Hello all!

i own a MCS 07 manual and i have been having some boost issues for 3 months now that cannot be solved! My mini has full milltek exhaust system, JCW air filter , Forge intercooler, folrge resonator delete hose and a custom tune since 2011(max psi is 18) It was working very nice since November 2013 that due to heavy oil cosumption i decided that it might need an engine rebuild.

So it was done, new piston seals(the ones i had were in terrible shape, very beaten up), and everything that had to do with the cylinder head(gaskets bolts etc). I also replaced my water pump the thermostat housing, HFPP,sparkplugs, coils, cylinder head cover and some worn piping, and the clutch. The car was assembled and i had to do some mild kilometers in order for the new piston seals and clutch to settle. After that when the car was ready to build some boost it would go up to 15-16 psi and then it would open the diverter valve and release all the pressure...We changed all the vaccum lines, the boost pipes, the MAP and MAF sensors, the intake manifold, the vaccum pump, the vaccum can the BCV and tried 5 new DV all stock but nothing changed. We tried 3 more turbochargers that were in used condition but were working on other cars properly and still the same thing. All electrical connections were checked as well. Replaced sparkplu All the timing values, temperatures and other values of the engine running in idle or in load without the turbo building pressure are spot on and nothing out of the blue. Smoke testing has been done and zero leak

The car would try to build boost and as soon as it was close hitting the max boost it would release it and would leave the DV valve open. Only if you released the gas pedal for like 5-6 secs it would close the DV valve. The weird thing is that in between these months the car would not work BUT for 4-5 times of 20-30minutes that would build and hold boost normally!....

Im totally dissapointed at this moment with this car because it costs a ton of money to purchase, a ton of money to run , and even more to repair. I would appreciate if anyone could give his 2cents on this matter and any info on what i may have skipped looking into in order to find the bloody problem.

Thank you all in advance ,
Pavlos

 

Interesting, Since the ECU is opening the diverter valve it sounds like a sensor reading Is out of spec or a sensor is working. The boost pressure could be building later causing an error, Does the boost seem to start later than a car with a stock setup (start 1600 full boost at 2800 RPMs) Does the car still have an oil consumption issue of did that go away after the rebuild? How many miles or kms did your car have before you rebuilt the motor? When you say you have a full milltek do you have a milltek catalytic converter or a down-pipe? Any other strange issues or sounds? Did you ever figure out where the oil was going, excessive crank case blow by, leaks, or burning oil? How many miles (or Kms) are on you car?

 

Thanks for the reply! The sensor after the intercooler(map?) was changed and the sensor on the intake manifold(temp and pressure?) as well. The boost starts building as per stock maybe a little higher since the ECU remap i had back in 2011. Full boost kicks in around 2800 rpm as well. The oil consumption went away with the rebuild of the motor. I had the motor rebuilt at 73.500 km and i have the milltek down pipe with catalytic converter and milltek cat back as well. The oil was burning mostly maybe some from the turbo as well. At the moment i have 74.500 kilometers.

 

It could be a tune issue did the problem start after you installed the map sensor. But most of the time (meaning 99.9% of all turbochargers we refurbished) are killed by back pressure in the exhaust system. And one of the biggest symptoms is high oil consumption, but not in all cases. However the oil burning symptom might have change since you changed the turbocharger and had your engine rebuilt but the problem may still remain. The first thing I would do is test the exhaust system for back pressure at the first O2 sensor. If there is any pressure in the system the catalytic converter and turbocharger will need to be changed. Also make sure you do the test at boost pressure.


There are other things that cause low boost pressure after a rebuild they are highly unlikely. Although if you find out it is not a pressure issue below are some other things that can cause low boost pressure.

• Timing issue (Mini Coopers have no key on the crank or cam, if they are not setup correctly the timing can be off or worse it is common for them to slip)
• High torque (if you have higher torque than a normal mini cooper due to mods or better engine the firmware will keep the boost pressure low. We have to overcome this when we tune for our K04 turbochargers)
• Low exhaust flow
• Boost pressure/intake system leak
• Incorrect air/fueling
• Wrong AR ratio on the turbocharger
• damage to internal or external components
• Clogged air filter
• Soot clogged straight through muffler (more common on diesels)
• Vanos issues
• Warn cam lobes
• Damaged BOVs
• also see our page http://www.jmturbocoopers.com/2885-B...DEVIATION.html

 

Did you ever find the issue with your car?

 

I'm also interested in finding out what your problem is/was! The stock firmware cuts boost at 4500 rpms? An ECU remap can fix this with some tuners.

 

Is there any fault codes?

 

Hello,

yes! finally i was able to sort out the problem. I changed this valve 11367537692 (non return valve) and i had a remanufactured turbo installed. Idont know what of the 2 did the trick but i suspect maybe i had bad luck with previous turbos. Boost is now proper again , but i still get some fault codes like P0420 and some that has to do with the coils. But the perfomance is there now. Waiting for the coils to arrive.