C280 Rough idle and misfiring/ need help

[bdragomir]

My 98 C280 Sport started misfiring and idling rough for quite some time. I took it to a "mercedes mechanic" with supposedly 30 years experience in Chicago (C&H Service) and after paying 160$ I found nothing. So here is the thing I started following the vacuum leaks around the engine and I found one coming out of the "Switching Valve SVI" (whatever would this be and going into under the intake manifold that is pulled out. I have almost no access there, can barely get my hand in between the intake manifold and the space from where I removed the air pump. Does anyone know how that hose can be put back on to the intake manifold besides removing the manifold out ...??

[mazdalowandslow]

Get asain hands?... Or long needle nose plyers? your misfire might be from a bad coil. Have you noticed when the misfire happens?

[bdragomir]

Originally posted by mazdalowandslow
Get asain hands?... Or long needle nose plyers? your misfire might be from a bad coil. Have you noticed when the misfire happens?

Misfire happens immediately after starting the car but is not noticeable when driving at hwy speed. I assume it is caused by the pulled hose as checking the O2 sensors it showed all of the being bad ...although all have been changed last week. Moreover, I got one good new coil and replaced the old one on the cylinders (456)having misfiring issue ...the issue persists. At the carb cleaner spray test it clearly showed getting "false air to the intake ...exactly where the pulled hose is. I'll try tomorrow with a long nose plyer but the position is so awkward ... not typical for a well thought German car.

[bdragomir]

Originally posted by bdragomir
Misfire happens immediately after starting the car but is not noticeable when driving at hwy speed. I assume it is caused by the pulled hose as checking the O2 sensors it showed all of the being bad ...although all have been changed last week. Moreover, I got one good new coil and replaced the old one on the cylinders (456)having misfiring issue ...the issue persists. At the carb cleaner spray test it clearly showed getting "false air to the intake ...exactly where the pulled hose is. I'll try tomorrow with a long nose plyer but the position is so awkward ... not typical for a well thought German car.
Been to a mechanic friend today and with 150$ together we lifted the intake manifold pulled out the left over of the old hose that broke inside/at the intake manifold exit. Replaced the two manifold gaskets and cleaned the injectors. All these (gaskets, carb spray, grease, vacuum hoses, and work added up to 201$!!! and 3 hours of work. To summarize the problem was the vacuum coming from the switching valve SVI to underneath the intake manifold because of this the car was throwing codes like cylinder 1, 4, 5, 6 misfire, PCV not working, O2 sensors not working, MAF not working. All the above concluding in rough idling altou at hwy speed car was running fine.
Chicago mercedes owners be careful where you go and how you accept the diagnostic one would give you. I had an expensive and bad experience with a shop I found recommended on benzworld.com (Carlos the C&H Service Owner) where I spent 160$ and got a completely erroneous diagnostic (he was asking 1600$ to solve the problem) from a self called mechanic with supposedly 30 yr of experience... bleah.. good luck and if you need any info regarding 1998 C280 please let me know as I have all the diagrams and repair instructions. Don't rush do your homework and you'll save tons of $$. :) :cool: :)

[JRE320]

Chicago mercedes owners be careful where you go and how you accept the diagnostic one would give you. I had an expensive and bad experience with a shop I found recommended on benzworld.com (Carlos the C&H Service Owner) where I spent 160$ and got a completely erroneous diagnostic (he was asking 1600$ to solve the problem) from a self called mechanic with supposedly 30 yr of experience... bleah..

Maybe he's the owner of C&H sugar...:D :D and not a Mercedes shop. Tell him that I said so..... :D :D :p

[bdragomir]

Originally posted by JRE320
Chicago mercedes owners be careful where you go and how you accept the diagnostic one would give you. I had an expensive and bad experience with a shop I found recommended on benzworld.com (Carlos the C&H Service Owner) where I spent 160$ and got a completely erroneous diagnostic (he was asking 1600$ to solve the problem) from a self called mechanic with supposedly 30 yr of experience... bleah..

Maybe he's the owner of C&H sugar...:D :D and not a Mercedes shop. Tell him that I said so..... :D :D :p

Well this Carlos claims to be an experienced Mercedes mechanic (??) but he definitely doesn't prove it ...might be modesty?? :D:D Already told him my opinion about his experience (same as this shared with you) and sure enough he didn't like it but sometime he has to accept the truth...