These plugs can and should be used on the coils AND the crank angle sensor connector so best to buy 9 per car.

Just figured out that SKP SKS1038 (rockauto is the cheapest I seen so far) is a great replacement for the factory crappy coil 3 pin connectors on ALL m113 powered cars.
https://www.rockauto.com/en/moreinfo...138341&jsn=352

My ml55 deff has intermitant coil connections particularly first start in the morning it was partially old sparkplug plug wires but now I replace everything I see it still does it to some degree (but less so) so started investigating the 3 pin coil connectors themselves. My e55 the plugs are pretty much all broken but seem to work ok atm but I do wonder if I get misfires on that sometimes due to this issue and they wont show as codes. Certainly the ml55 me2.0 doesnt throw codes unless its really bad im assuming the E55's with me2.8 are probably the same deal.

What I see online is most people are just replacing the plastic plug (because of broken locking tabs) with the same damn **** design plug with the same old terminal design!!!!! This is not the solution to the actual problems and they are only fixing one of the many problems with the original plug and not really because they'll just break again down the line anyways.

Anyway MB actually updated these plugs to a better design but they sell it as multiple pieces so you have to buy the plug the crimps and seals all separate. They updated the crimp to I guess what you'd call a clasp style with I think more spring load on the terminals whereas the original factory ones are like a rectangle box with tiny small spring terminals that make the connection. I think the SKP plug is easier to deal with as it comes as an assembled pig tail set so you can just solder and seal it into your existing loom rather than having to use special crimp tools and possibly ending up with wiring too short in the process.
Mercedes updated clasp style crimp (I think the SKP is the same general thing):



When I tested my ml with a cut down 0.8mm thick spade I cold feel one pin out of 3 on two or three coil connectors were too loose and had far less "grab" to them when inserting and withdrawing the spade. I havent checked the E55 yet but suspect I'll find something similar going on there. The design of the factory rectangle shape terminals and plastic plug housing allows the terminal to rotate on an angle in the housing and I think when inserted into the coil this also tend to make the springs inside get pushed out more than they are designed to be and they loose spring tension on the terminal.

SKP terminal style:



Original OEM pin style: (note how they are physically sitting on an angle in the plastic plug!!)

 

Awesome find!

 

I measured the wiring core when twisted on the skp its 1.150mm approx.
On the factory ML55 wiring its 1.390mm approx.

Will be interesting to see if the e55 used the same core size wire as the ml55.

These SKP's are listed for the ml430 coils so I think they are fine. Theres another version of this plug I think the part number is s1038 sold on summit racing for a couple bucks less than this skp. Would be interesting to buy that one too and see what size core wiring they used.

Im only cutting 30mm out of the factory loom so its a nothing imo and way better than dodgy connections that the stock plug gives.

 

I used these from Ballenger Motorsports when I did my engine harness:

https://www.bmotorsports.com/shop/pr...roducts_id/986

The little blue tabs lock the connector in place and work very nicely. I used 18 awg wires.

 

@austingtir
Not sure if it helps but on Amazon's product pic for S1038 you can see 16-14 14-16 AWG ( I think ) shrink wrap. 16 awg is 1.291mm.


Btw I am tempted to do it as well. So you cut off original connector with 3cm of original wire. Then solder one of these SKP or S1038 connectors. Are the wire colors matching? Also how hard is it to take the factory connector apart so as not to do any cutting and upgrade it with something like www.bmotorsports.... ? Any special tools needed or just pick/hook and pliers?

 

Get a cheap set of universal depinning tools: https://amzn.to/3GolWQD One of those will certainly work for depinning that connector.

 

This is a solution looking for a problem. I've worked on hundreds of M112/M113 engines where the coil connector lock breaks off. The rubber seal, wire harness shape and pins have enough resistance to hold them in place forever. Replace the zip tie holding the wire harness to the fuel rail for extra security. Never had a problem....Swapping pins and connectors will do potentially more damage as most people don't have the tools or skills to do this correctly. My pro tip: Don't mess with them.

 

On my ml55 I staggered the cuts so the connections arent right next to each other. The S1038 comes with crimps so if you've not soldered much that might be the way to go. I have alot of soldering experience so unless you've done a bit of soldering the soldering method is probably not the best route.

The proper way to do it is deff to depin cut the old crimps off and put new ones on but you run the risk of the loom ending up too short.... If you cut them right at the terminal it might work.

I'll probably try do it that way on my e55 sometime down the line to see if it can be done.


Depinning and new plugs and crimps is deff the best way to do it. Followed by soldering those pigtails in then followed by crimping.

There is also solder heatshrink but each one of those is relatively expensive by the time you get enough to do this job.

 

I agree to a point but my ml55 deff had a couple of loose crimps first I got in there with a needle and manipulated the crimp housing tighter and the car deff started better. If you dont have a problem with misfiring and you havent replaced everything then this is folly. Especially if you dont have the skills to do it properly.

 

Just had cylinder 7 plug come off after I accelerated on a nice straight road. I need a solution and thanks for the suggestion.
this also happened to my cls55 before as well. Not nice when its.a dark road.