We Replaced The Starter On This Mercedes & Now It’s Misfiring!

This Mercedes came in to the shop and everything seemed to be super cut and dry. The client had just bought it and now it wouldn't start. We drove it afterwards multiple times with no issues. Then, the next day we got a call from the client stating that the vehicle was running horribly. The check engine light is flashing and it's clearly misfiring. Did we do something to cause this issue? Can we figure out what's wrong? Join us as we perform the necessary tests to pinpoint the root cause of this issue and get her back on the road. We hope this helps. Enjoy!
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[@elcheapo5302]

She just found out why the car was for sale.

[@sollykhan2385]

The 6Million Dollar question that no one ever asks the seller is; 'Why are you selling this car? ' (if it's any good, then why not keep it?? 🤔

[@1primacron]

That engine sounds like an alien spacecraft when running.

[@sollykhan2385]

with the bad car's perhaps we can donate them to the Aliens 🙂

[@colinbattensby7180]

In my shop this week I have a Mercedes SLK 1.8 less that 5000 miles 9 years old Same engine same fault on cyl 3, thought it could be the control unit, but not sure, I have checked everything like you have, but didn't have the confidence to call the module. but having watched this fabulous video I'm calling it bad! thanks for the great diagnostic approach and content, keep up the good work.

[@sollykhan2385]

Make sure to test all the coils by substituting them in another order, then clear the codes and re-read codes to assess whats unfolding? remember also to do the compression gauge test and cylinder leak down test to establish whether the Head Gaskets good.

[@oldpostreviver2624]

I'm starting to get the feeling some dishonest customers are going to your shop knowing very well how honest the shop is, they go in saying : "I'm wanting to get a simple starter changed/replaced" Then the next day I complain that my head gasket was blown after you touched my car, knowing damn well it was a pre-existing condition.

[@StrongerThanBigfoot]

I very rarely ever trust the customer

[@StaticVapour590]

That stuff is actually kinda happening with old beater cars some customers like to drive around, I have witnessed it. Time for example: Car is over 20 years old and when there is a problem they bring it to a shop: Like let's say the blower does not work at all speeds, okay it's diagnosed as faulty blower motor resistor. Diagnosis and estimate repair cost is given to the customer, customer complains that the part/job is too expensive, when told that the price is what it is, they can find another shop to do it if they want to. Customer accepts the job.. That part gets replaced and customer is happy. Week or two goes by, customer comes back with different problem, now the brake pedal goes to the floor. Shop says they need to inspect the vehicle, to see what the problem is. Customer agrees, they inspect it and find out how rust has eaten away a brake lines from the rear of car, fluid is slowly seeping from the rotten pipes.. Customer is told what the problem is and what needs to be done. Then the customer flips out, complains about how the car was fine until this specific shop touched it and how they ruined his car. Customer is not willing to pay for repair and repeats that It should be done "under warranty". They are not willing to get the car towed to somewhere else, instead they keep on harassing about warranty and how the shop broke their car.

[@sollykhan2385]

you Nailed dude, 100% we had an avalanche of these morons in the past 3 Years, simply put when the Shop guys honest, humble and accommodating, they take advantage!

[@sollykhan2385]

Old school Mercedes used to be simpler and straightforward when they used an external ignition Amplier bolted next to the Coil, and older still in the day of Point,Condenser, rotor arm, and Dizzy caps, with Leads to each Plug, usually 1 of the leads or the King lead with the rotor arm defective. Nowadays any circuitry problem it then becomes big Dollar's and often a trip to the Main Dealership. Thank you for this great Video, much appreciated 🙂

[@burgegerm7878]

Do these three wire coils have a switching transistor inside of them? If that is the case, then the tougher part of the ignition switching is being done at the coil itself. Maybe this is some sort of software glitch where the module sets an error for a circuit issue.

[@sollykhan2385]

@@burgegerm7878 The switching is actually done from the ECU via the pulse from the CKP (crank position sensor+ Cmp- camshaft position sensor) although it has a Live to the coil, no Live feed wire is ever used as a pulse to switch high energy ignition systems.

[@seansmith1549]

Mercedes Benz + Paper Tag = "Y'all broke it when it was in here"

[@JimmyMakingitwork]

I just wish we weren't all seeing tired or broken German cars people just bought that need more work than they are worth. But man a good deal is hard to pass up. Doesn't sound right when you say it out loud. We just had a C250 with oil and coolant leaks, along with timing codes, customer only wanted to fix the coolant leaks so it was "drivable." Became upset afterwards that the engine still made valve train noise and the check engine light was still on. I wish they would turn repairs like these away if they can't be done correctly, you're being set up to fail.

[@jgeorges3061]

great approach and awesome thought process thanks for sharing.

[@usamaarshad9041]

YOU ARE A GREATEST MAN, PLEASE DO MORE ON ELECTRIC STUFF ❤

[@ThunderbirdRocket]

Thanks for providing this tremendous opportunity to keep learning from your excellent videos and vast experience / knowledge .

[@garysgarage3669]

I'm torn! For years Eric O "South Main Auto" has been the KZbin champion, But you guy's are really putting pressure on his title.

[@jodydewald19]

Great video. I am now wondering if you guys offer a "used car inspection service"? You wouldn't be able to discover every little issue a car has, or potentially has, but a thorough shop as yourselves may save a customer a lot of headaches down the road.

[@alrifainidal]

That is a great thought process. Thank you very much

[@Dave-dm3xs]

Good diagnosis. I would have put new plugs in it and coil on cylinder one also as a precaution, unknown vehicle history. I have seen similar ecu faults caused by ecu drivers overloaded by old plugs/ over worked coil packs. Have you tried Picoscope? I find there captures better and the software easier to manipulate

[@thisisyourcaptainspeaking2259]

My '84 chevy has been giving me the run-around with the starter solenoid for about a year. I finally isolated the problem to the firewall bulkhead connector.

[@greggc8088]

Honda turns the injector off quicker than any manufacturer I've seen. Of course cycling the ign will bring it back for testing but makes it tough when such a short period of time is given before happening again. I always wished there would be a scan tool function for disabling that protective strategy while diagnosing.

[@ThunderbirdRocket]

Good information Thanks

[@sheerwillsurvival2064]

Excellent video 👍🏻👊🏻 keep these coming great learning experience. Thank you

[@gwrider2146]

Another moral of this story is that don't buy a Mercedes (or any "premium" branded model) if you can't afford to own one as ownership of them includes the required servicing expenses people!!

[@TwIn603]

Daily tip. You can’t disconnect coils on Renault engines as the coils are earthed to each other so disconnecting cylinder one (flywheel side of engine 🤷‍♂️) coil with un-earth cylinder 4 also makes reading codes very confusing lol Moral of the story is pull the coil up out the cylinder don’t disconnect when looking for a bad coil.

[@plor1261]

One of the best videos ever.

[@lisapratt166]

These videos are the best. I gain great knowledge from them all.

[@ThunderbirdRocket]

Agreed ! Well said.

[@cotsabaca9269]

Finest Fault Finding

[@ThunderbirdRocket]

Nice 👍🏼 !

[@martinboucaud679]

Keep up the good work. I love it.

[@lanwickum]

Been there. Lessons learned.

[@AwesomeLife-h6p]

That particular ECM is KNOWN FOR LOTS OF TROUBLE and the dealer knows about it !!!!!! 1. The ECM wiring absorbs oil in parts of it. 2. The ECM fails from jump starts. 3. The ecm mosfets go bad for no reason. 4. The ecm loses programming for no reason and needs replaced. 5. The ecm can trigger false codes for no reason. 6. The ecm can hang up the transmission and cause horrible jerking or locking. It's a dam Mercedes and let me tell you something 😂, this is THE BEGINNING OF HER NIGHTMARES.

[@onemechca]

Great video as always bud. Just wondering if the coil was bad and took out the ECM. Do you think it would be wise to put a coil on it as well??

[@johnthompson6960]

A coil that’s not being controlled by the ECU should be very easy to identify. Maybe a primary pattern would be more useful.

[@BipVuongAnCapTheMuaMayBayXao]

Hey , buy the dc706 it will clone most of ecm tcm on market

[@avigoods719]

Does it work on cummins 6.7

[@StrongerThanBigfoot]

Im a big believer in the mechanic should be talking to the customer and doing away with service writers. We can do thier job but they cannot do ours.

[@kevinolson3321]

At what point would you check the number 1 spark plug or injector? Wondering if a spark plug could cause the grounding?

[@colinsmith8347]

I put a new starter motor in a Honda accord, after a day crank sensor fault occurred. End of story bad earth brush in New starter motor caused fault

[@WiekingderViking]

What is your definition of “new starter?” Most NEW starters are actually REBUILT by “someone, some where”

[@marshall1157]

engine makes a noise like power steering fluid a little low

[@theroyaltyautoservice]

I think that’s the mics and something they’re doing to that background noise. We are working on figuring that out with our new set up. 👍

[@marypyle6190]

Have you been looking for factory recalls ?

[@Nozinbonsai]

People think a service is checking every nut and bolt in the car kind of thing, but if you change their wiper blades and the next day it conks out its your fault.

[@tylerwilliams3868]

how do you like the harborfreight box? they sent you that right? did you make a video?

[@omdcarsandairplanes]

Might be a common problem on this engine. Had the same exact problem with a customer's car.. new Ecm fixed it.

[@shenyang2113]

Yes

[@thesmartguy3523]

Common issues on these M271 with the SIM271DE2.0 ECUs, the ME ignition driver gets cooked . . .

[@johnthompson6960]

That scope gives a really poor secondary waveform. Not really usable . You’re just guessing.

[@sherwoodcooke7766]

Not guessing at all but what scope would you suggest.

[@Foolish-diag]

Check freezer frame

[@rodvan-zeller6360]

I do a full scan before working on any vehicle including all the data in mode 6. Print and attach to the work order. Do you do the same?

[@johndonovan7018]

uhm mercedes + 1.8L in the same sentence... come on what is this. are we back to the 80s with the 190E

[@RR-bt5xv]

could a bad coil or plug taken out the ecm?

[@sheerwillsurvival2064]

Bad coil can

[@robertnicholson771]

The windshield guy scanned my car for codes before he touched the windshield. He said he had been blamed for all sorts of problems after replacing the windshield.

[@davidgoliath982]

if it dont crank how can it start?

[@hothmobile100]

Never had this problem with Toyotas.

[@carmo9693]

Too bad it is out of warranty by time. 8 yrs or 80K

[@abderrahimmark]

Diesel Mercedes Benz is better. more robust as always.

[@rodvan-zeller6360]

At 0:48 with this type of vehicle assume it is nothing you did wrong.

[@ScrappyDoodad]

I hope that doesn't happen to my EV

[@ozziesheppard17]

First?

[@digi3218]

Ninth?

[@davidcraven277]

In my opinion you should never buy used euro trash the original owner got rid of it for a reason

[@burgegerm7878]

The powertrains seem to be the weak part, though the unibodies and interiors seem to be pretty good. I have seen some of these types of cars in junkyards in good condition, seems like a big waste. Would be nice if people can just change out the powertrains for something simpler, like a toyota engine or something like that.