Rough Idle - MAF issues
#1
Junior Member
Thread Starter
Rough Idle - MAF issues
Hi All,
I purchased a basketcase 2006 ML350.
I checked the engine through the Camshaft Position Sensor and it all lines up.
Here's the issue; the car idles rough and throws the following codes:
Code Text
0629 Misfiring (P0300)
0645 Misfiring of cylinder 6 : Damages TWC (P0306)
0637 Misfiring of cylinder 4 : Damages TWC (P0304)
0653 Misfiring of cylinder 5 : Damages TWC (P0305)
Once I pull the MAF plug, the car idles nicely but throws MAF error codes (obviously).
I purchased a brand new MAF (Bosch) from amazon and the codes above noted above re-appear. Also, I tried a known good MAF and same errors reappear.
Alternatively, I
1) swapped the coils from Bank 1 to Bank 2;
2) re-gap'ed the spark plugs to 31mm (the plugs looked good, weren't fouled but all electrodes were pretty worn down and the gap on all plugs were approx. 65mm.
I think that the issue is MAF related, anybody have any ideas and / or experienced something similar?
Thanks in advance.
I purchased a basketcase 2006 ML350.
I checked the engine through the Camshaft Position Sensor and it all lines up.
Here's the issue; the car idles rough and throws the following codes:
Code Text
0629 Misfiring (P0300)
0645 Misfiring of cylinder 6 : Damages TWC (P0306)
0637 Misfiring of cylinder 4 : Damages TWC (P0304)
0653 Misfiring of cylinder 5 : Damages TWC (P0305)
Once I pull the MAF plug, the car idles nicely but throws MAF error codes (obviously).
I purchased a brand new MAF (Bosch) from amazon and the codes above noted above re-appear. Also, I tried a known good MAF and same errors reappear.
Alternatively, I
1) swapped the coils from Bank 1 to Bank 2;
2) re-gap'ed the spark plugs to 31mm (the plugs looked good, weren't fouled but all electrodes were pretty worn down and the gap on all plugs were approx. 65mm.
I think that the issue is MAF related, anybody have any ideas and / or experienced something similar?
Thanks in advance.
#2
Super Member
Hi All,
I purchased a basketcase 2006 ML350.
I checked the engine through the Camshaft Position Sensor and it all lines up.
Here's the issue; the car idles rough and throws the following codes:
Code Text
0629 Misfiring (P0300)
0645 Misfiring of cylinder 6 : Damages TWC (P0306)
0637 Misfiring of cylinder 4 : Damages TWC (P0304)
0653 Misfiring of cylinder 5 : Damages TWC (P0305)
Once I pull the MAF plug, the car idles nicely but throws MAF error codes (obviously).
I purchased a brand new MAF (Bosch) from amazon and the codes above noted above re-appear. Also, I tried a known good MAF and same errors reappear.
Alternatively, I
1) swapped the coils from Bank 1 to Bank 2;
2) re-gap'ed the spark plugs to 31mm (the plugs looked good, weren't fouled but all electrodes were pretty worn down and the gap on all plugs were approx. 65mm.
I think that the issue is MAF related, anybody have any ideas and / or experienced something similar?
Thanks in advance.
I purchased a basketcase 2006 ML350.
I checked the engine through the Camshaft Position Sensor and it all lines up.
Here's the issue; the car idles rough and throws the following codes:
Code Text
0629 Misfiring (P0300)
0645 Misfiring of cylinder 6 : Damages TWC (P0306)
0637 Misfiring of cylinder 4 : Damages TWC (P0304)
0653 Misfiring of cylinder 5 : Damages TWC (P0305)
Once I pull the MAF plug, the car idles nicely but throws MAF error codes (obviously).
I purchased a brand new MAF (Bosch) from amazon and the codes above noted above re-appear. Also, I tried a known good MAF and same errors reappear.
Alternatively, I
1) swapped the coils from Bank 1 to Bank 2;
2) re-gap'ed the spark plugs to 31mm (the plugs looked good, weren't fouled but all electrodes were pretty worn down and the gap on all plugs were approx. 65mm.
I think that the issue is MAF related, anybody have any ideas and / or experienced something similar?
Thanks in advance.
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flybd5 (06-02-2018)
#4
MBWorld Fanatic!
edwin, when there are misfire codes on all cylinders on the same bank, it cannot be a MAF issue. A faulty MAF would store its own code and would affect both banks.
If the above codes are the only ones stored, possibilities are : vacuum leak at the Intake Manifold (Left side), fuel leak at left side fuel injectors, clogged CAT convertor on left side causing back pressure, faulty spark plug leads.
I suggest buying spark plugs for both banks, but only replace those on the left side and see what occurs.
If not, spray Brake Parts Cleaner along the left side seam of the intake and see if RPMs increase. Do the same for injectors.
If not, buy an Exhaust Back Pressure Gauge and remove the O2 sensor before the CAT and install the gauge in its place. Start eng. and at idle, check gauge reading. Any reading above ZERO indicates a blockage. Then do the same at 2,500 RPMs.
The following users liked this post:
edwin.dario (06-02-2018)
#5
Junior Member
Thread Starter
When I purchased the car, in addition to the codes mentioned above, it had the following Stored Codes (which have not reappeared):
Code Text
2091 The mixture in the right cylinder bank is too lean when idling.
2095 The misture in the left cylinder bank is too lean when idling.
1425 Wheel speed signal is implausible.
I'm going to perform the following in their order and report back my findings:
1.:
Also, to confirm, the error codes were drawn from a Xentry / DAS.
Greatly appreciate it!
The following users liked this post:
edwin.dario (06-03-2018)
#7
Junior Member
Thread Starter
Maj. Dundee:
Unfortunately, I drove the car less than 5km before parking it in my garage.
1.:
My local auto parts store did not have the correct spark plugs but I swtiched the plugs on both banks and it gave the same errors after 3 minutes of the car running (from cold).
2.:
No increase in RPMs.
3.: No increase in RPMs.
Thereafter, I turned off the engine and I once again unplugged the MAF. The car idled well and I decided to do a little spirited drive and the engine worked really well during the drive.
Regarding test #4, I'll receive the tester tomorrow but if you have any further ideas, please do share!
1.:
2.:
3.: No increase in RPMs.
Thereafter, I turned off the engine and I once again unplugged the MAF. The car idled well and I decided to do a little spirited drive and the engine worked really well during the drive.
Regarding test #4, I'll receive the tester tomorrow but if you have any further ideas, please do share!
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#8
MBWorld Fanatic!
edwin, I'm running out of ideas but is this the MAF part number that you bought? Where did you buy it from and how much did you pay for it?
Have you checked all the gaskets and hoses near and around the MAF ?
#9
Junior Member
Thread Starter
Bosch part number is 0280218190. This is a picture of the box:
I will run the exhaust back pressure test tonight but given that the engine runs fine with the MAF unplugged, I am inclined to think that this is not a clogged-cat scenario. Thoughts?
Could this be an issue with the O2 sensors, is there a way to test them?
Thanks again!
#10
MBWorld Fanatic!
The sensor you bought is the correct one.
If there was an O2 sensor problem, there would be codes set, and there are none.
Removing the left O2 sensor for the exhaust back pressure test might be a little difficult. Hold off on this until the very end.
Please check all vacuum hoses.
If there was an O2 sensor problem, there would be codes set, and there are none.
Removing the left O2 sensor for the exhaust back pressure test might be a little difficult. Hold off on this until the very end.
Please check all vacuum hoses.
#11
Junior Member
Thread Starter
#13
Junior Member
Thread Starter
Although I'm not 100% certain, I think that I found the problem!
LEFT BANK:
RIGHT BANK:
The air flaps / swirl flaps!!!
Unfortunately, I do not have pliers which are long enough to test tonight.
What should I use to make sure that the actuator arms stay in place?
If anyone is interested in a very informative video:
LEFT BANK:
RIGHT BANK:
The air flaps / swirl flaps!!!
Unfortunately, I do not have pliers which are long enough to test tonight.
What should I use to make sure that the actuator arms stay in place?
If anyone is interested in a very informative video:
#15
Junior Member
Thread Starter
I reconnected the actuator arms without any luck!
I then proceeded to remove the air intake manifold and this is what I found:
The broken swirl flap is located on the side of bank 1.... I understand that this controls the "short runner", "long runner" for Bank 2, is this correct?
Think I found the culprit to my misfires?
I then proceeded to remove the air intake manifold and this is what I found:
The broken swirl flap is located on the side of bank 1.... I understand that this controls the "short runner", "long runner" for Bank 2, is this correct?
Think I found the culprit to my misfires?
Last edited by edwin.dario; 06-06-2018 at 10:30 PM.
#17
Junior Member
Thread Starter
Hi All!
So I finally had some time to install my rebuilt intake manifold:
BUT...... I broke the tabs on the connector going to the throttle body:
The connector slides out and I could not find a way to fit a zip tie.... does anyone have any recommendations?
Many thanks!
So I finally had some time to install my rebuilt intake manifold:
BUT...... I broke the tabs on the connector going to the throttle body:
The connector slides out and I could not find a way to fit a zip tie.... does anyone have any recommendations?
Many thanks!
#18
MBWorld Fanatic!
Clean the connector and look at it carefully with a magnifying glass and the will be a part number xxx xxx xx xx .
Post back with results.
Post back with results.
#19
Junior Member
Thread Starter
#21
Junior Member
Thread Starter
#22
Super Member
Educated guess is that the pins are held in place by a small leaf spring, and you have to carefully use something like a needle or pin from the connection side to get the leaf spring down so you can gently pull it out, then insert in the same hole on the new connector. I would suggest you get instructions from the dealer, since they sold it to you. I found a data sheet but it's in German.
Last edited by flybd5; 06-21-2018 at 03:47 AM.
#24
Super Member
Careful look at the data sheet confirms it. The tabs are there, in the holes, outboard side of each hold. You have to gently push them in and then gently pull the wire out.
#25
Junior Member
Thread Starter
Thanks, I'll give it a try!