Cleaning MAF, Spark Plugs, Throttle Body

[xvvvz]

First off, thanks to everyone who has contributed posts to these forums in the past. What a great resource. I hope to do the same as I slowly get to know this car.

I have been a long-time lurker here because I thought I might eventually be buying a 202. Last week, I finally bought a 99 C230 Kompressor with 27.5K miles on it and I am trying to figure things out.

A Haynes manual has been ordered and I am taking gamble on one of the CD shop manuals sold on Ebay (hopefully both arrive later this week). I called MB about ordering their CD shop manual although the woman said it is now $115 – up from $50 when I called about it in January! That is a bit pricey for me, so I will try the others first (Please PM me if anyone has thoughts on a group purchase/copy of this CD!).

In the interim, I have a few quick questions. The car runs well in general, but when it is cold, it is very, very slightly rough when accelerating from a stop until it warms up. Therefore, I thought I would check the obvious things. It really is a minor issue but I can be a bit obsessive.

The car has always been serviced at the stealership and had a major servicing 4k miles ago (at 24.5k) including plugs, fuel filter, 44k additive, etc. Sorry if my questions are basic, but I am new to Mercedes’ quirks and don’t want to create any extra problems. I have searched the archives here but still have some questions for which I didn’t find good answers.

Are there any dangers I need to know about when cleaning the throttle body? I cannot find any notation in the service records that this has ever been cleaned. My guess is that this might be needing to be cleaned since the car was driven around town a lot by an older woman. I have the good CRC TB cleaner and was just planning to disconnect the long tube from the MAF to access the throttle body. From there I was hoping to spray down the throat and do a bit of scrubbing with a toothbrush. Then reassemble quickly in order to get the car running before the gunk sludges up again. The engine won’t run with the intake disconnected, will it (my old Lexus sure won’t)? Any other pointers?

I have a can of the CRC MAF cleaner (thanks to the advice in this forum) and will clean that carefully. Thanks for the advice that I needed to buy the Torx heads with the hollowed-out tip!!!

The sparkplugs shouldn’t be a problem, but I am going to check them. Can you clean and regap the plugs for these cars? I assume the stealership just replaced the plugs with the same type that came with the car. The reason I ask is that many of the new plugs have special coatings which I am guessing might get removed if I use my normal cleaning method involving fine sandpaper, etc.

I am open to all advice and suggestions!

Thanks,
Doug

[1995c280]

it it was just serviced 4k miles ago, why would you want to changed the plugs again. but i guess that's a preference issue. if your going to pull each plug out to re-gap them...i would just replace them again. it makes much easier sense to me and they are cheap. might want to look into replacing the wires while your there too as they aren't too much either. i am not completely sure but i know some C230's came with 3 electrodes on the the sparks plugs so you can't re-gap them. not entirely sure if it applies to your car though. as for the MAF sensor...the cleaner is just a temporary way to save your sensor from failing. if it's bad...IT'S Bad - bottom line. also try letting the car warm up completely before driving. i also do this every morning (summer or winter) all the way to operating temp so the torque convertor clutch doesn't keep the car in 1st and 2nd gear for an extended period of time. also are you using good quality gas. always start with easy fix items rather than replacing the big and expensive things like a $500 MAF sensor.

also the BG44k has been known to cause bad idles for a period of time on mercedes vehicles. we still sell the stuff at my dealer but i am not too much of a fan of it. maybe if your car had alot of miles i would reccommend it but your car is still pretty much brand new!

NENAD...wut's a good fuel system cleaner he should try??????????

Jason

[OCKlasse]

Sea Foam for the fuel system cleaner hands down

[Proven Guilty]

agreed. seafoam brand rocks.

the 230Ks are pretty notorious for the slightly rough idle, it sorta just depends on if you start the car, and immediately drive it, or if you let it warm up for 60 seconds first.

the car is deisnged to use the supercharger for the first 60 seconds as an air pump to bring the exhaust and cats up to operating tempurature for emissions efficiency. that's probably why you notice it runs different when you immediately start it.

you could always have the computer codes read to see if anything is present, cause not everything will throw a check engine light (CEL)

[jnenad16]

Originally posted by 1995c280

NENAD...wut's a good fuel system cleaner he should try??????????

http://www.club202.com/forums/showthread.php?s=&threadid=5614&highlight=additives+optimal

nenad

[xvvvz]

>>it it was just serviced 4k miles ago, why would you want to changed the plugs again.<<

Actually, I really just plan to check them to make sure nothing is wrong since the car is new to me. If there were any crud on them, then I wanted to clean them off. Hopefully, after only 4k they should be fine :)

>>the cleaner is just a temporary way to save your sensor from failing<<

Yeah, I was thinking along the lines of preventative maintenance with possibly a side benefit of having an affect on the situation at startup.

>>also are you using good quality gas.<<

Normally, I use a top-tier rated gas but your question reminded me that I had to use Hess gas on a fill-up at the end of the long drive down here. I don't know if that is top tier or not. It was pretty inexpensive but then again so is Quicktrip and they are top tier rated. It will be top tier after this tank is used up.

>>also the BG44k has been known to cause bad idles for a period of time on mercedes vehicles<<

Good to know!

>>the 230Ks are pretty notorious for the slightly rough idle, it sorta just depends on if you start the car, and immediately drive it<<

Yep, that is the case. I let it idle for 5 seconds or so and then drive it slowly like a grandmother until it warms up. The Car Talk guys on NPR seemed to not like the sit-and-warm-up approach but they weren't talking about this specific car.

>>the car is deisnged to use the supercharger for the first 60 seconds as an air pump to bring the exhaust and cats up to operating tempurature for emissions efficiency. that's probably why you notice it runs different when you immediately start it.<<

Ah, ok. That certainly fits my pattern. I just have to get used to the differences between this car and my old Lexus. Definitely different beasts!

What about cleaning the throttle body? Nobody really commented on that. Is it pretty simple and along the lines of the procedure I mentioned I planned to take? I just don't want there to be some $2000 gizmo down in the throttle body waiting to be damaged by my cleaning:eek:

Thanks,
Doug

[rollinrealbig]

ya I liked sea foam! reminds me I gotta get some more!

I downed the whole bottle down the TB popped the intake back on and started the car - it would sorta choke but you tap the gas a little and it will start, with ALOT of smoke comming out the exhaust! :D

[rman]

Originally posted by rollinrealbig
ya I liked sea foam! reminds me I gotta get some more!

I downed the whole bottle down the TB popped the intake back on and started the car - it would sorta choke but you tap the gas a little and it will start, with ALOT of smoke comming out the exhaust! :D

i would think that a whole can is a little too much....i would be afraid of hydrolocking

i sucked up about 1/3 can thru my brake booster in my last vehicle, shut it off, wait 10 minutes, and then drove around. Everyone at the shop thought i was a moron cuz it was choking and blowing MAD white smoke...but in the end it was all gravy! :cool:

[jnenad16]

seafoam down the intake is alright,but I prefer the system one's foamy intake cleaner(not sure if they still make it). seafoam is liquid, so dont expect much of the intake to get cleaned, however the system one product is foam, so it will reach just about every part of the intake system.

nenad