Spark plug wires.

[Trae]

Hi guys,

I had been chasing a misfire on my 93' 500E for a month. I had replaced spark plugs, caps, rotors, and insulators behind the rotors thinking it might have been a moisture build up behind the cap. Car ran fine cold, BUT would misfire as soon as it reached operating temperature.

Then, I started focusing on the suppressors that fit over the spark plugs and the terminals that fit over the cap. Measured each wire for 2,000 ohms of resistance +-10%. Number 8 wire tested a little out of range, so I replaced the terminal and suppressor. Still, I had a misfire after warm up. The wires were a mix of Bremi terminals and Karlyn suppressors. I was not impressed with any of them.

Finally replaced all 8 plug and both coil wires with new Beru wires made in France. Dave sent me this link and I am very happy to report that my problem is solved. Select the wires that are specifically for YOUR YEAR MODEL because they are cut to the proper lengths based on year model. 1992-1993 500E, OR 1994 E500.

If you decide to do this job, Wurth Rubber Care will be your savior and make life very easy when adjusting wires and connecting them to plugs and caps.
Many thanks to Dave for his excellent pictures and link to these wires.

Also, many thanks to Jono as he told me about Rubber Care and wire numbers to the corresponding cylinders that are listed in the plastic tracks. It would be difficult to do this job without those numbers.

This was my first time to replace wires and it took me 4 hours to make mine look like Dave's pictures, but I think I could do the job in about 2 hrs. now. I ordered wire markers and clipped them onto the wires BEFORE I started the job by measuring each wire first and labeling them. Made it easier to keep up with the wires.

Link to PG Beru wires:
W0133-1599712 | Partsgeek.com

Wurth Rubber Care:

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After a few thousand miles, these wire markers will expand due to heat and slip around on the wires a bit, but none have come OFF the wires.
Shrink wrap markers should be used to alleviate the slipping problem.
Wire markers:

Amazon.com: Taylor Cable 41060 Clip-On Wire Marker Kit: Automotive

Buy Taylor Cable 41060 Clip-On Wire Marker Kit: Spark Plugs - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

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This photo shows the correct wire routing:
http://www.w124performance.com/images/M119/EZL/wires/M119_ignition_wires5.jpg

More pictures here:
Index of /images/M119/EZL/wires

 

[NotaBene]

I'm also in the process of trying to eliminate rough running problems. I'm at the point where I want to reroute my ignition wiring. I have two questions;

The wiring done by a previous owner/technician/amateur has two problems that are apparent. First, lengths are too long, and secondly, they have not used the channels designed for routing. Routing is like a plate of spaghetti.

Question 1, is it possible to cut and re crimp the existing wires? This provides two benefits, first, rerouting is easier since there is virtually no clearance to pull the female sockets through the tight openings, particularly a bracket that holds the fuel filter. Second benefit is that getting rid of excess length results in a neater result.

Question 2, as an alternative, has anyone removed the fuel filter power steering reservoir bracket that can advise me on issues that arise from doing this? I've attached the pic of the filter and bracket.

Thanks for any and all input.

 

[JC220]

I'm also in the process of trying to eliminate rough running problems. I'm at the point where I want to reroute my ignition wiring. I have two questions;

The wiring done by a previous owner/technician/amateur has two problems that are apparent. First, lengths are too long, and secondly, they have not used the channels designed for routing. Routing is like a plate of spaghetti.

Question 1, is it possible to cut and re crimp the existing wires? This provides two benefits, first, rerouting is easier since there is virtually no clearance to pull the female sockets through the tight openings, particularly a bracket that holds the fuel filter. Second benefit is that getting rid of excess length results in a neater result.

Question 2, as an alternative, has anyone removed the fuel filter power steering reservoir bracket that can advise me on issues that arise from doing this? I've attached the pic of the filter and bracket.

Thanks for any and all input.

View attachment 99923

That looks like they stood back 10 feet and threw those cables at the engine!

I would expect that once properly routed those cables should be OK length wise. Any extra length in cable can be tucked away under the plastic cam cover trims.

 

[NotaBene]

Yes, that might be an accurate description!

Logic tells me though, that with more efficient routing, I'll have greater excess length, not necessarily an OK situation. You're right, of course, I could tuck the excess under the cover, but that would keep me awake nights.

 

[195910]

I can see some chipped insulation. Best if you get a new set of wires and start doing the routing properly.

 

[gerryvz]

I agree. I'd just get a set of the Beru wires, which for $200 are of great quality and cut to the perfect lengths. Install and be done with it.

 

[NotaBene]

Thanks all of you for your input. I think I will get a new set of Beru wires. It had been my plan to test the resistance of each wire as I routed it, and in doing so I discovered difficulty in establishing continuity, let alone appropriate resistance.I continued for the point of seeing if I could do a better job of routing the wires, and did that. Once I cleared the jumble of wiring under the power steering reservoir bracket, I had enough room to work the insulators through. (And a thank you to all of you who graciously didn't correct my misidentification of the power steering reservoir. My mind was on a different planet.)

After rerouting the ignition wires, the idle is still rough, as I expected. The new set may solve the issue.

Using my new code reader, I identified 4 codes connected to the MAF sensor. As a quick test, I disconnected the MAF connector to see if the idle would smooth out; it did not. My gut tells me that doesn't necessarily rule out a problem with the MAF sensor.

So, the search continues.

 

[Allgonquin]

I just received my Beru wire set from Partsgeek. Looks quality but I have not done the install yet. Box is really large, by the way! When it was delivered I thought it was something else.

 

[Oldcar]

Hey guys got my new Beru wires today and only changed coil wires first which fit properly unlike other brands. These wires were original the oldest on car. Did a test and seems to be smoother running now ! Yes you can throw away old mbz plug wires......lol

 

[rayhennig]

got my new Beru wires

In 2020, MB in Bochum made up a lead set for my M104.980 and they fitted better than new Beru and NGK sets I had in stock. The issue was clicking into place over the spark plugs. The MB supressors clicked into place in a satisfying way. Beru and NGK would not - I had the feeling that they were not fully connected, if that makes sense. However, some ancient Berus would click into place so I suspect quality may have diminished over the years.

Has anyone asked MB if they can make up a set?

By the way, my MB supressors are Bosch and look like this:



RayH

 

[Oldcar]

In 2020, MB in Bochum made up a lead set for my M104.980 and they fitted better than new Beru and NGK sets I had in stock. The issue was clicking into place over the spark plugs. The MB supressors clicked into place in a satisfying way. Beru and NGK would not - I had the feeling that they were not fully connected, if that makes sense. However, some ancient Berus would click into place so I suspect quality may have diminished over the years.

Has anyone asked MB if they can make up a set?

By the way, my MB supressors are Bosch and look like this:

View attachment 219617

RayH

Maybe use some elbow grease ............ it may be just a tighter fit I hear mine click in....

 

[rayhennig]

Maybe use some elbow grease

Fresh out of stock.

R

 

[Oldcar]

Fresh out of stock.

R

If it doesn't go in at first twist then push...repeat as needed a Lemans female m119 race mechanic gave me this advice...it's actually true...

 

[Oldcar]

I agree. I'd just get a set of the Beru wires, which for $200 are of great quality and cut to the perfect lengths. Install and be done with it.

Spot on....mbz plug wires dont last forever as some people say...you can put them in the trash and feel good about it

Beru is # 1 just installed wires today along with new Beru plugs....remarcable performance increase