W124 Engine bay wiring looms

[d_jay1]

cheers mate. I'll hopefully recoup most of my money, but will list it with that mentioned as I don't want anyone else to suffer the same fate. I suspect the previous owner knew about it.

 

[d_jay1]

I've had another look inside the loom rail and that seems ok. I was going to take the cam cover off to look at the gasket that I think is leaking, so was wondering if that will help me take a look at any other loom damage? where else is it likely to be worn? The damage at the front of the engine seems to be from friction/movement as much as anything, so I want to make sure there is a problem before I decide what to do. thanks for all your help so far.

 

[Druk]

Using a scalpel or something else delicate cut gently into the wrapping along a cable. That will reveal if the insulation is rotten further along or if it's simply local damage. The rubber sheath at the plug end on the cable going to the maff is a fav candidate on the 320 engines.

You'd hope not to find something like this...

or this...

.

 

[Steven Stoole]

I've had another look inside the loom rail and that seems ok. I was going to take the cam cover off to look at the gasket that I think is leaking, so was wondering if that will help me take a look at any other loom damage? where else is it likely to be worn? The damage at the front of the engine seems to be from friction/movement as much as anything, so I want to make sure there is a problem before I decide what to do. thanks for all your help so far.

Dont give up yet! I repaired my loom all the way to the ECU. What i found was that only the wires to the coil packs were finished. I cut the wires at the ECU and ran new ones to the coild packs. You can desolder the plugs for the coild packs and reuse them again. Just buy some silicon wire and do it your self if you think you can do it. Mine was misfiring after i rebuilt the motor and i knew staright away that i had a short to the coild packs. Hope you come right.

 

[d_jay1]

thanks. I'll take a look later when I get home. is the MAF sensor on the left of the engine connected to the air box pipe?

 

[Steven Stoole]

Yes, it has a plastic clip that twists and you pull it off.

 

[d_jay1]

it actually all looks ok. gonna have a think as there's still a few bits I ned to do on it. May keep hold of it now if the missus will drive it!

 

[Martyn_n]

it actually all looks ok. gonna have a think as there's still a few bits I ned to do on it. May keep hold of it now if the missus will drive it!

Don't let that stop you keeping it. I've had mine ten months and the wife still refuses to drive "the tank" as she calls it. (I keep telling her it's pronounced Panzer!!)

 

[bobthecabbage]

e300d egr circuit not working

Hello, I'm working on a 93/94 e300d estate, the one with the wiring loom made of dust! I have got an intemittant/possibly now permanent problem where the egr and its associated flap are not operating. Also the flap is not operating in the crossover pipe and the flap in the intake manifold operates at low rpm which is apparently wrong. Is the EGR affected by the microswitch on the back of the injection pump? Does anyone know what each wire going to the microswitch does? I had to wrap them in insulation tape and may not have got them back in the right order!

 

[grober]

This of any help --its a petrol but you can see the egr and inlet resonance flap share some wiring. http://www.autolib.diakom.ru/CAR/Mercedes-Benz/1995/E320/SYSTEM WIRING DIAGRAMS/5419.pdf

That's normally supply 12v wiring = blue red in the diagram-- the ecu controls these units individually by selective switching to earth thus activating them.

 

[WesLangdon]

MB realised the error of their ways in early 96 I believe but just like the later "which cars are galvanised" issue its sometimes difficult to pinpoint exactly when the changeover occurred in relation to any individual car as the changes to the wiring would phased in for different models. I don't know who manufactured the actual faulty looms but its rumoured it was our own Joe Lucas who manufactured the insulated wire used. AFAIK none of the earlier single cam 4 AND 6 CYLINDER ENGINES were effected.

so my single cam 103 engine is unaffected? What about the 3 litre 24v 104 engine is that ok too?

 

[hogger]

hi there i have a c250 sport that wont change gear could that be a loom problem

 

[grober]

hi there i have a c250 sport that wont change gear could that be a loom problem

WHAT AGE IS YOUR CAR? IS IT PETROL OR DIESEL? The systemic wiring loom problem is due to a period when MB introduced biodegradable wiring insulation in attempt to make car components more environmentally friendly when they were finally scrapped. Unfortunately this bio-degradation started to happen in the cars themselves rather than landfill. It was limited to a period in the early 90's which was largely over by mid 1996. However all car wiring insulation of whatever vintage is subject to degradation [ looses plasticiser and goes brittle] due to heat- this is especially true of wiring in close proximity to /touching the engine block/head. This could only be effectively countered by the use of heat resistant insulation materials such as silicon polymers--- but that would be expensive! so in answer to your question if your car is post 1996 --its very unlikely.

ps there is a problem of gearbox fluid leaking into the controlling gearbox ECU due to faulty seal- well known fault-- it may be that's the problem?

 

[ajaxpc]

Starpartz: W124 engine wiring harness for £195 plus carriage.

Is this too good to be true?

http://www.starpartz.co.uk/products/124-series-engine-wiring-harness-rrp-350.html

Their website claims that they only sell genuine Mercedes parts ...

I'm a bit suspicious that they offer a 'generic' harness. It doesn't even say whether it's for a 320 ...

The part number is given, but I don't know what the right part number is. I'm going to look into it, but would be interested to hear from anyone that's dealt with them.

 

[tonywashere]

It looks used so you would have to check it carefully - no point in buying a harness with little life left in it.
There are several different part numbers so you'd have to check against yours.

 

[coupe deville]

about time somebody started making up these looms at a reasonable price, they could be made up in china or india for a score,
£650 + , = joke
over a barrel and death by bonga bonga springs to mind

 

[marty359]

Are the connectors and plugs for the looms available to buy separately?

Druk's pics in post #63 look moulded.

 

[Paul64]

too quick on the keys....!

 

[Paul64]

Does anyone know how many metres of cable it takes to re-loom a 95 300D? I used 2mm square cable to make temporary repairs which I guess is OK but I found 2mm silicone insulated cable for sale on the internet (for model helecopters!) that seems to sell by the meter, rather than the 100m roll, fortunately..!

This might be the way ahead as it's rated up to 180C so should be there for life!

Thanks

Paul

 

[BoyracerAU]

I've no idea, but this pic might give you some clues. No idea what car it's off though.

It's from this website.

Australia's leading Mercedes-Benz website