CEL on, rough running

[C280Rookie]

hi guys.
i need your help. i have a 96 C280. i just had the MAF and OVP replaced a month or so ago.
yesterday i was driving, then after a few minutes, the check engine light was on. suddenly, the car seemed to be hestitating and running rough, plus the pick up is slow.
i would like some feedback as to what could be the most likely thing next to replace.
unfortunately i haven't bough an obd reader so i am just relying on your kind advise.
thanks in advance.

[jearly462]

I had that same problem with my car. Took it to autozone and the code reader said I had a misfire on two of the cylinders. I gave it new plugs and wires and it went away instanly. Also after starting the car about three times the CEL went out.

[C280Rookie]

thanks jearly

i am afraid i can't take it to autozone as i might stall.
do you know if your autozone used an obd 1 or obd 2 scanner?

[slugger]

Just brought mine into my local Autozone and they used an OBD II scanner. Plugged it in and instantly provides a reading on any and all issues related to the check engine light. Autozone is too happy to do it.

Mine was a misfire on Plug 6. Replaced the spark plug and the wire (I just did all three wires to the 6 cyl. while I had it open) and I think the cost for the wires was like $70 total. They are a bit costly...

good luck!

[CKlasse]

Might as well go for Magnecor wires and Iridium plugs ! ;)

Anyhow, seems like your car is in the LIMP mode. If you are sure it is the plugs or wires, then unplug the ground battery cable for 10-15 minutes.. replug it. It should reset the LIMP mode. At least it can drive normally til the error occurs again.

Good luck

[Rocky]

Check the MAS again, maybe you got a faulty MAS. Also check the coil ends as these break down easily because of where they are located, the heat deterioates them quickly.

[C280Rookie]

thanks for your inputs.

i have a 96 c280 (built late 95), can i use an OBD II or is this an OBD I scanner?
i will ask my mechanic to check the wires and the MAS, maybe it is a faulty one.
CKlasse,
is there a big performance difference when using the magnecor wires?
have a nice day guys and thanks again.
i will let you know what is wrong with my benz.

[C280Rookie]

slugger

what year 202 do you have?
just want to know if my car has an obd 1 or obd 2.

thanks

[202rules]

Originally posted by C280Rookie
thanks for your inputs.

i have a 96 c280 (built late 95), can i use an OBD II or is this an OBD I scanner?
i will ask my mechanic to check the wires and the MAS, maybe it is a faulty one.
CKlasse,
is there a big performance difference when using the magnecor wires?
have a nice day guys and thanks again.
i will let you know what is wrong with my benz.

OBDII.

To make sure yourself, open the hood and look for a black tag that mentions OBDII compliance among other stuff, I remember looking for it and finding it easily but I forgot where, could be on the hood itself from the insde.

[CKlasse]

Just look for the 18 pin OBDII hook up underneath your dash - driver side

[C280Rookie]

202rules, CKlasse
thanks guys. i will look for these things today.

[C280Rookie]

hi guys

just got my car back from the mechanic last night. my problem was a cylinder (#4 i think) misfire. also, i had an ignition coil failure, and had to replace that too.

main thing is my car's running fine once again. just have to replace wiper blades or even just the rubber inserts.

has anybody used bosch wiper blades? just wanting some feedback.

thanks again guys for all your inputs.

have a good weekend.

[Rocky]

I doubt you needed a new coil. Like I said, it must have been the coil ends that attach the coil to the plug. $10 part I believe.

M104 coils and wires are pretty bulletproof.

[C280Rookie]

Originally posted by Rocky
I doubt you needed a new coil. Like I said, it must have been the coil ends that attach the coil to the plug. $10 part I believe.

M104 coils and wires are pretty bulletproof.

hi rocky

i was reading the the service receipts done on the car, and the coil was replaced before. unless what it meant was the coil ends.
i will clarify that with my mechanic tonight.

thanks

[Rocky]

The coil is a square box. attached to it is a long tube (coil end). The other side of the tube (coil end) attaches to the spark plug.

If the mech is saying you can't change that tube without changing the whole coil pack, he's lying. I did it myself. It's a faily common piece to break down as it is in a spot where alot of heat is generated. A break down of this piece cause misfires at high rpm.

[C280Rookie]

thanks rocky
i will ask my mechanic tonight on what really was replaced.
he's pretty trustworthy so maybe i just misunderstood the actual part he told me. guess i was just so glad i have my car back last night.;)

will let you know later.

thanks

[C280Rookie]

I asked my mechanic what was actually replaced. He told me that he replaced one coil, and wires. The plugs are fairly new so no need to replace them.

Car's running very well once again.

[Rocky]

so he reused the old coil ends?

[C280Rookie]

Originally posted by Rocky
so he reused the old coil ends?

yes, i guess he did. coil ends are not part of the wires are they?

is reusing coil ends bad?

[Denlasoul]

n/m

[Rocky]

Originally posted by C280Rookie
yes, i guess he did. coil ends are not part of the wires are they?

is reusing coil ends bad?


coil ends are not part of the wires. There are only 3 coil ends, one underneath each coil pack.

[C280Rookie]

Originally posted by Rocky
coil ends are not part of the wires. There are only 3 coil ends, one underneath each coil pack.

i believe he did replace the coil ends too. i didn't understand what the coil end meant previously. he did tell me that the coil needed replacing.
incidentally around how much are coils anyway? and how much are coil ends?

[Rocky]

How did he know the coil needed replacing?

Majority of the time it's the ends. you need 3, one for each coil at about $10 a piece.

Coil proce..not even sure. I don't think many people ever replaces them.

[C280Rookie]

Originally posted by Rocky
How did he know the coil needed replacing?

Majority of the time it's the ends. you need 3, one for each coil at about $10 a piece.

Coil proce..not even sure. I don't think many people ever replaces them.

hey rocky,

i will clarify with my mechanic on what really was replaced. he first said coil, i would think it is the coil itself and he probably replaced the coil end too. do i need to replace all three coil ends, or just the end from the coil? i checked the service record and one coil was replaced before. i guess you are just lucky you have yet to replace any of your coils.
my mechanic did change all of the wires for the plugs as you can't just buy one wire, it comes in a set.

[Rocky]

Originally posted by C280Rookie
hey rocky,

i will clarify with my mechanic on what really was replaced. he first said coil, i would think it is the coil itself and he probably replaced the coil end too. do i need to replace all three coil ends, or just the end from the coil? i checked the service record and one coil was replaced before. i guess you are just lucky you have yet to replace any of your coils.
my mechanic did change all of the wires for the plugs as you can't just buy one wire, it comes in a set.

I actually have changed just the coil ends. At $10 a piece, you might as well change all 3 while your at it. How I found out about my problem was that when I floored the car, engine would misfire at high RPMs. Check the CEL and code. Misfire. Did some research, pulled the coil ends. One was ripped on one side with reddish dust in it and on the tip.

That is right, you can't buy the wires individually but they and the coil pack are almost bulletproof meaning you shouldn't need to change them in a long long long time. 3 wires per set.

[C280Rookie]

thanks for the input on that rocky.

i hope my mechanic replaced the coil ends too. i will watch out if i get another cel.

i will tell my mechanic next time to double check the coil ends.

[Three Point 6]

Rocky knows whats up.....Heres the deal with M104 I-6 ignition. MB ignition uses 'resistor-less' plugs unlike Chevy's & Fords where the ohm load of the ignition system is regulated by the plugs(resistor plugs). I actually heard that the wires ohm loads never change on MB's so there isnt any 'wearing out' of the wires. MB's have the resistence built into the coil ends between the coil and the plug so you should NEVER have to replace the wires on our cars from what ive been told! Due to heat the coil ends ohm (resistance) changes over time much like wires on a Ford/Chevy do & need replacement. Mechanics can sometimes prey on the consumers 'mis-knowledge' of German cars and charge for wires on a coil job also. Sneaky bastards have to put kids through college & have beer money too right?

Now, some mechs just throw a set of wires and coil ends(which come with them) on it & say the wires were to blame not knowing that the stupid 'ends' were the cause & inedvertantly think that they are correct in the diagnosis/solution. Also some mechs are just like "screw it, I dont wanna put this thing back together and have it come back" & they would rather throw the whole secondary ignition kit on it so they 'over-work' the solution to reduce chance of double work on our lowered led sled back breakers in their shop!

My coil ends are starting to go again cause I hit it on the 280 last week & it went to sputtering. I just pulled over, & restarted the car & it went away. To get rid of CEL light I had to reset my battery in the trunk. I am going to buy the 3 coil ends soon for less than $50 and DIMself cause no indie or dealer is going to rape me on $350 again which I had to do once I found the real story over on.....

www.mercedeshop.com

Plus once I found out my 202 hood would go vertical it isnt as hard of a chore to do.

Every 35-45k miles my car needed coil ends. Currently at 87k and it messes up under full load. It will be my second time doing them. First time was at 38k miles & indie shop SWEAR my wires were bad and got me on wires also.