Hello all,
My 05 MCS threw a rod bearing. I originally misdiagnosed the "pinging" as a bent valve/timing issue and pulled the head. After realizing all was fine up top, I pulled the oil pan and found my problem (it was more than just "spun" it was nonexistent). My S has over 150k on it so while I had everything apart I decided to do a "rebuild" sans boring the cylinders and replacing rings.

Work Done:
Replaced all the gaskets
Pulled the supercharger and changed the oil (water pump side was clean amber color, supercharger side was nasty grey with metal flecks in it)
Replaced all rod bearings and cap bolts (as they are torque to yield)
Replaced timing chain and guides
Replaced cam position sensor (it's a long story)
Replaced head bolts (as they are torque to yield)
Replaced PCV valve hose (rigid hose on the left of system, I cracked this maneuvering it back into place so ordered a new one)
Replaced MAP sensor (one bolt was seized, actually cracked the flange around the sensor trying to get it off so this was replaced)
Replaced one of the injector O-rings (tore this remounting the fuel rail, bled fuel all over on first start up, found and replaced)
Added engine break-in additive, oil and anti-freeze
Used assembly grease to assemble all moving parts

Current Issue:
I started the car up (second time after injector issue was resolved) and it revved to ~4k RPM, then dropped and sputtered, found a rough idle around ~1k RPM and threw two codes.
P1239 (Pressure sensor intake manifold before compressor-input too low with engine stopped)
P1689 (Electronic throttle monitoring, level 2/3, torque calculation-error)

So, I did some searching around and these are commonly attributed to the MAP sensor and the Supercharger Bypass Valve, respectively. To try to eliminate the bypass valve I cleared all codes and adaptations, manually pressed the valve fully open and started the car again. This time it started up and idled just fine. Shut the car off and checked codes again. Only the P1239 came up. However my MAP sensor is brand new and the Bypass valve has some serious spring to it, so I'm at a bit of a loss.

Any help would be greatly appreciated.

Some notes:
I have inspected the supercharger boots, they seem fine, bolts are torqued down, feels firmly seated.

There is a small hairline crack in the rubber intake hose leading to the throttle body, but that has been there for years and has never caused me any grief.

I somehow managed to pinch the wiring leading to the TMAP sensor between the intake manifold and the supercharger during reinstall. Not wanting to tear it back down, I maneuvered the wiring out, slicing open the black outer sheathing, but upon closer inspection the wires inside look fine, no sign of damage. They seem to be bundled together with a clear epoxy coating giving them some extra protection/rigidity.)

Upon reinstalling the supercharger I did get the throttle body mounting bracket stuck on top of the bypass valve actuator arm. Not knowing this and thinking I was just having trouble getting the new water pump gasket inserted into the engine, I muscled it into place, bending the intake bracket. When I discovered what happened, I pried the bracket off and bent it back into place. Throttle body seated nicely as it should. After the rough start up I originally through I may have damaged the bypass valve during this, but it's still very difficult to open manually and when opened apparently operates as it should.

In my searching I have seen that the MAP sensor vacuum hose cracks easily, but given that activating the bypass valve manually allows for proper idle I'm assuming this hose is alright. I'd be happy to be wrong as this would be a cheap fix. Trying to avoid putting it back into front end service mode though unless necessary...

I know that's a lot of info, just wanted to be thorough. I'm pretty good with mechanical parts but vacuum systems aren't something I've had to troubleshoot with too much. I know there are a lot of lines, many of which were maneuvered around during disassembly/reinstall and may have been damaged, I'm not sure where to start or if there's a better way to assess the bypass valve. I don't fully understand how the valve is supposed to be activated so perhaps my issues lies there?

I really need to get this car back on the road ASAP as it's my daily driver.

Thanks in advance, all.

 

After reading your post and with my limited experience, the only that I can think of is that the supercharger intake duct (part #17517541096) is damaged or has come loose from the air intake inlet on the supercharger. That or the green supercharger profile-gasket (part #11610020836) is damaged or not seated properly. Both could cause vacuum-related issues.

 

Hey Beagle!

Thanks for the suggestion! I ended up putting it in front end service mode as I didn't have any clients this morning so I now have access to the supercharger again. I'll take a look at those parts. The black plastic intake duct (part #17517541096, thank you for listing these) feels pretty securely seated but I'll pull it and inspect the gasket (part #11610020836). I notice now after looking up the part number that the MAP sensor vacuum hose (part# 11651504943) also inserts into this duct so I'll have to give that a look too while I'm in there.

I did start it and try to rev it before pulling it apart. I should note here that it will not go above 2,000 RPM and isn't responding to gas pedal position very quickly even when mashing it to the floor, it kind of gets there when it gets there.

I've also noticed after getting better access to it that the bypass valve (part# 11617568423) doesn't seem to be moving at all. I was under the impression that it's supposed to be at least partially open at idle, so I'm beginning to think I did do some damage to that system. I still don't full understand what controls it's position though aside from it's own little "self fulfilling" vacuum tube. It looks like a passive system that shouldn't have a major impact on the cars ability to idle. Not sure why forcing it open helps.

Does anyone know if it's possible to open up the spring housing without damaging it to inspect the diaphragm (I assume there must be a diaphragm inside this to compress the spring)?

PS - Sweet rims on that JCW, Beagle.

 

First thing to check is the hose on the BPV..is it cracked..if unsure replace it with a good quality hose.
2...check the diaphragm ..they often tear and are the cause most of BPV failures..BTW it is NOT AVAILABLE separately. You will need a new BPV or a good used replacement if it is damaged.

I think the diaphragm is vacuum activated...so just pull the hose, apply vacuum and see if the arm moves.

Start there

 

1qwkmini, Thank you! Brilliant idea. Just pulled the hose off and put a vacuum hand pump on the spring housing. Perfect seal, not even a slow leak, arm moved smoothly. Will inspect the hose more closely after I'm done with clients tomorrow but I did not tamper with this during the rebuild so the problem probably lies elsewhere.

MiniBeagle, I did inspect the intake duct and gasket. No joy, they seem fine.

That did lead me to the MAP hose, however, I couldn't get to it easily. It comes in on the back side of the duct and I can feel that it's inserted but can't see it well to inspect for cracks.
Has anyone replaced this hose and if so, what was the best route to removing to inspect/replace?

Still wondering about the bypass valve. Can anyone help me understand how it's supposed to create vacuum at idle when it's plugged into itself, or am I misunderstanding its function?

Thanks all for your time and input.

 

BPV...butterfly is normally closed to allow for pressure in the intake manifold. Hose has a port on the intake side of the supercharger. When the throttle plate closes the supercharger is still turning and in turn creates vacuum in the charge pipe and opens the BVP and recirculates the pressure that the S/C is creating.

Map sensor...assume you are refer to the one just above the thermostat housing. The TMAP is on the intake manifold. MAP sensor could be installed incorrectly...1--remove the 2 screws holding it in and inspect the o-ring. 2 -- the plastic housing attached to the plastic hose (connects to the charge pipe at the other end) needs to sit above the metal bracket, then the MAP sensor and the 2 screws hold it all together.

Best thing to do for this hold situation is to pressure test the intake system. THIS WILL SAVE YOU A LOT OF TIME AND TAIL CHASING

Get/make something like this. https://turboboostleaktesters.com/3-inch-universal-boost-leak-tester-kit-billet-aluminum/. OR https://www.amazon.com/Turbo-Boost-Leak-Testers-Universal/dp/B07WQJ7G2C/ref=pd_sbs_263_t_1/140-7610048-9603035?_encoding=UTF8&pd_rd_i=B07WQJ7G2C&pd_rd_r= 24873a05-a07b-493a-ba92-304807345639&pd_rd_w=82Ed1&pd_rd_wg=AVMu9&pf_rd_p= 5cfcfe89-300f-47d2-b1ad-a4e27203a02a&pf_rd_r=26V8K912X5G4AYRB01Q6&psc=1&re fRID=26V8K912X5G4AYRB01Q6
Pressure up the system to 15 psi (open the throttle plate with a piece of rubber hose before clamping the unit on the throttle body), remove the air supply, watch the gauge, pressure should drop at less than 1 psi/sec in a healthy system. If faster than that start looking listening for leaks...soapy water helps a lot.

 

Thanks again, Qwk. I've only seen this done with smoke but I can make a pressure tester like that out of a PVC cap and a rubber hose for cheap. I will give that a try later tonight when I have some time to get to Home Depot. I'll have leakage out open exhaust valves though, no?

I did some reading on vacuum systems last night, makes more sense now, the vacuum is created by the down stroke of the piston pulling the air into the cylinder (naturally aspirated), so vacuum is strongest at idle until the supercharger/turbo (forced induction) creates enough positive pressure at higher RPM, which is what "boost" is. At least I'm learning something through all this... ha So it makes sense the BPV would be open at low idle and shut at higher speeds.

I do have the MAP sensor installed properly and it's brand new so O-rings are looking great. Unless I was sent a faulty sensor I should be good there.

Thanks again to those reading and replying here.

 

I was going to suggest that you just make one...but I didn't know how handy you were feeling.

You don't need to worry about valves...there is never a point when the intake and exhaust are open at the same time in these engines (unless you have the craziest cam ever). Even if there is some overlap like my Catcam...there is no oil pressure in the rocker arms, so on valve lift at low cam lift.

Cylinder leakdown etc is accounted for in the 1 psi/sec drop...otherwise it would hold steady if not leaks.

 

Well, after tearing apart the entire engine bay what's one more little DIY project? Of course they wouldn't be open at the same time, guess my brain is more fried from all this than I thought. Thanks, Qwk. Will report back with the results.

 

Thanks Qwk and Beagle for the helpful insights. After fashioning this $25 wonder and mounting it I quickly discovered the issue. Beagle, you were right from the start. While the supercharger intake duct profile gasket is free of cracks or gouges, it's bleeding air at a ridiculous rate. I removed it, cleaned it, greased it up a bit and seated it well, but upon a retest it wasn't any better. I have the gasket on order. Should be here early next week.

The boost tester was a game changer. I'm certain I'll be able to diagnose the issue now as it's easy to hear and feel where air is escaping. Will report back with a follow up once the gasket is installed.

 

When you install the new gasket...do yourself a favour and put some rtv sealant on the S/C horn...install the gasket on the S/C...then rtv sealant inside the intake tube flange...then install the tube. Make sure to leave it overnight before starting the car and doing any testing. Chased this issue for 2 seasons.

 

Glad I was able to help

EDIT: I guess I spoke too soon...

 

Hello again, all.

So, I installed the gasket prior to reading the RTV suggestion. Started it up in Front End Service mode for 30 seconds, seemed fine. Buttoned it back up and took it for a drive. Laggy throttle response, felt weak overall in the power production category. Ran codes, got 1239 and a new one, 1498 "Unmetered air after compression."

Hopped on here, saw the RTV suggestion. Tore it back down, reinstalled gasket with RTV, assembled back to FESM. Started it up this morning and got 1239 again plus 0171 "Mixture control (bank 1) - system too lean.

Starting to lose my marbles of this one, guys. Hoping to get it figured out without having to assembled and reassemble again. Any help would be appreciated.

Thanks in advance!

 

Did you run the boost tester after reassembly??? Start there...these are a PITA to put back together and not have intake leaks...that's why I bought a TVS

 

I was looking at your boost tester...
1-you need a gauge that goes to around 30 PSI max...you only need 15 psi max to pressurize it.
2- not sure how you are controlling the air you add...typically just use a schrader valve and tire filling type setup on the compressor hose.
3 -Fill it to 15 psi..remove the air supply and watch the rate at which the pressure falls. If less than 1 psi/ second (so around 15 sec or more to 0 psi) then you are good to go...OTHERWISE YOU STILL HAVE A LEAK.
Not sure how you can accomplish this with your current setup.

 

Hey Qwk, thanks for the reply.

The air compressor I have has a regulator on it, but it only goes down to 20 PSI, so I was a bit worried I was going to blow the seal I just created with the RTV by testing it again. I was hoping the new code would lead to something I could check without testing, but perhaps I don't have an option.

The BPV is opening and closing when the throttle is revved. If I let it idle it will drop to ~750 and return to ~1000 RPM every 10 seconds or so.

I'm pretty surprised how difficult this has been. I've never had issues like this before. It's not like I'm cutting corners, I've replaced every gasket I've encountered and am still having a great deal of trouble.

 

That's why I questioned your setup on the boost tester...need to change that. Remember it's the rate of pressure drop that tells you if you have an issue or not.

Speaking from experience...always test it after playing with anything on the intake side...intake tube, intercooler boots etc.etc.

You may have another issue with tmap sensor or?? but always start by testing intake for leaks.

 

Am I making a mistake by using an air compressor then? Should I be using a manual tire pump or something less aggressive?

Thanks again.

 

Compressor is fine...but you need to change your tester. 30Psi gauge and schrader valve.

Read this. https://turboboostleaktesters.com/ho...ost-leak-test/

 

The more I read about this issue the more common I find it to be so I'll be a little more detailed in hopes of helping others searching for this issue.

The coupler on my tester is air tight so I just pop that double fitting out and it holds air, but I swapped out for a 20 PSI max tire pressure gauge I found for cheap at AutoZone ($10) and that did make a huge difference. I can see the pressure mount a lot more clearly with the lower range. Thanks for that suggestion, Qwk!

It topped out at 10 PSI and then stopped, which I couldn't really see on the 300 PSI max gauge. I was able to find a pinhole leak at the bottom left corner of the SC inlet gasket. The more I messed with it the worse it got, dropped all the way down to 5 PSI and started leaking across the entire bottom section, so tore it down again...

I originally used RTV Red High Temp which isn't fuel-proof. It appears that some of the residue from inside the inlet duct (assuming a mixture of oil and fuel) dripped down once I rotated the duct back down for install and cut through the wet RTV, preventing it from solidifying and sealing properly (upon tear down that corner was wet and gummy, unlike the rest of the RTV). I cleaned all the RTV Red off, sprayed a good amount of parts cleaner into the intake duct and the SC and wiped out any remaining residue I could reach.

In my experience, RTV can make a big oozing mess if too much is applied, so I used it sparingly the first time. This time used a lot more of the Grey Advanced Formula (for high torque/vibration applications). This seal has been leaking from the bottom since the beginning so after seating it I pressed additional Grey Advanced RTV into the seam between the inlet duct and the SC on the entire bottom half (would have done the top half too but my hands didn't fit in there). I also placed a worm gear clamp (I believe 5" max diameter) around the flange of the inlet duct where it mounts to the SC. I had to use a Dremel to shave away some of the arm that mounts the set screw through the duct and into the SC body so the clamp wrapped around fully and squarely.

Given how much RTV I shoved in there, I'm allowing it a full 24 hours to fully cure before running another boost leak test. If this doesn't work I did pick up a "MotoSeal" RTV that's supposed to be able to stand up to fuel since that's what messed me up last time (this apparently is pretty nasty stuff though, the warning label is twice as long as the other RTV's and says clearly on the back, "may cause cancer," so I'm saving it as a last resort).

Will report back once I've tested this seal.

PS - A tip to anymore wrestling with this. If you remove the MAP sensor and free the hose that run to the SC inlet duct it allowed for a lot more movement of the inlet duct as I was trying to clean it and apply RTV evenly. I left this hose mounted the first time and was much too aggressive with it, which ended with me snapping the hose off at the black tapered mount on top. I was able to repair it with some flexible rubber hose and worm gear clamps. We'll see if it holds up to the boost leak. No issues up to 10 PSI so far.

 

Hello again All,

So, yesterday confused the **** out of me to be honest. After the patch job to the SC inlet I was able to get the system up to 15 PSI. I did this a few times and around 12 PSI I heard what sounds like an electric charging sound. I'm not sure if that was the supercharger spinning up due to the pressure or what... The drop from 15 PSI to 10 PSI only took about 2 seconds, but from 15-0 was about 15 seconds. So, I reassembled the intake and started it up. Same 1239 code, still revving from 750 to 1000 RPM... Cleared the code, started it again, same thing... Wanting to see if the BPV was functioning properly I revved it up to about 3000 RPM and let it drop to idle. To my surprise when it caught itself if idled perfect and held.

I decided to take it out of FESM and take it from a drive. Here's where it gets weird. There's a pretty loud lifter sound or maybe chain rattle coming from the engine when it's driven. When I idle at a stop light the Low Oil Pressure light comes on. As soon as I touch the throttle that goes away. Took it on the expressway to test out the top end and the sound it still there, but if I drop from 60 MPH quickly the loud engine sound will dissipate until the throttle is pressed again.

I was taking side streets home and at a red light the car just dropped from idle to stall and wouldn't start from 3 tries. Fourth one it went and returned to it's previous behavior...

I got home, plugged in my reader and was surprised that only the 1239 code came up even after the stall and failed starts... I popped the hood to search around a bit and noticed that two of the valve cover bolts looked wet. I gave one a half turn and it snapped off... Gave the second a quarter turn decided to walk away from it for the day before I did something else stupid.

I did add break in oil to the car. It instructed me to fill with normal oil to normal level and then add the additive and drive it from 500 miles. As a result, the oil is showing at the top of the dipstick range. Not sure if this is gumming up the oil pump at idle? Perhaps it's too thick/full to pressurize the chain tensioner and this is the sound I'm hearing?

At this point I'm dreaming up all sorts of stuff... Any help would be appreciated.

Is the 15-10 PSI leak down drop being quicker than the 10-0 PSI normal?
Anyone use a break in additive on these engine or experience a similar Low Oil Pressure at idle/stall?

Happy Friday. Thanks in advance.

 

I assume your scanner won't let you clear adaptations?

 

Break in oil isn't an issue..It's just a high zinc additive. You didn't really need to use it if you didn't do the rings or a new cam, and used assembly lube on the bearings.

Pressure test at 15 psi is a a little weak if it completely dropped to 0 in 15 seconds...generally it IS faster 15-10 but it usually hangs at around 5 psi for a longer time when things are sealed up properly...so I suspect you still have a leak somewhere. Soapy water is your best friend...spray it at every possible spot from the throttle body to the injectors/head/intake manifold interface. I suspect you still have a leak somewhere..maybe smaller than before but still a leak.

If you want to check your bypass valve...simply pull the hose off the diaphragm at idle. It will likely run like crap because the valve will close (uses intake vacuum to open the valve and recirculate intake air at idle). If it still runs the same then you probably need a new one.
Alternately you can open it manually at idle by pushing the black plastic actuator into the diaphragm...see if that smooths out the idle.

I suspect you have other problems...I don't know the full history of the issue, but it sounds like you have had and oil pressure issue that has lead to the tensioner problem. Loud tapping noise sounds like lifter issue. Both the lifters and tensioner are hydraulic and only function properly with good oil pressure. At his point if you want to carry on ....you need to remove the factory oil pressure sensor on the oil filter housing (factory is just an idiot light and is useless) and install some type of oil pressure gauge so that you can see the actual psi in the system. You can install an electrical or a simple manual gauge..your choice. A manual gauge with a short length of capillary tubing is easy, reliable and cheap. Depending on what grade of oil you use...on cold startup you should see 60-80 psi of oil pressure...for example I run 10w60 in my race engine and see about 85psi on a cold start...yours with lighter weight oil shouldn't be that high but I would expect at least 60 psi. On hot oil you should see at least 40psi.
Maybe missing O ring on the oil pickup?? pump then sucks air!!!


AT THIS POINT YOU SHOULD PROBABLY FIND YOURSELF A GOOD MECHANIC FAMILIAR WITH THE STRANGE BEHAVIOR OF MINI'S. They can be a PITA to diagnose and sort out.

 

Random thoughts:

Are you sure you have the correct MAP sensor above the thermostat housing...it is a different part # from the T-MAP sensor on the intake.
Have you tried a hand vacuum pump on the Bypass diaphagm to see if it is any good?

 

Hey All,

Hey, Black Forest! Thanks for the input. My reader shows no adaptations to be cleared. It's been run for less than 15 miles since rebuild. Still hit clear anyway, but no change.

Qwk, my BPV seems good now. It was being pulled in at idle and released under throttle before, but when I was using compression to simulate boost around 10 or 12 PSI it was leaking air in at the spring housing closure. RTV + electrical tape, no more leakage. I don't think it's the issue anymore.

The boost leak did slow down for the last 5 PSI, the first 5 is just pretty quick, 10-5 is moderate, it holds around 1-3 PSI for awhile. I'll test it again before I take anything else off. I have the oil MAP sensor. I did intentionally order the MAP and not the TMAP, but I'll switch out the old and see if anything changes.

Given all the noise I have and the fact that has pretty normal power productions now, I agree that I may have an oil pressure issue causing all the noise.

I did an oil change less than a week before all this happened so I reused the oil I had in there to work as sacrificial oil for the first 500 miles with the additive. I thought I got it all out, but it could have had small pieces of the bearing in there. I think I'm going to pull the pan and check the silk screen filter at the bottom of the pump and make sure there's no debris. I'll replace the oil without an adaptive as suggested and make sure the tensioner is engaged before I start it up again.

After that I may need to take it to a mechanic if issues persist. I've never let anyone else work on any of my cars, which is why this has been so frustrating. I'm the guy people call when they have car trouble. I should be able to figure this **** out. lol

There's not a European specific garage in town and I don't trust the dealer here. I had to call the corporate office twice to get them to take care of my rear fender rust at year 12, they just ignored my calls for months. When I got it back it was missing the fender arch on the passenger side and the CD changer was "broken," (not plugged in)...

Will do some research on mechanics if I can't sort this out today. If anyone knows of a good Mini garage close to Rochester, NY I'm all ears at this point.

PS - I did just watch a YouTube video of a mechanic pulling an oil pump after a rebuild like mine. It was clearly more for comical purposes than anything, they even do "chest" compressions on it at the end. A commenter said the same thing happened to them after a rebuild. Wonder if bearing debris bypassing the screen and destroying the pump is common.