Needing Advice: 94 C280

[Sulaco]

Over the years the sunroof has slowly but surely fallen completely apart. The only piece that's not broken is the glass itself. EVERYTHING but the glass and motor need to be completely replaced. I've had to drive around for the last, get this, THREE YEARS with the roof permanently in the "moon roof" position (because it howls like a sick dog in the fully-closed position). I'm told it's going to run $500 to have it rebuilt. Any idaes how to get the parts and rebuild it myself? I'm fairly mechanically inclined. I've done lots of minor jobs on the car myself (fixing the "loose" transmission linkage, replaced water pump, etc) and I am going to force myself to learn to do everything on the car anyways.

Secondly. Thanks to a leak in the trunk's lining (from the rear-end collision before I owned it) and a piece of paper clogging the drain hole in the trunk, the trunk FLOODED. I was in college and it sat parked in monsoon-rains and underneath a daily sprinkler for 3 weeks. I get in it, it won't start. The SRS, CEL, and battery lights are all on, but it won't start. I assume dead battery, open trunk, and I find the battery is half-submerged in water: along with all the other electrical junk back there. I assumed the car was dead. A total electrical failure. But I drained it and dried it for a week before messing with it again. And, God as my witness, it cranked right up and ran just fine. But the SRS light never, ever went off, and that auto-roll-down feature on the windows never worked again. Plus, that auto-roll-up when locking the doors feature for the windows/sunroof feature never worked again either. I found this rather expensive looking brain box beside the battery mounted on the frame rail. It was deffinitely under water in the flood, so I took it off and disconnected the 50 little wires from it. I cleaned the part completely (using electrical parts cleaner) and hooked it back up. Then, my windows stopped working. Some would roll down but not back up (until I banged on the brain-box in the trunk). I think the box itself is fine, but perhaps the tips of those 50 cables are ruined. Some of the tips BROKE OFF when trying to connect them again and I had to get creative on how I was going to hook that wire back up to it's intended lead. Plus, ALL of the remaining tips are so corroded and crusty that I can't clean them, or even tell what metal they are made of. My question is this: The dealership can't even begin to get me an estimate on what it's going to cost to replace those batches of wires that obviously run to the switches in the console. I have gone 2 years now without having windows that roll down now. I can take it no longer. If ANYONE can get me in touch with a junkyard or perhaps a parts dealer who can even identify (or maybe even sell) these harnesses, I would be VERY appreciative. I live in TN, and I'll drive to anywhere in the U.S. to remove the wires myself if I have to.

Aside from that, I'm having the same old MAF, O2 sensor, ignition, worn control arms, and the other usuals of an 11-year old W202 with 158k miles.

I had a new MAF installed 3 years ago. Few months later, the local Benz "specialist" tuned it up for me with a K&N filter (which some believe fouls out MAF's). And now, for the last year, I've had random misfirings which boot it into limp mode. I put new Bosh Platinum +2 plugs in today which worked like MAGIC on alleviating that problem, smoothed out the acceleration, vastly improved performance, and greatly increased responsiveness. I would have gotten those $12 iridium plugs if these redneck, backwoods parts stores carried them. Anyways, I drove around trying to force it to misfire (which always only happened when accelerating, gently or full throttle). Throughout an entire day of testing, it only misfired once/went into limp mode. However, with the new plugs, limp mode isn't NEARLY as weak. And one cause of concern is (with the new plugs installed) strange idling characteristics. It idles at around 600rpm, but randomly, quickly, and quietly shutters down to about 200rpm and instantly back up to 600. It never did that before the new plugs. I'm going to slowly but surely replace the entire ignition system. Next: the wires and coil connectors. Then, coil packs. Then, O2 sensors. Then, MAF (cheapest to most expensive). Or whatever it takes until the problem is completely solved.

[Sulaco]

Bump.

After installing the spark plugs, the engine's performance has increased greatly, and it goes into limp-mode far less often, but something is wrong with the idle. I mentioned it in the previous post, but it's really starting to worry me. When stopped and idling in gear, the RPM's seem to dance around, causing the car to want to jump forward every couple seconds if I'm not holding the brake hard enough. With the old, worn-black spark plugs, it did not have this problem. Could it be a poor choice in replacment plugs, or is there something seriously wrong?

I reset the CEL (disconnected the battery) and it's been 3 days. But the CEL has not come back on. Yet it's kicked itself into limp mode twice and idles very strangely (in gear only).

ANY ideas, please?

[benzdude280]

I would have to say that is an MAS problem. Probably in conjunction with the O2 sensor also. The best thing for right now is to have the codes pulled. Autozone will do it for you. Just to let you know, I had the same exact symptoms in my car. Replaced the MAS and O2. Runs like a champ now.

Cheers

[benzdude280]

Oh, and I believe the best plugs for our cars are the Bosch +4's. Just my two cents.

[jnenad16]

DO NOT USE platinum plugs in your car. 104 engines(inline 6 C280, E320, C36) are not designed to use platinum plugs. I ran bosch +4 in my 95 C280 for about 3months, and my compression went from 190+ psi on all cylinders to 150psi the highest. the plugs were dark red, indicating extreme cylinder temps, and my engine ran a few degrees hotter than before installing them. so my advice to you is to put either stock replacement plugs, of beru silverstone or beru ultra-x if you are into performance plugs. as for the ruff running of your car, get it scanned, see which codes pop up. according to your mileage, if you never replaced O2 sensors, do so no matter what, even if the code does not show up. also replace the wires and the coil ends, cooland temp sensor and add a fuel system cleaner to your gas next time you fill up. that module that you tried to fix next to your battery is called the convenience feature module. It controls your windows, seats and the onboard phone(maybe a few more things, but I just cant remember). the harness connecting to it can be cut from another car and spliced on to yours. good places to start looking for it would be:
www.unap.com
www.pgauto.com
www.peachstreetauto.com
these are just few auto recyclers I deal with, they might be able to help you out.

nenad

[Sulaco]

Looks like my next step is to replace the O2 sensor(s). Should I shell out the $300 and replace them both, or just the pre-cat sensor?

I'll be changing out the plug wires asap also, as well as the connectors on the coil-packs running down to the plugs. The plug wires did look a little crusty when installing new plugs the other day.

Plus, Autozone refuses to even plug into my car. It's a 94 and they won't even TRY to plug in their scanners and see if it has ODBII. I've read in several places that my car, although a 94, has ODBII and will work on the 96-current scanning systems. I called the dealership and they were saying it's $90 to diagnose my problem on their systems.

[jnenad16]

Originally posted by Sulaco
Looks like my next step is to replace the O2 sensor(s). Should I shell out the $300 and replace them both, or just the pre-cat sensor?

I'll be changing out the plug wires asap also, as well as the connectors on the coil-packs running down to the plugs. The plug wires did look a little crusty when installing new plugs the other day.

Plus, Autozone refuses to even plug into my car. It's a 94 and they won't even TRY to plug in their scanners and see if it has ODBII. I've read in several places that my car, although a 94, has ODBII and will work on the 96-current scanning systems. I called the dealership and they were saying it's $90 to diagnose my problem on their systems.
replace both O2 sensors, you can get them cheap at www.germanstar.net or www.thebenzbin.com
yes, your car is fully compatible with OBD2, if autozone wont scan it for you, just rent the scanner from them and do it yourself, the OBD2 connector on your car is located underneath the steering wheel closer to the center console, you will see a black rectrangular cover, flip it open and plug in the scanner.

nenad

[benzdude280]

Nenad is right. Your local autozone must be a bunch of pricks. The OBDII is super easy to use so just rent it and save fifty bucks from having to take it to the stealership.

Cheers.

[Sulaco]

I've done alot of looking around on every Benz repair forum I could find. I have found a large consenus that believes the platinum plugs are universally bad for pre-98 Benz cars. I've found alot of people complaining about the exact same characteristics as me after installing platinum plugs (especially Bosch). Acceleration is improved (for a few thousand miles) but idle is random and bouncy. Most people also saw a slight drop in fuel economy. I've been kind of suspicious that my car has burned more gas than usual, but just shrugged it off as being nervous. Well, it turns out that alot of other older Benz owners have seen a slight loss of mpg as well.

Since spending $12 on the recommended copper plugs is the cheapest place to start, I'll swap plugs tomorrow and see if my idle gets any better.

Still replacing those O2 sensors asap!

Thanks!

[Sulaco]

Well, I got the OEM plugs in. Bosch F8DSC Super Coppers. Most of the clunking around at idle has been eliminated. However, it does still idle somewhat strangely. With the old, worn out plugs it idled just fine, but had frequent misfires and backfires under acceleration. With the new ones, it accelerates like a new car, but idles weird. Confusing...

[jnenad16]

it might be the MAS. do the rpm's fluctuate up and down, or does the engine and car shake as well?

nenad

[Sulaco]

They fluctuate up and down when stopped and in gear. I PRAY it's not the MAF. I simply can't fix that for the next few months.

[benzdude280]

I would probably say it's the MAS also. Let me know, I have a brand new one that I can sell to you. Email me if you would like.

Cheers,

[estrellajon]

Originally posted by Sulaco
They fluctuate up and down when stopped and in gear. I PRAY it's not the MAF. I simply can't fix that for the next few months.

I had the very exact symptoms. Definitely the MAS. Changed mine and runs so much better. It's only $300 online. The faster you replace them, the better for your plugs. I learned that a bad MAS will make the car run richer and will foul the plugs sooner.

[LV202]

This is crazy.

First things first: get car CEL codes read, then replace as needed.

OBD connector is under the steering wheel. AZ always tells me I don't have obdII, and I tell them them I do, and to pull the codes!!

Get what the code is and replace as needed! Why throw good money away if the item is not needed?

Second and maybe just as important is the wiring harness issue....Do you have the original wiring harness? If you do (and they ALL go bad) it will cause misfiring and all kinds of symtoms, including what you are describing. Also it will cause all kinds of false CEL codes to be thrown out. People will chase these codes replacing away and nothing seems to fix the problem. The true culprit: degrading wiring harness.

I can't believe nobody on this site has not mentioned this.

Tell AZ you have pulled codes before and the port is under your steering wheel!!!

Check the condition of the harness...does it have exposed wire?

[estrellajon]

Originally posted by LV202
This is crazy.

First things first: get car CEL codes read, then replace as needed.

OBD connector is under the steering wheel. AZ always tells me I don't have obdII, and I tell them them I do, and to pull the codes!!

Get what the code is and replace as needed! Why throw good money away if the item is not needed?

Second and maybe just as important is the wiring harness issue....Do you have the original wiring harness? If you do (and they ALL go bad) it will cause misfiring and all kinds of symtoms, including what you are describing. Also it will cause all kinds of false CEL codes to be thrown out. People will chase these codes replacing away and nothing seems to fix the problem. The true culprit: degrading wiring harness.

I can't believe nobody on this site has not mentioned this.

Tell AZ you have pulled codes before and the port is under your steering wheel!!!

Check the condition of the harness...does it have exposed wire?

I agree. Definitely get the error code first. I started my first CEL issue without a code reader and its a shot in the dark. I have since bought myself one.

[Sulaco]

I am very well aware of the wiring harness issue. But I don't have the means of replacing it. I know I can replace it myself but I am in college, I'm poor, and I never have time to work on it. Not to mention the fact that I am parked in campus parking and the tools required are hard to come by right now. This summer I'll get on it and see if I can replace it, but that's a while away.

Secondly, all the sites that sell a wiring harness for my car, it lists 2 harnesses. I can't figure out which one to use...



A 165602-
F 135856-


Which is me?

[jnenad16]

Originally posted by Sulaco
I am very well aware of the wiring harness issue. But I don't have the means of replacing it. I know I can replace it myself but I am in college, I'm poor, and I never have time to work on it. Not to mention the fact that I am parked in campus parking and the tools required are hard to come by right now. This summer I'll get on it and see if I can replace it, but that's a while away.

Secondly, all the sites that sell a wiring harness for my car, it lists 2 harnesses. I can't figure out which one to use...



A 165602-
F 135856-

those numbers should be a range in your VIN.

nenad

Which is me?

[jnenad16]

my bad I quoted mysefl.
Those numbers are a range in your VIN.

nenad

[estrellajon]

How do I find out if the previous owner has changed the wiring harness or not. How hard is it to replace a warning harness?

[Sulaco]

Replacing isn't that hard. There's a guide for changing the wiring harness on a 1994 E320, which is virtually the same, or at least incredibly similar.

Linky (http://www.mercedesshop.com/wire_harness/1994_e320_harness.htm)

Takes a couple hours, he says.

[Sulaco]

Neither of those figures are in my VIN. Not even close.

[jnenad16]

I guess its best you call them. they can run a check with your VIN and get you the right part.

nenad

[LV202]

Where did my post(s) go????

[jnenad16]

Originally posted by LV202
Where did my post(s) go????
the site got hacked earlier today.

nenad

[Sulaco]

Well, since the posts were never recovered I'll try and remember what I posted.

I took my car to Autozone and got it scanned.

Codes 0304 and 1170(I think) came up.

Hooray.

I guess I'm just going to have to replace the wiring harness first.

[LV202]

Originally posted by Sulaco
Well, since the posts were never recovered I'll try and remember what I posted.

I took my car to Autozone and got it scanned.

Codes 0304 and 1170(I think) came up.

Hooray.

I guess I'm just going to have to replace the wiring harness first.

If you are gonna keep the car, your gonna have to do it anyway bro....

[justdexter]

Originally posted by Sulaco
I am very well aware of the wiring harness issue. But I don't have the means of replacing it. I know I can replace it myself but I am in college, I'm poor, and I never have time to work on it. Not to mention the fact that I am parked in campus parking and the tools required are hard to come by right now. This summer I'll get on it and see if I can replace it, but that's a while away.

Secondly, all the sites that sell a wiring harness for my car, it lists 2 harnesses. I can't figure out which one to use...



A 165602-
F 135856-


Which is me?

The numbers are part of your VIN. They are the last 7 digits to be exact. It's simply a range of numbers. Your VIN won't match exactly.

[Sulaco]

Originally posted by Sulaco
Neither of those figures are in my VIN. Not even close.

Neither of those figures are in my VIN. Not even close.

[Sulaco]

Bump.

Pardon the long-winded post. This forum has made me eat, sleep, breath, and live my 202 over the past few weeks.

I've been talking with JustDexter on AIM, and he's been a real big help. He helped me get over my complete stupidity about VIN ranges and parts--thanks man!

Well, I never did get around to replacing O2, MAS, or Wiring Harness. I'm not sure if my MAS is out again. Listening to Nenad, I believe him when he tells me I need new O2 sensors. However, I know for a fact my wiring harness is on the brink. Whatever codes AZ is telling me (just 1170 now, 0304 hasn't shown up in a long time) could very easily be a direct result of my wiring harness screwing everything up. I did clean my MAS using rubbing alcohol/simple green as other guides online have shown--but that didn't help anything. Anyways, that's all a story I can't afford to finish. Stealership says my harness is $767 for new OEM. That's only $100 more than the impossibly hard to find used/aftermarket ones.

Right now I'm concentrating on my notorious sunroof. I was wrong to say every part is broken. Only 1 part is broken. The passenger side angle has a pop-riveted guide that I can easily fix myself. But I think the main problem is all of the rubber guide jaws deteriorated. Upon disassembling and reassembling the entire sunroof over and over again, I discovered that the entire system relies on the glass being bolted in place AND all of the necessary rubber pieces to be in place in order for the system to maintain any form of strength and rigid structure. This entire time I've been taking my glass off, looking at all the parts just lying their loosely, and assuming that they all needed to be replaced. Well, I'm slowly learning that many of them don't need to be replaced--they just need the proper corresponding rubber and careful reassembly to make sure they all come together and grip just right.

Let this be a message to ALL who fear their sunroof--it is NOT that hard. I've found surprisingly little on sunroof rebuild/repair throughout the forums I search. Well, I think I've got it mastered now (except for MAJOR issues like replacing the track/motor. problems I don't have). I've taken every piece out, straightened all the warped ones, and ordered all the replacement rubber pieces. I feel I can safely say that if anyone is having sunroof problems, you can ask me and I'll try to help.

As soon as I can afford it, I'll be getting new brake rotors. My brakes vibrate like they're warped. I remove the wheel, spin the rotor, and I can see a dark spot on both rotors where it's obviously been hitting the pads more/less than the rest of the disc.

Plus, a question. Does anyone have an idea as to what could cause a harmonic resonance gently vibrating the entire car at 65mph+? I read it could probably be the motor mounts. I KNOW I need new motor mounts, shocks, and very obviously control arm bushings (they are still factory!). I had both flex discs and the drive shaft bearing (and housing) replaced about 6 months ago--didn't help (though they very obviously needed replacing anyways. They grounded me on the side of the interstate!).

The car's had this harmonic resonance for at least the last 5 years, and I'm starting to think I might be able to do something about it.

I love this forum, and most especially, my ugly, old, bone stock 202.

[LV202]

Not to sure what you mean, but sounds like it is probably the mounts.

Try rotating your tires first and see if that helps.

But yea, with 160k on the clock, and 11 yrs you could assume suspension parts are on the way out.

Fix these nagging problems and you'll get another 160k no problem.

Avoid the wiring harness issue and it will come back to bite you int the butt. Fried computer will cost you $$$$!

[Sulaco]

Werd.

My front right shock finally started creaking and squeeking this week. I've known they've needed replacing for at least 3 years. My car rides like a Honda compared to my sister's '05 w203. At least it's comforting to know my car can ride almost as good once I get the shocks/motor mounts/control arm bushings replaced. Plus, those warped brake rotors really make the car feel like a piece of shit.

Wiring harness will be replaced as soon as possible. I've decided I'm not bothering updating/replacing anything else on the engine until the harness can be afforded.

Plus, I've always had 3 warped wheels. My car was in a minor wreck before I bought it. The trunk lid isn't original, the spare was warped beyond use, and 3 of the wheels on the car were warped enough to still use, but I've always been suspicious that they wouldn't always be that way. One of them cracked last summer (I replaced it). I'm always on the look-out for a good deal on some good condition OEM painted aluminum 8-spoke wheels. I just can't make myself put aftermarket wheels on it.

Another 160k? Easily. I just suspect that with all the "restoration" I'm pumping into it now, at the end of that next 160k it won't need so much work (now that all the idiosyncrasies and kinks have been identified and attacked).

[mrjones]

As always, this site is most informative. I'm afraid to report that my beloved '96 M104 is suffering from disturbingly similar characteristics.

Idle is uneven, drops down occasionally and shakes the car.
At rpm's below 2500, especially when using the motor's torque (1/2 to full throttle) the engine definitely misfires, accompanied by the occasional backfire (I presume, it's a muffled bang).

The good news: I work for an MB dealership.
The bad news: They can't find the fault.

My C280 has been hooked up to their diagnostic machines many times, and only shows an ABS pump low pressure warning. I know this to be a genuine problem as my ABS light says hello on hot days and the anti-lock DOESN'T work when that happens.

Keeping in mind that I'm on the bottom end of Africa, with completely different-spec'd cars, it appears my car doesn't have a CEL or O2 sensors. Due to a lot of long-distance travel, the fluctuating octanes and absence of Unleaded in rural South Africa, my cats were removed about 3 months ago.
The problems started about a month after that (after the 180k service), but the MB mechs swear blindly that can't be the problem. They're pointing towards coils, fuel pump, or wiring harness, and from past experience it appears that if your 202 has a full service history with MB (which mine does) they will foot the entire bill for a new wiring harness.
The MAS has been in the back of my mind, and I'd like to keep it there until all other options have been exhausted.

My car's going in again next week to see how it behaves when it's cold. I found the misfires more frequent when the engine is at operating temps, although she has stuttered once or twice while reversing out of my garage in the mornings.

The only thing that doesn't add up is that my fuel consumption has drastically improved! But that's probably due to the sudden absense of the cats.

Add a busted viscous coupling on the cooling fan, the abovementioned dying ABS pump, and rapidly procreating rattles on the interior, and you'll understand why I'm starting to look out for another car. Breaks my heart though, I adore my blue C280. :(

[Sulaco]

Shakes and rattles on the interior? Nothing a good old philips screwdriver and a day's careful tinkering can't fix. I did it to mine! Tightened up all the screws in the entire center console (not nearly as many as you'd think). Tightened up all the screws in the door panels (2 per door). Tightened up screws below dash and on kick panels...

If you need any help, I'll gladly advise.

Do you know if your car came with the biodegradable wiring harness or not? You can probably have the VIN run at your dealership and they'll know. I wouldn't consider anything else until that's resolved.

But yeah, the frequent misfiring and sluggish performance on mine were almost completely cured by adding new OEM plugs. I'd like to replace the plug wires and connectors soon, but that's not a priority. My CEL hasn't been on in nearly 4 weeks now! It went from being on for 2 years straight to going off on its own (no, the bulb isn't dead).

But the replacement of my wiring harness is priority ONE.

Speaking of which, is anyone really sure of the position of the relay for the global window up/down feature (like when you lock the doors with the windows down, it rolls them up...)?

[mrjones]

Update: my car was in the workshop for a few days and they tested everything again. No error codes.
Not knowing what else to try, they upped the mixture.

Problem's still there and she's happily gulping more fuel.:bored:

[Sulaco]

Any ideas on where a guy could score a wiring harness? And how much?

[justdexter]

http://www.mercedesshop.com and then click the Buy Parts tab at the top. Enter the MB part number under the special order parts search on the left hand side. They did have them for $579 a couple of months ago when I ordered mine. That is the best place to get the parts and they are pretty fast.



Originally posted by Sulaco
Any ideas on where a guy could score a wiring harness? And how much?

[Sulaco]

Hi Dex!

[Denlasoul]

Sulaco-

One thing you may need to consider with your idling problem is you K&N filter with your new MAS. Now, many people will say K&N is a good product and will not cause MAS failure, and to a certain point I would agree. The problem with using this particular filter is that if there is excess oil on the filter, it could get onto your MAS sensor and cause it to fail. If I remember correctly, your MAS is located just upstream from your airbox, and your MAS could be really in harm's way.

If you are looking for O2 sensors, I have listed a good resource in the Parts section. I recently bought 4 O2 sensors and a MAS for around $650 shipped. All Bosch. In addition, I might be able to get you a wiring harness for a good price. I'll have to contact my source about that one, but it is a really good price.

As for all your other problems and such, I would suggest replacing things one at a time. Sounds like many of your OEM stuff is failing (most likely due to old age), so start there. It will be pricey but if you a DIY'er you can save some money.

[Sulaco]

I replaced the K&N with a paper Mann filter, heh. I'd already had a hunch it was a bad thing to have K&N oils so close to my MAS.

As far as I know, my O2 sensors are all original. Could they really be causing that much trouble? What benefits would I see if I replaced them both?

I've also noticed something new in the last couple days. While sitting in gear at a stop, there seems to be random misfires. Sudden quiet drops in RPM and jerks in the torque. They end as soon as I kill the A/C or put it in neutral.

[justdexter]

O2 sensors can cause quite a bit of havoc. I don't recommend dumping money into replacing all your sensors until you replace the harness, especially if you've noticed the wires deteriorating already. It's a good bet that you will need O2 sensors anyways if they are original. Recommended that they are replaced every 100K miles.

[Denlasoul]

Originally posted by Sulaco
What benefits would I see if I replaced them both?
Well, if they are faulty, then your air/fuel mixture will be off. So, if you fix it then your mixture would be correct, not running rich, and gas milage would be more higher.

[mrjones]

My Benz is healthy again!! :cool:

After closer inspection it turns out that the surpressor (coil end?) on #6 cylinder was busted, and another one was on its way out.
I tried all manner of driving styles on the way home, and not a single stutter or misfire. She idles very smoothly and runs like a dream! :cool:
I'm very happy again, as this problem was slowly ruining the car for me.

I've been told that an older 202 ('95, I believe) was turned down by DCSA for the free wiring harness upgrade because it was too old. Although not necessary (yet), the workshop will apply for my car as well. If I CAN get it as a freebie, that's a no-brainer.