Engine misfire - ignition wire questions

[roundeler]

My 2000 C280 has a a CEL with codes P0300, P0302 and P0304 and a rough idle with power issues at speeds.

I suppose that cylinders 2 & 4 are the offenders. Now I have never had this engine open, but anyone able to tell me if I need to replace wires or these "coil ends"? I hope this is simple and cheap, I could only find wires at $25 a piece online.

BTW which cylinders are 2 & 4 on the V6?

Thanks,

Mark

[Nelson Lago]

HAY dud i have allmost the same problem and my car idles bad and los of power. also my 5,6 cylenders are misfiring but it runs fine in revers werd huh well i am posting this because if you get the spark plugs and wires please tell me how much you payed and did it fix the problem..........ps why do most of you get parts off line why not the dealer in now there expencive but notthing in better then oem.

[roundeler]

I'm all for OEM, in my view, if the car was designed to work with certain equipment and you don't want issues, stick with it. I won't say that OEM is the best though, just the safest route.

As far as a source, the benzbin.com works OK for me. I haven't found any bargain basement prices, but the dealership will truely work you over at the parts counter.

Also, the service at Bloomington, MN Mercedes sucks. I have emailed them to no response, placed parts orders without followup calls, etc. What a shame, my BMW experience has been better.

I'll let you know how my misfire issue goes, I don't know which cylinders are which on the 2000 C280. I have been unsuccessful finding it online.

-Mark

[xvvvz]

www.autohausaz.com

www.buymbparts.com

www.importec.com (I think that is the name)

Those are some other good online places with decent prices.

[roundeler]

Looks like I found something on the 98-00 V6's

3 6
2 5
1 4

Looking at the engine from in front of the car.

The errors would make more sense if it was

5 6
3 4
1 2

I will be examing the right bank(driver side) today. Glad this is probably the easiest to access of the bunch. I will probably look at the ignition wires, check for continutiy and try unplugging them while the car is running... maybe even switching them.


- Mark

[roundeler]

OK, so there are 6 modules after unplugging each of them, it seems I have isolated it to the #2 cylinder ignition module. It is the front driver looking into the engine bay. Now how does the replacement process go? Am I right to suspect it is the ignition module is the culprit? Or could it be the plugs or wires? What's the story with these things? I'm not clear on the function of the ignition system of this car.

Thanks,

Mark

[jnenad16]

This is a tricky one. I would like to help, but without seeing the car myself, I cant point you in the right direction. it can be anything from a bad spark plug to a bad ME module and everything in between.

nenad

[roundeler]

I don't think it is spark, I got plenty when playing with the wires. Having disconnected the "module relay", I would not guess plugs. WTF is that thing that is held down with the torx bolt? Could that be the culprit?

Thanks,

Mark

[Nelson Lago]

i think its the coil u r talking about it has the spark plug wires coming off it

[roundeler]

6 coils on this car? I'm amazed. So I guess I check the coil out then? Thanks, Mark

[roundeler]

I found orange/yellow pastey stuff under my oil cap. I thought I had a blown head gasket! After some research it is just condensation found in colder climates when you drive short trips.

Took the #4 spark plugs out, they looked OK. Next I will take the #2 ones out. Still no answers on the misfires. The engine does shake and the it has a rough idle. I believe it has to be a ignition issue. Will check later today.

-Mark

[xvvvz]

>>I found orange/yellow pastey stuff under my oil cap. I thought I had a blown head gasket! After some research it is just condensation found in colder climates when you drive short trips.<<

Yep. I have seen pictures of this in quite few threads. If you hadn't read about it, it would freak you out for certain!

[roundeler]

Looked at my service records, it appears as if at 55k miles it hasn't had new wires or plugs since new. I swapped coils 1 & 2, an error code still comes up for P0302. So I guess I will buy new sets of plugs and coils.

Any chance this could be a fuel related issue?

-Mark

[roundeler]

So far I have replaced the passenger side ignition wires and plugs and the car smoothed out. Later today I will finish the rest. After reseting the codes through the week, it was narrowed down to P0302, so this was the problem, either the plugs or wires.