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I've read a whole bunch of threads about low boost on these cars and can't for the life of me figure out what is going wrong with mine. WHen I plant my foot, my boost gauge goes up to about half of the "max" bar when it used to go all the way. I figured this would be my check valve going bad again and I had one on hand so I replaced it. Sure enough the old one seemed to be bad, but replacing it did not solve the issue. My wastegate rods do not rattle back and forth at idle as would indicate an issue with those either.
The other odd thing about the behavior of the car is when I upshift, boost jumps from half to 3/4, but still wont go to full. What could possibly be causing this? Loose charge pipe maybe? I feel like that would be a no boost not low boost condition.
I've read a whole bunch of threads about low boost on these cars and can't for the life of me figure out what is going wrong with mine. WHen I plant my foot, my boost gauge goes up to about half of the "max" bar when it used to go all the way. I figured this would be my check valve going bad again and I had one on hand so I replaced it. Sure enough the old one seemed to be bad, but replacing it did not solve the issue. My wastegate rods do not rattle back and forth at idle as would indicate an issue with those either.
The other odd thing about the behavior of the car is when I upshift, boost jumps from half to 3/4, but still wont go to full. What could possibly be causing this? Loose charge pipe maybe? I feel like that would be a no boost not low boost condition.
If you read my post all the way through, I did, it was bad, I replaced it, and the issue persisted. Hence the post.
Yes I read it but the reason I mentioned it again is because the new check valve might still be bad, where did you source it from? As far as I know, MB does not sell the check valve seperately and only sell the entire pump assembly. Aftermarket ones aren't always going to work.
What you could do is get a scanner capable of scanning Mercedes codes to scan the vehicle could also see if there is something stored, might be limp mode or it can be simply the intakes (check both passenger and driver side for leaks or if it wasn't clipped well).
I have an Autel Scanner. No codes found unfortunately. It seems the new check valve is still bad, assuming that I should be feeling nothing when I take the hose off and the vehicle is running. At idle, no oil sprays out of it, however I am getting puffs of air pulsing out of the valve. I assume this should not be happening and I need to order a better quality valve. Where would you recommend I pick one up? Or should I jsut buy a bulk pack on aliexpress/amazon and blow through them until one holds air?
Yes I read it but the reason I mentioned it again is because the new check valve might still be bad, where did you source it from? As far as I know, MB does not sell the check valve seperately and only sell the entire pump assembly. Aftermarket ones aren't always going to work.
What you could do is get a scanner capable of scanning Mercedes codes to scan the vehicle could also see if there is something stored, might be limp mode or it can be simply the intakes (check both passenger and driver side for leaks or if it wasn't clipped well).
I have an Autel Scanner. No codes found unfortunately. It seems the new check valve is still bad, assuming that I should be feeling nothing when I take the hose off and the vehicle is running. At idle, no oil sprays out of it, however I am getting puffs of air pulsing out of the valve. I assume this should not be happening and I need to order a better quality valve. Where would you recommend I pick one up? Or should I jsut buy a bulk pack on aliexpress/amazon and blow through them until one holds air?
Last edited by Morflavo; Yesterday at 08:34 PM.
Reason: Forgot to reply to trigger a message
I recommend that you get a vacuum gauge and you measure the actual pressure
Here is what I am getting
M276TT vacuum pressure at idle
I bought a handheld vacuum pump from Amazon that can also be used to bleed the brakes
NOTE: if you are not getting at least 15 inches of mercury from your check valve then you should get another valve or install a secondary check valve like I did
I have an Autel Scanner. No codes found unfortunately. It seems the new check valve is still bad, assuming that I should be feeling nothing when I take the hose off and the vehicle is running. At idle, no oil sprays out of it, however I am getting puffs of air pulsing out of the valve. I assume this should not be happening and I need to order a better quality valve. Where would you recommend I pick one up? Or should I jsut buy a bulk pack on aliexpress/amazon and blow through them until one holds air?
Originally Posted by Morflavo
I have an Autel Scanner. No codes found unfortunately. It seems the new check valve is still bad, assuming that I should be feeling nothing when I take the hose off and the vehicle is running. At idle, no oil sprays out of it, however I am getting puffs of air pulsing out of the valve. I assume this should not be happening and I need to order a better quality valve. Where would you recommend I pick one up? Or should I jsut buy a bulk pack on aliexpress/amazon and blow through them until one holds air?
