M275 Coil Pack Conversion
 

I just wanted to share an idea I had and I don't know if it would work or not. As you all know, the main issue anyone who has ever owned a M137 or M275 has had to deal with at some point are the dreaded coil packs. Constant misfires and headaches are a result of stupid engineering by Mercedes at the time. If a cylinder misfires (which it inevitably does with this poor ignition design), you can't even replace that individual coil. It comes as a large, expensive whole unit of 12 coils that you must replace all at once even though other cylinders on the same bank may be fine. I'm not sure what it is with these cars, but most of us who had to deal with misfires and replaced our coil packs with all the proper precautions still end up with more misfires later down the line. This is unheard of with any other car.

Now back to the idea I had. I'm not sure if many of you know but Mercedes has recently solved this issue with their recent V12 models. They still use the same engine in their newest models albeit vastly upgraded for improved reliability. One aspect that caught my attention was the revised ignition system. They finally ditched that atrocious coil pack design for a normal design with two coils per pack. Take a look:

https://www.genuinemercedesparts.com...EyLWdhcw%3D%3D

Is it possible to retrofit these coils into our engines and have a normal, reliable, proper ignition system? The only obstacle I see is how to wire them properly since each coil pack has its own connector, but other than that I'm sure they would fit properly where they should. I remember seeing a video on here a long time ago with someone getting the M275 running on standard ignition coils, but I can't seem to find that video anywhere now. Needless to say, I really do think its possible to retrofit these and finally solve this long dreaded issue. What do you guys think? Any insight is appreciated.

Does anybody have any clue if this will work or not? I'm tired of constantly having to replace these coil packs as they are expensive and fail whenever they want, and I'm sure every member on here with a V12 feels the same way. I would be willing to be the first one here to attempt this project if it is theoretically possible, and it would be amazing to finally solve this massive design flaw if it works. Only challenge I see is creating a custom wiring harness that connects the oem plug to all 6 coil packs on each side and having the ecu recognize the coils.

I need new coil packs anyways, so its either I waste more money buying two new ones that will eventually fail anyways and do absolutely nothing for the M275 community, or I can buy 12 of these for cheaper than 2 new original coil packs and get to experimenting and potentially solve this crisis. I really need some answers and advice if I'm going to do this guys. I'm not holding anyone to it, I just think it would be nice to make owning these amazing machines much less of a headache for all of us.

That was my plan B, but then again that would do nothing for the sake of these cars. Just another coil pack failure and just another expensive replacement and the same old stories with the same old bs with these cars, regardless of lifetime warranties or not.

I want to finally solve this design flaw so everyone including myself will never have to deal with this horrible system ever again. I've been searching everywhere about how the new coil packs are implemented in the new cars so I can get an idea of how it will be implemented in the older engine, and the closest I got was these pictures I found of the coil packs in action from a custom V12 C-class build by Weistec. Take a look at the coil packs.

https://www.boostaddict.com/images/i...65_v12_3-1.jpg
https://www.boostaddict.com/images/i...65_v12_2-1.jpg
https://www.boostaddict.com/images/i...5_v12_22-1.jpg

For more pictures, go to https://www.boostaddict.com/showthre...ll-wheel-drive

From these pictures, I can't quite tell what they are bolted into. Looks like they're bolted into the valve covers, but I'm not for sure about that. Either way, if you're looking to mount this on the old engine, looks like a custom bracket needs to be made that bolts into the existing coil pack screw holes on the M275. Shouldn't be too hard or expensive for that. This isn't the hard part.

The hard part is figuring out the wiring situation. I'd like to say that you can just buy and use the coil pack wiring harness from the new engine, but from the pictures alone I'm not able to tell where the harness leads to or if it would even work with the old system. My best bet is figuring out exactly which pins on the old coil pack plug do what and wire them accordingly to the new coil packs through a custom made harness, or possiblly an easier way would be to just use the harness that's in the newer cars and custom wire it into the old plug. I wasn't able to find the new coil harness through the parts catalog, and can't find the part number for it, so if someone can find that it would really help in figuring out how to go about this. This wouldn't even be the hardest part.

The hardest part is getting the computer to work with the new coils. It's completely unknown if the computer will accept the new coils and have the old voltage transformer communicate with it and make it work as intended. I remember a video on here a long time ago where someone actually got the M275 running on standard coil packs from an S500. Unfortunately I can't find that video anywhere now, it would have been very helpful. It proves that it is possible to have the computer accept the new coil packs and make them work as intended. At the very least, I believe some reprogramming with star/das would be needed.

The best case scenario is if we just get the coil packs mounted and wired up properly and everything starts working as intended. The worst case scenario is if the computer and the other ignition components do not recognize or accept the new coils and prevent them from doing their job. I'm no engineer, so I can't say if there is a bypass for that scenario or not, so that's why I'm asking everyone to chime in and offer their thoughts and help. I really do think this is possible, we just need more people who are willing to get into it and figuring everything out.

That's a very ambitious endeavour, and I can appreciate the motivation. I happen to be repairing one of my coil packs right now. I don't regard ABC as a weakness any more, leaving only the coil packs as the glaring and frustrating weakness on our cars. The V12 has a lot in common with the contemporary V6 and V8, which used much more sensible and robust single coils per cylinder, so maybe there's a way to scale that up to a V12?

You have to ask my MB didn't do that themselves though. Maybe there isn't room for the air filters and intercoolers without the space-saving one-piece coil packs? On the other hand, they were introduced on the M137, which didn't need that space saving.

If you wanted to convert back to single coils, you might need a different cam cover design to physically accommodate them. Plus you have to be very familiar with all the ignition schematics for both the V8 and V12 engines. What power supply voltage do the single coils use?

I would be very impressed indeed if you can get this to work, but it's not something I would attempt. There are so many things that are frustrating about our cars, and I have a long list buzzing round my head right now, but sometimes you have to work round it. First thing is to make sure you're using the right plugs and the right gaps, and that nobody sold the previous owner M137 plugs instead.

Best regards, Nick

Hehehe Nick, nice to hear you!
Would love to hear from Hoaz too.
I have learned the hard way that many of the so called "coil pack failures" are actually deliberate cylinder shut downs by the ECU due to O2 sensor failures (or out of range).
Problem is: they are announced as "TWC damage" ONLY in SDS, not on any other CEL monitor program, and, can be reset easily via the programs available on smartphones.
A good procedure is to monitor the O2 sensors live with SDS. (it may be the upstream, but just as well the downstream monitor O2 sensors).
Our V12s are temperamental indeed (like a woman), and the ECU software is the same.

I was plagued with misfires (on my tuned car) for years, and I only got rid of them when I threw away the jubilee clips on the charge air pipes to the intercoolers, and replaced them with proper T-bolt clamps. I haven't had a misfire since.

Air in the IC system tends to induce misfires as well.

Nick

I agree with you Nick, the ABC has slowly overtime become less scary. With great write ups everywhere about it and an integration of fluid flush services that these cars never saw from their previous owners, it really doesn't seem that big of a deal anymore. It also isn't as prone to breaking as everyone was saying it is. Even if you aren't fond of the system and don't want to deal with its complexity, you can simply just convert it to coilovers and never have to worry about it again!

It's a different story with the coil packs. No matter what precautions are made, how carefully they are installed, or how they are used, they will fail no matter what. And it's a pain to deal with. And it's expensive. And there is no "conversion" solution for it. Often times they fail because something else has caused it to fail, and the extremely fragile nature of the coil packs doesn't cope well with its ridiculously high cost and complicated procedures. It is one of the stupidest design choices I've ever seen in a car, and I doubt it was made to conserve space. My best bet as to why they went with the awful complicated system was for the cylinder deactivation of the M137, and just didn't have a care to redesign a new ignition system when the M275 replaced it. It is highly apparent that the introduction of the M137 and later M275 was a huge downgrade in engineering development from the former M120. The only reason why I can't bring myself to ditch the M275 for an M120 is because of the turbos. It completely changes the driving experience, enough to fuel my desire to fix this glaring design flaw.

I don't think there needs to be any modification done to the cam covers if the M279 coil packs are going to be used. It pretty much fits in the exact measurements where the old coil pack would go, or at least that's what I think. the M279 is essentially the same engine except the engineers this time around decided to grow a brain and fix the design flaws. If you're talking about retrofitting the M113 coil packs into our engines then that is a different story. I really remember someone doing that here, and there was a video of it but I can't find it anywhere. It is the world's best kept secret at this point. The hardest part would be figuring out all the wiring and schematics as you said.

I spent all my free time yesterday repairing a couple of coil packs, when I could have been gardening instead.

Funnily enough, I had previously repaired one of them three years ago. Fortunately it was only original coils that had failed. I'm not sure I'd want to replace a coil more than once. Those foil wires are rather a bit fragile.

The M279 transplant should be more feasible, but I think they have to interface with a different ECU.

Nick

I finally found the video of the M275 running on M113 coil packs:

Looks like it can only be done with either a standalone ecu or someone who has the knowledge and ability to somehow make it work with our stock units. I also noticed that in the video there was no more voltage transformer after the conversion. They used the M113 coil packs but those look like a pain to mount and wire up, so I hope the M279 coils can take its place and still work with the ecu. I can't really do much at this point but to encourage someone who knows a lot about ecu software tuning to try and make it possible. I heard speeddriven went out of business too so getting a hold of them to ask how they did it would also be a challenge.

Nick would you please elaborate more on this! Can you explain which clips do you mean? Photos if possible

Regards

The clamps that hold the intercoolers to the hoses down by the turbos. Nothing much to explain, the factory clamps are garbage.

I use Mikalor Supra W1 and W2 68-73mm hose clamps.

Nick

Do you have the link to the correct size? I want to order the same

Just buy this:
https://www.ebay.com/itm/2-5-4-Ply-T...72.m2749.l2649

I just ordered them to replace the stock tubes and clamps. These will do much better than what the oem setup has to offer.

Be careful with those cheapy T bolt clamps. They aren't full stainless and the nut can rust fairly easily, making them one time use.

Full stainless ones are much more expensive but last far longer, as long as you don't gall the bolt. Little bit of anti-seize goes a long way on those.

Is the pipe stock size 2.5 inches?

I posted about this sometime ago as well as the m279 made some cool improvements that could benefit us m275 owners.

After thinking about the possibility of swapping these coil packs in, the problem in my mind has to do with what our coilpack actually is. From what I know, our coil packs have a built in monitor for misfires and the internal chipsets run these back to the main ecu. On a e60 m5 v10, bmw used separate little control units that monitored misfires in the same way. Again, my understanding is that this function is built inside our coilpacks. I am sure the new m279 ecu has the system built in or deals with it in a different way.

Because of this expense and difficulty, I agree with what others here have said-the coilpacks we have are not that bad after the first replacement. I also strongly believe that proper maintenance will prolong the life of them drastically. Replace spark plugs at shorter intervals and replace the red insulator boots every single (and I mean every single) time you remove a coilpack.

On another note, don't be so sure that Mercedes changed the design only because it "lasts longer". For example, perhaps Mercedes dealers were having issues breaking Coilpacks when removing for service or maybe the new system is cheaper actually. In the end, my original Coilpack lasted 12 years and 80k miles in a hot twin turbo engine bay that makes 600hp. That ain't too shabby if you ask me.

It looks like that function can be bypassed with some ecu tuning, since speeddriven was able to do it. It is totally possible as you can see from the video that they put out, but I have no knowledge about ecu tuning and actually have no idea how easy it is to trick the computer to bypass the stock coil packs. If someone here is an expert on ecu tuning then they would help us out a lot on this matter.

Also, what did you do that made your original coil packs last so long? I've never heard of those going that far, let alone half of what you said. I just replaced mine with good used units that had only 20k miles on them 2 years ago and they already failed on me.

They all last that long usually. My car is an '03, had 75k miles on it when I got it. I tuned it within a couple months of me getting it like 2 years ago, first coil pack broke when removing it to do plugs (one coil stayed in the head), but was working. Second one crapped out maybe a year later. I replaced the igniter also when I did the left pack. 15 year old car with 80k miles needed a pair of coils and igniter, not the end of the world to me. Yes they are expensive but not bad relative to the cost of the car. If the replacement ones last another 15 years and 80k miles, it will be way longer than I need them to last.

Wouldn't it have been great to replace only one broken coil individually rather than throwing away the other 11 perfectly working coils you had? As well as spending over 1k on a new one? This is where the main problem comes in. Sure, they may last long if everything is untouched and the car is taken well care of, but as soon as it comes time to replace spark plugs or a single misfire shows up its all downhill from there. Its a real pain to have to replace the entire unit just because of one bad coil or plug. The m279 coil packs are far better designed and much easier to maintain. You would only have to pull off one coil pack for one cylinder that may be misfiring, without touching or damaging or having to replace the other perfectly working coil packs. Also, they have no chance of breaking when pulling them because they use long rubber insulators that go into the cylinder head instead of metal coils that are prone to breaking off the main coil module. It's stupid how it took MB 15 years to fix this design flaw.

In the 90s when this engine was designed, anybody running a v12 was using two controllers to run the engine like a pair of I-6 engines, as there wasn't an M/E out there that could handle the ignition requirements. This system is far and away better than most of the equivalent systems when it comes to overall reliability. Yes, the coils are more tedious and expensive than single coils, but have you ever had a v12 BMW with ignition issues? I'd take a simple coil pack replacement any day over that, even at $950 per side.

Lots of things on these cars are an engineering compromise. My PSE gave out the other day. I could **** around and buy a used one, try to band-aid it, all the options are there. Or I could spend $500, put a new one in, and be done for another 15 years. My time and the hassle is not worth the little bit of money saved, if I have to spend multiple times fixing the same system/problem.

Anybody buying a V12 Benz hoping to fix it for cheap, is in the wrong car. You have to be prepared for these things on these cars. I am a tech at MB, and I've still spent probably $1/mile on maintenance since I bought the damn car. The difference is, I have no fear that the car is in good working order, I push the car as hard as I want and i'm not worried about some rebuilt coil pack taking a **** on me, or whatever. Little money spent is well worth it when I can blast down the highway at 140 in complete comfort, at any time, over and over again.

That would be a good excuse if it were the first v12 that mercedes designed.

The M120 engine is superior in almost every way to the M137/M275. It had a normal ignition system. It also had DOHC, 4 valves per cylinder, and other superior design features that its successor lacks. It was a far better designed engine. Still wondering what was going through their heads at MB.

Only downside is it didn't come with turbos, hence why I, as well as most of us, are stuck with the flawed M275 :nix:
Which leaves me to think, why the hell does the M137 engine even exist? No turbos, less power, and FAR more unreliable than the previous N/A V12?

I've seen those old V12s go over 400k miles. I still haven't seen an M137/M275 with at least 200k on the clock.

Had to be a reason they replaced the M120 rather than updated it?

There's nothing "unreliable" about the 275, it has expensive coils. They fixed that with the 279. they've been using the same basic 137/275 engine for 20 years and it hasn't really been an issue with anything. AMG has stated there will not be a new V12, they are spending that effort on developing more relevant engines, so the 279 will likely be the last v12 engine architecture we see for a long time from MB.