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If you’re running predominately short journeys, it could be a blocked DPF.
I’ve heard a taking it on decent run & holding higher revs should clean out the DPF.
Could be a quick / cheap first step ?
z
Morning all, I know there's a few car nuts on here so thought I would ask a question relating to a rough running diesel on cold startup. I have an XC60 with the 2.0l D4 engine and when I start it in the morning, it can sometimes hesitate, and kangaroo down the road. I've noticed its worse if I have the AC on but it's not always the case. It also doesn't always do the rough running, and its an intermittent thing, maybe 70% of the time.
I reckon it could have something to do with the EGR valve? Maybe that or something else. Before I take it in to get it diagnosed for plenty money, is there any value in trying a fuel additive, or one of the "spray down the throttle" type treatments? Could it be DPF related? No warning lights, and I've plugged in a very basic OBD2 reader and seen no codes on that or any pending.
Thanks.
If you’re running predominately short journeys, it could be a blocked DPF.
I’ve heard a taking it on decent run & holding higher revs should clean out the DPF.
Could be a quick / cheap first step ?
z
Thanks Zelig, Its mostly motorway driving, though with the amount of traffic, it's always stopping and starting. I did consider that this morning, and did about 60 miles at about 3000 rpm. It felt a bit dodgy driving in 3rd at 60mph in the left lane. I wish I knew what the parameters are for initiating a DPF regen.
you can try taking the valve off and use a parts degreaser liquid, i use Jizer ( yes it is really called that ) made by Swarfega.
it frees up the value, turning the black crud to a liquid. I use an old tooth brush. The valves jam with the crud, i used to clean the one on my van every so often.
but diesels can have all sorts of problems with their injection and fuel delivery systems, the heater plugs can go bad ( on older ones at least, im not sure if newer diesels have those ) spark plugs and many other parts can make them run badly.
I've never understood this as surely the whole point of the DPF is protect the environment, therefore taking the car on a high rev A road blast will just release all the caught particulate into the atmosphere anyway. In any case, if the DPF is blocked it should throw a warning light on the dash.Originally Posted by zelig
From the stories I have heard, once the filter gets to this stage it is best to just replace it (although this usually comes at quite a significant cost), but the situation is likely to recur.
I believe the whole idea of running it like this is to get to operating temperature-so the particulates are burnt off - not blown out.
z
I`ve had the 'DPF regenerate' warning light twice on my Jag 3.0 XF during several years ownership. Running it for 20 minutes in low gear fixed it both times. The problem with my car is short runs, very rare I drive further that 7-8 miles each way, which isn`t ideal for a big diesel motor. I`ve also had battery problems in winter, where the short runs aren't sufficient to keep the battery charged, so I end up charging the battery quite often.
My previous car (Jag 2.2 diesel X type) had the ERG replaced at 27000 miles under warranty, I used to do 40 miles a day in that car so it got plenty of use.
Might be best for the OP to take his car to a garage for sorting out, sometimes it's best to bite the bullet.
I understand that, but the particulate has already been through a heat cycle, so is essentially just soot which won't be vapourised by the temperatures in a diesel exhaust system.
Vaporising carbon would require very high temperatures - like >3600°C.
I think this process is more to do with oxidation of the carbon (soot) rather than a vapourisation.
Hence, getting to higher temperature is required/beneficial (as is the presence of oxygen).
z
z
I think you need half a tank of fuel for the regeneration process to kick in
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Snake oil
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I was looking at a Volvo 2.0 d a few years a go and the egr valves are a well known problem and I was advised against getting one by a local Volvo specialist said they had at least 2 a week In and they cost about 1k to replace
I used this a few years ago on my wife’s BMW, did the trick https://www.milneroffroad.com/produc...ith-dpf-an0009
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One of my wife's company cars, a BMW 320D had the problem as well - we thought. Ultimately it were the back brakes that had bound. Check that, although your car's symptoms are not directing to that. Diesel additive is mostly used for cleaning the injectors to pass the (well at least Dutch version of) MoT. And it works good. Follow the instruction carefully. What also helps: a fault finder. Gives various codes when things are wrong. These devices are becoming more and more 'generic' so there's a chance that a simple shop down the road has one and can perform a test.
Update, just before I wanted to post this, one of the mechanics of the classic car shop came with a different story. Something about a broken spring inside the throttle body. Just saying that the error code might help you before anything else.
I remember that my Saabs had a special program for the dealer to run until the exhaust becomes extremely hot. That also helps to clean the internals.
I acquired a cheap Saab 93 TTiD about a year ago and was concerned about the DPF as my commute is 10 miles round trip and total 3K miles pa.
I got an OBD reader and via an app, monitors the DPF. When it reads high 90s or even 100%, go for a blast and it quickly regens.
I feel this is something that should have been built into the car at the factory.
I think problems occur when a regen is taking place and it is interrupted. Then again, how are most people to know.
Just be mindful that with frequent regenerations, the oil will need changing more frequently due to dilution. In order to encourage heat in the DPF, diesel is injected on the exhaust cycle, but some will find it's way past the piston rings into the oil, diluting it. Obviously the oil won't be as effective doing it's job with diesel in it and engine wear is more likely.
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