cracked the solenoid cover. looking for a tool that can clamp onto the metal housing to rotate atm- a g clamp perhaps?..
In reply to Nick1812P:
mine at the very low end of real world mpg, along with the other drivers who don't bother to replace their egr valve
In reply to montyjohn:
rather like that stuck injector, it can now rotate by hand (as far as valve will allow), but haven't managed to pull out yet..patience.. got a pry bar set on order as per video above
is carb cleaner better than wd40 for this sort of stuff?
Post edited at 14:15
In reply to montyjohn:
halleluja, it's finally out thanks to lots of soaking, twisting, and finally twisting and pulling with a trusty mole grip
https://photos.app.goo.gl/CRAHPuvYSs53qvHu9
new one would need reprogramming?
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In reply to magma:
I did mine (VW 1.9tdi), along with the throttle body a couple of years ago. Cycled the ignition a couple of times, cleared the fault code off and went for a drive. Engine management light has never come back on and the problems with boost and power were sorted. My van's 2007 though and about as sophisticated as a house brick.
In reply to montyjohn:
> It's almost certainly the EGR motor that's gone based on the code.
Got the new EGR fitted but now getting PO0489 (circuit low instead of high), so ECU probably needs telling about new valve?
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