Part 2 - this is when it really did get serious! rebuild pictures. using the same techniques others have listed on here already. having my own photos (there are only a few here but I took loads of images) was essential and i could not have done this without them to gaze at... a lot!

 

part III: will it start?
fitting photos and yes it did start as did my breathing!

 

nice work! thanks for the pics

 

Very nice! Looks very similar to the inline 6 engine wiring loom, just twice the connectors

 

Nice one. I rebuilt a V8 loom a while ago, but no matter what I tried I never did manage to get the pins out of the injector plugs and the multi-plug, so I stripped back the insulation, soldered new wires into 1/4 inch stubs connected to the pins and then popped heat shrink tubing over them

If you have any secret tips on how to do this, please let me know!

cheers

Dave

 

g0oil: just follow the instructions in this diy or ScrapingScraps:
http://www.benzworld.org/forums/w140-s-class/1625688-engine-wiring-harness-rebuild-diy-step.html

Shows how to get the pins out of the main connector etc.

 

Oh, trust me I tried it .... to the point where I almost took a sledgehammer to the whole thing!

Cutting the plugs apart with a Dremel was no problem, and that bit worked fine. The loom is still OK, it's just not as neat a job as ScrapingScrap's

I have another one to do so will give it another go....

cheers

Dave

 

We all commend the effort you are putting in, but you realize that if your engine harness (what you're showing) is going or gone, that your body harness (engine harness times 4 basically) is most likely also going or gone and will need to be rejiggered. The effort to replace the body harness is very extensive. Note the photos:

 

Not this horse crap again :surrender:

The "body harness" does not deteriorate like the engine harness, I have never heard of that happening..

The upper engine harness, lower engine harness and the wires in the electric mirrors are the only ones that go bad..

Stryker, everytime some one make sthe effort to rebuild their harness and do a great job about it, you get so upset that you post those same tired ass pictures.. dude you are seriously bored... why dont you go take a ride one of your dealership maintained flagships and shut the f#%$ up. :surrender:

 

Great work! Donkshophorse!!! Another successful rebuild!

 

Why, MafiaDon, I didn't know you cared!

Meantime, you may want to review: They are working on a V12, an engine that produces a prodigious amount of heat, unlike the engines you may be familiar with. And with an engine compartment that is literally filled with the M120 engine, with the 3.2liter engine in the same engine compartment, you've got enough extra room to place a washer and dryer in there.

More heat, the faster the soybean-wrapped wires go. And if the body harness isn't addressed, you run the risk of LITERALLY blowing your motor. That's how I got my 1992 600SEL. The rube that owned it in California didn't realize his body harness had started to short out the car and it produced a too-rich fuel mixture for the engine and *voila* engine cylinder wash, leaving scorched cylinder walls. Which can't be corrected by boring. You throw the whole thing out and start over. Like I did.

So, Genius, listen to someone who got a free car because the bozo that owned it prior to me didn't know his body harness was gone. Got that??

Body harness deterioration from a 600SEL:

 

those two pics of "faulty wire" you just posted are pics of the upper engine wire harness! (The exact one that is common to fail and needs to be replaced / rebuilt.) I can see the MAF connector in pic 1 lol :big laugh::big laugh::big laugh:

Wheres your pics of the "faulty body harness" that you, AND ONLY YOU seem to think needs replacing? The earlier pics showed some wiring, but none of that was deteriorating..

So even your own pictures disprove your theory..

I dont care what you got from where and who.. Bottom line is that you dont do any repairs yourself, and cant even turn a single wrench without assistance. (This admitted yourself)

SO if the "stealership" told you YOUR body harness was faulty, and charged you $5000 to replace, then that is your loss and ignorance!:big laugh::big laugh:

So even though I dont work on V12 engines, Im not stupid enough to believe your fact-less rantings. NOBODY has EVER backed your "body harness" misdirection.. You are alone on that one, so keep those thoughts to yourself..

You have posted those same useless pics on several other threads, we get it, you are retarded.

Moving on...

 

As you see fit.

Meanwhile, I've got the old harness in a bag in storage for the value of the connectors make it worthwhile. Soybean dust all over the place, raw copper wires showing all over the place.

But the work Donkshophorse is putting in is too valuable to be wasted if he does not check the wiring harness (body harness) that connects all the various components of the car, including the 'mouse coffin' where the car's computers are. Mr. Don would have you believe the brightly colored component (that tie into those computers) in the photo is from the engine harness. Do not believe him. He is wrong.

And if you choose to follow the advice herein NOT to check your body harness, well, my conscious is clear.

You see, I've been where you are right now.

 

I would have to agree with Stryker that the heat coming off a V12 is something to behold and change the normal way of looking at things. When I test drove a 95 C140 V12 the owner said it was not over heating; he would not hear of it. Well the temperature gauge must have been lieing then. He had it checked and the dealer said it was fine too.

Still, I wasn't buying it... Later he reduced the price by almost 5k

For that reason alone I would be concerened about things that do not normally suffer from heat, being affected by heat in the V12.

In addition, personally at least, I'd be wanting to double check something if a man who has 4 W140 V12's working well, suggests it's worth just looking at - just to make sure.

Surely, there's no harm in that and instead perhaps valuable information even if the engine harness is fine...

 

Stryker, give us some evidence. Repetition isn't evidence, it's repetition. With thousands of 600s out there certainly you should be able to find 5 or 10 threads on body mounted harness failure. We'll give you the whole world, needs to be in English, not that we don't trust you with translations.

 

Ive checked the body harness on my S320, (Granted engine half the size, but still can produce similar degrees of heat) and the body harness looked brand new! all the insulation was intact, and felt solid.. No worries there, but my main engine harness is crisp.. Either replacing or rebuilding mine soon.

Im just saying, in the entire history of the W140, I have NEVER heard of the body harness failing due to deterioration of the insulation. Regardless of engine size, and location.

So even though it might worth it to have a gander at the wires running to and from the coffin box, and the ones running just behind firewall.. I wouldnt look any further if those are all in great shape like they always are..

The ONLY reason the top and bottom harnesses fail is dues to the immense heat of the engine, and the fact they positioned right on the engine itself. Again, regardless of engine size.

The mirrors fail due insulation deteriorating form the mirrors being folded, positive and ground wires "short circuit" causing minor glitches, sometimes even smoke.

Unless I hear of multiple other cases and see for myself that a body harness has failed, besides strykers biased opinions and misdirections, I will not believe a single thing he says about this topic.

The W124 model also suffers from failing engine wire harness, aswel as the W202.. NONE of those cars were ever reported to have deteriorating body harness from engine heat / age..

Lets stop the hogwash, and commend a great harness rebuild!

 

One thing to keep in mind - on M120 engine the MAF connectors are part of the body harness and the wiring there is always a problem. Mercedes has repair kit for these two connectors only.

 

Mafia Don,

I respect you comrade! However, I am not sure this is totally hogwash!

If as Myarmar says on the M120 engine the MAF connectors are part of the body harness, so maybe Stryker has a point?

Still, as you say - commend a good rebuild...

One other point for us to bear in mind is it seems to me many V12's never get properly repaired, so that may be why not all of us know as much as Stryker about V12's...!

Rich

 

Myarmar did mention that Mercedes has repair kits for those connectors ONLY. The two MAF connectors on the body harness can fail because they run over the engine. But those are easy to repair, you do not have to replace the entire body harness just for those few inches of wire that went bad.

I have seen the MAF connector on the body harness of a 1997 S320 LWB. I was going to buy the wire harness if the MAF connector was part of it, but when I saw that, I decided not to buy the harness. (Even though it was in near perfect condition at a good price.) I did consider buying and modifying it, but I did not want complications, especially since i have to pay more a less for a plug and play replacement. So I am still looking..

Stryker may own a few V12's, but when it comes to knowing about the technical aspect, he pays the stealerships to sort them out. SO why is he even replying on a DIY thread if he cant even change a tyre without assistance?

im sorry, but I know hogwash when I see it.

 

Mafia Don,

Thanks for you post. It's all a bit over my head - although, I don't understand the animosity that I sometimes see in posts to Stryker! I mean, I'm sure he can change a tyre? Comrade, is that really the best way to put it?

You see, I speak from experience of having dealt with Stryker off line, and he helped me buy a wonderful W140 over long distances telling me what to look at sending pics back and forth. I learned so much. Naturally, I'm grateful - and he was right.

So forgive me, but I feel obliged to speak up for him, as in all his dealings with me he has been a perfect gentleman and a friend, and bloody helpful techincally. And I don't like to see us cursing out or laughing at our fellow Forum members.

How about this:- would you be satisfied with replacing hogwash, with something like "I'm not sure that's exactly right" That's the sort of thing the British say when they think its crap!

All the best, & respectfully!

 

lol..

I hear u Rich.. Nah, no animosity comrade..

its just irritating when a person repeats the same incorrect information, and can misguide other members and guests into believing his misconception is correct. This discussion has been closed multiple times, yet he feels the need to "copy and paste" those same pics and incorrect info..

I got no beef with Stryker, i was only joking about the tyre, im sure he can do at least that lol..

We all comrades at the end of the day

I like the pics of his cars that Stryker uploads, besides that I have not learned a single thing form his comments on this forum.

Guess you could say we from opposite ends of W140 ownership.. He can afford to drop thousands at the stealership to fix every minor problem and not have to get his hands dirty.. I cant, so I have no choice but to do almost everything myself, obviously our views will be completely different in that case.

All in respect though..

 

Awww, Don, you're going to hurt my feelings....

I've changed the wiring harnesses on my 1995 coupe and the 1992 sedan. I guess I didn't have to.

Gee, why would I do that??

That's all. Proceed at your own risk.

And btw, I know how to change a wheel and turn a wrench. But that's what I have people for, people who are better at it than I am. Thanks for your concern.

And Thank you, Rich. But as Forrest Gump says, 'Stupid does as stupid is.'

 

I would find this discussion so much more useful if anyone, just one person, would please post a full explanation of just what the "body" wiring harness is. Exactly where does it run? What does it connect to? Just how far into the body does this particular harness reach? Stryker's point is poignant that there is degradation of wires beyond those contained in the harness for the fuel injectors, but the constant use of the phrase "body harness" without detailing its extent is less than helpful. Myarmar is trending in that direction. So, who will be the first to post a wiring diagram or EPC parts diagram or anything more useful than a pic of spaghetti hanging out of an engine compartment. I'd like to be taught the nodes where this "body harness" of the earlier cars terminates.

Stryker, it should be easy to prove your point if you've got the old "body harness." Post pics of every inch of it and let's see the degradation. Obviously there is interest in seeing this.

Brett

 

My cars have two wiring harnesses: the upper harness (or engine harness) and the lower harness (referred to as the body harness) and they serve the components that suit their nomenclature: the engine harness is the one the runs over the top of the engine, runs along the channel above the V12's air plenum.

Meanwhile, the body harness ties together all the systems in the car, including the computers (mouse coffins), running along the lower portions of the engine through the passenger side of the interior to pick up the ABS and tranny sensors.

The spaghetti shown in the photos I provided share the extensive elements involved. I think there are close to 50 different connections on the body harness, each one tied to a sensor or body component, many of which are in the engine compartment, but not all.

It took us about 5-hours just to disconnect the old body harness in my 1992. It took another 7-hours to install the new one. I took a shot of the old harness on the floor of the shop once it was taken out of the car. In fact, I saved it because you never know if a connector might be needed.

 

All I can say now that I have found rats eating my W126 wiring, surely I should be thankful I don't have a W140 with wiring harnesses out here in the boonies....

Thanks for all your constructive comments Mafia Don, Brett, Stryker and all... - as for us V12 aspirationalists, this will all be more good education to steady us on our way when we finally buy a M120 coupe for under 5k!!! and rebuild her...

Kordell - way to go man, so it is true, gold is at the end of the rainbow....?

Tell us more from the great cold North - which I hear is not so cold right now...

 

I'd say those pictures could also be used as evidence that the harnesses don't fail. It's a bear of a harness but that one looks to be in pretty good condition. The problems I've heard of in the past have been limited to 600s and only certain areas of the engine compartment, readily repaired on the car.

Stryker has used the fact that someone told him to replace the harness on his 600 as evidence that they are destined to fail on all 140s - 320s, 420s, 500s and 600s. That's spreading misinformation and it degrades the integrity of the forum.

 

I'd say those pictures could also be used as evidence that the harnesses don't fail. It's a bear of a harness but that one looks to be in pretty good condition.

ARE U BLIND MAN !!!!

Kordell,

Ok, I have never worked on an M120 harness and I am having problems interpreting your pictures. The MAF connection is part of the body harness in 600s and, due to location, will fail. Sounds like everyone agrees on this point. Fair enough. I believe someone mentioned a repair kit for the affected areas so that one doesn't have to disassemble half of their car in the process.

Can you tell me if your body harness is only toasted in those areas, or throughout the entire harness? It appears that much of this harness is in good shape other than a few areas.

A picture is worth a thousand words and I feel that the matter of total body harness failure could be laid to rest if you could provide photographic evidence of catastrophic failure throughout.

 

AND THE REST OF THE HARNESS IS NOT FAR BEHIND FALLING APART PUTTIN IN IT IF YOU REPAIR THE AREAS THAT HAVE FAILED AN WAITING A YEAR TO PULL IT OUT AGAIN TO THIS TIME THROUGH OUT IS NOT WORTH THE LABOUR NOR TIME !!!!

 

thanks for the feedback, lots of replies while i slept this end! i have checked visible areas of the lower/body/other wiring harness and see no cause for concern at this time but i accept this may already have changed in some areas I cannot see. All i can say is the bits I can get to on my motor seem ok and i did move them around a bit to see if the hairline cracks I noticed on the upper hanress were being a bit shy in showing themselves down below - no problems... yet? this is one of my regular maintenance checks on the motor. i bought it as a project car and it has supplied me with a few projects but at the end of the day it is an unusual and powerful motor and needs a bit of tlc, it is now nearly 20years old after all. i just love working on it though, it is a bit special and that is why we all love the W140 models i guess.

happy days!

 

if anyone knew where to get fiber glass hood made with small cowl or vents to distribute some of the heat out of the engine bay this would help us all for the future cause HEAT KILLS!!!

 

if anyone knew where to get fiber glass hood made with small cowl or vents to distribute some of the heat out of the engine bay this would help us all for the future cause HEAT KILLS PEROID!!!

What's a peroid? If heat kills peroids, then I think the peroids should be saved