124 loom [again]

[coupe deville]

sorry guys, been a lot wrote on the pesky loom recently so, altho my motor , - 104, is running well, warm up good, idle good etc, i thought i would give it a thorough inspection. I suspect a previous owner has replaced it as it looks as it should. All the connectors have been numbered in paint as if a prep for renewal apart from the twin wire that goes to the camshaft magnet [ number 3 in pic]and then loops around to 2 other connectors which i dont know what they are , [numbers 1 and 2 in pic]. These wires crumbled before my eyes as i inspected them . Is it feasable that the loom has been replaced but not this part , i have made temp repair and motor is still running ok

 

[grober]

This post of any help? PeachPartsWiki: W124 Engine Wiring Harness Replacement The more detailed picture in the DIY seems to show some form of vacuum switching device- perhaps something to do with emissions control?

 

[Martyn_n]

I replaced my loom last month ('95 E320) and my loom did not have the second two connectors you highlight, only the inlet cam solenoid. Having said that mine doesn't have the vacuum component you have in front of the exhaust cam so wouldn't need them.


The wires to the camshaft solenoid were the worst affected on my loom (and they are part of the main loom) and the reason I replaced the loom. My car also had no obvious electrical problems but I am convinced it has been smoother since replacement, placebo effect no doubt.

 

[kth286]

those extra connections (1 & 2) are the EGR wires.

It is part of the exhaust gas recirculation emissions control but was discontiinued for later 124 E320s.

the system can get clogged and cause a faltering engine.

 

[coupe deville]

I replaced the loom today, just finished. The car is running great , warm up and tickover spot on, engine revs seem to pick up faster and i can now rock it with the throttle again, something that it had lost. I haven't took it out of the garage yet as I'm waiting for new plugs to arrive so I haven't put the engine cover back on. I cleaned the throttle body and air valve while I was at it. One puzzle was the throttle body connector was not part of the old loom that I removed, but there is one on the new loom but it is the wrong shape and size , slightly smaller, so its hanging there like a spare part

edit, looking at the old loom gawd knows how the engine ran at all

 

[kth286]

As hinted earlier, your generation loom was different in some respects to the later 104 looms.

Have you been given the correct look (by VIN) ?

 

[coupe deville]

The dealer, MB Eastbourne just asked for the reg number, the loom is exactly like the one I took off ( EGR connector etc at the front of the engine), except the new loom has a throttle body connector which is not the correct size and has nowhere to fit to as the old throttle body connector is still in situ and routes back to the ecu down the nearside wing and must connect to the ecu via one of the other plugs, although I haven't traced it back as the car is running ok. I read somewhere that there are so many variants of loom that MB standardised the replacements into 3 or 4 variants.
The car is running great so obviously the throttle body is functioning as it should.

 

[coupe deville]

Anyone with a 124 on original loom, don't have a looksee as it self destructs as you peel back the tape, but you are risking big bucks damage until it's renewed. Second pic shows 2 of the injector connections. Fitted new plugs today and been for a test drive, . Car is running better than it's ever done while in my keep . Loom £750 + but worth it

 

[trapperjohn]

Nice one Dave. Hope it repays you many times over.

 

[coupe deville]

Hi John, thanks, Ive been looking for a Cayman S, about 5 years old, £20k ish but the old girls really flying now so she's a keeper for a year or two. Tell your mate Mr IBW that we will call and see how the old buffer is the next time we're oop north, but we've being going to Whitby a lot instead of the Lakes as SWMBO as turned into a bloody Goth

 

[trapperjohn]

Ill be seeing him tomorrow so Ill pass on your warm regards!!