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-   -   D4204T Help! V50 2.0D, intermittent power loss - no fault codes (https://www.volvoforums.org.uk/showthread.php?t=74634)

Martin_Butcher Jun 17th, 2009 21:23

Help! V50 2.0D, intermittent power loss - no fault codes
 
Hi,

I have a V50 2.0D (05 reg) which I bought at the turn of the year with about 25k miles on the clock. With the exception of the below, its a lovely car.

However ... on several occasions the engine has experienced a significant power loss as described below. I have read a lot of posts on this board, but none of them quite match up so I have posted the below to see if anyone can offer advice.

The symptoms are like this:

1) Driving along normally - say 60ish in 5th gear,

2) You accelerate, and as you are accelerating suddenly the engine power just disappears - but no warning lights, messages etc.

3) Back off the revs, engine power comes back so you can maintain speed, however if you start to accelerate again and demand more power, again the engine power will disappear

4) This will perhaps happen 5 - 20x if you keep repeating the above sequence but then the car returns to normal and all the power you can want (without needing to stop the engine). Then it won't happen for another month or so.

Now last time this happened (nice straight bit of the fosse way!), I noted that at the same point the engine lost power you could hear a sound of releasing air (a bit like when you release a pump from a tyre) coming from the engine compartment area.

I took the car into TMS Volvo in coventry and no fault codes. They inspected various parts (not sure what) but the summary was bring it back when it becomes repeatable.

Would welcome any thoughts.

My thoughts at the moment are:
1) Its not a problem that generates a fault code (that must narrow it down some, unless diagnostics has failed as well)
2) It probably not a hose as that would likely happen all the time, not happen for 5 mins in the middle of a journey and then mysteriously disappear.
3) urrrm??

I would be most grateful for any help!

Thanks,

Martin

Martin_Butcher Jul 13th, 2009 20:34

Well, I am taking the car to the garage again on wednesday to see what else happens. I must admit that I don't have high hopes...

I would also welcome anyone's views on how to deal with this. At the moment TMS are basically saying, we're really sorry, but we can't help until there is a fault code.

As I see it, the car is in warranty, it has a fault, it is a dangerous fault, volvo should fix it. Volvo way, we're really sorry but we can't fix it.

Is there anything more they can do that plugging in a fault reader? Should I be asking them to take the car back?

Thanks,

Martin

grass hopper Jul 13th, 2009 20:46

hi Martin,if its a euro 4 possibly faulty particulate trap sensor,the fault code will be stored,but if not,worth replacing and test.

if the fault happens often just leave it with the dealer to fix and test.

Martin_Butcher Jul 13th, 2009 20:57

Hi Grass Hopper,

It is a Euro 4. The fault is happening about every 500 miles or so, so it is a bit of a difficult one to leave with the dealer to test. You take it, they drive it and say 'no faults, test drove fine!' Which it does 99% of the time.

Volvo have said no fault codes to date. Is this a simple thing to replace a particulate trap sensor?

Thanks for your advice,

Martin

grass hopper Jul 14th, 2009 00:06

hi Martin,it is very easy to change,fits at the side of the battery cover,2 hoses and one screw and 1 connector,and not too dear.

changed many of these,but it normally logs a code ! and usually you have to switch of the engine to reset back out of limp home mode.

another possibility is a intermitant faulty/sticking EGR valve.

faults like this are horrible to diagnose for a technician if its only every 900 miles,and very frustrating for you.

it might be worth asking who you bought it off if they had any problems and if anything has been replaced.but i guess they will say it was ok.
regards GH.

Martin_Butcher Jul 14th, 2009 22:25

Hi Grass Hopper,

intermittent faults are the worst. I am a eletrical engineer (big stuff) and have had to diagnose a few faults like this. Normally just end up hanging more and more test gear on until you find the problem / anomaly.

Is it possible for volvo to do anything like this - fit additional diagnostics - manually force a DPF regen sequence and see if this makes the problem occur again?

Unfortunately, the people I bought it from are the volvo garage that are looking at this problem, so I sure it was fine prior to sale! I will ask them to let me know if it has had any parts changed on the engine though - they should be able to tell as it has a full volvo service history.

I have also been posting on the Honest John website. An email from HG said 'probably just a DPF regen occuring' and a separate post on that website also said the same. This seems a bit extreme for a normal event.

I have also been wondering could driving style impact this? I tend to do mostly local miles (and love 6th gear because it is so quiet), then longer journeys when this seems to happen.

Thanks for all your help.

Martin

Martin_Butcher Jul 15th, 2009 22:48

Well, the car has been to the dealers today.

No fault codes!

They have updated the engine management unit software and regenerated the DPF.

They also said a new EGR valve was fitted before we bought the car this year.

Lets hope this does the trick!

Martin

7050man Jul 21st, 2009 18:24

Just picked up on his thread and hopefully my experience may help.

My car had a similar problem with sudden loss of power when revving over 3k rpm, when accelerating heavily. It was intermittant at first and then got more frequent and it then started occasionally to lose power at higher constant speed (motorway conditions).

After two trips to dealer, a split fuel pipe was found, that was drawing air in and causing fuel starvation. No leak was evident where split was.

Re DPF discussion, I don't think problem would be there anyway. If DPF pressure differential sensor was at fault, car would probably not rev above 2800 rpm and this symptom wouldn't clear until engine is stopped and then restarted. No engine warning lights would show under this condition.

As has alraedy been said, if this sensor fails a fault code will be logged which will show up sensor straight away.

I hope this helps. Good luck.

colinmbrown Jul 28th, 2009 21:18

Hi all,

I've had my V50 (Euro 4) since the end of May and have put 5000 miles on it (now done 51,000 miles). A couple of weeks ago it started with the similar power loss described above whilst accelerating or cruising with the revs below about 2000rpm. It either refuses to rev or does so very slowly until about 2000rpm, above which it revs happily. There is no sooty smoke out of the exhaust which would indicate an EGR sensor failure from what I have read on the forums, and the best way I can describe it is something interrupting the fuel flow to the engine.

Usually it clears within 20 seconds but comes back randomly, sometimes after a hundred miles or so, but more often it occurs several times within my 20 mile commute. Occasionally there is just a blip in the revs whilst accelerating for a second or so.

Yesterday I had the car fully serviced as the independant delaer I bought it from claimed to have serviced it before putting it on sale but more and more now I'm thinking all he did was change the oil. The mechanic said the air and fuel filters looked like those of a car that had done 20,000 miles instead of 5,000 and the fuel filter was very "cruddy".

After the service, the car's doing it just as frequently but to a lesser degree, so the air in the fuel line would kinds make sense. Is there a straightforward way to check if there is air in the fuel lines?

The other thing I was considering was adding an additive into the fuel tank to see if cleaning through the system would make a difference. Any recommendations?

colinmbrown Jul 28th, 2009 21:21

On Wednesday last week the garage hooked it up to the diagnostic computer which gave a code of P1412, but they didn't know what it meant as they said it was a "Volvo-only" fault code. Anyone know what it indicates?


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