Last time I checked my OEM wastegate (it's in a box in my garage), it was closed until a vacuum was applied to the diaphragm, then it would open. Opening allows exhaust gases to escape without turning the turbo to build boost. So, open WG = no boost! This is why I suggest you ensure the linkage is indeed keeping the WG closed until vacuum is applied to the diaphragm. Granted, it's a new turbo, but was it installed with all the TLC needed? And was the linkage set properly at the dealer / factory?

Maybe while checking the cat, you could visually check the WG too?

 

WG is normally open until vacuum pulls it closed. I will definitely go back through and check it out.

I have manually operated the WG using a mity-vac, so I know it closes -- visually verified that vacuum would pull it completely closed prior to installation. But it never hurts to go back and make sure I didn't screw something up during installation.

 

Here's someone else's input on P2885 --- https://www.northamericanmotoring.co...ml#post4218828 Since you've already changed the turbo, maybe look at workmanship? And, take a close look at the wastegate, then analyze it yourself, how it's supposed to function and what it does by opening or closing.

 

Will be gone for a few days, but had a chance to take the Mini to work today. Installed the new MAP sensor in the boost tube, cleared the codes and left the scanner connected to see some live data.

Still comes back with the 2885 code, but it is making some boost now. I can see the boost controller (solenoid) and diverter valve actuation being called for by the ECM. Noted 1230 hga as a peak, 3rd gear WOT out on the highway, so I'm assuming I am seeing 18psi, but *very* much lag. I did learn that the ECM commands the charge solenoid as you increase throttle, but normal steady state, does not -- as I interpret it, the wastegate is released/opened under normal stead state, but every time you increase the throttle, it activates the solenoid, and pulls the wastegate closed.

To the suggestions above, I haven't had a chance to pull the heat shield and validate the wastegate linkage adjustment. I did take a peek thru the O2 sensor with the borescope, wastegate fully closes when manually actuated and the CAT looks clear from the top side.

When I say lag, I mean, it used to jump forward in 1st or 2nd when you ease on the throttle (in sport mode) -- that doesn't happen anymore. Same with rolling on in a higher gear.

Guesses, at this point, seeing as how all of my other experience with non-Mini's has been turning out to be somewhat irrelevant...
* not enough vacuum (now that I learned more about the ECM and solenoid operation), via weak vacuum pump, bad solenoid, or collapsing lines (have the new lines and solenoid, but haven't installed)
* something I haven't attacked, carbon buildup in the intake
* wastegate linkage adjustment
* ??

Sorry for all the rambling. One day when I figure this thing out, I will simplify into a troubleshooting guide. Appreciate the input from the hive.

 

I get confused easily --- what is your "1230hga peak" reading? Almost looks like a vacuum reading using inches of mercury on an Absolute gauge. 1230 would be a huge vacuum and nowhere near 18PSI Boost. If you're converting positive boost PSI to inches Hg (a bad idea), use a minus sign. Take a look at an external manifold pressure gauge that uses both units for confirmation. If this is a reading from a scanner, what function is it?

OEM waste gates are operated on a duty cycle --- not continuously as you suggest. When WGDC is read at the OBD II connector, it's shown as a percentage. They can be tested using a constant source, but the ECU pulses it at a variable rate, as needed for driving conditions. You can test the vacuum pump by connecting it directly to the WG diaphragm and watch the linkage --- linkage moves, pump is OK.

"the boost controller (solenoid) and diverter valve actuation" as you describe them, when actuating, are both dumping boost. Your "boost controller (solenoid)" is actuating the waste gate, dumping boost into the down pipe, and the DV is dumping it back into the turbo air inlet.

 

Yeah, I seem to be confusing myself regularly on this motor.

I'm using the Schwaben scan tool (from ECSTuning), under the Mini diagnostics and live data monitoring -- don't have the ability to change the measurement units in most cases.

Maybe a more simple question -- is the solenoid a normally open (vacuum flows through) or normally closed (no flow, dumps the vacuum from the output line)?

When I hit the throttle, the solenoid shows as "activated" -- I'm reading that as goes from open to closed (applying vacuum and closing the wastegate). When I let off throttle between shifts, the DV activates and bleeds off boost back into the inlet.

I can try, as you suggest, connecting the WG directly to the vacuum pump (have done it before at idle) and watch it pull the WG closed. I'm also assuming that driving that way is asking for a blown headgasket or other major failure.

 

Good luck ---

 

Big_iz, your 1230hga has been bugging me --- any chance it could be 1230 milli bars (1.23bars) instead of hga? Using bars as a unit of barometric measure is common in other countries, and 1.23bars is a low but reasonable number when boosting.

 

Sorry, OBW, been out of town a few days, just got back last night.

Re-read my own typing and I screwed up -- should be hPa (hectoPascal). I'll dig the scanner back out tonight, pull up the data, and RTFM this time

 

A little more research at break, OBW, you are correct in that it does equal 1.23bar