I Used Bugatti Veyron Parts & An Alex Trick To Fix My CL65 AMG V12! You Won't Believe What Happened! 

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The frustration is real with this one…

Don't apologize for not fixing the Mercedes in this video, Alex. Sometimes youtube videos don't demonstrate the sometimes real struggles automotive technicians run into when diagnosing problematic cars. I know it's frustrating for you, but you're showing us, your audience, what it's really like to be a technician. I was a dealer technician for 19 years, and I started in 2003 right out of high school, similar to you. It's a great job, but not every day is a win. Keep up the awesome work, and don't give up.

Hey Alex, European diagnostic technician here! Don't give up, I enjoy watching your videos as no 1 technician knows everything. I think its time for an oscilloscope on a fuel injector on each bank and a coil inductive pickup on each bank (this would be tricky with the large all in one coil) Then I would move on to using a pressure transducer in the exhaust and intake. Are your intake temps staying manageable or are they still shooting up after some continuous full throttle? If they are, you have an airflow issue.

I have had a dozen turbo cars (some that ran at 30+psi) and that honking noise at WOT was always present if they had a decent boost leak. I would presurize your turbo system to make sure you don't have a boost leak.

I think we all love the CL65 and I am actually glad it's giving you a LOT of trouble because it makes the best content on RU-vid!! Thanks for sticking with it Alex!

These are my favorite Legit vids, the ones where not everything works out. Not everyone can throw new parts at a problem to make it go away, and it shows that Alex is more like the rest of us. Frustration happens!

Hi Alex, long time follower here! I am a tuner living in Belgium and 90% of the cars i tune are European cars. My guess is somethings wrong with the tune because its not that easy to tune those cars with bigger injectors and turbos etc without the tuner logging al parameters. Especially the bigger injectors, thats why the fuel pressure is going down. Autel is also not a great logging tool for those mercedes because allot of parameters you are not able to log. What i would do is put back the stock injectors and write the original stock tune on the car and see how the car reacts. The bigger turbos wont give any issues with stock tune because on those ecu’s the throttle body will cut the amount of air going in the engine to keep the requested air mass under control. I wish you goodluck and cross my fingers that you find the probem! Goodluck👏

I would watch countless videos working on this car with nothing being accomplished. Its simply my favorite to see someone who knows what they're doing, out of their comfort zone, and having to truley problem solve. This is what people miss from being a mechanic.

Random note about your body temps on the infrared camera- I’m an A&P mechanic who bought an infrared camera to use for troubleshooting planes and after shining it at my hands I asked exactly the same question. The answer was so obvious I cringed… your internal temperature is higher, but given that your skin is a thermal shield, you lose about 4-5 degrees from inside your body to your skin. Try pointing it in someone’s mouth and you’ll see what I mean. Anyways, love the videos as always!

2 things, Alex. The car now going rich when it goes into limp mode could be the second pump you've added. After that, I think you need to try a catless exhaust and tune.

With the weird honk noise the intake produced under high load and WOT, combo that with the car suddenly going very rich and into limp mode, maybe it is collapsing/has collapsed an air filter from the upgraded turbos? I have only seen this a few times on EcoBoost F150 raptors. People will upload a tune, tune increases boost pressure, and it collapses the OEM paper air filter, causing limp mode/rich codes from restricted airflow. Not sure what filters you're using, but those sure looked like stock air boxes, so I assume they're factory. Hope this helps man! Love the content as always!

Alex, man. The persistence, patience, and passion you’ve shown throughout the entire CL saga is truly admirable. Huge props to you for continuing to fight when almost all would have quit by now. I am very okay with this being such a long term project, because not only is it a great addition to the channel and your fleet, but it shows people a very real part of the automotive hobby. Keep on keepin’ on 👍🏻

Keep on the CL Alex. Ultimately its not about what car you work on. Your teaching most of us "Home Mechanics" how to think out an issue. Its super valuable content to the ones that pay attention

Check all you body grounds on all computer boxes and voltage box for the fuel pumps. A had a problem like yours and I had a tiny ground lead under the hood that was 90% broken off the fire wall. That was after 6 months of banging my head off the wall trying to find a problem and lots of $$ later it was a 25 cent wire. Good luck! Just keep telling yourself I love my car! Lol. Cheers

Legitimately one of the most informative detailed automotive channels. Dude literally telling you the size of the bolt while he's taking it out. If someone took that car to a dealer they probably deemed it none repairable to them before they ever put a 2nd pump on to resolve the problem. I have the same problem with a 14 6.2 ltz Silverado gets plenty of voltage 0 issues besides wide open throttle fuel pressure drop. Bought it as a remanufactured lemon buy back. Only drops fuel pressure under wide open. Replaced pump 3 times filter 2 times new lines fuel rails new injectors same issue if you floor it the fuel drops to about 25-30 psi and it falls on its face and goes haywire. They replaced the ecm at the last dealer as a last ditch effort. Never a problem for me since I don't floor it everywhere but best bet I'm adding a second fuel pump after seeing this video

Keep at it legend, I think I speak for many when I say these CL65 videos are our favourite content on your channel (along with other AMG cars). How stupidly epic is it going to be when you get the car running perfect! Big love & support from New Zealand, Mitch

To prevent the squirt, remove the fuel pump relay while the engine is running.

You can figure this out Alex keep going don’t give up on the CL 65

*Alex adds an entire second pump that the car was never designed for* "Why is it running rich at WOT?!"

Thanks for the Lou Malnati's shout out! I am on the Lou's IT team, we'll have to drop off some deep dish for you some time!

I have a 2005 CL65 AMG that had this exact same issue, the dealership couldn’t figure it out. I replaced both coil packs my self and that fixed the issue, never went into limp mode since. I found these coil packs can throw the car into limp mode intermittently. I also have a 2006 S65 AMG that had a similar issue and I also replaced both coil packs. That did not fix it. Ended up changing the ignition transformer. Silver box on the middle of the engine. That fixed it. I would definitely say you have a ignition issue not fuel. Hope this help’s!

Wow such a journey! We're with you Alex, you'll get this working. Can't wait for another episode.

As a computer geek with 45 years of experience, I have learned that when working with computers if the error is consistent, it is a software error, if it is inconsistent, it's hardware.

If you’re looking for a tuner here in the states, I would love to tackle this. I can do remote dyno sessions with you as well. You have a few things going on that I 100% can fix.

Don’t apologize Alex!! That’s what modding cars really looks like when you get into issues trying to make the car actually run

I bust out laughing when the fuel blew out the second time 😅 Only because I've been there too, thinking I got it figured out only to mess up again. With ya, not at ya!

@legitstreetcars my dad is thinking your issue could be with a ground. Check all the grounds for oxidation and rust for all the components for fuel and ignition ( ecu, fuel pump, injectors to coils) hopefully this helps. It could be just an electrical issue that doesn’t give enough power to the components. Maybe this is why when u switched over the cobra part you had the same issue

From all the years I've watch your videos,there is one thing and that thing is that you will fix it,you never stop working on a project, either its getting boosted or just getting a repair,I know you will fix it,no matter what, that's the thing I like and boosting cars,vans or trucks,you will fix it Alex

We are SO pleased to see an update on the CL65. There's a huge amount of progress in this video and it's obvious you are very, very close to getting it spot on. Keep going, this is going to be phenomenal once complete and that is only just round the corner.

Check for a collapsing fuel line between the tank and the filter/pump. Check the tank pick-up for crud blockage. And yeah, check if the catalytic's rattle.

Hi! Former MB tech here, while there is a clear difference between engines, I've had similar issues in the past on inline 4 kompressor's of the W203 (same era) series, when engine temp rises, engine performance falls and you get the "misfire" condition which also simulates low fuel pressure on max pedal request, the fix for that is not the fuel pump and filter, but the fuel rail pressure switch.

I had a similar situation with my turbo. It would run up to high rpms under partial throttle with no issue, but if given full throttle under load it would stumble and throw a check engine light. Turned out I needed a different temperature plug an gap for a tuned turbo. Runs like a champ now.

I’ve been here for years for the V12 (and Cobra) content. Thank you for showing us all your troubles and being truthful. You’re my favorite RU-vidr.

Check the return fuel line to the tank. Maybe this is causing the issue. The other thought I had was to find someone with the same model CL65 and compare them side by side to eliminate issues.

I will never forget when you said three or four years ago “if you know how to wrench, these can be great reliable cars”

Hi Alex, I've owned a 2003 CL600 for over 10 years. I'm Korean, so my English is not good, so I hope you can understand my words. I had the same issue in my car, and that symptom was low RPM at wide-open throttle. It sometimes does not happen in manually selected gear mode, which entails high RPM. Long story short, surprisingly, it was caused by boost pressure leaking that affected the turbine actuator's movement. It caused improper boost(I assumed over boost) and fell into limp mode. I had changed tons of parts such as fuel pump, fuel filter, screen in fuel thank, spark plugs, both coil packs, fuel pressure sensor, fuel pressure regulator(especially, ECU doesn't catch fuel pressure because it has isolated fuel pressure regulation system), all of the vacuum lines, boosting pressure sensor, and atmosphere pressure sensor, etc. You can fix this problem by checking and replacing the parts on the turbine outlet to the throttle body, such as rubber pipes, clamps, aluminum pipes inlet o-ring, and 3-direction intake pipe and clamps connecting the throttle body and heat exchanger. After that, you can feel full boosting(without kick down) at low rpm WOT condition.

I told you long ago - full throttle exhaust flow is moving the matrix in a cat; creating backpressure and triggering the limp mode -

Massive respect for not giving up on this car...

kudos to you Alex. I am supper impressed that you have not given up on the CL! It's definitely frustrating, even just watching. It will be very rewarding when you get it totally fixed! I've had machines nearly break me also. Keep your head up and know that you are teaching everyone a valuable lesson: Don't Quit.

Remarkable how entertained I am watching you work. I’m frequently in situations that require trying multiple tests to find the answer. Your struggle is the same for all of us working with automation of any kind, mechanical, electrical, technical… it’s all emotional, challenging and ultimately rewarding when success is finally achieved.

Not sure if anyone mentioned, but those pressure sensors are reading in absolute pressure. Where 14.7 would be atmospheric and 0 is a perfect vacuum. So at 4psi it is in vacuum and at 22psi is about 7psi of boost.

This is what it takes to be a excellent technician never giving up thinking and networking figuring out solution. When they ask why is it so expensive to fix my car i am going to send them this video. Technicians/business owners get accused of ripping people off when we struggle like this to figure the problem. It will be glorious when you figure it out dont give up.

When swapping out the fuel pump the additional pressure and fuel released suggests that the fuel line is pinched somewhere towards the engine. Perhaps the engine moves under torque at wide open throttle and restricts the amount of fuel in the line to the engine.

Finally a video upload on the CL. I love your patience and how you work on an issue continously while not giving up. We know that you will eventually resolve the issue.

On the rich A/F signal, exhaust temperature comes to mind: - pcm control systems incorporate exhaust temp modeling in order to predict turbine and cat temps and protect for hardware limits. The initial wide open pedal (WOP) lambda of ~0.75 (10.6/14.1) looks decent for an engine of that size w/ turbos, but the rapid dip down to ~0.62 (8.8/14.1) might indicate the pcm is calculating a high turbine inlet temp and is adding fuel to protect hardware. - Before heading down this route, i would check if you are able to collect pcm data through the cal software and see what fuel parameters are available to measure. There might be a signal indicating the lambda target source which could lead you to the root cause. - You mention IATs being high, which is interesting because IAT and ECT are usually the main inputs to the model. I would collect WOP data on IAT and as many of the coolant temp sensors you can (there's usually several of them) to see if there are any irrational readings. - If everything checks out then you might actually be exceeding temp limits on some or all of the exhaust components, at least according to the exhaust temp model. You may end up needing to loosen up these limits in the cal or disable them entirely. Generally speaking, the unfortunate reality of troubleshooting issues on modified semi-modern cars is it really requires a deeper understanding of the engine control system to pinpoint issues quickly. Normally you can get by with an OBD tool and reading DTCs, but the case here might be the OEM calibration is operating well outside of it's design intent and will need more development to get things working correctly.

CL65 is the best of all series. Even better than the DeLorean one. Hope some day you'll be able to sort out the issues with her. Reading lots of tips in the comments, though. LSC's followers are the best.

Keep Pushing Alex! As much as its so frustrating watching this car dodge and weave your punches, I love the honest, humble videos and the endless troubleshooting. I know I'm not alone when my car starts playing hard to get too. Thank you

Sounds quite industrial without the cats and linked exhaust attached. This is because you're hearing 2x separate, unlinked straight 6s with no silencer. Shows how important and X or H pipe is on a V engine.

Could be a bad cell in the battery? When the motor is demanding more voltage could be dropping voltage at the pump.

I'd check the throttle body. Had an SLK with a similar issue cutting power under boost, and the throttle body needed to be replaced. Also check the ECU for potential corrode connections.

That was an honest effort Alex! I probably speak for many who have been through an episode of frustration garage like this and you are way more calm and collected than I would be. Amazing content! Keep up the positive energy!

Hey Alex, great to see more content on the CL. I can see the frustration in your face but I know your tenacity. Keep digging, you'll find it! I look forward to the next video. Cheers!

Restriction on the vacuum side of the pump? Maybe an issue with the pump hanger or a partially collapsed fuel line

Love your CL65 videos, so much knowledge and experience applied to fix misterious problems!! And the part that I respect the most, you doing important maintenance and repairs "while you're at it" , top notch job Alex, cheers from Brazil

Yeah Alex! Your channel is on fire man, so glad to see the CL again! Dream car. You'll get it figured out and you'll definetly come out wiser and stronger, keep it up we're all backing you! Love from South Africa

Absolutely LOVE the references to Independence Day👍🏻👍🏻👍🏻😂😂

lol man, you're brilliant. Unbelievable trouble shooting. I'd have scrapped it after this long lol

Got to appreciate somebody sacrificing their eye sight to get that v12 running

Personalized plate suggestion: “N3M3S1S” 🤣🤣🤣🤣 YES (NEMESIS)

Mercedes issues are never as simple as one might think, and if anyone knows that, it’s Alex! I’ve had a bunch of different issues I’ve been tracking down and attempting to solve in my 2005 E320 (ironically the same spec as the CL65) for the past few months. Just don’t give up!

Ten minutes in..... nope... ain't gonna be the filter! Fifteen minutes in.....nope... ain't gonna be the pump! Know you'll get it eventually Alex! You're an extremely competent, patient, plain awesome technician when it comes to diagnosing issues with vehicles. I've learned quite a lot by watching you work! Thanks once again for an amazing video! 💙🙏🏼

Hoovie still laughing all the way to the bank with selling you this car I still love it though

Fixed or not, the research, investigation and analysis you offer is still very satisfying!! The best part of my weekend is started by watching your videos!

Mate. Respect that you not giving up. No fake sema nonsense. Real life.

after you added the second fuel pump it looked like fuel pressure was spiking up to like 75 psi. If the car uses a static fuel pressure regulator, then the computer is expecting 55psi all the time, it may be getting rich because it's keeping the pulse width at what it is expecting the need is at 55psi. I would try putting a manual fuel pressure controller off of the second pump prior to going into the Y. That should keep your overall fuel pressure at 55psi and eliminate the rich condition, if the above is the cause

Alex I think most will agree these vids where the struggle is real is why we love this content. It shows a more realistic view of what it’s like to be a mechanic! Keep up the great work and we’ll keep following along unit we taste sweet victory!

A roller coaster of emotions in this one, appreciate its not a 5 min fix like some of the other car problems. Your resolve is strong though, you won't let it beat you. We'll see the CL again, hopefully in all its full power glory because what a wonderful thing they are. Love the humour pieces in this re a certain 4th of July movie, 👏

When you went to release the pressure the second time I said "that hose is going to fly out" and then laughed as it did lol

Alex is one of the very few REAL mechanics still around. His persistence and perseverance in whatever he is doing is quite amazing. 👏🏻 It is admirable the lengths that he goes to to figure something out! 👏🏻 As Always, May God Bless you and yours! 😇

Alex, this roller-coaster of emotions... Killing me. :) Max, awesome memes. As usual, good content. Thanks!

It's all about the quest. It's very very interesting content. Used to spend days watching my dad fixing electronics. Now I see you detecting what is wrong with the car. You are excellent in filming this whole endeavor. Well done. Keep at it.

You rock Alex! Thanks for taking us along with you through this odyssey! You'll figure it out!👍

You’ve got a boost leak past the MAF sensors. Explains why you’re going rich mid pull. It’s pretty audible with the whistling sound during pulls

I think you are right, throttle body. A throttle body closing at wot under boost with bad TPS giving false reading would give rich condition and low power (no air flow). Rare, but possible, the throttle servo and TPS can function independently of each other.

I understand how frustrating these things can be; however, for me this is amazing content because as a viewer you learn so much and it's so interesting to riddle along.

Alex, you have no idea how much I appreciated your works on this car. I've always wanted a 65 chassis and maybe an SL65.

I think this is a great video Alex. These kind of challenges will truly test your merit and you really do demonstrate your knowledge here. Keep at it buddy, you’ll nail it and all of us will love seeing that happen with you 👊🏻

Respect 🫡 to your perseverance brother! You can not let this car defeat you!!! 😅

Thanks for undertaking this. I've always wanted one of these CLs but if I ever get one, I'll make sure it's a CL55.

Alex, THANK YOU THANK YOU,please never give up on YOUR CL65 ! I’ve been watching you since your first video & of-course your 2003 E55 Series and when you got your E55 wagon dream car, and the CL 65 and on and on, I felt like I was there with you dealing with all the ABC issues.’ for the longest time I would message you on every video you did, please please work on that CL 65 AMG, CL 65 AMG, I can’t wait to get this dialed in and I know you will. I was even around in the beginning when you where able to respond to everybody’s input, WOW How are you have grown in so many ways very impressive and happy for you. You’re a wonderful guy. Legit streetcars forever.

I think your fuel line has an issue. It's either collapsing or ballooning somewhere. I think you have a flow issue, not a pressure issue, but as you know, pressure is related to flow as well. Get a flow meter on there somehow.

You must have taken the delorean and went back to the future for this one. Sun and green trees in January in Chicago. 😂😂😂

One thing to consider and not sure if you have addressed it yet, but I was having the same issue as you with the check engine light coming on and going into limp mode when in heavy acceleration but would run normal after restart- turned out to be the APP sensor (Accelerator Pedal Position Sensor). If one or more of the circuits in the APPS is worn it will cause an inaccurate reading with TPS, Air/Fuel mixture, fuel pressure etc.. It was a cheap easy fix in my case and might be the culprit with yours. Hope this helps..

Alex is the type of guy to legitimately work not one, but two Independence Day references into his video. We'll done sir, we'll done.

Alex you are the man. All your stuff is awesome

I'm here only for frustrations and dreams destroyed and the best one is the host showing it all. I don't even care about the builds. He's the product not the vehicle. And once he fixes it...another one arises. Never ending content! I love it. Cars are moneypits no matter how much you repair, modify, and keep. Time and elements is the final culprit. And worst if the driver revs it constantly.

We're with you Alex. Please keep going on the project! You're so close!

Alex keep doing what you do mate!!

Hello Alex, hope you are doing well. Im not a car guru but could it be a software issue? I mean torque management kicking in and lowering timing and fuel. As I remember you did port, changed the turbos(not sure) and put bigger injectors. More power and torque so the torque management is kicking in to safe the transmission

I am a fan even thought I wouldn't do most of the mechanical work you do, don't have the knowledge but I always learn a thing or two plus enjoy your projects. I am a car guy still at my 70 years.

Should you have mentioned the extra fuel pomp for the new mapping? Don’t despair we are with you! Love your videos!

Alex, may the force be with you💪. They don't break easily, but when they do it's a disaster of many connected evenly affected components.

Alex is so funny lol, I love the "thinking out loud" humor

Love this and all your videos. The struggle is such a part of it and it is super relatable. Thanks Alex!!

I like that you show the problems ALOT of us carheads go thru. Thank you for keeping it real with us

Brilliant channel always enjoy your videos, keep up the great work 👍🇬🇧

Alex, I hate to say it, but the somehow makes me feel better. The way you normally fix everything is uncanny, so for a problem to stump you seem more human. Good luck with it, and I will be here to see what happens when you fix it!

We are with you Alex!!! Keep on it!!! Can't wait to see more videos of that awesome AMG!!!

You're doing a great job working through the potential problems, Alex. You're probably among the few people on earth who have the knowledge, experience and patience to figure out the issue. After all the things you tried, if it's not the throttle body, could it be that the ECM is faulty? That is, all the mechanical/electrical things are working and all the sensors are returning acceptable signals, but the ECM is misreading them and going haywire. ???