Just replaced the crankshaft position sensor in my 1990 420SEL at 150k miles. Initial symptoms started around 140k - felt like the transmission was slipping - a sudden loss of forward momentum; symptom then grew to the car turning off at random while traveling at speed - VERY DANGEROUS. Replaced the sensor and the problem was solved. Replace yours - you don't want to have the car die on the interstate at speed because you lose power everything and could quickly get rear ended. Great video - thanks!
Hello Shadowrider You will have to be the most explicit repair guide out there.Thank you so much. I have the exact same problem that you had. You saved me a ton of time. Good luck and keep it coming!
One of the best videos on TH-cam showing an everyday's man diagnosis that can be easily followed. I am highly impressed how you broke down your diagnosis so that we can all follow through. Great great video.
Thank you very much. I really enjoyed this video. I have never started my 560 sec for a long time cause I lost hope in it. But after your video I now know what's the problem. So thank you for the bottom of my heart. Please keep making more videos. 🙏🔥❤️🙌
You have an amazing gift of explaining and breaking apart the complicated into something digestible. I have the same car. So please post if you ever figure out the high idle issue. Thanks for the great tutorial.
I'm wildly late to this video, but I'd like to offer my thanks too! This is by far the most informative info I've found on this engine, it's truly excellent. Just as a bit of additional information, you can't 'clock' the distributor cap incorrectly, the screws holding it down are unevenly spaced around the edge. It will only fit in one (the correct) position. Terrific content, thanks again!
Thank you for posting such a methodical, careful video. Same thing happened to my 420 SEL, however after replacing the Crankshaft Positioning Censor it still did not start. Next part in line was the Ignition Control Module. I bought 2 used ones, just in case. After replacing that the car is running again! :) and again thank you for this video.
Looking at buying a 1991 Mercedes-Benz 420 SEL with 122K miles that has been sitting since 2013 - can you please provide an evaluation process to prepare the vehicle for starting and possibly draining the fuel from the tank and review other components before starting it, maybe refer to other resources so the reviving process is successful
Hi thanks for taking the time to post your troubleshooting problem regarding cps,I've just purchased a w126 300 se with one previous owner and car has only covered 48k miles from new and as I do with any classic I buy although service history is there I like to just double check myself for piece of mind on the ignition system and replace what may have been missed. On that note car ignition components all good and not showing any signs of wear. I'll keep your tips in mind for future old school diagnostics is the best way. Thanks.
My 300sel just purchased acting same as your symptoms hope it gives same results however I just wanted to say great how to video to diagnose the same symptoms. It gives me great info on what to do to diagnose my mechanical problem .
really good information for the W126. the high idle may be the OVP relay. Mercedes OVP relay repair other causes: 1. Idle control valve 2. Idle control unit 3. OVP relay 4. Throttle position switch 5. Worn injectors 6. Broken/brittle/missing/disconnected vacuum hose(s)
Great summary. I have a similar problem with a 380 SEL and will be testing and, I am sure, changing the crankcase sensor, Ignition Control Unit and the Overload Voltage relay. Parts seem to have come down in price. Thanks for this video.
Dear shadowrider , thanks for your Excellent informative video , after watching your video , i was able to diagnose my 560 SL for no start and my problem was with Crankshaft Position Sensor . I could not find the part for it but i have a 91 300 E parts car which i took off the CPS and put it on on my 560 SL and it started right up . I will have to locate a new CPS but until then i can drive my car . Thanks again and keep up the good work .
Very wonderful and helpful information, no mechanics or dealers would ever match your analysis. My 1991 MB420SEL, presently not running is supplying parts for my 1989 MB420SEL(280KKM)My 89MB560SL(145 K KM) misfiring at times Perhaps the whole set of spark plugs wiring and the distributor need to be changed. Keep up Shadowrider 460
The sensor on the front of the engine is what runs the tachometer, I don't recall if you mentioned that or not in the video. Good job showing how you diagnosed the no-start issue. Too many people just throw parts at it these days. I love these w126 Mercedes...they're quite nice to have as daily drivers, and generally don't break the bank too badly to keep them on the road (if you do your own work).
Thank you for your video. Same thing has happened to me 3 times now. RAA couldn't figure out what was wrong as by the time they arrived, car had cooled down and started straight away. When my mechanic looked at it and tested everything, his conclusion was dodgy fuel and the advice was keep the fuel level over half a tank full as it is probably a vapour lock. Car wouldn't start again tonight after driving for 7 minutes and parked for 5. Restarted after 10 minutes but stalled after 2 minutes. Three quarter tank full. I will consult with my mechanic as to your solution as I know this wasn't something he checked. Hopefully this is the problem. I will update once a permanent solution is found. Just for the record, the spark plugs and spark plug leads were all replaced 5000K's ago. Distributor cap and all filters have been checked.
Very good DX, great job of eliminating possibilities, sure saved a heck of a lot of $$$$ because Mercedes charges about 160.00 an hr you could have had a expensive bill, so in the end all you needed to replace was the CPS and replace the cap, rotor and wires which is good maintenance for wet weather driving because when wires get wet the car wont run, you are good at electrical DX
I want to thank you for such educational and interesting stuff, which allows even for me - amateur - to make problem diagnosing process with my 126 SEC.
WOW !!!...WOW!!!...Simply FANTASTIC Video, You really did an awesome job at explaining this electrical problem, I own a 1990 420 SEL...same exact problem. You sound so Honest and Knowledgeable. Is there any mechanic like you out there?...probably not. I live in Boston Massachusetts. Can you fix my Benz or...can you refer me to someone as good as you ?. Reply...pleeeeeease !!!
Ok well today I discovered that the crankcase sensor had already been replaced, I thought the wire looked newer but when i removed the air cleaner saw that the person who replaced it just left it dangling, one end melting on the manifold. I did a quick mulitmeter test for resistance and the new cable checked out to be functional. I performed a fuel pressure test today. Results were good with fuel pressure 48 psi cold and off, 49-50 at idol and no change when the engine reached operating temp of 82 deg C. here is where I am now. car will idol well in the driveway for 30-45 mins until the temp gets to 82C then it begins to sputter. wondering where to go from here?
thanks for another great video !!!the sensor is just like a magnetic pickup on a guitar ! also same as the abs sensor on the wheels ! and diff !! hi from australia
Hi there interesting video, we have one over here in England, similar model, with a similar problem it has no spark, i dont think its the crank sensor because there is no spark at all no even when cold...we have tested the crank sensor on Labscope and looks ok, this one has a cam sensor inside the distributor, which we also tested on scope and its ok, i done a manual test on the coil and got a spark out of it, tested all the powers and grounds on the module...there is no coil primary switching, the only thing left is the module so were fitting one of those...hope it works, if not it will be easier to test things with a new module on...from Fred in England.
Your high idle is most likely related to your clutch fan actually sticking on I noticed right on start up that your clutch fan was spinning, that should only engage when Engine warms
Same happened to me one day with my 93 Cadillac Fleetwood. Problem was the 22 year old Ignition Control Module gave out. Upon examination it was corroded and rusted inside.
yes, as another poster said cosmoline. they used to put it on everything, guns etc... not sure if they still use it tho. i too had a cps fail on my volvo 240 wagon, caused by deteriorated insulation making the sensor short and the car to not start/stay running. but the volvo was a 92, and the sensor was only about 13yrs old at the time. interesting video as usual!
It was a challenging issue to track down since a bad CPS wasn't my first guess as to what could be wrong. I'm just glad I could finally find the root cause and restore my confidence in it again so that I can drive it without fear of it breaking down. I shudder to think what the dealership would have charged to diagnose and make these repairs. The parts alone were around $520.
To make a suggestion if you use Simple Green on your white walls on your 72 Lincoln that will clean them up if you don't like scrubbing them but you can use, it works great and then of course armorall or something of the same type of wheel stuff. Its funny how many of the same car as me and you have owned the same type I had a Lincoln Mark 786 LSC I had a Mercury Grand Marquis 86 I have a 93 town car of 2010 Town Car I've had a f250 4x4 a 92 with the 460 in it. So we have the same tastes and likes in cars for sure
Ronald i would like to asked you a question in regards to my old CPS..i have the two bolts out ...and the CPS bolt is out ...but it is very hard for me to pull it out...can you help me out
Shadowrider460 have you replaced the timing chain, guides, and tensioner? I bought a 1990 420sel with 90,000 original miles, without warning, I went to start the car and the timing chain jumped timing due to a failed plastic guide. There was no rattle to forewarn me of the looming potential of a failure. The engine was running smoothly beforehand. Now, I need to do a valve job in addition to the timing chain and guides. I haven't decided if I am going to do that or scrap the car. It's a real shame since the car is in beautiful shape otherwise.
Yes. I didn't do the work, but I have all the maintenance records. The chains and guides were replaced not that long ago. I'm sorry to hear that your chain broke. If you can afford it or do the job yourself, then I would keep the car. It'd be a shame to scrap it as these W126's are getting harder to find. If you get it running, then I would also replace the drive shaft flexible couplings as well.
I have the same car...rough idle just started happening...engine has a rough time turning over when hot. I replaced the cap n rotor but nothing has changed. help !
Hi…i have a question and the Same Problem Like you. I have no spark out of the coil on my 560sec. I diagnosised the crank shaft position sensor but now I’m a bit confused. My old sensor I took out and it shows me the same as yours between 0.800-0.960 megaohms…your old one shows the same…but when u put your new one in it shows aswell 0.860 mega ohms so how do I know mine is bad? Thanks
you should also change the ignition coil if it is original, it has been revised and is less likely to destroy ignition control units - assuming the rest of the ignition system is well maintained.
That's not a bad idea. I was already thinking along those lines when I purchased the spare EZL a while back. Having a spare coil in the trunk may be a lifesaver one day.
+shadowrider460 a bad coil burns ignition module at times than both will have to be changed to attain function again , indeed diagnostic is a nightmare for many shops , and no one tells the story
It just amazed me that this car ran 187,000 miles on the original cap, rotor, and plug wires. In fact, these parts could still be used but I wanted to do a complete job if I was going to replace the CPS.
very useful video. I have one comment however. When the EZL was being tested in the video, the red wire is shown as connected to the center post on the distributor cap. this is a little confusing to me. I thought the red wire (to create a gap) should have been connected to the high voltage cable coming from the ignition coil to verify if there is a spark coming from the ignition coil.
Idle must be at 550 solid all the time!!! If not you will have ongoing running problems such as harsh gears shifting, lumpy idle and rough driving at low speed etc.... You can start with the coolant sensor and the ICV, the valve itself can be adjusted slightly for smoother running. The best test for these engines, is the engine must feel like it died when you approach a red traffic light. The only thing tells you that the engine is running the RPM sitting at 550, otherwise it's waste of time!!!
well done video I ACTUALLY OWN BOTH MODELS 1991 420 SEL AND ALSO 1991 560 SEL THE 420 SEL TROUBLE STARTING AND THE IDLE IS LOW AND THE 560 SEL DRIVES FINE BUT THE IDLE TOO HIGH
The other day, I drove my 1988 420 SEL in very hot weather and parked it in the sun for about 40 minutes. When I went to start it, the car wouldn’t crank or make any noise when I turned the key. The accessories were working fine, and the battery is brand new. After an hour, it started as usual. What could be the issue, and is there a video about it? Thanks for the videos.
Good, good video!! Thanks, so if your MB stops, when gets hot, this could be it?? Mine is 500SEC/ 1984, must have similar sensor?? How much was that sensor, CPS??
Hello, what is the Mercedes piston no A 1170304918 A 1170301018 As it is not available in the Middle East Is there another piston with the same size and dimensions and a different number? Do you have information? Tell me, thank you
I'm looking at one 86 40k , in your opinion do you think I'll be heaving allot of problems ? No one knows what kind of maintenance it has had , it looks like new. Thanks
I would spend a few hours here on youtube watching Mercedessource and mercedessource.com...these are great cars but finding someone who can diagnose issues can be tough.
Thank you so much I'm going through the same problem with w126 my problem is that I can not found the part, I have even called in Germany they don't have it ,can you please help me with the website, so I can order the part. Thank you.
Your high idle problem may be an ETA issue. I have a 92 400E with the same problem and it appears the ETA is the issue. If you can get the computer codes you would be able to narrow it down.
Hello Shadowrider, my wife’s 89 560 sel also stalled. It cranks but will not start. There is spark and I checked the resistance for cps and it is within range. I smell fuel but I do not hear the fuel pumps cycle. I replaced the fuel relay with an aftermarket one and also tried swapping my old relay and still will not start. I am not getting any voltage reading on the pump either with the key on. What would you recommend? Thank you.
hi shadowrider, first thanks for all videos including this one. I also have 420 sel and trying to fix it. In this video on 33.10 you mention shortly about "cylinder identification sensor" - I noticed on my car that this front end sensor is not attached a all but it is plugged in; wondering where to stick it??.... car doesn't work properly, dlack smoke, rough engine bcs of that I guess...
Very good video, I have 1989 560sec and I just get same issue few days ago now I know what to do , thank You very much , did you ever fix high idle? If yes please let me know how
That "clearcoat" is actually called cosmoline, I beleive. When I worked for BMW they shipped new cars over seas and coated many components with cosmoline, similar to a wax to prevent seasalt coroding components. Most dealerships will use a degreaser to clean it off.
I have heard of that product before and in this context, it makes allot of sense to use it during shipment. It does seem to have done an excellent job of keeping corrosion in check.
Hey shadow rider may I make a suggestion on improving the looks of your old Lincoln that you have try scrubbing the white walls it would make it look better with nice clean white walls and definitely need to get some white walls for your Roadmaster those raised white lettering tires or not the right ones. the right look for that car for sure definitely need some white walls ok take care your beautiful car collection I have one myself we have a lot of the same cars me and you and had the same cars I had a mark XII LSC1986 I have a 2010 town car I have a 1993 Town Car I have a 2003 Chevy s10 pickup a Mercedes Benz ml 320
I've never liked the raised letter tires on the Roadmaster either and feel that they don't look good on that car. They are in fairly good shape though and I hate to get rid of good tires. So I'll run them into the ground and look forward to a new tire purchase in which I can finally purchase the right tires for this car.
Hi Shadow Rider, Just noticed some oil leaks in my Mercedes. Any quick words of advice from you on how to deal with this. Thanks in advance for your help !
Oil leaks are tricky to find. The best way is to clean the affected area very well and start watching it to see where the leak originates. Typical areas are the valve cover gaskets, oil cap gasket, front crankshaft seal, and rear main seal. If the fluid is red, it's transmission fluid. If it's dark, then it could be engine oil or power steering fluid.
I want a car like yours .... And i've been seeing your videos to see what kind of maintenance or issues I might run into if I decide to purchase one I have my eye on a used one but it has almost 200,000 miles the one that I have is a 1986 Mercedes 300 SE with 156,000 miles but the car that I'm inquiring has a lot more miles . Do you still have this car or are these videos old
They shipped the wrong plugs and I had to send them back. Besides, these plugs have about 20,000 miles on them and are still good. I'll probably end up changing them next year and possibly do an upgrade.
shadowrider do you have a contact I could talk to you about this model, I am looking at the same model benz and need some assistance on maybe a simple problem or very well could be a major one.
my email is randypari@gmail.com. The car idles very well, but when I have it in drive when I give it gas from a complete stop it likes to sputter until it gets up to a speed of around 25, its still a great cruiser when its on the highway, what could be the problem?
first think I'm going to do in this situation is: pouring fuel 100ml thru MAF (remove air filter cover and poor the fuel on MAF plate) and crank if the engine start to run for two seconds, that will tells you that the ignition is fine
You have a thin jumper attached to the center of the distributor, then looking for a spark? The spark comes off the coil, via the short HT wire that GOES TO CAP. Oye....
if the crank angle sensor is failing, the EZL should have a code 17 logged. It knows when you are cranking and if it does not see a crank signal it will store the code. Obviously you should clear the codes before making an assumption and repeat the test
I don't recall a code listing for the EZL in the service literature I have but then again, I may not have all the literature available. I know I don't have the transmission manual, sadly. That sure would have made the diagnosis easier but as it turns out, it's good to be able to troubleshoot things the old fashioned way just in case you don't have all of the information or diagnostic tools at your disposal. I'm happy to report that after another heat soak along with a 10 mile test drive, the car performed flawlessly and never missed a beat. I now have confidence in this car again that I'll be able to go on a long journey with no issues.
Thank you for a informative video. Do you know if this part will also work on the 5.6l in the 560SL (1987)? If so, where did you purchase your part? Thank you.
My car has been just undriven now, couple, three years, and seems to start / or not start at all, when I sometimes go and try, must have some fuel/ problems, standing so long?? I put new fuelfilter, and pump last time I drove it a little bit, couple years ago, and put "marinegasoline" in a tank, should I change accumulator also in a fuel system?? Or fuelpressure sensor?/ Thanks again, good job =))
Mine sat for many years. It was drivable at first, but eventually it couldn't start. I replaced the fuel filter, pumps and fuel pump relay. Eventually I replaced the fuel pressure regulator which was the culprit. The car didn't start up immediately. I had to replace the spark plugs and dried the flooded engine. Here are signs of bad pressure regulator: www.doityourself.com/stry/7-symptoms-of-a-bad-fuel-pressure-regulator
This is the last car that you would be able to repair with your bare human hands without a pocketful of money intervention. Might as well learn how to fix it yourself. they are nice cars worth keeping.
I don't thinck your car have original miles....i know itas have 20+ years but......i observe that american version are not so resistent in time as european......i have a e200 K from 1997 and it's have 337.000 km ......no problem with cranck sensor ....i only chenge the sparck wires and the thing that make sparck(it's have 2 ).....i like very much W126....enjooy it and most important redpect the oil from your engine.......at my W210 i chenge the oil at 8000 km......i wish to buy in the future a W126 ...a W124 ....a W140 ....
Just replaced the crankshaft position sensor in my 1990 420SEL at 150k miles. Initial symptoms started around 140k - felt like the transmission was slipping - a sudden loss of forward momentum; symptom then grew to the car turning off at random while traveling at speed - VERY DANGEROUS. Replaced the sensor and the problem was solved. Replace yours - you don't want to have the car die on the interstate at speed because you lose power everything and could quickly get rear ended. Great video - thanks!
Hello Shadowrider
You will have to be the most explicit repair guide out there.Thank you so much.
I have the exact same problem that you had.
You saved me a ton of time.
Good luck and keep it coming!
One of the best videos on TH-cam showing an everyday's man diagnosis that can be easily followed. I am highly impressed how you broke down your diagnosis so that we can all follow through. Great great video.
Thank you very much. I really enjoyed this video. I have never started my 560 sec for a long time cause I lost hope in it. But after your video I now know what's the problem. So thank you for the bottom of my heart. Please keep making more videos. 🙏🔥❤️🙌
You have an amazing gift of explaining and breaking apart the complicated into something digestible. I have the same car. So please post if you ever figure out the high idle issue. Thanks for the great tutorial.
Resolving the problem starts at 45:00. Thanks for uploading your video it’s very helpful
I'm wildly late to this video, but I'd like to offer my thanks too!
This is by far the most informative info I've found on this engine, it's truly excellent.
Just as a bit of additional information, you can't 'clock' the distributor cap incorrectly, the screws holding it down are unevenly spaced around the edge. It will only fit in one (the correct) position.
Terrific content, thanks again!
Thank you for posting such a methodical, careful video. Same thing happened to my 420 SEL, however after replacing the Crankshaft Positioning Censor it still did not start.
Next part in line was the Ignition Control Module. I bought 2 used ones, just in case. After replacing that the car is running again! :) and again thank you for this video.
I have the same car 91 Mercedes 420 milkshake and my motor has got 517 Thousand Miles and still going strong
Looking at buying a 1991 Mercedes-Benz 420 SEL with 122K miles that has been sitting since 2013 - can you please provide an evaluation process to prepare the vehicle for starting and possibly draining the fuel from the tank and review other components before starting it, maybe refer to other resources so the reviving process is successful
Hi thanks for taking the time to post your troubleshooting problem regarding cps,I've just purchased a w126 300 se with one previous owner and car has only covered 48k miles from new and as I do with any classic I buy although service history is there I like to just double check myself for piece of mind on the ignition system and replace what may have been missed.
On that note car ignition components all good and not showing any signs of wear.
I'll keep your tips in mind for future old school diagnostics is the best way.
Thanks.
It has been several years since you did this great video but it is still relevant to today. Thank you.
Just wanted to say THANKS for taking the time to make this video, it really helped me out alot! 87' 420 SEL
WWKD What Would Kent Do
Please keep posting videos; I enjoy your narrative style.
My 300sel just purchased acting same as your symptoms hope it gives same results however I just wanted to say great how to video to diagnose the same symptoms. It gives me great info on what to do to diagnose my mechanical problem .
really good information for the W126. the high idle may be the OVP relay.
Mercedes OVP relay repair
other causes:
1. Idle control valve
2. Idle control unit
3. OVP relay
4. Throttle position switch
5. Worn injectors
6. Broken/brittle/missing/disconnected vacuum hose(s)
I thought about that and tested it. It tested fine, but they're not expensive. It may be worth purchasing a spare and trying it to see if it helps.
THANK YOU - this is the ONLY video on the internet showing the CPS location for this year car! I'm about to give this a shot...
Great summary. I have a similar problem with a 380 SEL and will be testing and, I am sure, changing the crankcase sensor, Ignition Control Unit and the Overload Voltage relay. Parts seem to have come down in price. Thanks for this video.
Dear shadowrider , thanks for your Excellent informative video , after watching your video , i was able to diagnose my 560 SL for no start and my problem was with Crankshaft Position Sensor . I could not find the part for it but i have a 91 300 E parts car which i took off the CPS and put it on on my 560 SL and it started right up . I will have to locate a new CPS but until then i can drive my car .
Thanks again and keep up the good work .
Very wonderful and helpful information, no mechanics or dealers would ever match your analysis. My 1991 MB420SEL, presently not running is supplying parts for my 1989 MB420SEL(280KKM)My 89MB560SL(145 K KM) misfiring at times Perhaps the whole set of spark plugs wiring and the distributor need to be changed. Keep up Shadowrider 460
Thanks a lot for detailed explanation. Your advice is still valid with W126 owners worldwide. Greetings from Kazakhstan! 👍
The sensor on the front of the engine is what runs the tachometer, I don't recall if you mentioned that or not in the video. Good job showing how you diagnosed the no-start issue. Too many people just throw parts at it these days. I love these w126 Mercedes...they're quite nice to have as daily drivers, and generally don't break the bank too badly to keep them on the road (if you do your own work).
Thank you for sharing your experience with us, i enjoyed the whole thing! Keep your car and please and keep talking care of her
Thank you for your video. Same thing has happened to me 3 times now. RAA couldn't figure out what was wrong as by the time they arrived, car had cooled down and started straight away. When my mechanic looked at it and tested everything, his conclusion was dodgy fuel and the advice was keep the fuel level over half a tank full as it is probably a vapour lock. Car wouldn't start again tonight after driving for 7 minutes and parked for 5. Restarted after 10 minutes but stalled after 2 minutes. Three quarter tank full. I will consult with my mechanic as to your solution as I know this wasn't something he checked. Hopefully this is the problem. I will update once a permanent solution is found. Just for the record, the spark plugs and spark plug leads were all replaced 5000K's ago. Distributor cap and all filters have been checked.
Very good DX, great job of eliminating possibilities, sure saved a heck of a lot of $$$$ because Mercedes charges about 160.00 an hr you could have had a expensive bill, so in the end all you needed to replace was the CPS and replace the cap, rotor and wires which is good maintenance for wet weather driving because when wires get wet the car wont run, you are good at electrical DX
I want to thank you for such educational and interesting stuff, which allows even for me - amateur - to make problem diagnosing process with my 126 SEC.
WOW !!!...WOW!!!...Simply FANTASTIC Video, You really did an awesome job at explaining this electrical problem, I own a 1990 420 SEL...same exact problem. You sound so Honest and Knowledgeable. Is there any mechanic like you out there?...probably not. I live in Boston Massachusetts. Can you fix my Benz or...can you refer me to someone as good as you ?. Reply...pleeeeeease !!!
Ok well today I discovered that the crankcase sensor had already been replaced, I thought the wire looked newer but when i removed the air cleaner saw that the person who replaced it just left it dangling, one end melting on the manifold. I did a quick mulitmeter test for resistance and the new cable checked out to be functional.
I performed a fuel pressure test today. Results were good with fuel pressure 48 psi cold and off, 49-50 at idol and no change when the engine reached operating temp of 82 deg C.
here is where I am now. car will idol well in the driveway for 30-45 mins until the temp gets to 82C then it begins to sputter.
wondering where to go from here?
thanks for another great video !!!the sensor is just like a magnetic pickup on a guitar ! also same as the abs sensor on the wheels ! and diff !! hi from australia
Hi there interesting video, we have one over here in England, similar model, with a similar problem it has no spark, i dont think its the crank sensor because there is no spark at all no even when cold...we have tested the crank sensor on Labscope and looks ok, this one has a cam sensor inside the distributor, which we also tested on scope and its ok, i done a manual test on the coil and got a spark out of it, tested all the powers and grounds on the module...there is no coil primary switching, the only thing left is the module so were fitting one of those...hope it works, if not it will be easier to test things with a new module on...from Fred in England.
Your high idle is most likely related to your clutch fan actually sticking on I noticed right on start up that your clutch fan was spinning, that should only engage when Engine warms
Same happened to me one day with my 93 Cadillac Fleetwood. Problem was the 22 year old Ignition Control Module gave out. Upon examination it was corroded and rusted inside.
I have the same year and model. Wish you could help me to get the SRS light to go out. I've tried everything I know
yes, as another poster said cosmoline. they used to put it on everything, guns etc... not sure if they still use it tho.
i too had a cps fail on my volvo 240 wagon, caused by deteriorated insulation making the sensor short and the car to not start/stay running. but the volvo was a 92, and the sensor was only about 13yrs old at the time.
interesting video as usual!
It was a challenging issue to track down since a bad CPS wasn't my first guess as to what could be wrong. I'm just glad I could finally find the root cause and restore my confidence in it again so that I can drive it without fear of it breaking down. I shudder to think what the dealership would have charged to diagnose and make these repairs. The parts alone were around $520.
To make a suggestion if you use Simple Green on your white walls on your 72 Lincoln that will clean them up if you don't like scrubbing them but you can use, it works great and then of course armorall or something of the same type of wheel stuff. Its funny how many of the same car as me and you have owned the same type I had a Lincoln Mark 786 LSC I had a Mercury Grand Marquis 86 I have a 93 town car of 2010 Town Car I've had a f250 4x4 a 92 with the 460 in it. So we have the same tastes and likes in cars for sure
Ronald i would like to asked you a question in regards to my old CPS..i have the two bolts out ...and the CPS bolt is out ...but it is very hard for me to pull it out...can you help me out
Hi I have a 1990 black 560 sec and it’s having some issues starting up I have to spray stating fluid to get it to run any ideas what it could be ?
Thanks a lot! It was a very useful video in troubleshooting electrical/injection issues! :)
Do you have access to a PDF or workshop manual that lays out the replacement of the CPS? I have the exact same problem on mine.
Shadowrider460 have you replaced the timing chain, guides, and tensioner? I bought a 1990 420sel with 90,000 original miles, without warning, I went to start the car and the timing chain jumped timing due to a failed plastic guide. There was no rattle to forewarn me of the looming potential of a failure. The engine was running smoothly beforehand. Now, I need to do a valve job in addition to the timing chain and guides. I haven't decided if I am going to do that or scrap the car. It's a real shame since the car is in beautiful shape otherwise.
Yes. I didn't do the work, but I have all the maintenance records. The chains and guides were replaced not that long ago. I'm sorry to hear that your chain broke. If you can afford it or do the job yourself, then I would keep the car. It'd be a shame to scrap it as these W126's are getting harder to find. If you get it running, then I would also replace the drive shaft flexible couplings as well.
ozelot250
I have the same car...rough idle just started happening...engine has a rough time turning over when hot. I replaced the cap n rotor but nothing has changed. help !
What would have been your next step? Is there a way to test the coils? I sure could use some help with this issue.
Hi…i have a question and the Same Problem Like you. I have no spark out of the coil on my 560sec. I diagnosised the crank shaft position sensor but now I’m a bit confused. My old sensor I took out and it shows me the same as yours between 0.800-0.960 megaohms…your old one shows the same…but when u put your new one in it shows aswell 0.860 mega ohms so how do I know mine is bad? Thanks
you should also change the ignition coil if it is original, it has been revised and is less likely to destroy ignition control units - assuming the rest of the ignition system is well maintained.
That's not a bad idea. I was already thinking along those lines when I purchased the spare EZL a while back. Having a spare coil in the trunk may be a lifesaver one day.
+shadowrider460 a bad coil burns ignition module at times than both will have to be changed to attain function again , indeed diagnostic is a nightmare for many shops , and no one tells the story
Thanks for the tip on finding the date code on the ignition components. I had no idea.
It just amazed me that this car ran 187,000 miles on the original cap, rotor, and plug wires. In fact, these parts could still be used but I wanted to do a complete job if I was going to replace the CPS.
Where do I send the donation? Incredible training video! Many thanks!
very useful video. I have one comment however. When the EZL was being tested in the video, the red wire is shown as connected to the center post on the distributor cap. this is a little confusing to me. I thought the red wire (to create a gap) should have been connected to the high voltage cable coming from the ignition coil to verify if there is a spark coming from the ignition coil.
same thing happen to me, it was the fuel pump relay.
Idle must be at 550 solid all the time!!! If not you will have ongoing running problems such as harsh gears shifting, lumpy idle and rough driving at low speed etc.... You can start with the coolant sensor and the ICV, the valve itself can be adjusted slightly for smoother running. The best test for these engines, is the engine must feel like it died when you approach a red traffic light. The only thing tells you that the engine is running the RPM sitting at 550, otherwise it's waste of time!!!
well done video I ACTUALLY OWN BOTH MODELS 1991 420 SEL AND ALSO 1991 560 SEL
THE 420 SEL TROUBLE STARTING AND THE IDLE IS LOW AND THE 560 SEL DRIVES FINE BUT THE IDLE TOO HIGH
You didn’t show us how you tested the ignition coil. You told us how but didn’t show us
Where did u get ur new sensor? I can’t find one for my 87 420 sel anywhere. I called Bosch and Mercedes’. Do u have one for sale 🤔🤔
The other day, I drove my 1988 420 SEL in very hot weather and parked it in the sun for about 40 minutes. When I went to start it, the car wouldn’t crank or make any noise when I turned the key. The accessories were working fine, and the battery is brand new. After an hour, it started as usual. What could be the issue, and is there a video about it? Thanks for the videos.
1987 mercedes-benz 560 SEL breakdown ?
Good, good video!! Thanks, so if your MB stops, when gets hot, this could be it?? Mine is 500SEC/ 1984, must have similar sensor?? How much was that sensor, CPS??
Thank You very much for this video, I really learned a lot, amazing. Thanks again
Awesome video. Extremely well done. Excellent teacher. A+
Whats the part name he pulled at 1:05:03 thank you
help ! ignition system mercedes 560sel 1987 !
Hello, what is the Mercedes piston no
A 1170304918
A 1170301018
As it is not available in the Middle East
Is there another piston with the same size and dimensions and a different number? Do you have information?
Tell me, thank you
Anyone know the part number for the CPS? Or maybe where to get one for less than $600? 🤦🏼♂️
Please someone help me find the diagnostic tool for this car w126 1986 420SEL
I'm looking at one 86 40k , in your opinion do you think I'll be heaving allot of problems ? No one knows what kind of maintenance it has had , it looks like new.
Thanks
I would spend a few hours here on youtube watching Mercedessource and mercedessource.com...these are great cars but finding someone who can diagnose issues can be tough.
Thank you so much I'm going through the same problem with w126 my problem is that I can not found the part, I have even called in Germany they don't have it ,can you please help me with the website, so I can order the part. Thank you.
Your high idle problem may be an ETA issue. I have a 92 400E with the same problem and it appears the ETA is the issue. If you can get the computer codes you would be able to narrow it down.
Hello Shadowrider, my wife’s 89 560 sel also stalled. It cranks but will not start. There is spark and I checked the resistance for cps and it is within range. I smell fuel but I do not hear the fuel pumps cycle. I replaced the fuel relay with an aftermarket one and also tried swapping my old relay and still will not start. I am not getting any voltage reading on the pump either with the key on. What would you recommend? Thank you.
I think the guy has left this world.
hi shadowrider, first thanks for all videos including this one. I also have 420 sel and trying to fix it. In this video on 33.10 you mention shortly about "cylinder identification sensor" - I noticed on my car that this front end sensor is not attached a all but it is plugged in; wondering where to stick it??.... car doesn't work properly, dlack smoke, rough engine bcs of that I guess...
Very good video, I have 1989 560sec and I just get same issue few days ago now I know what to do , thank You very much , did you ever fix high idle? If yes please let me know how
That "clearcoat" is actually called cosmoline, I beleive. When I worked for BMW they shipped new cars over seas and coated many components with cosmoline, similar to a wax to prevent seasalt coroding components. Most dealerships will use a degreaser to clean it off.
I have heard of that product before and in this context, it makes allot of sense to use it during shipment. It does seem to have done an excellent job of keeping corrosion in check.
Hey shadow rider may I make a suggestion on improving the looks of your old Lincoln that you have try scrubbing the white walls it would make it look better with nice clean white walls and definitely need to get some white walls for your Roadmaster those raised white lettering tires or not the right ones. the right look for that car for sure definitely need some white walls ok take care your beautiful car collection I have one myself we have a lot of the same cars me and you and had the same cars I had a mark XII LSC1986 I have a 2010 town car I have a 1993 Town Car I have a 2003 Chevy s10 pickup a Mercedes Benz ml 320
I've never liked the raised letter tires on the Roadmaster either and feel that they don't look good on that car. They are in fairly good shape though and I hate to get rid of good tires. So I'll run them into the ground and look forward to a new tire purchase in which I can finally purchase the right tires for this car.
Hi Shadow Rider, Just noticed some oil leaks in my Mercedes. Any quick words of advice from you on how to deal with this. Thanks in advance for your help !
Oil leaks are tricky to find. The best way is to clean the affected area very well and start watching it to see where the leak originates. Typical areas are the valve cover gaskets, oil cap gasket, front crankshaft seal, and rear main seal. If the fluid is red, it's transmission fluid. If it's dark, then it could be engine oil or power steering fluid.
*****
I want a car like yours .... And i've been seeing your videos to see what kind of maintenance or issues I might run into if I decide to purchase one I have my eye on a used one but it has almost 200,000 miles the one that I have is a 1986 Mercedes 300 SE with 156,000 miles but the car that I'm inquiring has a lot more miles . Do you still have this car or are these videos old
+Ram M457 Yes he still has it. shadowrider's w126 actually has about 200k as well.
hello do you still answer questions?
Did you ever fix the high idle?
I haven't watched the vid all the way through, but reading your description you say you did wires, cap and rotor. Why didn't you do plugs as well?
They shipped the wrong plugs and I had to send them back. Besides, these plugs have about 20,000 miles on them and are still good. I'll probably end up changing them next year and possibly do an upgrade.
shadowrider do you have a contact I could talk to you about this model, I am looking at the same model benz and need some assistance on maybe a simple problem or very well could be a major one.
my email is randypari@gmail.com. The car idles very well, but when I have it in drive when I give it gas from a complete stop it likes to sputter until it gets up to a speed of around 25, its still a great cruiser when its on the highway, what could be the problem?
first think I'm going to do in this situation is:
pouring fuel 100ml thru MAF (remove air filter cover and poor the fuel on MAF plate)
and crank
if the engine start to run for two seconds, that will tells you that the ignition is fine
You have a thin jumper attached to the center of the distributor, then looking for a spark? The spark comes off the coil, via the short HT wire that GOES TO CAP. Oye....
You didn’t show where on the EZL where to connect the multimeter
Change the coil too if you have this M/B.
Do you always put premium gas in it?
100th Comment!
Awesome Video! All the comments ring true. God Bless!
Excellent video!
if the crank angle sensor is failing, the EZL should have a code 17 logged. It knows when you are cranking and if it does not see a crank signal it will store the code. Obviously you should clear the codes before making an assumption and repeat the test
I don't recall a code listing for the EZL in the service literature I have but then again, I may not have all the literature available. I know I don't have the transmission manual, sadly. That sure would have made the diagnosis easier but as it turns out, it's good to be able to troubleshoot things the old fashioned way just in case you don't have all of the information or diagnostic tools at your disposal.
I'm happy to report that after another heat soak along with a 10 mile test drive, the car performed flawlessly and never missed a beat. I now have confidence in this car again that I'll be able to go on a long journey with no issues.
Excessive resistance / open circuit of the crank angle sensor when hot is also a known failure mode so you will be fine im sure ;)
NOTICE HE NEVER SHOW THE VOLTMETER LEADS THAT HE CONNECT TO , TO TEST THE RESISTANT.
Thank you for a informative video. Do you know if this part will also work on the 5.6l in the 560SL (1987)? If so, where did you purchase your part? Thank you.
dokenbaw p
You are a God Send🤞🏾❤
I wish you wld show us the vacuum check valve bro please ❤️❤️❤️
Thank You very much
you got my problem.
Thanks again
My car has been just undriven now, couple, three years, and seems to start / or not start at all, when I sometimes go and try, must have some fuel/ problems, standing so long?? I put new fuelfilter, and pump last time I drove it a little bit, couple years ago, and put "marinegasoline" in a tank, should I change accumulator also in a fuel system?? Or fuelpressure sensor?/ Thanks again, good job =))
Mine sat for many years. It was drivable at first, but eventually it couldn't start. I replaced the fuel filter, pumps and fuel pump relay. Eventually I replaced the fuel pressure regulator which was the culprit. The car didn't start up immediately. I had to replace the spark plugs and dried the flooded engine. Here are signs of bad pressure regulator: www.doityourself.com/stry/7-symptoms-of-a-bad-fuel-pressure-regulator
Where is it located in my MB 500 SEC?? how much is a new one??
sir you are amazing
I am a big fan
check the voltage regulator
Very nice. Explain. Stap by stap Thanks
great job. did the same on mine
This is the last car that you would be able to repair with your bare human hands without a pocketful of money intervention. Might as well learn how to fix it yourself. they are nice cars worth keeping.
i have same problem with 1990 Mercedes 420 sel it make me sick after that i sale it as rubbish
ai have a w 126 model 260 se 6 cylinder no airco buy it was siting about 3 years what ai have to do! !!!!
Nice!!
This is biblical
I don't thinck your car have original miles....i know itas have 20+ years but......i observe that american version are not so resistent in time as european......i have a e200 K from 1997 and it's have 337.000 km ......no problem with cranck sensor ....i only chenge the sparck wires and the thing that make sparck(it's have 2 ).....i like very much W126....enjooy it and most important redpect the oil from your engine.......at my W210 i chenge the oil at 8000 km......i wish to buy in the future a W126 ...a W124 ....a W140 ....