'96 C36 44kmiles trying to pinpoint driveability problem...STILL
 

I Got my car in Sept '02 w/ 38,000 miles on it. Ever since week 2 of ownership it has a dead miss condition that shows itself undr one of 3 different driving conditions. All of which require the car to be under some type of acceleration (past 1/2 throttle) If I drive the car like it wasn't intended (like a catholic nun) it is ok. First things first, I took it to a dealer expecting the best service(MB North Houston) They put a new MAF on it and said..'fixed!' 3 days later it presented itself again. Took it back. This time the shop foreman went for a ride w/ me. I duplicated the problem by slowing down for a merging turning lane & getting into the gas to accelerate(70% throttle) the car stutters and upon stopping you can tell that the car isnt running on all 6 holes. It shudders and bucks. If you turn off the engine & Immediatly turn it back on, the idle is good again and it runs great! this happens to me almost every day I drive by the way. They put new plugs in it & said..'it had a bad plug in it?' OK........whatever. After them wanting $220 for the plug job I told 'em to shove it. they went ahead and comped the plug job @ 00.00. (I still have $660.00 in the MAF that was OK to begin with!!!) I still feel like I got taken for $660 bucks cause the problem actually came back. It took almost 10 days to do it again though after the plugs were put in??

That is why I am confused. I havn't changed my driving habits at all either. I feel like maybe it is a software issue since I have ASR, electronic shift, fly by wire throttle body ETC; I get NO CHECK ENGINE LIGHT EVER! Is it my fuel system??? I was told that it was probably my throttle body since I get the stumbling at certain throttle angles @ certain speeds/loads/downshifts.

Here is another clue, since week two of ownership w/ the problem starting, my cruise control quit working above 65 mph. I noticed it was kinda lazy upon acceleration w/ the collumn stalk. It will hold the speed I set but just for a second and not engage. I was told that the stuff for the cruise, & idle speed were all integrated into the T/B. I was told by an indie repair shop owner that this is the bain of all W202 cars - throttle body & engine harness. I was told by a tech @ MB north Houston that I have the 'goodwill' warranty harness already done on mine.

So I've got a new MAF & plugs w/ maybe 1,500 miles on 'em & an AMG merc that runs like crap when I get on it a little bit. Makes me wanna go got a 5-speed M-coupe sometimes???? Somebody please give me an honest educated opinion here, cause I dont wan't to be the next person who reinforces the 'ole reputation about benzes breakin down all the time! I love my car but I might sell & join the ranks of the anti Benz people if this issue can't get taken care of..Later

Kiley Feagins
Houston, TX

'96 Silver C36
Clear corners, flat badge
H&R sport spring lowered
Fresh Sikkens repaint

The "throttle body" is called the throttle actuator, and it is a part that goes bad. I had to replace mine.

It's an expensive gamble, though, as the part is a little over $1,000.

Also, faulty cruise control is a sign that your actuator is going bad.

Engine wiring harness? Symptoms sound about right, but I thought that was a non-problem by the '96 model year.

- Jim

That was my first guess, but his post says the wiring harness was already replaced by the dealer under warranty.

Have the coil ends, not the coil packs replaced..do it yourself...3 coil ends i believe, cost is like like $10-$15 bucks each? Very cheap, see what happends.

wiring harness could be a possibility..very expensive.

As to the cruise control, I had the same problem. It turns out..believe it or not the cause was I had different brand of tires on the front and back.

Sounds like BS? I kid you not. once I bought new tires of the same brand it worked again. The dealership also swapped out new rims and tires from the showroom C43 to test it out and it was the fact that I had different brand of tires on.

I go with Rocky on the coil ends. They are so intermittant and so hard to diagnose and such a common problem that we replace them when we do plugs.

You will have to remove the air intake over the valve cover then with an allen head remove the center of the valve cover exposing the three coils and 3 ignition wires. You will need only three ends.
Hope this helps!
Chris

Hey Guys, Where are the coil ends located under the hood, & what are the pieces I will need to re-move to get to 'em?? I will need 6 of 'em right?? They are screw on deals right?

that's weird, as I had what sounds like a similar issue. When I hit past 50% throttle(usually meant I had to do the 4-2nd gear kick down), the car shuddered and acted way bizarre. I took it in and my wire harness was bad, the insulation had worn and wires were shorting out. New harness and the baby runs like a champ now, $1200 later >:-(

One of my neighbours is the owner of our "old" 1995 C36. (One of our other neighbours has our "old" 1997 BMW 528i. A trend?)

Last night while doing some work outside (shoveling SNOW) I aksed him about the car. He loves the C36, but had the same problem you're describing a few months back. The dealership replaced the coil ends ($140CDN p/l) and it was the cure.

So, I put in another vote for the coil ends.

hey stroked,

gillybenztech outlined this procedure for me to do the sparkplugs. it might be a slightly different layout but you'll figure it out. there are 3 coils, you replace the ends underneath that go onto the sparkplugs.

m104 spark plug replacement

What colors are the labels on the coils? If blue, toss 'em. If no, remove the coils and ends, look into the end of the coil and look for oil residue on the brass/copper center piece of the coil. If you have oil, replace it. The oil is what cools the coil packs and when they leak, they overheat and break down under high load.

On some 104's the knock sensor harness is seperate and the harness will come apart allowing the sensors to short, throwing into a fixed timing map that has little to no balls, I had a 111 engine (4 banger) that would drop #3 injector with this issue. (never have figured out the attachment between the 2)

However, I've had more bad coils on 104's than resistor tips and almost as many bad coils as harness's.



Joe

Hey joe p,

Where are the knock sesors(on the side of the block) & where should I look as far as wiring goes for the bad insulation? I have actually 'learned' to drive a certain way to avoid the 'miss' situation. If I wait long enough after downshifting & keep the throttle angle low enough until a certain speed is reached, then I can lay into it W/O getting my stuttering issue. Which kinda sucks B/C I'm driving around the computer! Even Motor Trend says they would still rather drive an older slower manual trans M5 over the new E55 automatic that runs 117mph in the quarter b/c they say it is so finickey to drive due to all the computer stuff????

First thing you need to do is check those coils and resistor tips. If you dont find a problem there, take it Houstons Park Place North and ask to talk to Bo Mclung, big tall drink of water, looks to be dumb as a rock but, he's a good tech. Tell him you talked to me (Joe from Raleigh) and ask him what he thinks about after a test drive. I really think you'll find your problem with either the resistor tips or the coils themselves. The latest version of the coil has a square body with a recessed center section in relation to the peaked center section.


The reason the car will suddenly go to skipping at idle is because ME saw the misfire and turned that injector off. On restart there is no misfire, therefore ME leaves the injector on. Whats really odd is the lack of a check engine light while its skipping but, it still might have a stored versus current code.


The knock sensors are under the intake in the side of the block right around #2 and #5 clys. I'm thinking your car has a harness that includes those connectors in it. Odds are that is not your issue but, worth looking at if no faults can be traced out in the secondary ignition. One surefire way to either eliminate or condem the coils is to swap 'em out and go run it hard. I actually have a set of test coils I pilfered off a blown motor just for this purpose. (without a dyno its tough to get loads right and play with a scope)


Joe

Hey Joe p,

My Front coil is Bosch

02w14

0 221 506 444 is the pt#

BAck two coils are Benz original

95w50

000 158 70 03 pt#'s

My Intake boot that connects the plastic pipe to the throttle plate was ripped apparently by a tech in a hurry also allowing a possible vac leak AFTER the MAF (no trouble codes??) I was reall attentive to getting that back together as well as possible. It looks like a genuine pain in the ass to get from the bottom by the throttle plate itself. That leads me to believe that the tech who probably noticed it also just didn't care either. Reply w/ opinion thanks

Here is a pic of my coils, and the damaged boot that attaches the intake pipe. I don't know if imagestation formatting will work or not.(sorry if it screws up)

http://www.imagestation.com/picture/....jpg.thumb.jpg

http://www.imagestation.com/picture/...1/fca7a5e0.jpg

Here is the Boot.....Whata ya think??

http://www.imagestation.com/picture/...7/fca7a490.jpg

time for a new boot, I'd do coils and tips too. The boot really isn't that hard, just drop the secondary resonance chamber off. (4 torx right behind the boot on top of the intake. ) Reach in with a 7mm socket on a 1/4 drive wobble and extension from the backside of #6 runner, loosen the clamp and pull it off, remember to pop the chamber out of the side off it at the same time. Reverse it to install, a little WD40 works wonders for making it slide right in. Lean mixtures will make these skip too so you might want to try the boot first, just remember it have adaptive abilitys, it'll take a few miles for it to reset itself.





Joe

Hey joe, when you say tips, do you mean a part that is underneath the coil??? Or the wires??

The coils are the wires.

Your engine has no distributor - thus no spark plug wires.

Your engine, like other M104 engines, uses a coil pack, with 3 coil wires and 3 high tension leads. Each coil wire is responsible for firing two cylinders. One coil wires goes to one spark plug, and piggy-backs to the next cylinder via a high tension lead.

The "tips" are the resistor boots, or resistor ends. They attach to the end of the coil wire.

Replace the three resistor boots under each coil wire.

Also, since the resistance is in the boot, make sure you are running non-resistor copper core plugs.

what he said. :D



joe

Sorry guys but I have many questions. I've done plugs a hunderd times on my American vehicles so this is a little different..Is the small flathead brass screw the only thing holding the coil in place? The opposite corner is a locater boss?? I assume the coil needs to be persuaded out by just pulling on it or turning it?? Is there a resistor end underneath the coils??? So I am correct in assuming that each wire is at least 2 pieces? Do you just pull the end off & push or screw the new resistor tip on?? I assume I will need to check for continuity w/ a Fluke or voltmeter to verify??Are the spark plugs supposed to be just 'snug' when re-installed or is there a torque rating that needs to be strictly adhered too? Thanks for being helpfull so far!

Plug wires & resistor tips did it!! Oh yhea - someone removed my check engine bulb. It is working now & the car runs great. Thanks guys for all the info.

Kyle Feagins, Houston,TX

'96 C36, brilliant silver, clear-corners, bad lower control arm bushings

Just to let you guys know, I just replaced my boots and wires however instead of buying them from MB I bought mine form Autozone, dont laugh because they sell bosch wires that are solid copper just like OE and they come with new coil boots as well for just 89 bucks, pretty sweet I think plus they have a lifetime warranty.....NICE!:D

That's really great bad, but so as everyone doesn't spend so much it should be known that MB list price for the coil ends which are always the problem is $11 a piece or $33 for all three. If you just like replacing resistors, the other three can be had for $13.35 a piece (or 40.05 total).

The wire never goes bad, but if it did I would make a new one from some packard 440 and two terminal ends MB # 000 159 14 38 at list $1.40 each and you have a complet ORIGINAL not bosch aftermarket set up for less money BUT as with real things no lifetime warrantee.

Oh, and BTW, those prices are list price; fastlane would of course do better! Personally, I just like to replace the three coil ends each time I change plugs.

Thats great info to know, I have a BAD relationship with my local MB place(they have one jack of all trades mechanic who is great for just throwing parts at it until its fixed) and the place i do all my other business with is 45min to an hour away...so Autozone was closer and my car started running sooooo bad I couldnt wait for mail order...but its great news for the future....and as far as the wires...it looked like they were arching pretty bad after all they have 182k miles on them, but again thanks for the info!!

Oh yeah if you are paying list the cost through MB for all the resistors is a total of 73.05 . For 15 bucks more you get the wires,lifetime warantee and no hassel of crimping or cutting..just my thoughts!

The point is the wires never go bad. If you have an open circuit the voltage spike goes to maybe 35,000volts. Normal voltage is about 10kv. This open circuited voltage will jump through any wire, old or new.

Understood, thats good to know, I getting pretty familiar with my MB as I( yes myself) just replaced the wiring harness as well, but Iam by no means certified or have the experience that you have, Iam mostly familiar with US cars as I have restored, modded etc many....but was not familiar with solid copper wires and their longevity, all I saw when I pulled the inspection plate were very stiff wires that had mulitple burns through them so I though it was prudent to replace them knowing how poorly my other wiring is made in my car. Please accept my apoligies if I offended.
Thanks,
Chris

badbenz,

FYI, i always get my parts from Fastlane's Phil in one day, never fails!

Bad,

I'm sorry if you thought I was correcting you. You did fine. I reply like this to keep the record straight. I meant no offense. Most people will get their problems starightened out with the three pieces under the coils.