innit_gareth

Hi all,

First post here. Please bear with the description...

I have a 54 525d 100,000 miles E61 (mix of motorway and town miles)- which recently lost all power - seems to be in limp mode.

Took it to the dealers for them to look into it - diagnosed cracked exhaust manifold reducing back pressure to turbo- 90 % sure that this would fix the problem - but no guarantee - had this done.

They also serviced the car so the cost for the manifold and service was 1100 quid.

This did not fix the prob - they then diagnosed a blocked partiulcate filter - quoted approx 1400 quid for a new one - but did not guarantee this was the prob. They would not put on a test filter to ascertain if this would cure the issue though as they said they are too expensive a part to do that (when paying £105 per hour I would have expected they would do this) - they also tried to force a dpf regen - this did not work either - apparently because the dpf was too far gone.

Instead of carrying on I took car to an indy - they are convinced it is swirl flaps causing the soot build up and blocking the dpf. The bmw dealer said if this was the case it would be flagged immediately - they also gave the egr and turbo a quick visual inspection and said they both looked fine.

So I got them to remove the dpf and thought I?d clean it myself having seen another informative thread on the forum.

On cleaning the filter did not seem blocked at all - put hose in at pressure - water came out as quick as it went in - and water was pretty clean. I put some carb cleaner in anyway again and mostly clean water came out. Surely a dpf can't be blocked if water can run through so quick?

Anyway - now I have no clue what the loss of power is down to - the indy garage still reckon its the dpf - however with the dpf seeming unblocked could this still be the cause. Could it be the MAF / air temp sensor of pressure sensor - and if so would the dealers diagnostics have picked this up.

Any suggestions gratefully received - the car has been off the road for a fair while now :-(

phelix

Sounds like you need to find a dealer or an indy with better diagnostic capability. It would seem both are just shooting in the dark at your expense, unwilling to provide any sort of assurances that the money of yours they're spending will resolve the problem.

Items like the MAF and temperature sender can be monitored with a diagnostic computer to ensure their values are within range for the operating conditions. If the car has gone into limp-home mode there must me some error codes logged - what are they?

mmitev

+1
it is shocking to me how people just get ideas out of the blue on how to spend thousands of your money...
just find a good independent shop that understands these cars, there are quite a lot of them with high mileage around now and most problems should be common knowledge by now.

just a wild suggestion: once I had the car in limp mode (E61 530d) and it turned out that the rubber hose from the turbo to the engine was loose. it was a 5 minutes fix. this is so obvious that they must have checked it on your car, but who knows...?

AJH

Did it happen quickly or was it a gradual process?
Any smoke coming from the exhaust?
Is it misfiring?

JasonH

You need to find a better garage. Swirl flaps are a problem but don't cause the DPF to block up - they're supposed to reduce soot.

Your DPF sounds clear to me.

You need to find out what your fault codes are then work out what may trigger those codes.

A broken vacuum hose is quite likely.

Where in Wales are you?

innit_gareth

Thanks for the responses.

JasonH - I'm based in Swansea.

I've bought myself an obd can cable so on the 4th July when the dpf is refitted I'll have a look at some diagnostics. I'll also get the indy to check the vacuum hose.

AJH - The performance seems to have been a gradual decline for several months (this could have been due to the cracked exhaust manifold??) and then a sudden step into limp mode. I haven't noticed an excess of smoke from the exhaust and its not misfiring.

phelix - I'm not sure what the error codes are now - the dealer did show me on some print outs - which I wasn't allowed to take away - however - from what I remember - they seemed to suggest a very high pressure differential over the dpf - well out of normal bounds.

You are all right in that it seems a shame that people are prepared to just try to get you to incrementally pay a shed load of cash in relation to the cars worth without fully diagnosing the problem up front.

AJH

I have a cracked manifold on my 530d - no adverse affects to the performance as yet

I can understand why they would diagnose a blocked dpf but as you said it's clean

A blocked fuel filter would cause a gradual decline in performance. if its black its dirty

A blocked air filter would have the same effect but you'de also get black smoke from the exhaust

Dont know enough about the swirl flaps but as the other guy said they are supposed to reduce soot. Maybe check they are operating correctly and the linkange is not seized?

Check air pipes are all connected. Turbo waste gate connection pipes.

Turbo and egr fine?

If nothing is obvious then the next step is too put it on diagnostics to check fuel pressures etc.

Have a nice crimbo

narvselius

Well, both yes and no. The problem is that they seem not to be able to find the root cause which is clear from the "oups, here's another error we must fix". I don't think it's because they like to pump your bank account dry, but more that they don't understand how to read the error messages. Instead of understanding what's behind the error message, they may only look at the message in isolation and replace exactly what is suggested by the computer. And that's often the wrong way to resolve a problem.

Agree to the others, find a new garage that understand what error finding really means...

innit_gareth

Here's an update to this sorry saga.


After 3 separate attempts at regenerating the DPF - I've had the dpf removed with a bypass pipe and the ECU remapped (Long Life exhausts did the work).

The car is still the same - ie knackered - no power - feels like something is holding it back.

I did see the diagnostics before this was done with the independent - and the computer said that backpressure was 450mb or something from the dpf (160 is at a 'higher' level). So I thought it must be the dpf even though it seemed clean...

Does anyone have any ideas of what could be wrong - this is turning into a really expensive, time consuming nightmare.



Cheers

mmitev

I am by no means an expert, but given this evidence, could it be a faulty pressure sensor then?