V50 Engine 2.0D : Increased fuel consumption

[The Thong]

Originally Posted by Teddy1975

So, on the way home from work it happened again without any prior notice while driving. Mechanic is out of ideas but has ruled out the DPF. He says it might be the EGR that's sticking in the open position because the EGR pipe was extremely hot when I arrived at the garage, and he asked me to log the two EGR parametres in Vida now while it's driving poorly, and hopefully it will go back to driving fine again some time real soon so I can log it then for comparision.

There are still no codes set apart from those three nagging about the audio system missing (I removed the original basic sound system and installed an after-market head unit and amplifier), but of course they aren't related to the fuel guzzling.

I had the pre-DPF. I had cold starting problems, smoke under acceleration. As a temporary measure I blanked the EGR and dang it…. The smoking reduced, the starting got better annndddd would you believe the NOX levels dropped. There was a surprising side effect too…. I gained 4mpg and that wasn’t according to the trip meter but working it out tank to tank. Those EGR’s in the V50’s are rubbish. I left the plate in it after that and disconnected the EGR (don’t try this at home kids).

TT

[Teddy1975]

Anyone who knows what to look for in this data logging from Vida?

When I started this morning (not part of the log that's being played back in the video), the egr duty cycle did go up and down, but as the engine got to temp, it froze at the values in this log: Data logging.

As far as I can tell, that's not normal behaviour?

[Teddy1975]

An update on this very costly and on-going problem.

After speaking to a former Volvo dealership/garage, they recommended I'd replace the DPF, even if the reported differential pressure looked fine and within spec.

I would have replaced the DPF myself, but I couldn't find anyone with a lift that I could loan, so I had the garage replace it. Since then, I haven't driven much in the car after getting it back, but it now drives fine again. Hopefully I'll manage to drive more than a couple hundred kilometres before the fuel consumption shoots through the roof again.

So to summarize, parts that have been replaced:
- MAP and IAT sensors,
- First 1, then all 4 fuel injectors,
- Yet another MAP sensor, as the one that had been installed by the local garage was crap according to a Volvo mechanic. Now a VAG MAP sensor has been fitted, which supposedly is better than Volvo OEM.
- EGR valve
- DPF

Not going to add up the total cost, but I'll be spending the next 4 months paying off the bills.

Hopefully the next update will be me saying that I've filled the tank 3 or times without further problems related to the fuel consumption.

Regards,
Teddy

[SnineT]

Some cars do just eat it tbh, it can be something that wasn't quite right from the factory to how it's been run in or the wrong oil used in the past or even a previous owner if that applies has had it tuned and said nothing when they sold it.

If they're talking dpf's it says they have dropped to pin the donkey on it and you will just continue to spend on it and still be where you were at the beginning.

[Teddy1975]

For almost a year the car has run sort of fine, although it regenerated the new DPF fairly often, every 250-275 km of driving mostly country roads 80-90 km/h. But better than what it was when it regenerated back to back all the time.

A month ago it began to smell like an old diesel tractor from the 50-60s, again, sort of like it does when regenerating the DPF, except it reeks all of the time now. If it was a petrol car, I'd say it was running rich, but apparently a diesel can't run rich. It regenerates more and more often, now I can drive 135-150 km before it regens again, which means one regen every work day as there are 75 km between my home and work. Also, the fuel consumption is somewhat elevated, up from 4.8 to 5.9L/100km, with no change in my driving pattern.

Almost every time I go onto or exit the motorway, the car will enter limp-mode and give the annoying Motor System Service Required amber warning message, and sometimes (rarily) will lose all power, as in if I push on the accelerator just a slight bit, the engine will immediately drop in rpms, at which point I have to pull over, turn off the engine and turn it back on, after which it will happily carry on as normal, as if nothing had happened just before.

Took the car to a certified Volvo/Renault/Dacia garage this time and asked them to please find out what is wrong with my car. They called me today and said that my car was kind of a unicorn, an old V50 that's driven 324k kilometres and doesn't have any faults, at all! No DTCs set, nothing. They don't often see that. (I did tell them it didn't have any errors set when I handed it in...)

Two mechanics have looked at it and deemed it completely healthy, and claim there's no smell. They can't recreate the issues I'm experiencing in the time they had available for test driving the car. I understand that, but it still doesn't mean my car has a clean bill of health.

Now I wonder if it could be the aftermarket hose I installed between the intercooler and the "throttle" body, instead of the OEM plastic square tube that had split. The new hose is rather flexible like a radiator hose... I don't know if it can be sucked flat and prevent air from going to the engine which would probably cause it to run poorly and perhaps generate enough soot to warrant those very frequent DPF regens?

I also found that the vacuum hose going to the actuator below the throttle body was quite loose when I fiddled around it the other day. I don't know if loss of vacuum could be the cause of my problems but I'm reaching for straws now.

Does anyone have any ideas except to wrap my car around a tree and cash in what I can get from the insurance? I really don't want to do that as I wouldn't get anywhere near what I've spent on the car so far.

Thanks,
Teddy

[daroo]

A friend of mine owns a V50 2.0d, which used to experience occasional power loss and poor gas mileage. The culprit turned out to be the throttle body, which has two butterfly valves. It's important to ensure that both of these valves move smoothly, and you can find instructional videos on YouTube to assist with this.

Initially, I attempted to repair the old plastic throttle body (the piece of plastic that makes the valve moving), and it appeared to be in good condition after the repair. However, it didn't resolve the issue. I ended up purchasing a used throttle body on eBay, which did successfully address the problem. I also recommend replacing the small vacuum hoses with high-quality silicone hoses.

The problem with a broken butterfly valve in the throttle body is that it remains open instead of closing and opening only during DPF regeneration.

[Teddy1975]

Thank you for the suggestion!

Do you know if the valves should be moveable when the throttle body is off the car? I'm fairly sure one of them was stuck when I last had it off, but I didn't want to force it in case it wasn't supposed to open without vacuum being applied to it.

Thanks again,
Teddy

[daroo]

both the valves are moveable, the left one is normally open, the right one is closed. You can move the valves with your fingers but they should come back in position once you remove your finger because there is a spring, like spring loaded.
connected to the spring housing on both sides there is the small vacuum hose that you should verify that is connected.

[Teddy1975]

I'll check it tomorrow if the weather permits, otherwise I'll see Friday

[Teddy1975]

So, I removed the throttle body, or intercooler bypass (name depends on who you ask, Volvo or the French), and one flap was turnable with light press of my finger. The other seemed stuck, but with a little more pressure it would move about 15-20 degrees, or about quarter of the way open. It felt as if it spun without moving the actuator, so perhaps it has loosened from the shaft. I don't know, it just didn't feel the same as the other one.

I thought that that was the culprit, but decided to test with vacuum, so fitted a 60 millilitres syringe to the port and pulled the plunger back. Both flaps moved as they should with about the same amount of vacuum.

Since I was in that area anyway, I decided to replace one of the vacuum lines that I thought was a bit torn and seemed kind of loose. On my test drive it seemed to be running better without that nasty smell, but I will see when I go back to work on Monday if it really has helped.