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Checking a mechanically bad solenoid you need a vacuum gauge first and foremost so you can trace vacuum integrity on whole car vacuum system too.
This is a must have tool, vacuum and pressure capable. I have this one.
You will benefit a lot from this dual purpose vacuum and pressure capable hand pump + its fitting accesories. Even vacuuming radiator coolant system to prevent hidden air pockets you can use this.
No need naughty Xentry, Launch Creader Elite for Benz is the greatest El-Cheapo under US$200 scanner to date I seen and own.
Mind you I have 3 scanners and mild naughty and very naughty Xentry too. So total 5 now.
These 2 must have tools is approx US$250 at the most.
Buy these 2 and we can proceed on how to troubleshoot your solenoid in great detail and that Launch baby scanner will do you good in the long run.
Yes, you can easily verify the operation of the "transducer" with a cheap Amazon vacuum hand pump as I did. Some auto parts stores actually "rent" this kit among other tools. You pay for it and get a full refund upon return.
Problem fixed ?! Any of you fixed the low boost problem on out M276 ? My c43 amg has this problem, i change all vacuum parts, vacuum is mint but i guess is the wastegate flappers that are going bad... some ideea for changeing this ?
Problem fixed ?! Any of you fixed the low boost problem on out M276 ? My c43 amg has this problem, i change all vacuum parts, vacuum is mint but i guess is the wastegate flappers that are going bad... some ideea for changeing this ?
This check valve can cause low boost too. This is a 2 check valves in one.
During engine breathing not under boost aka "vacuum" or below 1 ATM, the oil vapor and fuel vapor get sucked by the intake manifold. The check valve allows that.
The check valve item 71 above, its top side check valve section facing windshield or flywheel if for oil vapor.
Its radiator facing check valve section is for fuel vapor.
When not under boost
When under BOOST and if that check valve failed or open up, your boost goes to engine cranckase and get sucked by RIGHT SIDE BANK 1 turbo.
Basically u loose boost.
This check valve can cause low boost too. This is a 2 check valves in one.
During engine breathing not under boost aka "vacuum" or below 1 ATM, the oil vapor and fuel vapor get sucked by the intake manifold. The check valve allows that.
The check valve item 71 above, its top side check valve section facing windshield or flywheel if for oil vapor.
Its radiator facing check valve section is for fuel vapor.
When not under boost
When under BOOST and if that check valve failed or open up, your boost goes to engine cranckase and get sucked by RIGHT SIDE BANK 1 turbo.
Basically u loose boost.
How can i test this valve ? And how should i check it "on boost"?
As per video, my check valve is mild leaking, very mild. I replaced it anyway.
Dont do more than 15PSI test pressure yah. M276 3.0 turbo boost max is only 0.8 BAR or 11.6 PSI.
A new check valve would hold pressure better. The video is not uploaded yet, its on my PC back home. Me now out of town.
Make sure you test fittings are not leaking.
I’ve had a few instances where I didn’t have any boost. When I restart the car, it comes back (most of the time). It happened again today.
Original Part:
When I pull vacuum on the vacuum supply (the smaller of the two connections), it release very slowly. When i blow through it, nothing comes out of the larger port (the one that connects to the waste gate actuators). I reinstalled this one and went for a drive. It seemed better, but I won’t know until I get some more road time in it.
New part:
When I try to pull vacuum, it drops immediately. It doesn’t hold anything. When I blow through it, air flows through the OUT port. This is the one that gave me issues yesterday and today where I wasn’t getting any boost.
I have already replaced the brake check valve. I’m confused on which one is functioning properly or if I need to order another replacement.
This photo is with the original part and the engine idling. If I read the PDF correctly, it should read at least 480mmHg and 0mmHg when disconnected. I put a “T” in it to see what it would read. Any help would be appreciated!
Mine will kill boost if it was too high or too low while driving. A safety feature, apparently. Why too low I don't know, seems redundant. Point is it will, and the fix is restart.
So it sounds to me like your solenoid is Off, like when it sees too much/little boost.
The solenoids job is to simply let air in to reduce vacuum. That vent port on the side is said air inlet. So it should be getting high vacuum from the vac pump, then the solenoid is what controls how much of it the turbos get. The ECU controls the solenoid by a duty cycle that closes the air vent. So a 10% DC basically doesn't do squat and lets all the air in, killing vacuum. A DC of 100% would be completely closing the air vent and the turbos get all the vac from the pump.
It does this air control by opening/closing the vent hole, not like a regulator or valve, but pulsing the vent On/Off until it gets the avg pressure it wants. Kinda like a switching power supply. Or your lump sum paycheck vs the steady bank acct drain.
There is also a Catalyst heating mode where it may let all the air in. So if you see 0 at idle, I'd keep watching to see if it starts working at some point. If not, and it didn't fault out from driving, then something is up. You mentioned the brake check valve, but on my car there the brake valve is next to the turbo valve, not one in the same. And the turbo valve tends to fail. Not sure if you have that separate turbo valve, but fyi.
Mine will kill boost if it was too high or too low while driving. A safety feature, apparently. Why too low I don't know, seems redundant. Point is it will, and the fix is restart.
So it sounds to me like your solenoid is Off, like when it sees too much/little boost.
The solenoids job is to simply let air in to reduce vacuum. That vent port on the side is said air inlet. So it should be getting high vacuum from the vac pump, then the solenoid is what controls how much of it the turbos get. The ECU controls the solenoid by a duty cycle that closes the air vent. So a 10% DC basically doesn't do squat and lets all the air in, killing vacuum. A DC of 100% would be completely closing the air vent and the turbos get all the vac from the pump.
It does this air control by opening/closing the vent hole, not like a regulator or valve, but pulsing the vent On/Off until it gets the avg pressure it wants. Kinda like a switching power supply. Or your lump sum paycheck vs the steady bank acct drain.
There is also a Catalyst heating mode where it may let all the air in. So if you see 0 at idle, I'd keep watching to see if it starts working at some point. If not, and it didn't fault out from driving, then something is up. You mentioned the brake check valve, but on my car there the brake valve is next to the turbo valve, not one in the same. And the turbo valve tends to fail. Not sure if you have that separate turbo valve, but fyi.
I managed to get another drive in this evening. Boost was there…like maxing out on the gauge! I’m not sure if that’s good or bad at this point. No codes or anything which is what is driving me crazy. I thought that without it being able to enter boost, it would throw a code. I’ve scanned it and nothing pops up. That’s why I’m at a loss.
I’ve had a few instances where I didn’t have any boost. When I restart the car, it comes back (most of the time). It happened again today.
Original Part:
When I pull vacuum on the vacuum supply (the smaller of the two connections), it release very slowly. When i blow through it, nothing comes out of the larger port (the one that connects to the waste gate actuators). I reinstalled this one and went for a drive. It seemed better, but I won’t know until I get some more road time in it.
New part:
When I try to pull vacuum, it drops immediately. It doesn’t hold anything. When I blow through it, air flows through the OUT port. This is the one that gave me issues yesterday and today where I wasn’t getting any boost.
I have already replaced the brake check valve. I’m confused on which one is functioning properly or if I need to order another replacement.
This photo is with the original part and the engine idling. If I read the PDF correctly, it should read at least 480mmHg and 0mmHg when disconnected. I put a “T” in it to see what it would read. Any help would be appreciated!
To test your VACUUM PUMP itself, you need engine to be running and that vacuum gauge of yours attached to the small test fitting at the brake booster.
TEST 1 - At brake booster
Plug off the small fitting at vacuum pump first, the one for the turbo actuator.
TEST 2 - at vacuum pump small port ( the one going to turbo boost controller ) <<< corrected
Plug off the BIG fitting at vacuum pump first, the one for the brake booster. Engine must be running.
03-03-2023, 03:40 AM
So total 5 now.
