Vacuum leak or bad MAF? W164 Bluetec
08-27-2021, 11:22 AM
#1
Junior Member
Thread Starter
Vacuum leak or bad MAF? W164 Bluetec
Hello.
My 2010 ML350 Bluetec is going crazy again. Fix one issue and another comes up in a matter of weeks. Annoying!
So now I have some intermittent acceleration issues, as well as intermittent rough idling. Also have horrible mpg.
I am suspecting a vacuum leak. When I accelerate, I can hear a whistling sound. I can also hear a "whoosh" air sound when I accelerate with the windows down.
I scanned with Autel AP200 and got the following codes:
- 146100 Control deviation is too large (Current)
- 111500 The regeneration frequency of the diesel particulate filter is not ok. (Stored)
- 14B200 A plausibility error exists in the component 'hot film Mas airflow (MAF) sensor'. (Current & Stored)
- 123900 Charge pressure is too low (Stored)
- 153600 An internal fault exists in the component 'Nitrogen oxide (NOx) sensor upstream of the selective catalytic reduction (SCR) catalytic converter. (Stored)
- 16F700 Disregard this fault. (Current)
I cleared these codes and 16F700 is the only one that comes back immediately. 146100 and 14B200 and 123900 come back in a couple of days to a couple of weeks. 153600 comes and goes on its own. 111500 typically goes away until I force a regen (The dpf seems to be getting more soot faster since these issue began, so sometimes I force a regen to clear the soot).
I'm building a smoke machine to test for vacuum leaks based on YouTube videos. However, I'm new to engines so I have no idea what hose in the engine to plug in the smoke machine for a smoke test. I believe there are different components... exhaust, intake, and others. Please if you know about this, let me know where I have to plug in the machine to smoke test each component.
If anyone has any suggestions, please help. Thanks!
My 2010 ML350 Bluetec is going crazy again. Fix one issue and another comes up in a matter of weeks. Annoying!
So now I have some intermittent acceleration issues, as well as intermittent rough idling. Also have horrible mpg.
I am suspecting a vacuum leak. When I accelerate, I can hear a whistling sound. I can also hear a "whoosh" air sound when I accelerate with the windows down.
I scanned with Autel AP200 and got the following codes:
- 146100 Control deviation is too large (Current)
- 111500 The regeneration frequency of the diesel particulate filter is not ok. (Stored)
- 14B200 A plausibility error exists in the component 'hot film Mas airflow (MAF) sensor'. (Current & Stored)
- 123900 Charge pressure is too low (Stored)
- 153600 An internal fault exists in the component 'Nitrogen oxide (NOx) sensor upstream of the selective catalytic reduction (SCR) catalytic converter. (Stored)
- 16F700 Disregard this fault. (Current)
I cleared these codes and 16F700 is the only one that comes back immediately. 146100 and 14B200 and 123900 come back in a couple of days to a couple of weeks. 153600 comes and goes on its own. 111500 typically goes away until I force a regen (The dpf seems to be getting more soot faster since these issue began, so sometimes I force a regen to clear the soot).
I'm building a smoke machine to test for vacuum leaks based on YouTube videos. However, I'm new to engines so I have no idea what hose in the engine to plug in the smoke machine for a smoke test. I believe there are different components... exhaust, intake, and others. Please if you know about this, let me know where I have to plug in the machine to smoke test each component.
If anyone has any suggestions, please help. Thanks!
08-27-2021, 05:02 PM
#2
Senior Member
"I am suspecting a vacuum leak. When I accelerate, I can hear a whistling sound. I can also hear a "whoosh" air sound when I accelerate with the windows down."
Most likely/common audible leaks are from the boosted-air plumbing, going from the turbo out front of the radiator to intercooler core, and back to the intake.
Most common failure is on the rubber hose going forward, it connects in front of the motor and goes to the left of the radiator.
Looks for oily/greasy patch where is curves forward. The rubber hose may have split, or the o-ring seals where it connects may leak.
Most likely/common audible leaks are from the boosted-air plumbing, going from the turbo out front of the radiator to intercooler core, and back to the intake.
Most common failure is on the rubber hose going forward, it connects in front of the motor and goes to the left of the radiator.
Looks for oily/greasy patch where is curves forward. The rubber hose may have split, or the o-ring seals where it connects may leak.
08-28-2021, 03:48 AM
#3
Junior Member
Thread Starter
"I am suspecting a vacuum leak. When I accelerate, I can hear a whistling sound. I can also hear a "whoosh" air sound when I accelerate with the windows down."
Most likely/common audible leaks are from the boosted-air plumbing, going from the turbo out front of the radiator to intercooler core, and back to the intake.
Most common failure is on the rubber hose going forward, it connects in front of the motor and goes to the left of the radiator.
Looks for oily/greasy patch where is curves forward. The rubber hose may have split, or the o-ring seals where it connects may leak.
Most likely/common audible leaks are from the boosted-air plumbing, going from the turbo out front of the radiator to intercooler core, and back to the intake.
Most common failure is on the rubber hose going forward, it connects in front of the motor and goes to the left of the radiator.
Looks for oily/greasy patch where is curves forward. The rubber hose may have split, or the o-ring seals where it connects may leak.
I removed the silver pipe and examined the green seal and it looks fine, but I replaced it anyway. I examined the other seal for the black plastic pipe that connects to the silver pipe, and that seal was pretty much destroyed. I replaced it thinking I had found the problem, but the car is still giving the same intermittent issues. I'm going to check it again to see if the seal isn't seating right. That particular pipe just seems a little loose to me even after I tighten the clamp screw.
I've done a visual inspection on other pipes and hoses in that area but they look good. However, I also smell exhaust in the cabin sometimes... or burnt diesel? Not sure the exact smell. Could an exhaust leak cause all this and throw these codes?
08-30-2021, 08:27 PM
#4
Senior Member
When I could smell exhaust-y smell from the dash vents, it was from a leaking injector.
The common-rail injectors are clamped down with TTY (torque-to-yield) single-use bolts - holding the injector body against a circular brass seal between the injector and the head.
(Down a fairly deep bore. The injectors get sticky from this leak and have to be pulled hot, either with a slide hammer, which often damages them or with a specialty puller, which is hard to get on the back two cylinders and is hard to source anyway)
My car has 170k miles on it, roughly. If the mileage is getting up on yours it may be worth doing the injector leak-down test, it mostly takes a little time putting a test rig together.
I ordered the syringes from an eBay seller, and there was some wait time for them to arrive I think it was a 10-pack. That and a long pack of aquarium hose, and some zip-ties.
I had extended, hard starting which became really noticeable last winter. I got really suspicious of the charging system, but in the end I replaced 2 injectors and that fixed both the hard starting and the blow-by coming around the bad seal.
I promised an update on that - it's been roughly 5k miles since then and the motor runs well - no adaptation / transfer of coding numbers done at all.
The ECU just re-adapted the injector fine-tuning to suit the (off-throttle) needs for emissions. (Mine's non-Bluetec)
And no injector-related trouble codes since then.
As far as vacuum leaks go, I suspect the only use for vacuum on your application is for the brake booster - there's just one half inch line running from the vacuum pump to the brake booster. That's the way it is for my car anyway.
If there was actually a leak of any real consequence, you might feel it in a hard brake pedal.
But if you think about it (it pumps the air out of the line and puts it where? Into the crankcase)., the big side effect of a real leak would be additional crankcase venting, and the prospect of oil consumption and/or oil leaks from the usual places: on the boost side of the turbo, and where the PCV system joins the batwing (MAF housing, before the turbo inlet).
The first time I had a real issue with a boost leak in this car - the same hose you're talking about, had about a 2-inch split right at the lowest point after it passed out of the aluminum turbo outlet and muffler, and turns forward to the intercooler.
It made a pretty big mess of rags I used to wipe it up and see. The union of the aluminum pipe with the (bakelite?) muffler is a really jury-rigged clip and o-ring arrangement, IMHO.
I've seen mechanics mess that one up multiple times. Then it will blow oil and noise backward under the aluminum pipe and around the front/center of the motor. Another mess.
But the hot-side boost hose, it's kind of indicative of the design thought in this vehicle.
Rubber boost hoses should be built much more sturdy than this. I never had any issue from the comparable one on my TDI, which had 335K miles on it before I parked it.
Those hoses should really be bent aluminum pipes for most of their length, with short coupling hoses at the ends.
I'm gonna make a project out of fabricating a set, one of these days...
Best of luck / keep checking things!
The common-rail injectors are clamped down with TTY (torque-to-yield) single-use bolts - holding the injector body against a circular brass seal between the injector and the head.
(Down a fairly deep bore. The injectors get sticky from this leak and have to be pulled hot, either with a slide hammer, which often damages them or with a specialty puller, which is hard to get on the back two cylinders and is hard to source anyway)
My car has 170k miles on it, roughly. If the mileage is getting up on yours it may be worth doing the injector leak-down test, it mostly takes a little time putting a test rig together.
I ordered the syringes from an eBay seller, and there was some wait time for them to arrive I think it was a 10-pack. That and a long pack of aquarium hose, and some zip-ties.
I had extended, hard starting which became really noticeable last winter. I got really suspicious of the charging system, but in the end I replaced 2 injectors and that fixed both the hard starting and the blow-by coming around the bad seal.
I promised an update on that - it's been roughly 5k miles since then and the motor runs well - no adaptation / transfer of coding numbers done at all.
The ECU just re-adapted the injector fine-tuning to suit the (off-throttle) needs for emissions. (Mine's non-Bluetec)
And no injector-related trouble codes since then.
As far as vacuum leaks go, I suspect the only use for vacuum on your application is for the brake booster - there's just one half inch line running from the vacuum pump to the brake booster. That's the way it is for my car anyway.
If there was actually a leak of any real consequence, you might feel it in a hard brake pedal.
But if you think about it (it pumps the air out of the line and puts it where? Into the crankcase)., the big side effect of a real leak would be additional crankcase venting, and the prospect of oil consumption and/or oil leaks from the usual places: on the boost side of the turbo, and where the PCV system joins the batwing (MAF housing, before the turbo inlet).
The first time I had a real issue with a boost leak in this car - the same hose you're talking about, had about a 2-inch split right at the lowest point after it passed out of the aluminum turbo outlet and muffler, and turns forward to the intercooler.
It made a pretty big mess of rags I used to wipe it up and see. The union of the aluminum pipe with the (bakelite?) muffler is a really jury-rigged clip and o-ring arrangement, IMHO.
I've seen mechanics mess that one up multiple times. Then it will blow oil and noise backward under the aluminum pipe and around the front/center of the motor. Another mess.
But the hot-side boost hose, it's kind of indicative of the design thought in this vehicle.
Rubber boost hoses should be built much more sturdy than this. I never had any issue from the comparable one on my TDI, which had 335K miles on it before I parked it.
Those hoses should really be bent aluminum pipes for most of their length, with short coupling hoses at the ends.
I'm gonna make a project out of fabricating a set, one of these days...
Best of luck / keep checking things!
Last edited by B34chBum; 08-30-2021 at 08:30 PM. Reason: clarity
09-03-2021, 12:38 PM
#5
Junior Member
Thread Starter
When I could smell exhaust-y smell from the dash vents, it was from a leaking injector.
The common-rail injectors are clamped down with TTY (torque-to-yield) single-use bolts - holding the injector body against a circular brass seal between the injector and the head.
(Down a fairly deep bore. The injectors get sticky from this leak and have to be pulled hot, either with a slide hammer, which often damages them or with a specialty puller, which is hard to get on the back two cylinders and is hard to source anyway)
My car has 170k miles on it, roughly. If the mileage is getting up on yours it may be worth doing the injector leak-down test, it mostly takes a little time putting a test rig together.
I ordered the syringes from an eBay seller, and there was some wait time for them to arrive I think it was a 10-pack. That and a long pack of aquarium hose, and some zip-ties.
I had extended, hard starting which became really noticeable last winter. I got really suspicious of the charging system, but in the end I replaced 2 injectors and that fixed both the hard starting and the blow-by coming around the bad seal.
I promised an update on that - it's been roughly 5k miles since then and the motor runs well - no adaptation / transfer of coding numbers done at all.
The ECU just re-adapted the injector fine-tuning to suit the (off-throttle) needs for emissions. (Mine's non-Bluetec)
And no injector-related trouble codes since then.
As far as vacuum leaks go, I suspect the only use for vacuum on your application is for the brake booster - there's just one half inch line running from the vacuum pump to the brake booster. That's the way it is for my car anyway.
If there was actually a leak of any real consequence, you might feel it in a hard brake pedal.
But if you think about it (it pumps the air out of the line and puts it where? Into the crankcase)., the big side effect of a real leak would be additional crankcase venting, and the prospect of oil consumption and/or oil leaks from the usual places: on the boost side of the turbo, and where the PCV system joins the batwing (MAF housing, before the turbo inlet).
The first time I had a real issue with a boost leak in this car - the same hose you're talking about, had about a 2-inch split right at the lowest point after it passed out of the aluminum turbo outlet and muffler, and turns forward to the intercooler.
It made a pretty big mess of rags I used to wipe it up and see. The union of the aluminum pipe with the (bakelite?) muffler is a really jury-rigged clip and o-ring arrangement, IMHO.
I've seen mechanics mess that one up multiple times. Then it will blow oil and noise backward under the aluminum pipe and around the front/center of the motor. Another mess.
But the hot-side boost hose, it's kind of indicative of the design thought in this vehicle.
Rubber boost hoses should be built much more sturdy than this. I never had any issue from the comparable one on my TDI, which had 335K miles on it before I parked it.
Those hoses should really be bent aluminum pipes for most of their length, with short coupling hoses at the ends.
I'm gonna make a project out of fabricating a set, one of these days...
Best of luck / keep checking things!
The common-rail injectors are clamped down with TTY (torque-to-yield) single-use bolts - holding the injector body against a circular brass seal between the injector and the head.
(Down a fairly deep bore. The injectors get sticky from this leak and have to be pulled hot, either with a slide hammer, which often damages them or with a specialty puller, which is hard to get on the back two cylinders and is hard to source anyway)
My car has 170k miles on it, roughly. If the mileage is getting up on yours it may be worth doing the injector leak-down test, it mostly takes a little time putting a test rig together.
I ordered the syringes from an eBay seller, and there was some wait time for them to arrive I think it was a 10-pack. That and a long pack of aquarium hose, and some zip-ties.
I had extended, hard starting which became really noticeable last winter. I got really suspicious of the charging system, but in the end I replaced 2 injectors and that fixed both the hard starting and the blow-by coming around the bad seal.
I promised an update on that - it's been roughly 5k miles since then and the motor runs well - no adaptation / transfer of coding numbers done at all.
The ECU just re-adapted the injector fine-tuning to suit the (off-throttle) needs for emissions. (Mine's non-Bluetec)
And no injector-related trouble codes since then.
As far as vacuum leaks go, I suspect the only use for vacuum on your application is for the brake booster - there's just one half inch line running from the vacuum pump to the brake booster. That's the way it is for my car anyway.
If there was actually a leak of any real consequence, you might feel it in a hard brake pedal.
But if you think about it (it pumps the air out of the line and puts it where? Into the crankcase)., the big side effect of a real leak would be additional crankcase venting, and the prospect of oil consumption and/or oil leaks from the usual places: on the boost side of the turbo, and where the PCV system joins the batwing (MAF housing, before the turbo inlet).
The first time I had a real issue with a boost leak in this car - the same hose you're talking about, had about a 2-inch split right at the lowest point after it passed out of the aluminum turbo outlet and muffler, and turns forward to the intercooler.
It made a pretty big mess of rags I used to wipe it up and see. The union of the aluminum pipe with the (bakelite?) muffler is a really jury-rigged clip and o-ring arrangement, IMHO.
I've seen mechanics mess that one up multiple times. Then it will blow oil and noise backward under the aluminum pipe and around the front/center of the motor. Another mess.
But the hot-side boost hose, it's kind of indicative of the design thought in this vehicle.
Rubber boost hoses should be built much more sturdy than this. I never had any issue from the comparable one on my TDI, which had 335K miles on it before I parked it.
Those hoses should really be bent aluminum pipes for most of their length, with short coupling hoses at the ends.
I'm gonna make a project out of fabricating a set, one of these days...
Best of luck / keep checking things!
Here's an update. I examined pretty much every hose I could find and they are all good. No cracks, no brittle. The only problem was that black seal that connects the plastic pipe in front of the engine to the aluminum pipe that connects to the turbo. That seal was horribly damaged and I replaced it. However, there was no change.
So a few days ago, I started the car and my headlights started blinking... dash lights too. Classic signs of an alternator problem. The car has always started without any issues... no hard start whatsoever... so I ignored it and kept driving. It drove horribly for half a mile or so, and then corrected itself and started driving well.
Fast-forward to 2 days ago... my battery light came up while driving. Power steering shut off, but the battery got me home, thankfully. I plugged in the scanner the next morning and it said my alternator was dead. I popped the hood and, viola, my coolant was empty. Turns out my water pump died and leaked alllll the coolant onto the alternator and fried it. Talk about bad luck.
Anyway, working on the water pump and alternator now. I'm now leaning towards that being the problem throughout. The whistling sound I heard whenever I accelerated sounds like a classic pulley problem, or even alternator problem. And the intermittent loss of power would also fall on the alternator slowly dying over time as the water pump leaked. Possibly.
Now, this has given me a chance to really dig into the car. I've removed the throttle body and egr elbow to access the water pump easily. This gave me a chance to inspect all the seals and, thankfully, they are all perfect. However, I've noticed that my oil filter housing might be leaking. I'm guessing a gasket somewhere in there is bad, so I'll order those. My guess is that the leak might have gotten all over the serpentine belt and contributed to the damage of the pulleys, and perhaps caused it to not turn the alternator well as it might have slipped several times.
I'm still waiting on parts to get delivered, after which I will install everything back and test the car out to see if that's where the problem was all the while.
As for the alternator, I'm finding it difficult to find one here (Nigeria). There aren't too many diesels here so parts are always a pain to find. So I've opened up the alternator and it is extremely dirty. It is caked up with carbon. It looks horrible. Diodes are fine, resistance and continuity seem fine...continuity on the rotor is fine as well, and the brushes look ok. So I'm guessing it is just too gunked up to work properly. I plan on giving it a good, extensive clean with qd electronic cleaner inside and out and hope to God that it works fine. Thankfully, the bearings are fine and the voltage regulator doesn't look burnt.
I'll keep the forum posted on how this goes. It would be interesting to see if all the MAF and boost codes were caused by a failing alternator. Imagine that!
09-17-2021, 04:42 AM
#6
Junior Member
Thread Starter
UPDATE
For anyone who might have a similar issue, here's how I solved it:
After replacing the water pump, I found a guy that fixes alternators and he restored mine. Reinstalled it and got the car started.
After that, I was finally able to get a hold of Xentry/DAS. I ran a number of tests on the air/vacuum system with DAS, especially the MAF sensors and Boost. All tests passed with flying colors so that convinced me that none of the components were faulty.
Next step was adaptations. I reset pretty much everything that has to do with the air/boost system. Apparently, you even have to perform a reset after replacing your air filters, and I had replaced mine twice before without ever performing a reset!
After all adaptations/resets with DAS, the car seems to be back! Moral of the story is to get your hands on Xentry ASAP! If you own a Mercedes and are into DIY, Xentry is simply a must have. I am now a believer.
Thanks!
After replacing the water pump, I found a guy that fixes alternators and he restored mine. Reinstalled it and got the car started.
After that, I was finally able to get a hold of Xentry/DAS. I ran a number of tests on the air/vacuum system with DAS, especially the MAF sensors and Boost. All tests passed with flying colors so that convinced me that none of the components were faulty.
Next step was adaptations. I reset pretty much everything that has to do with the air/boost system. Apparently, you even have to perform a reset after replacing your air filters, and I had replaced mine twice before without ever performing a reset!
After all adaptations/resets with DAS, the car seems to be back! Moral of the story is to get your hands on Xentry ASAP! If you own a Mercedes and are into DIY, Xentry is simply a must have. I am now a believer.
Thanks!
