W124 Engine bay wiring looms

[Druk]

Hi,

Can anyone describe some of the warning signs of a failing wiring loom?

Thanks

Check the loom, look around the injectors, coils and sensors for signs of failed insulation. Mine had the low tension wires replaced at some point, so they looked good, but they had been spliced into a failing loom. If it's starting to go my recommendation is sort it before it does play up. It can damage ECU's if it shorts.

If the engine loom is poor the chances are the throttle body and lower harness is as well, slice open a couple of inch's of insulation and take a look.

I've just had mine rebuilt by Si-leck and very happy too. It took around 3 weeks, came back nicely labelled, fitted perfectly and quick to install. The car started and settled into a good smooth idle, everything working fine.

A pic below of the lower harness. The insulation crumbles as you disturb it, it's pretty obvious when it's gone.

Have a close look at where some of the wiring emerges from engine connector plugs at and around the front of the engine. The camshaft plug for instance. Usually there's a 1/2" or so of cable exposed before it disappears into a sheath. If there's any sign of crumbling insulation there then a closer more intimate look at the coil wiring is recommended. However this is usually intrusive and if damage is found then the engine really shouldn't be started until full remedy is done. One turn of the key with ignition wiring which has been disturbed can be enough to fry the engine ECU.

 

[Charles Morgan]

a couple of electrical hiccoughs recently on a very wet motorway run -

Describing them may help us think about the issue with more information.

 

[ml55amg]

Loom of Doom

Hi all on the loom thread!
My S124 320 project cars loom has too had it's day. I've been looking at options and trying desperately to save costs on the restoration.
I have the chance to buy a Delphi loom from a R129 at a reasonable price, question is will it fit?
The part numbers are very similar 1244403433 for the estate and 1295403633 for the SL is this a possibility or am I being plain stupid?
Any help greatly appreciated..

 

[YOREVOL]

i looked into second hand looms with no luck. you have to get a loom from a car with the same options ie: ASR and cruise control etc.
i am now looking towards si-lec to make one.

 

[JCW1]

Another satisfied SiLec client here. Top value and service.

 

[RichardF]

Hi all on the loom thread!
My S124 320 project cars loom has too had it's day. I've been looking at options and trying desperately to save costs on the restoration.
I have the chance to buy a Delphi loom from a R129 at a reasonable price, question is will it fit?
The part numbers are very similar 1244403433 for the estate and 1295403633 for the SL is this a possibility or am I being plain stupid?
Any help greatly appreciated..

Phone an MB dealer. Mine gave me 2 part numbers, 1 for the original and 1 for the updated Delphi harness. If your part number was taken from the original loom, you don't want one of those.

You may get lucky, I didn't, so Si-leck rebuilt it. Very happy too. You will probably need your throttle body rewired, again Si-leck did this at the same time. Don't forget your lower harness, not too hard to make up yourself.

For me to go the used loom route, it would have to be significantly cheaper than a rebuild, just in case of hassle factor. It's nice to have the back-up of a knowledgeable guy @ the end of the phone.

Good luck.

 

[EuroCarParts]

Hello,

Just wanted to let you know that there is a great site called Car Service | MOT & Car Repairs | Local Car Garages & Repair Deals. It will introduce you to a network of acclaimed local garages. Its just a question of typing in your registration number.

Regards,
Seyi

 

[grober]

Hello,

Just wanted to let you know that there is a great site called Car Service | MOT & Car Repairs | Local Car Garages & Repair Deals. It will introduce you to a network of acclaimed local garages. Its just a question of typing in your registration number.

Regards,
Seyi

Sorry to say this Seyi but this is a specialist topic on a problem unique to Mercedes vehicles of a certain age. Its a problem very few Mercedes main dealers have any experience in either. You can probably count the number of specialists in the UK who can offer real concrete help on the back of your hand. Under the circumstances a website offering links to local garages [ however competent on routine repairs of many manufacturers] is somewhat misleadling.

 

[EuroCarParts]

Sorry to hear that. Hope you find the help you need.

Seyi

 

[johnmcc]

Around £300

DiD Harry's mate sort you out in the end? I've been in touch with Harry and his problems eventually came back again.

I think I might now be in the same boat, only bought the car a couple of weeks ago!


Thanks

 

[Joloke]

I don't have an issue with my loom as such as I have an early Pre-facelift car

I do however have an issue with one small part of the loom and looking for solutions?

I keep getting an issue where my ignition lights disappear and my battery wont charge

My car has a new battery,new alternator and so it was suggested I look at the OVP relay

At a cost of over £70 I bought a new one only to find the new one did the same thing but found if I unplugged one and swapped it over it would remedy itself intermittently

Ive since bench tested both the Old and new relay and both work fine,in fact the date on the original shows it was a replacement just a few years ago :bannana:

The one thing that seems to cure it is either wiggling the wires to the socket and/or taking it out and re-seating it every other day

Don't want to replace a whole loom just for that so any ideas for fixing the issue permanently guys?

 

[Peewee74]

There should be a small paper label on the loom just inside the battery/ecu compartment, immediately behind what you call the sub-firewall or even hidden by it. This will have the part number and crucially the date of manufacture. If <1999 , if >1999.

Steve

Does this mean my 190e with m102 engine is a culprit as the label has 1987 as a year on it.
This is a puzzler as I was all the time concerned about my w124 coupe with m102 engine but had read that the m102 engine wasn't affected my loom issues

 

[RichardF]

Does this mean my 190e with m102 engine is a culprit as the label has 1987 as a year on it.
This is a puzzler as I was all the time concerned about my w124 coupe with m102 engine but had read that the m102 engine wasn't affected my loom issues

You won't have the dodgy soy based insulation on your harness, this is later, and definitely degrades and requires replacement.

However you still have a 30 y/o harness, so treat it as such, insulation can still degrade with time and heat.

 

[Peewee74]

You won't have the dodgy soy based insulation on your harness, this is later, and definitely degrades and requires replacement.

However you still have a 30 y/o harness, so treat it as such, insulation can still degrade with time and heat.

Thanks Richard, I know, I worry about the age of the insulation as I know it has gone hard in some places especially where it sits on the rocker cover.

 

[Alar]

Hi, my 1993 320CE-s original 1993 manufactured loom has finally give up. Found the part number, but there is very little info about it. It´s not even in EPC anymore. How can I find a part number for a new updated loom? I am ready to get a new one from the dealer, but would like to know the partnumber beforehand, to search around littlebit
This is my existing loom:

Chassisnumber WDB1240521C019494
Thanks for the help

 

[RichardF]

When I wanted one for my SL the local MB parts dept gave me 2 numbers original and updated.

I chose to have it rebuilt by Silek in Kent. Considerably cheaper, plus he rewired the TB at the same time.

Don't forget the lower harness, only a couple of wires so do this one yourself.

 

[patso84]

sorry for asking a question here...but I want to know are there any good mercedes parts apart from the original mb dealer ones?

 

[Steven Stoole]

sorry for asking a question here...but I want to know are there any good mercedes parts apart from the original mb dealer ones?

Have a look at febi bilstien they are German parts and are very good quality. Another brand is Meyel ( think it's spelled like that), they make a lot of OEM parts. I'm open to correction but when I was looking for suspension bushings etc for my W124 they had some parts exactly the same as the OEM ones and quality is brilliant. Hope this helps

 

[hotrodder]

AIUI both Febi and Meyle love a bit of reboxing and quality can vary i.e. the companies may be German but the parts themselves... may be better than OCAP or Q Drive tat most of the time and other times may just be in a nicer box?
Also worth remembering that things may have changed a lot since 124s were in production with companies being sold, merging with others or outsourcing production etc

MB use various different suppliers and in many cases have several sources for any given part. If/when buying from someone other than MB then the ZF parts group is a safe bet... Lemforder suspension/steering components and bushes, Sachs/Boge dampers, Sachs viscous fan clutches etc. Springs are best bought bought from the stealers due the way the correct rate is calculated unless lowering it with a Bilstein B6 kit or whatever

Origonal rads were usually Behr, these days it's Behr-Hella and i'd rather buy a Nissens rad personally. Dunno whether you'd get a Behr rad from MB (124 rads are insanely priced from MB) or if it'd be a Valeo or whatever. Ignition components from MB are usually Beru or Bosch, filters usually Hengst or Mann. They have a long list of suppliers for things like brakes and are often fairly close to aftermarket suppliers on a brand for brand basis for things like Jurid brake discs etc. OEM/OE quality exhaust suspects would include Eberspacher and Ernst

ALWAYS get a price from a dealer (or look it up online at MB inchcape parts if you have a part #) before spending any ££ as while they're sometimes comically expensive genuine parts are occasionally competitive/sooooo close in price it's not worth going elsewhere. Sometimes MB are cheaper than aftermarket cheanese tat from the usual suspects, even when the day has a Y in it and they have a [cough] "sale" [cough] on

 

[syncropaddy]

Have a look at febi bilstien they are German parts and are very good quality. Another brand is Meyel ( think it's spelled like that), they make a lot of OEM parts. I'm open to correction but when I was looking for suspension bushings etc for my W124 they had some parts exactly the same as the OEM ones and quality is brilliant. Hope this helps

:fail

Both Febi and Meyle are rubbish and neither ever made parts for Mercedes Benz. They both make or source copy/spurious parts to fit your car and are nowhere near the quality of the Original Equipment Manufacturer.