I've had a nagging problem for over 1 year. The garage insists that since there are no CEL codes, the car is fine. I know my car. The car is not fine. I have lost my boost somewhere along the line after my faulty turbocharger was replaced.

The car idles fine, there is no CEL, there is no smoke out the back of the car. The air and fuel filters have been changed, I have secured, inspected and cleaned the intake piping. I removed ALL the intake piping and went over it with a microscope, I inspected the air filter and reseated it, the MAF looks clean.

Here is the problem I have. The car sounds loud on acceleration and there is no get-up-and-go on WOT. Garage had it up on the hoist and nobody can seem to find an exhaust leak. Operation and idle are flawless. Clutch and flywheel are new. Turbo is new and functioning properly as far as I can tell.

The only issue I can seem to identify is if the car is sitting at idle and I blip the throttle so the rpms go up, as the rpms go down, I hear a distinct buzzing noise, like one of those joke hand buzzers. I cann't identify precisely where it is coming from, but it may emanate from the region of the EGR valve (the car is a diesel version of the Clubman). I cannot verify this because the EGR is under the air filter so I can't operate the car with the air filter out to confirm. Basically it's like this: throttle blip, then "vrrrrrm" then as idle dies down "bzzzz" for 1/2 to 1 second then quiet normal idle. Maybe the buzz lasts for 1 second max.

Since the garage is not being helpful (no CEL means no problem!), I guess this is a DIY investigation. Does anyone have any suggestions as to how I can proceed?

Would a faulty EGR cause loud engine operation under WOT? My gut feeling is an exhaust leak due to the loud engine noise, but I can't find any evidence of one.

 

Do you have a mechanical boost gauge to verify your "lack of boost" claims?
Have you data-logged a 2nd gear and 3rd gear pull with a Bavarian Technic scanner?
Have you scanned the vehicle for faults? Just like you noted, they may not be a CEL, but there could be a current fault code(s) stored.

- Erik

 

Thanks for the response. I can directly reply to your questions.

I do not have a mechanical boost gauge and I am not aware of a gauge that fits the PSA diesel engined models of the Mini. I have read that one can DIY a boost leak tester but I have not built one. This might be one option to pursue. However, I am not sure that it is indeed a boost leak (despite my thread title).

I do not own or have access to a Bavarian Technic scanner. My car is neither an R50, nor an R56. It is an R55 with a diesel engine. Additionally, I do not have the financial resources to purchase one in order to resolve a problem whose resolution may cost less than the scanner itself.

The dealership has test-driven the car and looked for logged faults. According to what they tell me, the car is not logging any fault codes. Their logic is that no fault codes means no problem. My opinion differs.

I am assessing the loss of acceleration power (perhaps this is a better description than "boost loss") based on having owned the car from new for 3 years and having been the sole owner and driver of the vehicle. I have also driven an identical Clubman model (with the same diesel engine) and have noticed a very large difference in the performance of the two vehicles. This difference has also been noticed by the owner of the other vehicle.

I had thought that the dealership would be able to diagnose this issue, but it has been approximately 1 year now and I am getting frustrated that it cannot be resolved.

I am trying to pursue alternative solutions that the community may offer as I am slowly eliminating a number of possibilities and am running out of ideas to pursue.

 

You should be able to retrofit one into the intake system, downstream from the turbocharger, to accurately measure boost pressure of the system.

The Bavarian Technic unit is able to read all 1st-Gen (R50, R52, R53), and 2nd-Gen platforms regardless of variant (R56, R55, R57, R58, etc., etc.)

Ok, so have they compare data-log runs between yours and a "good working" diesel R55?

Start with fresh eyes and determine the following:
1.) whats your current output boost level? Is that factory spec?
2.) how is fuel trim?
3.) are the injectors properly clean and flowing correctly? Or is there a blockage?
4.) fuel delivery - check the fuel pump and filter assembly; test output pressure against factory specifications.
5.) verify the EGR is clean, with no exhaust carbon deposits.

Yes, it sounds tedious, but you will need to systematically confirm or deny that individual components are in top working order if you cannot pinpoint with fault codes.

- Erik

 

Okay, thanks again.

Is the retrofit usually a large job? I can handle simple DIY projects like air and oil change, tire rotation, MAF cleaning, etc... but I don't have a full set of mechanics tools and can't afford to make a mistake on the car since it's the only car I have.

I had checked the Bav. Tech. website and was under the impression it worked only for R50s and R56's. I see this is not the case. My problem here is cost - I think the least expensive unit is about $300 American.

The dealership is only looking at my car and not looking at live data. They are simply looking for logged codes. Since they aren't seeing any, they are telling me the car is fine and that it would log a code if there was a problem. I disagree with that view.

I'm not sure how to go about checking fuel trim, injector flow or fuel rail pressure. I assume that can be done with the Bav. Tech. scanner?

Inspection of the EGR had already crossed my mind. I am looking for a DIY for the R55 on how to do this. One solution could be to browse the Peugeot forums, since the engine is the same used in Peugeot HDi models.

Would a blocked EGR cause loss of acceleration power? If so, how? If the valve were stuck open and recirculating exhaust gasses into the combustion chamber, wouldn't I get poor idle? I'm not sure what would be the symptoms if the valve were stuck closed and not recirculating exhaust gas?

 

Nevermind/Edit.

 

No, it's pretty simple; you simply tap into a boost hard pipe or a MAP sensor adapter to accept the gauge tubing.

If you're looking to tackle this independently, you'll want to invest in a scanner.

Fuel trim through the oxygen sensor (are those installed on the Euro diesels?) can be read through a scanner like a Bavarian Technic.
As for fuel pressure at the injectors, a pressure gauge can be hooked up to the mechanical fuel line and readings can be compared to OEM spec.
As for injector flow, physical removal of the injectors is required and tested.

That's as good start; especially since this North American board doesn't have any diesel owners - it's not available here.

If it's anything similar to the Volkswagen / Audi TDI engine, then definitely yes.

- Erik

 

Okay, thanks for this. I'm going to re-contact the garage and ask if they can read live data from the car. The engine in the 2009 Cooper D is also used extensively in Peugeot and Citroen forums. I browsed some and came across a possible issue with the turbo solenoid valve. In some instances it doesn't hold vacuum and the turbo doesn't adjust its variable vane geometry properly. I think the dealership can measure proper output to the solenoid.

In the meantime, I have doped the tank with diesel injector cleaner and I have some MAF cleaner on order. I also found a split seal that connects the intake pipe to the turbo and it is now slated for replacement. I'll proceed with these steps first, then contact the dealer about the solenoid.

I'll post updates here as they come in.