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so, next step is to "change oil" in wastegate actuators and perhaps the vacuum pump as well - there must be a bunch there given the membrane was destroyed... that might explain all kinds of boost/response issues.
how can u even access the turbos without removing the motor?
Tasos suggested in the video above (6:25) you can remove these actuators with the motor and turbos still installed. On my ML63 the drivers side (US) would be difficult but the passenger side looks much easier.
I have checked both actuator rods and they appear to be returning immediately to their default position when pulled from above - I can only assume there is not enough oil, or hopefully none at all, to stop the correct function of the internal membrane.
also, @kennyd suggested in this video to check the line that connects to the vacuum solenoid on top. Mine seem to be clear of any trace of oil
finally, I'm yet to check on the condition of the recently installed 'MagiDeal' vacuum check valve - as a back up I've ordered two additional replacements from two different stores on AliExpress - less than $25NZD delivered for both. The reason is I'm still suspicious why the new check valve I installed accepted air pressure in both directions.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Originally Posted by jcarsnz
The reason is I'm still suspicious why the new check valve I installed accepted air pressure in both directions.
If I remember correctly, the wastegate on the turbo is normally closed, meaning full boost without vacuum. (At least that what it was on a 2000 Audi A4 I had. When the vacuum line became detached for some reason under full acceleration, the boost and detonation punched some holes in the pistons.) I'm thinking that vacuum needs to go to atmospheric pressure (versus negative) for boost and negative pressure for bypass (wastegate being open). Otherwise, you would never build boost. But that also kinda defeats the purpose of a check valve normally. It'll be interesting if the new valves coming flow both ways. The one I ordered should be here in a day or two.
I believe these use vacuum to hold the wastegate closed. That's why issues with the boost control vacuum lines, or a torn wastegate diaphragm result in low boost. I think the check valve is part of the vacuum pump operation. I don't think the wastegate control/vacuum pump circuit, the way Mercedes has done it here, has ANYTHING to do with intake manifold pressure (i.e. boost). I should know but I don't.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
The purpose of the wastegate is to limit boost by opening and bypassing the turbine. It is normally closed. Modern turbos with an electrically controlled wastegate actuator will detect a maximum boost condition and use the boost pressure to open the wastegate. If the hose comes off the actuator canister, as it did on my Audi, the wastegate stays closed and the turbo continues to build boost until something breaks.
As you pointed out, it appears that Mercedes uses a separate pump, and not boost pressure, to open the wastegate as programmed. That said, does Mercedes' turbos use normally open wastegates?
Ok that was way WAY too hard. Went in via Xentry Simulation and fiddled around. First I triggered a low boost code to see if it would explain how the system worked. Nope. Then I decided to press my luck and try the WIS links (which don't usually work). But somehow it opened WIS and brought me to the functional description index. Found "charging" (which at first I thought was for the battery) and lo and behold, I found the thing we have been looking for. I don't know why the software is so bad. It's really frustrating.
As I thought, the wastegates are normally open. Vacuum closes them. The diagrams are what to focus on for best understanding. The words are slightly confusing (again, as usual). Diagram P09.00-2114-82 shows boost control solenoid (Y77/1) with <5% duty and with atmospheric pressures in the boost control system as a result. The tension spring in the wastegate holds the wastegate flap open.
Diagram P09.00-2115-82 shows >5% duty. Again, this is a dumb way to say it because the duty cycle graphic clearly indicates majority on time of pulse width, so I'd say more like >85%. Anyway. Now it shows vacuum in the wastegate actuator line (exposes that plumbing to the vacuum pump, component #12), working against the tension spring, holding the wastegate flap closed. This is very clearly depicted.
It doesn't say it applies to the M276 but I'd bet it's the same there, too. Bonus info: says the intercooler pump comes on at 35C and off at 25C. I can tell you this is incorrect. That's closer to how the M113K did it. Actual control temps are like 45C pump on and 40C pump off.
2015 SL400 (M276 Turbo), 2014 C350 Sport (M276 NA), 2004 SL500 (M113), 2004 Audi TT225 (BEA)
Now everything makes sense. And Normally Open is much safer than Normally Closed. You may lose power (i.e., become NA), BUT you won't melt pistons or blow holes in them.
I removed the tune and did my test: mild acceleration starting from ~2000rpm, in 7th and 6th gears, without triggering a downshift. Without the (stage 1) tune the car barely accelerates without any rpm fluctuations, there is clearly not enough power which makes sense. With the tune car accelerates better and lack of power manifests in rpm (engine sound oscillations) that I previously attributed to "power cutoffs". I started feeling better about the behavior, will check again after re-indexing plugs and replacing remaining old coils.
@PeterUbers I have about 60K miles on the car, my vacuum membrane did not have time to disappear into the engine completely, but notably degraded.
I've replaced the valve with one bought from Amazon but with 15 days delivery time. It came directly from China. Installed and decided to check it after a week: when I pulled it out the membrane and the bottom plastic piece remained in the pump. Not sure if it separated when I pulled it out or if it was already broken. My theory is that it was not letting air pass properly and the vacuum pulled the plastic off. Picture below is the original valve to the right and the second valve to the left.
I've replaced the valve with one bought from Amazon but with 15 days delivery time. It came directly from China. Installed and decided to check it after a week: when I pulled it out the membrane and the bottom plastic piece remained in the pump. Not sure if it separated when I pulled it out or if it was already broken. My theory is that it was not letting air pass properly and the vacuum pulled the plastic off. Picture below is the original valve to the right and the second valve to the left.
did the new one help any performance issues you had prior to removing it to check it out after a week?
I read here that someone tested the valve and it was not working properly. I did not test it initially, so I decided to give it a look and that's what I found. I replaced the original one because of the fluttering of the actuators. It did initially solve it, but I did not check it again, so not sure if it was still working or not.
Checked my new valve after 2 weeks on the car and it came out the same way - in 3 pieces. Membrane was intact, reinstalled it back. More importantly there was no oil in vacuum line leading to boost solenoid, so the new valve likely doing its job and perhaps the original also worked even with half disintegrated membrane.
I did a waste gate test in xentry to confirm wastegates are working. Didn't see an easy way to remove wastegates and check for oil inside on e63.
Will check the vacuum line for oil later, without removing the valve itself.
Originally Posted by Cla1111
I've replaced the valve with one bought from Amazon but with 15 days delivery time. It came directly from China. Installed and decided to check it after a week: when I pulled it out the membrane and the bottom plastic piece remained in the pump. Not sure if it separated when I pulled it out or if it was already broken. My theory is that it was not letting air pass properly and the vacuum pulled the plastic off. Picture below is the original valve to the right and the second valve to the left.
New check valve arrived from AliExpress and this one appears to work correctly. I could pull air in the direction of the vacuum but could not push air the opposite way.
Removed previous faulty check valve (from Amazon) and found it was in three pieces, just as shown in the photo above from @Cla1111 .
Before installing the latest check valve I took the opportunity to push compressed air through the line at the solenoid.. a decent amount escaped at the other end of the line.
Then installed new check valve. Engine performance is no better or worse. Hopefully this check valve will be more effective at keeping oil away from the vacuum line.
New check valve arrived from AliExpress and this one appears to work correctly. I could pull air in the direction of the vacuum but could not push air the opposite way.
Removed previous faulty check valve (from Amazon) and found it was in three pieces, just as shown in the photo above from @Cla1111 .
Before installing the latest check valve I took the opportunity to push compressed air through the line at the solenoid.. a decent amount escaped at the other end of the line.
Then installed new check valve. Engine performance is no better or worse. Hopefully this check valve will be more effective at keeping oil away from the vacuum line.
i wonder tho - despite it coming out in pieces - does it work appropriately while it's installed and affixed to the socket it goes in? Even the OEM ones from the factory comes out in pieces, no? What am I missing
@PeterUbers yes I'm sure you're right, shouldn't matter if the part comes out in pieces when removed. I was more referring to the issue that @san40 and I noticed where the Amazon check valve allowed air to flow in both directions - this seemed like faulty behavior.
So, this might seem like a dumb question, but if these replacement check valves seem to be of no better quality (or of worse quality) and offer no extended longevity or benefit over the original, why not just pull it out, fish out the bits that remain in the pump, reinstall the original (now "empty") check valve housing, and run a simple inline check valve? Super easy to check and replace if necessary. Also, it would be exposed to less environmental factors such as vibration and heat. It would likely last longer and would be simple enough to access that it can be easily checked every oil change.
Mitsu - good idea in theory, however, we are talking tiny variations in BAR here to actuate the waste gates. I have had turbo cars for ever....never have I had one nearly as hot as the 5.5, the 4.0 from what I have seen is even hotter. While there are many theories as to a better way to skin this or that cat - I can tell you from my "Mitsubishi" days....I had a (aging myself)....Blix SBC Id boost controller on DR650 turbos...I had to change the vacuum lines to route a gReddy(?) BOV - anything out of the ordinary on that vacuum line and things went bad, fast.
That said, I would never not ever get an Amazon or AliExpress or what ever check valve. They do not cost enough to worry about the price as compared to melting the pistons in my engine. Unless the car is massively tuned (and the folks that play that game accept the risks)...well, get the OE check valves.
Considering the fact that the check valve itself does not appear to be obtainable by itself from either Ford or Mercedes, it would appear you're left with but one option, in that case. Replace the entire vacuum pump. I'm sure they're not inexpensive, and from the look of things, the valve won't last long, regardless.
Considering the fact that the check valve itself does not appear to be obtainable by itself from either Ford or Mercedes,.
I have yet to find a part for any of my w-212s or my older C240 or my C300 or the GLS 580 my past GLS 550 and on and on that I was not able to acquire at the dealership. Well but possibly for a passenger side rear suspension unit for an e63s wagon... you have a better chance to get in seeing Dr Kevorkian then getting that particular unit.
I have yet to find a part for any of my w-212s or my older C240 or my C300 or the GLS 580 my past GLS 550 and on and on that I was not able to acquire at the dealership. Well but possibly for a passenger side rear suspension unit for an e63s wagon... you have a better chance to get in seeing Dr Kevorkian then getting that particular unit.
Make no mistake, you CAN get the part. It just so happens to be available ONLY with the entire vacuum pump.
01-05-2024, 02:41 AM
