Used c280 engine harness on ebay

[benzaddict]

Hello, I was just searching on ebay and came across this used C280 engine harness. I know nothing about it other than I saw the auction, but it's cheap if it's in good shape. Thought it might help someone.....

http://cgi.ebay.com/ebaymotors/MERCEDES-BENZ-C-280-Engine-Wiring-Harness_W0QQcmdZViewItemQQcategoryZ46098QQitemZ801 8812881QQrdZ1

[Sulaco]

YES.

I've been waiting for my next tuition refund check to buy a new harness. Guess I can buy this one instead, provided it works.

Plus, mercedesshop.com just upped their price for these from $569 to $659. That's only $70 off the stealership price.

[rollinrealbig]

Hmm ... id only buy one if it was exactly for my car ... wires can be tricky.

yea these things are expensive for some reason ... if you think about it - its a bunch of wires!

LoL go to auto-zone and buy 100ft. of wiring and make your own LoL just kidding dont try that!


:)

[Sulaco]

Seller says this:

"No estimate on the miles for the harness. My 97 sucked in some water and bent a rod. The transmission fluid looked like strawberry milkshake. So I purchased a used drivetrain from a 1995 (less than 90k). However, the harness looked much newer than the engine. It has a 7/96 production date embossed on the plastic. So, I assume that it was replaced in late 96 or early 97. They send the VIN with the parts from the salvage yard. It showed being wrecked in 2003 with the last service around 88k. The connector got damaged in shipping. I hope that helps"

Not sure if I should buy it now. Could very well be the older harness that still has problems (but yet to break down only having 80-90k miles on it).

But my judgment is clearly impaired at the moment. I'll be waking up at 8:15 my time to re-examine the info and decide whether or not I want to bid.

[Sulaco]

Well, I bought it. Figured $40 is worth a shot at fixing my wiring harness. I'd pay $40 for a slim chance that it will save me $600 more. If it doesn't work, I'll order the real thing the next day (seeing as how I was going to change it out this xmas anyways).

[GPReyes]

stupid question but how do you know when you need to replace your harness...it seems that people I meet who see my car is a 202 always ask "how's your harness?"

will mind need replacing anytime soon? 1995 c280)

are there peformance symptoms for this?

[Sulaco]

Well, if your car still has the original engine wiring harness, then you will someday need a new harness. It's common lore around here. 1994 through 1996 m104 engines produced by Benz came with a faulty engine wiring harness. The subcontractor (I assume) manufactured the wiring harness with biodegradable materials insulating the wires inside the harness. After years of hot/cold dry/wet use, the insulation starts to break down and chip away. New harness is $650 if you want to buy and install yourself. If you want the stealership to do it, it'll run you about $2000 for all, methinks.

Symptoms: car won't start, lots of misfires, rough idle, rough acceleration, inexplicably goes into limp mode constantly...

The list goes on and on. The harness controls EVERYTHING electrical about the engine, so if it's going bad, LOTS of things will happen. You'll start replacing individual parts here and there trying to fix it but no matter what you replace it won't fix. It's actually really quite random.

Edit: Performance symptoms? For me, yes. It's getting lots of random misfires (codes 0304 and 0300, 0400 for EGR malfunction) and goes into limp mode EVERYTIME I give it any throttle...which causes an immediate drop of at least 50hp. I have to feather it everywhere I go in order to keep it from going limp..and sometimes it's going to go limp no matter how hard I try.

[GPReyes]

hey...that was really informative....

haven't had those problems (knock on wood)

hopefully the former owner replaced mine...

but at least now I know what to look out for...

many thanks..

[GPReyes]

hey...that was really informative....

haven't had those problems (knock on wood)

hopefully the former owner replaced mine...

but at least now I know what to look out for...

many thanks..

[Sulaco]

Well the "new" harness is in and it is definitely the right one, and was apparently in good enough condition to make a difference. However, there are still some other problems. But with my MAS, plug wires, coil packs, o2 sensors, and all other parts all being so old, I have no idea where to look.

Now, on crank, it cranks right up. Hasn't done that in at least 5 years.

However, whenever I hit the gas to give a healthy rev (or just give it half-or-more throttle on the highway) it backfires/misfires. To be more precise, on the highway it will backfire once, then begin misfiring randomly--only it will not go into limp mode now. And when stopped and revving it, it will misfire on revving up, but not on the way down. It only went into limp mode once while holding the wheel all the way over, stopped, in gear, with heater on high (tried to make it go into limp mode this way a bunch of times but only actually went into limp mode once).

My father and I assume it's some problem with the plug-wires/coils (seeing as how they all might be factory original!). So, I take the MAS off, remove the crossover tube, and remove the spark-plug cover. We revved it at night with all lights out trying to find some wild spark in the dark. There was no spark. And not only that, it ran alot better. It still misfired a little (after several tries) but ran very obviously better with the MAS disconnected, the crosssover tubing gone, and the plug in the crossover tubing disconnected.

We re-assemble the whole thing and try it normally--misfires again. So, disconnect the MAS while it's still running and it revvs noticably better for a few tries. Then, we disconnect the sensor in the back of the crossover tubing (with MAS still connected) and it refused to rev at all.

Help! Almost there!

[jnenad16]

the misfiring problem could be the wires/coil ends. you dont necessarily have to see the spark/arc in the dark to determine the wires are bad. I would change the coil ends for starters, if nothing happens, then you might want to change the wires as well. also, the if the revs improve with the mas off, then the mas is definitely the problem(or at least one of them). but one thing that stand out in my mind is vacuum leak. you should go over every single intake connections and vacuum line. even if they look ok, at least replace the vacuum connectors(those rubber elbow pieces). have you had a chance to scan the ecu? might hold a clue to your troubles.

nenad

[benzaddict]

Cool, I'm glad it worked out for you! That will save a lot of money. I'm with jnenad about the vacuum leak, I would check around everywhere for a vacuum leak, the backfiring would make me think there is a vacuum leak. It could also be the air mass sensor, but usually they don't backfire, they just rev extremely slow. If it's misifiring and the plug wires are original, I would recommend replacing them just as basic maintenance. Bosch makes a full wire set for these cars now, if you can't find one local I can get you a set for $65. I would definately check your spark plugs as well, they could be badly fouled from months of misfiring abuse from the bad harness.

If you don't have access to a scanner I would start with the maintenance stuff before popping for a $250 Air mass sensor. If oyu do have access to a scanner, let us know what codes you get.

Good luck.....

[Sulaco]

Wow. Thanks for the speedy and very helpful replies, guys.

I ordered a new coil and a new coil end today from importeccatalog.com

I recall getting P0304 alot for the last couple years but just assumed it was always the old harness causing it. I'll put this new coil in that spot and test. Today I noticed the coil end on #4 is chipping away at the end at the plug. Strange.

Plus, the coil-end on number 6 had goo in it! Some strange, greasy goo that was orange in color and smelled like freaking ear wax (my father agrees!).

[Sulaco]

Installed new coil and connector on # 4. Seems to have fixed the problem. Let it idle until at normal operating temp, then I turned the AC on high, held the brakes, put it in R, and turned the wheel all the way to the left to see if it would missfire anymore. Never misfired once. Didn't miss any on revs either. But it does seem like the throttle response isn't what it used to be, which I'm sure is the MAS/O2 sensor(s). But I'm just happy as it is.