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The vacuum pump is normally packed with engine oil.
Yet the pump pressure is negative: a vacuum that sucks what's connected to either its main port or accessories.
These pumps are not short-lived service items ie. low suspicion of a bad pump.
I just hooked up a vacuum gauge to the outside of the new check valve - it’s pulling 24 inches. I then went downstream to the input of the boost controller - 24 inches. I’m not sure of what the spec is, but vacuum appears to be adequate.
Boost controller took a dive perhaps? I’ve heard that’s an issue on the 278/M157.
Boost controller took a dive perhaps? I’ve heard that’s an issue on the 278/M157.
I curse you to hell for saying that....thanks to you that is the next thing that will go in my car (that is still in the shop with a new $1600 TCU waiting to be programmed). Yeah, YOUR FAULT.
That said, I am not familiar with the boost controller failing as a big known issue as much as so many other things.
I curse you to hell for saying that....thanks to you that is the next thing that will go in my car (that is still in the shop with a new $1600 TCU waiting to be programmed). Yeah, YOUR FAULT.
That said, I am not familiar with the boost controller failing as a big known issue as much as so many other things.
Guys on the Facebook M157 Marketplace say they keep a spare boost controller and check valve on hand to deal with this. The boost controller is $50 or so.
I have never not ever heard of that. I've been known to hang out with the w-212 forums and I also have the V8 twin turbo in our SUV and I for some reason have never heard of that particular issue. I keep coils handy at all times just in case but I've never heard of keeping a boost controller
I have never not ever heard of that. I've been known to hang out with the w-212 forums and I also have the V8 twin turbo in our SUV and I for some reason have never heard of that particular issue. I keep coils handy at all times just in case but I've never heard of keeping a boost controller
Boost control solenoid to be exact.
I have 100k miles on the SL 63. Can’t say that things don’t go bad.
Xentry was pointing toward tests to check out the electrics with the solenoid so must be some kind of issue. The car went from running like a beast to throwing the CEL/code and now having **** poor response (like half the pedal is dead). Seems to be the next thing in line especially considering how it failed.
I have 100k miles on the SL 63. Can’t say that things don’t go bad.
Xentry was pointing toward tests to check out the electrics with the solenoid so must be some kind of issue. The car went from running like a beast to throwing the CEL/code and now having **** poor response (like half the pedal is dead). Seems to be the next thing in line especially considering how it failed.
That's when only Xentry can help all the way with acurate testing.
The boost controller can go bad without being dead, it fails its precise regulation or slow to respond.
That thing is PWM controlled. Its basically a shaker, minute shaking of valve seat we can't see by eye.... as suction pressure regulation method.
I have replaced mine in 2021 ( 7 years old , approx 30,000KM ), because it was kinda noisy when tested , I created a leak on purpose.
The problem with failed check valve at vacuum pump is, if left long enough, oil will travel to the turbocharger vacuum control system and may end up at the
vacuum actuator of turbo wastegate. Tasos video has shown how much oil that round thingy can hold under its membrane.
Since oil is liquid and not compressible, the vacuum actuator can not do it maximum pull inwards and you loose boost.
M276, M278, M157 wastegate controller is SUCK ( vacuum ) to maintain pressure.
Vacuum pump is oil bath design, hence it can create the vacuum.
In common vacuum pump we use to vacuum our HVAC, it has reed valve like 2 stroke engine, open and close that reed valve.
In our car, the reed valve is replaced by the thin silicone membrane inside the fittings , the one often torn off or lost, the one for turbocharger boost control.
The big port which is for the brake booster, also have check valve, same duty like a reed valve.
Go and test your vacuum pump, at the small check valve for the turbo, if only 24 inch mercury negative, it is not good enough.
Below is the vacuum at the boost solenoid port itself the one towards the vacuum actuator for wastegate, still 27 inch Hg. Vacuum losses due to small long hose and any tee or is normal.
The vacuum pump itself , at the vacuum pump, or at the brake booster.....when healthy must deliver near 29.xx inch hg vacuum.
I have an absolute sensor installed at brake booster sensing port. It read the brake booster vacuum aka vacuum pump vacuum value.
Since it is an absolute sensor PSI-A, when at sea level 1 atmosphere, it will read 14.7 PSI positive.
When vacuum reaches 29.xx inch Hg vacuum, it will be zero PSI-A,
Cold engine start. Near sea level location. Some left over suction before engine kill the day before, hence pressure did not start at 14.7 PSI-A, but 13.31 PSI-A.
Log is at 5Hz, 5 data points per second.
Below is about first 90 data points only , for above graph of 130ish data points. But It easy easier read on how fast the vacuum pump is creating vacuum.
For those more comfortable using Vacuum Inch Hg unit, conversion is below.
My sensor is the 2nd row, Absolute Pressure PSI.
.
The sensor I use. I mount it under the black steel cross member.
.
This shows how much brake booster is using the vacuum reserve. All vacuum pump has Liter Per Minute rating.
The PID Banks Gauge has is CCP ( Crankcase Pressure ), thus I use that as there is no PID for Vacuum Pump
The boost controller can go bad without being dead, it fails its precise regulation or slow to respond.
That thing is PWM controlled. Its basically a shaker, minute shaking of valve seat we can't see by eye.... as suction pressure regulation method.
I have replaced mine in 2021 ( 7 years old , approx 30,000KM ), because it was kinda noisy when tested , I created a leak on purpose.
The problem with failed check valve at vacuum pump is, if left long enough, oil will travel to the turbocharger vacuum control system and may end up at the
vacuum actuator of turbo wastegate. Tasos video has shown how much oil that round thingy can hold under its membrane.
Since oil is liquid and not compressible, the vacuum actuator can not do it maximum pull inwards and you loose boost.
M276, M278, M157 wastegate controller is SUCK ( vacuum ) to maintain pressure.
Vacuum pump is oil bath design, hence it can create the vacuum.
In common vacuum pump we use to vacuum our HVAC, it has reed valve like 2 stroke engine, open and close that reed valve.
In our car, the reed valve is replaced by the thin silicone membrane inside the fittings , the one often torn off or lost, the one for turbocharger boost control.
The big port which is for the brake booster, also have check valve, same duty like a reed valve.
Go and test your vacuum pump, at the small check valve for the turbo, if only 24 inch mercury negative, it is not good enough.
Below is the vacuum at the boost solenoid port itself the one towards the vacuum actuator for wastegate, still 27 inch Hg. Vacuum losses due to small long hose and any tee or is normal.
The vacuum pump itself , at the vacuum pump, or at the brake booster.....when healthy must deliver near 29.xx inch hg vacuum.
I have an absolute sensor installed at brake booster sensing port. It read the brake booster vacuum aka vacuum pump vacuum value.
Since it is an absolute sensor PSI-A, when at sea level 1 atmosphere, it will read 14.7 PSI positive.
When vacuum reaches 29.xx inch Hg vacuum, it will be zero PSI-A,
Cold engine start. Near sea level location. Some left over suction before engine kill the day before, hence pressure did not start at 14.7 PSI-A, but 13.31 PSI-A.
Log is at 5Hz, 5 data points per second.
Below is about first 90 data points only , for above graph of 130ish data points. But It easy easier read on how fast the vacuum pump is creating vacuum.
For those more comfortable using Vacuum Inch Hg unit, conversion is below.
My sensor is the 2nd row, Absolute Pressure PSI.
.
The sensor I use. I mount it under the black steel cross member.
.
This shows how much brake booster is using the vacuum reserve. All vacuum pump has Liter Per Minute rating.
The PID Banks Gauge has is CCP ( Crankcase Pressure ), thus I use that as there is no PID for Vacuum Pump https://youtu.be/kbCPWBkcvnY
.
Sometimes I really hate this site… I use a Google account to logon (because it screwed up my username) and most times it trashes my posts. I had a very long response that I lost, too. Frustrating and this is the only site that does this and I’m on many. But I digress.
Not even sure of where to start. Lots to digest here.
Regarding vacuum, are you saying 29 inches in the minimum needed to work properly? The engine seems to run well otherwise. It’s smooth - brakes are strong and so on.
I do feel that the boost control solenoid took the dive. The car was running like a beast until I pulled into the driveway and the CEL was set. And now I hear nothing from the turbochargers so my thought is that they’re being left open. Even with low boost I’d expect to hear something but they’re dead.
I did test drive with and without the Volvo check valve and without it set a current p0299 code vs stored from the last drive cycle with the check valve installed.
I plan to grab a new MightyVac today so that I can test my waste gate actuators. What do they need to hold? 5-inches?
Lastly, on a trip to DC last month, I hit a hole in the road on the interstate (construction zone). Ever since I’ve had a rattling sound coming from the passenger side front when coming to a stop. Probably a loose heat shield but I need to get under there and look. The sound is random. Sometimes it won’t do it at all. could be related?
I have heard and seen the wastegate actuator rod rattle.....
My understanding is that it will only rattle at idle as you take off. With the new check valve, movement of the rod on the passenger side has ceased. Without the check valve, it was rapidly moving back and forth. With the new one, it was oscillating a very very small amount (less than 5mm) and then ceased altogether. It's now as solid as the driver's side. The sound I have really does sound like a heat shield. I've listened to waste gate rattle noises (mostly BMW) and this doesn't sound like that at all.
I drove the car to the office today. It seems to be driving with a little more power than yesterday, but I still have the CEL illuminated. I figure it will take some cycles for the CEL to turn off - I could not turn it off in Xentry even though Xentry said it could be turned off at the component level within the module (didn't work). I'll check this evening to see if the code comes back as current or just stored.
Question... when low boost is encountered, I've heard that the ECM will put the car in limp mode. Is that what I'm possibly experiencing right now?
Sometimes I really hate this site… I use a Google account to logon (because it screwed up my username) and most times it trashes my posts. I had a very long response that I lost, too. Frustrating and this is the only site that does this and I’m on many. But I digress.
Not even sure of where to start. Lots to digest here.
Regarding vacuum, are you saying 29 inches in the minimum needed to work properly? The engine seems to run well otherwise. It’s smooth - brakes are strong and so on.
I do feel that the boost control solenoid took the dive. The car was running like a beast until I pulled into the driveway and the CEL was set. And now I hear nothing from the turbochargers so my thought is that they’re being left open. Even with low boost I’d expect to hear something but they’re dead.
I did test drive with and without the Volvo check valve and without it set a current p0299 code vs stored from the last drive cycle with the check valve installed.
I plan to grab a new MightyVac today so that I can test my waste gate actuators.What do they need to hold? 5-inches?
Lastly, on a trip to DC last month, I hit a hole in the road on the interstate (construction zone). Ever since I’ve had a rattling sound coming from the passenger side front when coming to a stop. Probably a loose heat shield but I need to get under there and look. The sound is random. Sometimes it won’t do it at all. could be related?
.
For the red text : Regarding vacuum, are you saying 29 inches in the minimum needed to work properly?
No, 29 inch Hg is not a minimum to work the boost controller, but if a vacuum pump must be able to do at least 28-29 inch Hg. Near perfect vacuum 29.92 inch Hg will not happen, 29.2 ish inch Hg can happen...as shown by my vacuum pump.
If say 24 inch Hg at the vacuum pump itself, It shows the vacuum pump is aging and/or the membrane in the check valves (2) is not seating very well, and/or there is a suction leak somewhere or even the brake
booster seal for its ambient air can leak too. The one for the pedal.
To me my brake booster vacuum is of prime importance hence I place a sensor there, not the turbo boost solenoid....but monitoring vacuum pump performance indirectly also monitor the vacuum avialability for boost controller.
The boost controller does not need super high vacuum to actualy create maximum boost or more accurately to fight pressure of the wastegate flap, I mean no need 29 inch Hg that is for sure.
For the text in blue : I plan to grab a new MightyVac today so that I can test my waste gate actuators.What do they need to hold? 5-inches?
Here is my 2021 archive :
.
. ENGINE IS OFF - 13 inch Hg only, but even at idle there is no boost to fight.
Actually for the sake of fun and knowledge, I can do a live while under boost test, I can re-route my vacuum sensor hose if I get a suitable Tee and extra hose and see
my Right Bank wastegate vacuum actuator at WOT or any high boost of the turbo, does boost controller add more vacuum ?
2nd gear pull to WOT is good enough, in fact M276.820 comfort turbo maximum boost is not at WOT, but at approx 4,500 ish RPM .
Sometime in a week or two I will do the test, now still raining often every other day and I do not want to wash my car
For the red text : Regarding vacuum, are you saying 29 inches in the minimum needed to work properly?
No, 29 inch Hg is not a minimum to work the boost controller, but if a vacuum pump must be able to do at least 28-29 inch Hg. Near perfect vacuum 29.92 inch Hg will not happen, 29.2 ish inch Hg can happen...as shown by my vacuum pump.
If say 24 inch Hg at the vacuum pump itself, It shows the vacuum pump is aging and/or the membrane in the check valves (2) is not seating very well, and/or there is a suction leak somewhere or even the brake
booster seal for its ambient air can leak too. The one for the pedal.
To me my brake booster vacuum is of prime importance hence I place a sensor there, not the turbo boost solenoid....but monitoring vacuum pump performance indirectly also monitor the vacuum avialability for boost controller.
The boost controller does not need super high vacuum to actualy create maximum boost or more accurately to fight pressure of the wastegate flap, I mean no need 29 inch Hg that is for sure.
For the text in blue : I plan to grab a new MightyVac today so that I can test my waste gate actuators.What do they need to hold? 5-inches?
Here is my 2021 archive :
.
. ENGINE IS OFF - 13 inch Hg only, but even at idle there is no boost to fight.
Actually for the sake of fun and knowledge, I can do a live while under boost test, I can re-route my vacuum sensor hose if I get a suitable Tee and extra hose and see
my Right Bank wastegate vacuum actuator at WOT or any high boost of the turbo, does boost controller add more vacuum ?
2nd gear pull to WOT is good enough, in fact M276.820 comfort turbo maximum boost is not at WOT, but at approx 4,500 ish RPM .
Sometime in a week or two I will do the test, now still raining often every other day and I do not want to wash my car
Sure, but Xentry logging wise into CSV file I only get to use it for VVT test, 120 seconds.
I never tried logging ( CSV) on Xentry for other parameters, only seeing it live...yes.
Driving and watching Xentry screen is not safe. I have HDMI video out recorder to do that. Thus I can log for as long as my laptop battery can last.
Or install screen recorder on the laptop where your Xentry is .
.
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Most likely your ECM will use torque as final decision maker and not turbo boost.
This is what is done by ECM for M276.8 MED177.3.1 Stock, no modification
My engine torque is supposedly 480Nm max.
Here 1st gear, ECM will not allow above 480Nm to happen.
You can create you own custom list like above.
The most bottom one. INDIVIDUAL ACTUAL VALUE GROUPS.
Depending on your Xentry type. If you are using OpenPort PassThru, that thing is too slow to log this many parameters and is no faster than 1 data per second.
If you use benzninja.com Xentry and his reccomended C4, it is very fast and can do 4-7 data points per second, so I don't miss a glitch, if any.
The factory-ish check valve came in last night and I installed it (the Volvo part was removed).
The CEL is still on but the power is back so much so that the car got rather sideways once into the boost when I got on it hard going to dinner.
I will check vacuum and test over the weekend if I have a chance. My son is graduating high school tomorrow so the weekend will be filled with festivities to celebrate his accomplishments.
The factory-ish check valve came in last night and I installed it (the Volvo part was removed).
The CEL is still on but the power is back so much so that the car got rather sideways once into the boost when I got on it hard going to dinner.
I will check vacuum and test over the weekend if I have a chance. My son is graduating high school tomorrow so the weekend will be filled with festivities to celebrate his accomplishments.
The factory-ish check valve came in last night and I installed it (the Volvo part was removed).
The CEL is still on but the power is back so much so that the car got rather sideways once into the boost when I got on it hard going to dinner.
I will check vacuum and test over the weekend if I have a chance. My son is graduating high school tomorrow so the weekend will be filled with festivities to celebrate his accomplishments.
Well, now I know something is up between the boost solenoid and the actuators. There was no oil found in the solenoid connections so I think I caught the check valve issue early - thankfully!
I setup my vacuum tester and found zero vacuum on the line coming out of the solenoid. Moving on I unplugged the actuators and tested the diaphragms on each one - both hold vacuum fine. So somewhere in the dual-branched line is where the problem lies.
I’m debating on replacing the line with factory parts or rigging up my own assembly. The dealership is right up the street and I would imagine it’s something they keep on hand - probably not cheap though! I can probably make up my own lines for a fraction of the cost, but I do like to keep things rather factory-like.
The car still seems to drive okay but the CEL is still on so I guess it knows. Can’t believe how power the car is without the turbochargers working properly - maybe I’ve just gotten used to it. But, she still got pretty nasty in the upper rpm’s - I guess it’s all in how the waste gate operation is setup on these engines.
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on your son graduation.
