mini low speed surge /missfire

[kiwi 911e]

Hi I need some help please.2007 COOPER S low speed surge problem.under low speed conditions it surges bad and runs rough.have changed plugs and coils but no improvement at all .have sprayed sea spray into inlet and added to fuel to clean carbon and still no improvement.car has traveled 90 000 km.the throttle seems to not respond when depressed slightly as well.It has no fault codes at all.I am thinking hp fuel pump but would like other opinions first and how do i test the hp fuel pump.I am a experienced mechanic but have not worked on these mini before.thanks.

[Luccia at Pelican Parts]

You need to walnut blast or clean the valves in order to truly get rid of the carbon build up. Unfortunately, this is something that needs to be done about every 50k miles on the R56 N14 direct injection engines. How many miles are on your R56 and have you done a true carbon clean up? We have more info on it here: MINI Cooper R56 Turbocharged Engine Carbon Cleaning (2007-2011) | Pelican Parts DIY Maintenance Article

What scanner are you using to plug into the OBDII to check for faults in the DME? Are there any fault lights triggered on the dash at all? You'd most likely get misfire and a code that points to the HP if it was faulty, but it could be an issue. You can test it to rule it out of the equation. Figure #10 at this article here: MINI Cooper R56 Fuel Pump Testing (2007-2011) | Pelican Parts DIY Maintenance Article shows you how to test the HPFP with a scan tool.

Let me know what you find out.

[kiwi 911e]

Hi Luccia thanks for the reply.No i have not done a true carbon clean up and will sort this first. i have only sprayed sea spray into the inlet when engine is running and added to fuel with no results.no fault lights at all and the scanner found no codes at all.car has travelled about 55k so due for a clean cheers.
I will test hp fuel pump as well.

[Dave at Pelican Parts]

Seafoam is OK as a fuel system cleaner and when used appropriately can clean up a bit of soft deposits. It does approximately nothing at all to the coked-on carbon deposits that build up in the intake ports of direct-injected MINIs.

Try the walnut blasting process. It may not fix the problem, but it will at least solve one thing.

--DD

[Luccia at Pelican Parts]

Those are the big items to get done and checked off the list first. Also, there is an extended warranty on the HPFP so if yours is faulty I highly recommend you call your local dealer and give them your vin number. They will tell you if your MINI qualifies, but I believe you should. Report back and let us know how your MINI is acting after you do a carbon clean up and test the HPFP.

[kiwi 911e]

Ok will do and will get back to you asap.Again thanks for your help cheers

[kiwi 911e]

Ok so fixed the problem with carbon clean up thanks again .
have now got code 1631 throttle valve spring actuator spring test any idea on fixing this thanks

[Luccia at Pelican Parts]

Originally Posted by kiwi 911e

Ok so fixed the problem with carbon clean up thanks again .
have now got code 1631 throttle valve spring actuator spring test any idea on fixing this thanks

Glad the clean up resolved your issue. Replied in your other thread: http://forums.pelicanparts.com/bmw-mini/964538-code-1631-a.html