misfire, ignition coil problem?

[benz4life]

1997 C230 , 235K miles
Engine is shaking at low rpms, has no power, so I guess its a missfire. I replaced the plugs 2 months ago and now i have same problem. Oh, the plugs I have now will be replaced to F8DC4, after more research, I found out that this are the one I need, I will go to a store to pick them up. So I took out the coils
I have two ignition coils, but they look different
one is like this:


and one like this:



Why? Is one Bosch and one after market? Both coils need to have same specs? If so, I can just get 2 similar, rockauto.com has them for 35/piece- not bad i guess - also jcwhitney.com $22/piece and thebenzbin.com 31 i think.
One of them has a small crack, where the spark my escape also I can only measure one resistance on both of them a low value like 7ohms I understand that would be the primary and the secondary should be around 10K(??) ohms but doesn't show anything? Anyone has the specifications for the resistance? And how exactly can i measure them?
I am afraid to do the spark test since I don't know exactly how and also because of the engine vibration, I don't have an assistant to press the gas pedal.
The wires have a resistance , so I guess they are ok.
I appreciate any help.

[Sulaco]

One in first picture is OEM. 2nd one looks like a newer replacement. I'd bet the OEM coil is the bad one. The coils can look differently, that's fine--as long as they work! Sorry, I have no info on specs.

You're very, very correct in using the OEM Bosch plugs. Don't use any other type of plug in that engine. Also, go to autozone and get codes pulled for free to find exact data on which cylinder(s) have issues. If you're not using the OEM plugs, I'd replace them first. The coils might be fine already!

check www.partsgeek.com or www.autohausaz.com for best prices in the US for parts.

[benz4life]

thanks for the reply sir, will install the "right" plugs and than report back. The coil in the second pic (flat surface) is the one that has a crack.

[cassard]

I have the same problem of misfire. it happens only when I got at more than 3500 RPM, then the misfire happens and it shakes on the Idle, ect.

Is there any way to know if it's the plus or the ignition Coil ?

[benz4life]

just put the new plugs in (Bosch F8 DC4) , car started normally but after 7-8 seconds the engine started to shake again so I think I will just order 2 ignition coils.

[hvmercy]

If you had posted a CEL code it will pinpoint which coil is actually giving you the problem.

[benz4life]

I appreciate it but I don't have an OBD scanner (yet) and I don't want to drive the car to Advanced Auto Parts or Autozone. I just ordered two ignition coils on ebay for $52.40 USD and I will replace both. Hopefully will work. I will report back after I get them and install them.

EDIT : I got yesterday the coils and installed them. Looks like its working now!

[Christopher]

WHAT EVER HAPPEND WITH THE PROBLEM!!!!!!!!!!!!!!!! i have the same issue!! it went away for a couple of days and ran pretty well but today my car actually turned off at idle for the first time at a stop light and the shaking is horrible, i just replaced all my plugs it urned on fine but after about 3500rpms it started messing up again. was it your coils after all?

[benz4life]

WHAT EVER HAPPEND WITH THE PROBLEM!!!!!!!!!!!!!!!! i have the same issue!! it went away for a couple of days and ran pretty well but today my car actually turned off at idle for the first time at a stop light and the shaking is horrible, i just replaced all my plugs it urned on fine but after about 3500rpms it started messing up again. was it your coils after all?

I was reading somewhere in a youtube comment that if you put different spark-plugs than recommended in the manual , might damage the ignition coils. Two weeks after i put the new platinum plugs my car did same problem. I ordered 2 ignition coils , replaced them and put old type copper spark-plugs and now works fine.

Reading this thread might help: http://bit.ly/HQ6CKK

[SD202]

WHAT EVER HAPPEND WITH THE PROBLEM!!!!!!!!!!!!!!!! i have the same issue!! it went away for a couple of days and ran pretty well but today my car actually turned off at idle for the first time at a stop light and the shaking is horrible, i just replaced all my plugs it urned on fine but after about 3500rpms it started messing up again. was it your coils after all?

sounds like an ignition coil problem if you had an obd scanner you could find out what cyl # is misfiring. Move the coil packs around and see if it misfires on the same cyl or if the misfire has moved in correlation to the coils being switched.

[Christopher]

I was reading somewhere in a youtube comment that if you put different spark-plugs than recommended in the manual , might damage the ignition coils. Two weeks after i put the new platinum plugs my car did same problem. I ordered 2 ignition coils , replaced them and put old type copper spark-plugs and now works fine.

Reading this thread might help: http://bit.ly/HQ6CKK

ive heard that a lot also, the ones i replaced were the the recommended plugs and it had the same problem. honest opinion i think plugs are plugs although you might be right. the new ones i just installed are the recommended bosch platinum plugs from autozone. if the plugs were the cause of the problem and caused my "new" coils to give out i'd sue. but in this case it had the FR8DC'S to begin with

[Christopher]

sounds like an ignition coil problem if you had an obd scanner you could find out what cyl # is misfiring. Move the coil packs around and see if it misfires on the same cyl or if the misfire has moved in correlation to the coils being switched.

thats before i switched around the coils

now this is what it says

[Sulaco]

ive heard that a lot also, the ones i replaced were the the recommended plugs and it had the same problem. honest opinion i think plugs are plugs although you might be right. the new ones i just installed are the recommended bosch platinum plugs from autozone. if the plugs were the cause of the problem and caused my "new" coils to give out i'd sue. but in this case it had the FR8DC'S to begin with

WARNING: autozone doesn't know their ass from a hole in the ground when it comes to what's recommended with MB cars. ONLY use F8DC4, and NOT the FR8DC4. The FR8DC4 has an extra transistor in the plug, which overstresses the coil and plug wire. This is a problem with 99% of all plugs you try to put in this car. The copper OEM F8DC4 is the only plug that the M104 should be using. Other plugs have the added transistor as well as incorrect heat ranges. I've used other plugs before, too, but not for long. They always worked fine at first but didn't last long. In some rare cases, the tip of the plug can melt and flame up, dripping tiny drops of metal into the combustion chamber. This problem seems to be amplified if using cheap gas.

After you swapped the coils and the codes changed, did the car perform differently?

[Christopher]

im going to go make a scene, i'll tell you what happends when i get back from autozone

[Christopher]

now lets see what happends

[Christopher]

ok still same problem, even with the new f8dc4's so im guessing the other plugs mest up my coils.. so im filing a claim tomorrow filing a law suit. they should test there products on the products that it was designed for before they start selling them

[Christopher]

ok still same problem, even with the new f8dc4's so im guessing the other plugs mest up my coils.. so im filing a claim tomorrow filing a law suit. they should test there products on the products that it was designed for before they start selling them

[Christopher]

Fault log report generated by Torque for Android
=================================================

Vehicle VIN: Not present
Vehicle Manufacturer: Unknown
Vehicle Calibration ID: Not present

Current Fault Log
------------------
P0300: Random/Multiple Cylinder Misfire Detected
P0303: Cylinder 3 Misfire Detected
P0304: Cylinder 4 Misfire Detected

Pending Fault Log
------------------
ECU reports no pending faults

Historic Fault Log
------------------
ECU reports no historic faults
Other discovered fault codes
(possibly pending, current or manufacturer specific)
----------------------------------------------------
ECU reports no other fault codes logged

End of report.


could this also be a factor? its missing one screw.. and the coils dont all have the little gold things that slide on when you place it on top of the plugs.. and what if there facing the wrong way? anyways im gonna go speak to the manager and demand new coils because the plugs they gave me messed them up.

[Christopher]

WARNING: autozone doesn't know their ass from a hole in the ground when it comes to what's recommended with MB cars. ONLY use F8DC4, and NOT the FR8DC4. The FR8DC4 has an extra transistor in the plug, which overstresses the coil and plug wire. This is a problem with 99% of all plugs you try to put in this car. The copper OEM F8DC4 is the only plug that the M104 should be using. Other plugs have the added transistor as well as incorrect heat ranges. I've used other plugs before, too, but not for long. They always worked fine at first but didn't last long. In some rare cases, the tip of the plug can melt and flame up, dripping tiny drops of metal into the combustion chamber. This problem seems to be amplified if using cheap gas.

After you swapped the coils and the codes changed, did the car perform differently?

so i filed a claim today even though the car still runs like crap i feel a lot better today, hopefully UCC (Uniform Commercial Code) mitigation of damages get compensated with a legal remedy under the perfect tender rule. fun being a business law major. lets see what happends