My Mercedes c class diesel misfires on start up?

1st thing in the morring it starts up 1st time but misfires and smokes a bit for about 20 sec and then ok, also knocks a bit . then ok for rest of the day drives fine. does anyone know whats the problem. thanks

My Mercedes c class diesel misfires on start up?
What you describe sounds like a bad glow plug. The cylinder in which the glow plug is not working will not have been heated up enough to ignite the fuel/air mixture that is in the combustion chamber upon first start up. Once the engine heats up the cylinder then is warm enough and operates correctly.





If you have not replaced the glow plugs, obtain an ohm meter and check the resistance across the input of the glow plug and the grounded case. If you have an "open" circuit, in other words the heating element is burned out, then replace all the glow plugs.





Glow plugs do wear out. If you are not mechanically inclined take your car to a good shop that is familar with diesel engines and have them perform the test.





I think you will find that for about $8 each you can replace the glow plugs and be just fine.





CAUTION: removing glow plugs CAN be somewhat tricky. So unless you are a skilled mechanic have a certified mechanic do the work where the shop has insurance to cover any problem that may arise if the mechanic accidently breaks off the glow plug in the head. It has been known to happen and can be very expensive if it does.





Hope this helps
Reply:don't think its glow plugs as it starts first time for him must be injector sticking Report It

Reply:Yep sounds like a worn diesel injector to me, citroen's suffer the same, try running it low on diesel not to low then put a diesel injector cleaner additive in it and give it a good thrash for 10miles. if that doesn't cure it you will probably need a new injector, Roughly £145 from Mercedes.Hope this helps
Reply:Do a diesel purge. diesel giant.
Reply:A sticky injector.

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