Large loss of power P0300 to P0306
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Joined: Jul 2011
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Cl65 AMG
Large loss of power P0300 to P0306
I have a number of codes related to misfires, 7 in all which includes P0300. The problem started months ago when from time to time I would bet a CEL for 3 or less misfires but would never cancel out any cylinders. I would just clear the code and move on. Last week I gave it some juice on the freeway and lost at 2 or 3 cylinders. Just cycled the key and the problem was gone (CEL still on ).
This time just softly from a stop the car just shut down 6 cylinders or so. I cleared the code and same thing happened again. It got to a point that just idling would cause the car to be running fine and then drop 1/2 or so of the cylinders.
I broke it down this afternoon and everything went well but I did find some water/coolant on some of the plugs & boots. I am sure its from me playing around with my inter-coolers. Bleeding them off etc. I honestly can't tell if the coiled are original (100k on the car). I really want to have this problem get solved but don't want to replace good coils. The car didn't miss until it was ran today for at least 1/2 hour so maybe the water began to vapor up hence the misfires.
I guess I can mock the coils up and preform output tests to see if there is any glaring lack of firing voltage as well as test the injector flow rate. I have a tester made for GM cars but it will give me an bench mark to measure differences. The engine is spotless with no oil leaks of any kind.
I guess I can mock the coils up and preform output tests to see if there is any glaring lack of firing voltage as well as test the injector flow rate. I have a tester made for GM cars but it will give me an bench mark to measure differences. The engine is spotless with no oil leaks of any kind.
I will take a lot of pictures if anyone is interested.
My engine mounts are past due so I may replace them as well since I have them in my garage. I understand the engine needs to come out of the CL to do this so being a pro Tech I should be able to handle the job. I am sure however theres a lot of other things more entertaining to do in a 100 degree garage. 
Last edited by driveability; Jul 26, 2012 at 11:19 PM.
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cl600
looking forward to the photos. don't think the engine has to come out for the mounts. may have. TO BE RAISED THOUGH. I HAD A SIMILAR PROBLEM, MIGHT WANT TO CHECK THE IGNITION MODULE ON TOP OF ENGINE AS WELL, BUT IN YOUR CASE PROB. COILS, OR the rubber pieces. tech checked for carbon deposits on coil packs when checking mine. i didn't havr any carbon and then he found an intermitent short in the ignition module. replaced and solve my problem.
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Joined: Feb 2010
Posts: 390
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From: SoCal
CL65, FJ80, Sportsmobile 4x4, Model X Plaid
Had the same PO codes and symptoms as you.
I also didn't want to replace the Coils, so I started with a new transformer/iginition module.. the limp mode with one coil pack erroring still happened.
I ended up getting new coils (with the new part#'s), sparks and red boots and the beast is back better then it was ever before.. no cel's at all.
DIYed it and actually really enjoyed the tear down and the put back..and getting to know the M275 engine...
Are you sure it was clean as a whistle in all your spark plug cavity holes? I cleaned every one of them(spark plug cavity) with a hemostat/veva and simple green until they were spotless.. Especially check cavity holes around cylinder 1 and 2 (I think) right under where the Oil Filler is.. I had a path of old spilled oil that went from the side of the oil filler, that flowed right above the first two cylinders and right into the cavity hole.. in my case, the oil coated the red boots and shorted it, so in the beginning before the whole coil pack gave out, I would get CEL's when I gunned it above 3000 rpm.. then in the end, I got the same symptoms as you..with the whole coil pack giving out..
Notice the path any missed oil would take from the oil filler cap area..
Clean as a whistle:
here is a before it was clean, notice the old oil that came from the oil filler miss:
I also didn't want to replace the Coils, so I started with a new transformer/iginition module.. the limp mode with one coil pack erroring still happened.
I ended up getting new coils (with the new part#'s), sparks and red boots and the beast is back better then it was ever before.. no cel's at all.
DIYed it and actually really enjoyed the tear down and the put back..and getting to know the M275 engine...
Are you sure it was clean as a whistle in all your spark plug cavity holes? I cleaned every one of them(spark plug cavity) with a hemostat/veva and simple green until they were spotless.. Especially check cavity holes around cylinder 1 and 2 (I think) right under where the Oil Filler is.. I had a path of old spilled oil that went from the side of the oil filler, that flowed right above the first two cylinders and right into the cavity hole.. in my case, the oil coated the red boots and shorted it, so in the beginning before the whole coil pack gave out, I would get CEL's when I gunned it above 3000 rpm.. then in the end, I got the same symptoms as you..with the whole coil pack giving out..
Notice the path any missed oil would take from the oil filler cap area..
Clean as a whistle:
here is a before it was clean, notice the old oil that came from the oil filler miss:
Last edited by NRL; Jul 27, 2012 at 12:21 PM.
Super Member
Joined: Jan 2004
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From: Del Mar, CA
2003 CL600 2005 745Li
You can look at the part numbers on your coils packs, the original coil packs where on the weak side and will fail sooner. MB redesigned them so if you look up a new coil pack it will have the newer part number and compare to yours so you will know what you have.
Some guys have coil pack issues soon after getting an ECU tune, old weak coil pack and new high power tune can cause the old weak coil pack to fail.
You DIY guys are great, keep the pix coming !!!
Thanks
.
Some guys have coil pack issues soon after getting an ECU tune, old weak coil pack and new high power tune can cause the old weak coil pack to fail.
You DIY guys are great, keep the pix coming !!!
Thanks
.
Thread Starter
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Joined: Jul 2011
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Cl65 AMG
I checked the part numbers and I have an "04 & 05" in the coil part numbers. Looks to be original ones just over 100k. Before I bought the car the PO replaced the transformer/ignition module bla bla bla LOL forgot the MB description. My plugs look fine, I will carefully clean them with my media blaster. Funny there NGK F1. With a part number like that you they are pricy. Yes most would just replace them but iridium is durable.
I do have a quick question, my plugs have the Mercedes Benz emblem on the NGK F1 plugs. Is that what one would expect to see from a dealer serviced car or could they be original factory plugs. They sure don't look original looking at the center iridium electrode.
I do have a quick question, my plugs have the Mercedes Benz emblem on the NGK F1 plugs. Is that what one would expect to see from a dealer serviced car or could they be original factory plugs. They sure don't look original looking at the center iridium electrode.
Senior Member
Joined: Feb 2010
Posts: 390
Likes: 2
From: SoCal
CL65, FJ80, Sportsmobile 4x4, Model X Plaid
I checked the part numbers and I have an "04 & 05" in the coil part numbers. Looks to be original ones just over 100k. Before I bought the car the PO replaced the transformer/ignition module bla bla bla LOL forgot the MB description. My plugs look fine, I will carefully clean them with my media blaster. Funny there NGK F1. With a part number like that you they are pricy. Yes most would just replace them but iridium is durable.
I do have a quick question, my plugs have the Mercedes Benz emblem on the NGK F1 plugs. Is that what one would expect to see from a dealer serviced car or could they be original factory plugs. They sure don't look original looking at the center iridium electrode.
I do have a quick question, my plugs have the Mercedes Benz emblem on the NGK F1 plugs. Is that what one would expect to see from a dealer serviced car or could they be original factory plugs. They sure don't look original looking at the center iridium electrode.
I put in NGK Iridiums..
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Senior Member
Joined: Feb 2010
Posts: 390
Likes: 2
From: SoCal
CL65, FJ80, Sportsmobile 4x4, Model X Plaid
The plugs are the same.. I just wanted new ones.. supposed to be 100k miles or 5 years which ever comes first..
It's going to pure like a kitten.. and roar like a lion..
Last edited by NRL; Jul 29, 2012 at 09:38 PM.
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Thread Starter
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Cl65 AMG
I don't disagree, could have been described a bit more up lifting to the
car. At 42 hundred pounds it hard to get a big rush even from 600 hp. Coming from a 25 hundred pound car with 450 hp and a stick there is a big
difference when hammering the throttle down. I love the idea of going fast without making a lot of noise and causing a riot. Also the complete package of the 65 gives me far more peace of mind going fast.
I'm torn between wanting this engine package in a 3k poind car. Now that woudl be the best of both. That was my thought when I bought the engine & transmission from a wrecked 65. Looking this car over in detail it would be hard to engineer everything into a sub 3k package but it woudl be so fun trying.
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Joined: Feb 2012
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2005 CL65
I don't disagree, could have been described a bit more up lifting to the
car. At 42 hundred pounds it hard to get a big rush even from 600 hp. Coming from a 25 hundred pound car with 450 hp and a stick there is a big
difference when hammering the throttle down. I love the idea of going fast without making a lot of noise and causing a riot. Also the complete package of the 65 gives me far more peace of mind going fast.
I'm torn between wanting this engine package in a 3k poind car. Now that woudl be the best of both. That was my thought when I bought the engine & transmission from a wrecked 65. Looking this car over in detail it would be hard to engineer everything into a sub 3k package but it woudl be so fun trying.
car. At 42 hundred pounds it hard to get a big rush even from 600 hp. Coming from a 25 hundred pound car with 450 hp and a stick there is a big
difference when hammering the throttle down. I love the idea of going fast without making a lot of noise and causing a riot. Also the complete package of the 65 gives me far more peace of mind going fast.
I'm torn between wanting this engine package in a 3k poind car. Now that woudl be the best of both. That was my thought when I bought the engine & transmission from a wrecked 65. Looking this car over in detail it would be hard to engineer everything into a sub 3k package but it woudl be so fun trying.
jfyi, I had the same codes and symptoms as you and after I installed the coils the car ran as it should without any codes or problems.
Thread Starter
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Cl65 AMG
I received my coils yesterday and installed them. Job went smooth, but I had a misfire. P0305 was setting so I cycled the key and cleared the code and came up with a P0305 & P0205. Since there were parts on top of the injector connector I removed the heat exchanger and air cleaner housing and disconnected the #5 injector. Checked it for resistance and found it to be good. I removed #6 injector connector and it felt as if it was seated deeper in terms connected to the electrical connection. I inspected the electrical output and sizing of the female terminals in the connector. All checked great. I made sure the connector seated correctly and reinstalled the above parts. Fired up and ran perfect. Drove it 50 miles (easy) with great results. Love having it back in action !
I'll give it a hard run tomorrow ! 
Anytime I do any work on my 65 I always keep everything in order & clean so not to make a mistake. One small nut can do a lot of damage 
and no one wants that happen. I"m now waiting on the "Killer Chiller" to arrive.
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I received my coils yesterday and installed them. Job went smooth, but I had a misfire. P0305 was setting so I cycled the key and cleared the code and came up with a P0305 & P0205. Since there were parts on top of the injector connector I removed the heat exchanger and air cleaner housing and disconnected the #5 injector. Checked it for resistance and found it to be good. I removed #6 injector connector and it felt as if it was seated deeper in terms connected to the electrical connection. I inspected the electrical output and sizing of the female terminals in the connector. All checked great. I made sure the connector seated correctly and reinstalled the above parts. Fired up and ran perfect. Drove it 50 miles (easy) with great results. Love having it back in action ! I'll give it a hard run tomorrow ! Anytime I do any work on my 65 I always keep everything in order & clean so not to make a mistake. One small nut can do a lot of damage and no one wants that happen. I"m now waiting on the "Killer Chiller" to arrive. Also, after misfire codes are set and reset the bosch engine mgmt adaptations need to be reset for feedback (problem still present/ resolved) to be accurate.
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Cl65 AMG
I did change the filter a few months ago,
and the old one wasn't restricted . These filters are often overlooked at least in the average car that has a serviceable one. 
If the filter was seriously restricted I would have for sure replaced the pump. I seen a lot of cars come back in a few months needing a pump. A seriously restricted pump just hammers fuel pumps to death. Since inspecting the #5 injector connector no other codes or issues have surfaced. When it first started the engine had a miss for sure and the light came on quick. I've driven the car 100 miles and runs well. Nice to have it back on the road
Thread Starter
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Cl65 AMG
Personally I would love to transfer the guts of this car into a light chassis. Maybe a 944, 325i. Call me crazy but it would be fun to build. I come from a smaller car zone. My V8 914 weighed 2400 lbs and really had some kick. OH no my wife is coming
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2005 CL65
I wish someone would do something like this. I realize it would be pricey and a lot of work to fit the eng/trans into a smaller car, but there's got to be someone that's crazy enough to do it!
