Hi I've just taken my C180 1998 to the Dealer because if I push the car it just splutters and back fires. If the car changes down it misses and never recovers, I have to pull over switch off and switch back on and then I can pull away?? Merc Test shows Number 4 coil fault at some time, plugs were OKay but looked dirty so suggest replace and the throttle body was full of oil. My car is only worth a few hundred and they want £400 to do this work with no guarantee that it will fix the problem. I can't imagine it's plugs as it never misses a beat at constant rpm even at 5000. Its just when I accelerate hard and it kicks down...? Any advice would be great. Thanks Just
Spluttering '98 C Class...
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Not familiar with your exact car but some general comments/suggestions.
Does your car have the one coil for two cylinder setup? Is it only one cylinder that mis-fires? If both are true, then the chance for a bad coil is not very high.
If not, then try to swarp two coils to see if the misfire moves to a different cylinder.
I would recommend you to dis-connect the wire from both the plug and the coil and inspect. Then use electric contact cleaner to clean them well and put them back (make sure they snap in).
My experience has always been that these ignition parts are kind of reliable but some times these contacts get dirty and corroded. So cleaning them is the first and cheap thing to do.
Does your car have the one coil for two cylinder setup? Is it only one cylinder that mis-fires? If both are true, then the chance for a bad coil is not very high.
If not, then try to swarp two coils to see if the misfire moves to a different cylinder.
I would recommend you to dis-connect the wire from both the plug and the coil and inspect. Then use electric contact cleaner to clean them well and put them back (make sure they snap in).
My experience has always been that these ignition parts are kind of reliable but some times these contacts get dirty and corroded. So cleaning them is the first and cheap thing to do.
I just looked up your particular car.
It seems there are two engine configurations. however both seem to use one coil for two cylinder setup. So you have only two coils for 4 cylinders. See the pictures below but you need to know which one applies to your car.
Item 38 and 41 are the coils in the respective pictures.
It seems there are two engine configurations. however both seem to use one coil for two cylinder setup. So you have only two coils for 4 cylinders. See the pictures below but you need to know which one applies to your car.
Item 38 and 41 are the coils in the respective pictures.
Attachments
That's a great help thanks, I will change the plugs and the coils if necessary and see if that cures it. Thanks for the diagrams, they are a real bonus. The dealership also noted that the throttle body is full of oil, is this likely to have anything to do with the problem or if not is it something that really needs addressing? Thanks again. Just
When you do the plugs, you can see how "full of oil" it is.
Again, I am talking about generals here but your engine should have the same things. If you remove the air ducts between the air filter and intake, you should see something that feeds from the valve cover to the intake. This is the crankcase ventilation. Sometimes the gas coming out of it carries a little oil. A little is normal but "full of oil" could indicate problems.
So clean up the oil using whatever products you have in your market and check again in a little while to see if the oils come back.
Here is a link you can read about it. Forget about the parts they use for examples but just the principle.
PCV valve - Wikipedia, the free encyclopedia
Again, I am talking about generals here but your engine should have the same things. If you remove the air ducts between the air filter and intake, you should see something that feeds from the valve cover to the intake. This is the crankcase ventilation. Sometimes the gas coming out of it carries a little oil. A little is normal but "full of oil" could indicate problems.
So clean up the oil using whatever products you have in your market and check again in a little while to see if the oils come back.
Here is a link you can read about it. Forget about the parts they use for examples but just the principle.
PCV valve - Wikipedia, the free encyclopedia
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