Affiliate Links: Here are some links to products we used in this video on amazon in case you want to try this: Soldering iron: amzn.to/2AZXYcs Contact cleaner: amzn.to/2B0PKRk Replacement sender should yours be beyond repair: amzn.to/2KWzqsN (2 Year warranty)
"This thing is broken now, so what's the worst thing that can happen, break it more?" LOL Great video man, it details the trials and tribulations we all go through working on these old diesels
I think my entire life could be summed up with that statement lol. With these glorious but at times troublesome machines you have to have a sense of humor and be able to laugh when some random thing quits working or there is a sudden large puddle of some kind of fluid from a seal that despite its name has decided not to seal anymore
A friend of mine on a Greek island owns three of these lovely cars. He asked me to fix the fuel gauge. A really satisfying job to do. Great access after removing first aid box. All I will add is make sure everything is scrupulously clean. I polished the central shaft with Brasso and fine steel wool. Also clean the float too as well as the inside of the aluminium tube. I also cleaned the outside of the tube with steel wool and WD40. As we saw, the three wires are very fragile as these things are 40 years old so once you withdrawal the gubbins from the aluminium tube GO EXTREMELY CAREFUL WITH THE WIRES.!!! I clamped mine in a vice by the 46mm nut. You can also check the float moves freely by immersing it in an old plastic bottle with the neck cut off. Fill with water and watch if the float rises unhindered and doesn’t have a hole in it. After, spray with WD40.
Excellent advice! Cleanliness is indeed key, these fuel tanks can get really gunked up over the 40+ years they've been around. I got a bad tank of diesel last year and I think it gunked my sender back up again. Going to have to pull it out and clean it all back up again. Good reminder to buy diesel at stations that sell a good quantity of diesel, it'll grow nasty algae if it sits for a long time at a gas station that doesn't sell much!
Great video, good information, good use of visuals, and nice calm instructions on how to do the job, oh how I wish more youtubers would follow your lead.!! Many thanks from the UK.
@@mmm4638 This will prove challenging as diesel fuel is a combination of different molecules. However, A good approximation of the chemical formula of diesel is CnH2n, which leads to The reaction of diesel combustion being: 2CnH2n + 3nO2 ⇌ 2nCO2 + 2nH2O 🤣
I'm still wondering where all that gunk came from. Gauge has been working good until just recently it has begun hanging at about 1/2 full sometimes, I'm not sure if the center rod is rusty again, I'll need to pull it back out, but its been several years, I can't complain!
Testing the cable for the gauge, triangle, gauge triangle gauge needs to get a Nobel Prize for it. Remember the gauge is only measuring the resistance of the cable as that is how the gauge works - it monitors resistance. Also, the socket can be wired differently to the video with reference to the "blanks" and the guide pins, so need to find the ground first via continuity and then + and -.
Its sure a relief to know if the problem lies in the sending unit or if there is another issue up the line. There could be an issue with the resistance being off and being inaccurate, I have seen that where connecting the wires directly like I did may make the gauge move but the resistance of the wire or ground source could cause the gauge to read inaccurately with the actual sending unit resistance.
@@trythistv Hi could you please help me with this sender unit question. I have a Mercedes 190e W201 1987. Is there a particular sender unit for my car or one fits all. I need to get a new sender unit but which one for my car.
@@siriperera6974 So from the quick research I did, Your sender is slightly different from on my car, that could be because it has a gas engine, or it is 5 years newer and a different body style, either way it looks like this is what you need according to everything I could find: amzn.to/3CAicZ7 It shows an earlier part number (2015420304) which has been discontinued and replaced with the one I linked (2015420504)
Im going to have to give this a go. Ran wvo/diesel for 10 years straight and its all over the place. Its completly sporadic , so due for a cleaning im sure. Thanks for the knowledge and confidence booster😅
I've had more trouble with pump diesel in my blue car than I have ever had with WVO in my grey car (I don't think the channel has seen the grey car yet, its due for an introduction soon though) But it can certainly cause some gunk to build up and those tiny wires are very sensitive to any change in resistance
My very first Mercedes, and first car entirely was a 1980 300sd, I drove that car for years, loved it. Got me into Mercedes and I fell in love with the om617 engine. Almost identical to my w123 that I have now except for a few little odds and ends. I miss that w116. It was a great car.
Thanks, I couldn't make videos like this without folks like you watching them! I hope your fuel sender repair goes well! Mine works much better than it did, it does still have a little quirkiness right at about 1/2 tank, I'm guessing I didn't get the wire quite clean enough when the float sits right there.
The wire beside the contact was the best tip yet. I will have get into my sender and check if that is my problem as well. Thanks for this bit of information. JIM H
Thank you so much for this video. You saved me some good money. Took that flux capacitor out and cleaned it as you said. Only sacrificed my toothbrush and some contact spray! All works well again. Cheers
Probably best to retire that toothbrush. Or gift it to someone... Probably retire it lol. Glad the video was helpful, it sure is nice to have a functional fuel gauge, even if it is a bit depressing to watch it go down with the prices the way they are.
Man that stuff was NASTY!!! My gauge worked great for a while, but has recently begun acting up again, not sure if its more gunk or if something else is up. Car has been running awesome tho! Just took about a 2000 mile road trip, never even skipped a beat.
@@trythistv Haha I actually enjoy nasty stuff when I dive into my cars myself. It means it's original and not tempered with (because most end up being serviced by noobs to save a few bucks). My r107 is fine but I'm addressing a '91 w124 4matic these days, and boy let me tell you, the parts bill is stacking up! I had a mechanic address a fuel smell from the rear, and after being unable to find culprit, he pulled the tank and cleaned it and patched it in a place or two, not only did that do NOTHING to the fuel smell (we now suspect its the entire tank), fuel gauge stopped working too. It's stuck at 1/4th mark. So just waiting on a big enough wrench to open the fuel sending unit with. I have to thank you for the follow up after the service, knowing whether it worked long term or not is a HUGE help!
@@shaazy you know that is a phenomenal way of looking at it. My gauge does still work, but it tends to flop around a bit once you're below 1/2 tank, which makes me suspect some gunk/algae in my diesel, it seems harder and harder for me to find good diesel in TN.
@@trythistv Haha thanks. I've actually not that much of an experience with old diesels for precisely that reason, bad fuel. Sticking it out with petrols. Ive been refraining from filling mine more than half cause of that darn fuel smell. It starts up and drives fine, but the smell makes me feel I'm wasting fuel when I don't drive it for a few days. Below half tank, needle's stuck. Couldn't get hold of a big wrench today, so the job's moved to tmrw.
Excellent! Been exactly there and done exactly that! Grabbed as many of these as i could from the local bone yard knowing that they were indeed VERY expensive to replace. Broke the fine wire like yourself but not sure I ever got to the point of figuring out the correct path for the wire on the float as I had enough in the garage to just grab another and keep moving on. I do love those diesels though! Especially the 5 cylinder Turbo Diesel venerations. I got pretty good at working with all the vacuum and getting those pesky transmissions to work flawlessly. Wonderful engineering, craftsmanship and materials that makes them so satisfying to own and operate given one is willing to take the time to figure things out like you do! Excellent video brother! This will be VERY helpful to the next guy doing the very same thing. Little chilly there, but you've got that beanie on so your good! Take care!
I have a 84 300d been sitting since 01. I hv had it couple weeks. Been driving it daily after going over and replacing dry rotted vacuum lines, Changing fuel and filters, alot of cleaning and freeing up windows and sunroof.. Still a work in progress.. Transmission was shifting through the gears way to soon before having time to gain enough rpms to accelerate with traffic without manually shifting up to drive as speed picks up. I adjusted the cable and helped some. Will pull out and keep up w traffic but still goes through the gears too quick. Any suggestions? Only had 92500 on it and was took e tremely good care of until it was parked on a carport and was just started and moved every on e in a while to keep it running. Any suggestions are appreciated this is my first mercedes to fix up.
@@bradleesykes8764 Hey Bradlee. I'd have numerous suggestions. TrythisTV is a wealth of knowledge as well, but I'm happy to share my vast experience with the 5 cylinder diesel if you'd like. How do we communicate outside of TH-cam? Happy to yak with you on the phone if we can figure that one out. Take care.
I just got an 80 240d ,and I'm learning. I came from vws ,so at least I'm a little aware of European stuff. Anyways ,it's been great ,I've put like 80mi on it in about a week here. This thing gets great fuel mileage, the fuel gauge hasn't even moved yet! Well, this morning it quit like 400' before work. I know diesel,it felt like it ran outta fuel. So I dumped in 5 gallons, and the gauge didn't move🤣🤣🤣 Primed it up and off I went to the station and filled it up. Wow ,what a concept ,repair something! I priced em at around 200$ or so, but if it'll "clean up" I'll give it a try! Thanks for the vid!
6:24 AHA! My warning triangle is on all the time and the gauge reads half. Lol I was wondering what that light was. I'm still not done going thru tht owners manual.
I debated replacing my fuel sender, but I'm of the ideology that if its already broke, and I'm planning on replacing it, what can I hurt by taking it apart? Saved my old fuel sender, and saved some money that I can spend on some other project lol. You'll grow to love that 240D, they aren't the fastest thing around, but comfortable, well built and full of personality.
Thank you very much trythistv, i was just looking for the dimension on the drive socket. 46 mm. You just made my day. Also very nice to see the rest. How you fixed the sending unit. Fabolous! Greetings from Norway and my -80 230E.
You are very welcome! Glad it helped you out, I do believe it is the same socket for the fuel level sender and the tank strainer on the bottom, at least on the diesels, I'm unsure if the fuel tanks are the same in that way on the gasoline models, but they're a great car either way!
Ok guys before you purchase a new fuel sending unit try and clean the electrical connection on top of the unit first. Don't make the same mistake I did, and purchase a new VDO sending unit which didn't solve the gauge Fluctuating issue. I took the old one apart, and cleaned it up well put it back together and used a 220 grit sand paper to clean the electrical connection on the sending unit. It works perfectly fine now.BTW it's a 1995 E320
Very helpful!! Mine is a 73 450SLX, but same concept. Mine had sat outside for 16 years with no driving, so you can guess what the tank/sender looked like!
Phew yeah sitting doesn't do anything good that's for sure. Senders of this style were used on a ton of cars, I had no idea they were used on the gas engined cars too though. Thanks for the info!
@@trythistv The center rod had lots of corrosion, but cleaned up OK. But the contacts and washers and nut at the bottom were so rusty I didn't even recognize what they were. And I broke the ground wire, despite being VERY careful. I'll try soldering it tomorrow...
fine video. I have 2 W123 cars and the sending units don't send after the tank becomes half empty. Looking fwd to a fix. Yet another reason to own these cars which are FIXABLE in a home garage rather than the expensive junk being made today.
Most definitely! Being able to perform my own maintenance and repairs saves me a fortune, and is quite enjoyable too in my opinion. I do need to pull my sending unit back out, fuel quality is horrible in the rural town I live in, even with fuel tank cleanings and multiple biocide treatments it always comes back and messes up my sender and stops it from reading properly after a few years.
I cleaned mine with Simple Green; then soaked in isopropyl alcohol for an hour; cleaned it with small brushes; lightly sanded the metal rod; sprayed silicone spray on the rod before installing; works great!
Great video. You're not going to believe it but my sender has no fill up hole, it only has a hole on the top. I'm driving crazy right now, I don't understand the reason, should I drill it and make the hole?
Could be that the bottom plastic thing does have a path that fuel could take to make it in that would make it less susceptible to sloshing causing erratic readings, but it could also be prone to any debris settling into that area. I feel like a 1/8 inch hole near the bottom of the aluminum tube certainly wouldn't hurt anything, but I would be super careful drilling it, you can see how delicate the wires and everything is inside of it, don't accidentally nick one of those with the drill!
Thank you very much for the video, it helped me a lot to fix my problem, but I would like to replace the thin wire with a new one, and how it is tied or bent at the bottom because I do not know if I have placed it correctly or incorrectly.
Here is what I've read about replacing the wires: the thicker ones don't really matter at all, they just need to be a wire that conducts power for the low fuel light, some thin copper wire will be fine. The teeny tiny silver wires are 37awg nichrome wire, here is a link (it's an affiliate link) to some that should be an exact replacement for those super fine resistance wires: amzn.to/37IpSLf I do believe they get soldered onto the sender frame. Very important that those are the right resistance, otherwise the readings will be skewed or it may not work at all.
Did you find a type of guitar string that works for the resistance wire? I've heard that a 37AWG resistance wire (Like this: amzn.to/3yA3EHq) is the correct gauge and such, but have not tried it personally as my wire is still mostly ok
Just wondering if you would know, if on my 89 300ce Mercedes 2 door, if I can delete all the stock exaust mufflers and catalytic converter up to the Oxygen sensor or , even the sensor, with after market muffler and pipes, and not have issues!! Thanks for the vid on the sender unit?? Any idea the size of O ring on the sender unit??
I can't see any reason you couldn't, if there is no downstream o2 sensor, then it won't make any difference in how the car runs, other than you'll fail emissions tests if your location requires them. I'm not sure on the O-ring size, I should measure mine though, I bet they tend to degrade on the gasoline cars!
Boa tarde amigo. Falo do Brasil . minha w116 300SD foi substituido o tanque por um de mitsubishi l200 . sensor diferente. Sei que neste sensor na parte superior tem um diodo retificador. Voce sabe me informar qual é?? Sem ele o ponteiro do marcador fica oscilando buscamente. Abraço
Able to pull out the sender and get it pretty well cleaned up and reinstalled. The gauge now works, mostly, but the indicator bounces down to E on occasion. Is this just an issue with one of the contacts? I also see you have a video on the tank screen, which I had replaced 2 yrs ago. Watching that next. Thanks.
For the most part I've found the weird twitchy gauge issues are all the sender. I am certain someone somewhere has experienced a failed cluster needle thingy too but I personally have not. Often a little dirty patch on those crazy fine wires will be what's making it flail like a madman. The tank strainer is a messy job for sure! Catches a lot of crud though so it's worth checking out with the amount of years we have on these cars now.
@@trythistv I tested the cluster and the gauge works fine. I may pull the sender back out to do additional sediment removal and when I do I will pay more attention to cleaning the wires with cotton balls with diesel or brake cleaner. I had someone change the strainer out for me a year ago. But after additional tank cleaning, I'll either replace again or look further into your upgrade of putting the goldenrod setup in the engine compartment.
I would highly doubt it, the wires inside the sending unit are so tiny they wouldn't carry any current at all. If the sending unit is to blame, its easy enough to test, just pull the connector off the top of the sending unit and leave it disconnected. What is your car doing that you say it has a short?
If you're talking about the little plastic nub, it is just there to orient the plug in the correct direction, there is likely a cutout or hole in the plug that would sit on that plastic pin. Just make sure you've got the plug on facing the right way and it won't hurt anything to be missing.
If I'm understanding correctly it zigzags so that it touches the inside of both flaps and holds a teeny tiny amount of pressure outward on each flap so that it makes a good connection, but be very gentle as that wire is extremely fragile
@@manuelmantilla4536 I'm struggling to explain it, the little flaps were ever so slightly offset on mine, so one was shaped like a < and the other like a > and the wire went in the middle so >|< like that, it puts just a tiny amount of pressure on the flaps due to the offset so that it makes a connection
No battery, just connect one plug to the other with a wire. It measures resistance not voltage, so connecting the 2 wires together should make the gauge flop from empty to full when the key is in the on position
So the kit I've got is this one: amzn.to/3lySKfq But for some reason it is showing not available now. I've also seen this: www.thingiverse.com/thing:2778966 if you know someone with a 3d printer they might be able to whip up one of those for you!
The thicker ones don't really matter at all, they just need to be a wire that conducts power, some thin copper wire will be fine, the teeny tiny silver wires are 37awg nichrome wire, here is a link to buy some: amzn.to/37IpSLf (Affiliate link, I'll get a commission if you buy from that link, if you'd rather not, just search amazon for "uxcell 37awg hearing wire cr20ni80")
I did this to my 380sl, but found out my fuel sender is working good, can it be the cluster cause mine shows fuel when filled up, but delays when I lose more gas and goes back in forth to half full to sudden quarter tank
It could be the cluster itself, but before you look into that I'd check the grounds, It is quite common for the connections to corrode ever so slightly behind the cluster (Brown wires are ground) and with that little extra resistance from the corrosion it throws off the more sensitive gauges like the fuel gauge that is looking for slight resistance changes.
if I can find someone with a jeep that'll let me tear it all apart lol. The fuel tank needs to be dropped, or a hole cut in the floor for sure, there is no access designed into the jeeps that I'm aware of, and then its an integrated unit, fuel pump, sending unit and such all comes out as one piece.
I need to redo mine as well, I got some bad diesel and it gunked it up, if you ever get diesel in east TN, pay attention to where you see all the trucks and buses at, fill up there. these little stations with low fuel turnover have cost me more than I'd like to know about.
I love Seafoam. Biobor JF is good stuff too, kills off algae/bacteria or whatever stuff grows in diesel, I try to treat my tanks every so often now, then check the filters after a few drives.
I do believe all the W123 used the same fuel sender, so yes. I also believe the W126, W124, W116 and possible others all used this sender, or at least one similar enough that the same steps to test and repair it would apply.
The sender for my car is 123-542-04-04, I suspect the w126 you've got should use the exact same part. I know the peachparts/pelicanparts site lists near everything available, or you can always try eBay, now and then there is a cheap used one on there
It sure is a goofy looking nut, probably not really meant to be "user serviceable", but we'll make due and keep our amazing old cars going as long as possible!
It sure did! Been working great ever since. You can pop the connector off and test it with a jumper wire to see if it is the sender or something else before you pull it out of the tank
I did a video where I pulled the strainer, and ended up cutting the screen off because it was so clogged up with nast! (I have a massive water separator/prefilter screen that catches gunk very effectively, I wouldn't advise removing the tank strainer with the stock filtration) Algae is an insane problem in the rural east TN area I live in. My wife took the car once, filled up at a different station than usual and got 2 miles down the road before the whole fuel system was gunked up with algae. Another friend filled up his brand new truck, and didn't make it out of the station before the water in fuel light came on, and then the truck shut down, and it ruined some very expensive cp3/cp4/injectorey parts (I'm unsure what the modern bits are in diesels, I know my Bosch pumps and thats about the extent of my knowledge)
Great Video - Any Ideas - I did every thing you suggested - circuits were OK - wires were OK - looping the wires through < & > contacts was OK - tried it outside the tank - IT STILL DOES NOT WORK - Desperate now , from the UK
Did you test it with a multimeter? There should be resistance that varies with float position on pins 1 and 2. And did you test the gauge by jumpering the connector as I showed? They have a terrible habit of the ground wires behind the cluster getting a bad connection, and in some cases the gauge itself on the cluster decides to give up the magical smoke that makes it work.
@@trythistv Thanks very much for your prompt reply - This is used unit i got from a breakers yard . I opened it up & it looks OK & was fairly clean & slides well. I did the car test - fuel gauge & warning light both worked. When I put my multimeter on the pins of the sender - I get NOTHING - on all pin combinations .Does it mean I will have to buy an OEM new one - but I can not see anything wrong with it. Thanks again.
That strikes me as something has internally failed, it is possible the connection between the inside where the wires are and the pins on the outside has failed seeing that the wires and slide are in good shape. Knowing your wires and gauge/light are all functional basically tells you the problem is the sender, whether finding a good used replacement or if new senders are being produced how cost prohibitive it would be to procure one is ultimately the decision to be made. It would also be possible to take a socket and multimeter and check cars in a junkyard until a functional unit was found, I understand that gas and diesel mercedes used this same sender for a very wide range of models and years so it shouldn't be awful to locate one.
@@trythistv Thanks very,very much for your help .I assumed it was a problem with this particular sender.But what I did not understand was - if the wires were soldered to the pins - How could I not be making a circuit - I do not understand - Looks like I will have to buy an OEM .
@@trythistv Just to let you know. Try as I might, I could not get my S/H sender unit to work .Even though it had all three wires in place ,clean, & the float slides easily ,BUT I could not get a ohms reading across the pins. I ended up buying a new OEM unit for £194 .It now works OK. - Albert
You're sure a nice likeable guy, and gave great info, but you should never go around a clock factory, clean such things very gently with Berryman, lacquer thinner, etc using fine brush, until spotless, put fine pumice on wires, slide up and down until wires are bright, and the slide contacors will be just so,, final wash it all, clean the plug-in contacts, barring trouble elsewhere, it will work. Thanks! No ridicule intended! 🌈lol
I've been told I'm a little heavy handed at times, If it gets the job done though... This sending unit is still working great! lol, I do appreciate some of the tips, I've been meaning to get some Berrymans stuff, I've heard it works wonders.
the hard plastic lines rarely ever break or have issues, but the rubber connectors are all usually at various stages of decomposition by now. an 83 will be nearly the same as my car, minus 1 cylinder and a turbo, but vacuum wise that shouldn't be a huge difference. You can block off the central locking, if the issues are in that system this post has some excellent diagrams here: www.peachparts.com/shopforum/1247118-post5.html Then there is some of the highest quality ones I've ever seen over here: www.justanswer.com/mercedes/7z9ow-mercedes-benz-1983-new-question-vacuum-schematic-240d.html
I'm barely fluent in English, much less any other languages but I think you're referring to condensation? If so, you're exactly correct! The condensation inside the fuel tank can cause that algae to grow and it makes a right mess of the tank and fuel sender!
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Affiliate Links:
Here are some links to products we used in this video on amazon in case you want to try this:
Soldering iron: amzn.to/2AZXYcs
Contact cleaner: amzn.to/2B0PKRk
Replacement sender should yours be beyond repair: amzn.to/2KWzqsN (2 Year warranty)
Really appreciate your videos. All of us MB diesel owners thank you!
"This thing is broken now, so what's the worst thing that can happen, break it more?" LOL Great video man, it details the trials and tribulations we all go through working on these old diesels
I think my entire life could be summed up with that statement lol.
With these glorious but at times troublesome machines you have to have a sense of humor and be able to laugh when some random thing quits working or there is a sudden large puddle of some kind of fluid from a seal that despite its name has decided not to seal anymore
Well my mate, you can rest easy knowing that I enjoyed your video and learned a great deal.
Thank you
No wonder I slept so good! Glad you enjoyed the video, hope it helped you with your fuel sender!
A friend of mine on a Greek island owns three of these lovely cars. He asked me to fix the fuel gauge. A really satisfying job to do. Great access after removing first aid box. All I will add is make sure everything is scrupulously clean. I polished the central shaft with Brasso and fine steel wool. Also clean the float too as well as the inside of the aluminium tube. I also cleaned the outside of the tube with steel wool and WD40. As we saw, the three wires are very fragile as these things are 40 years old so once you withdrawal the gubbins from the aluminium tube GO EXTREMELY CAREFUL WITH THE WIRES.!!! I clamped mine in a vice by the 46mm nut. You can also check the float moves freely by immersing it in an old plastic bottle with the neck cut off. Fill with water and watch if the float rises unhindered and doesn’t have a hole in it. After, spray with WD40.
Excellent advice! Cleanliness is indeed key, these fuel tanks can get really gunked up over the 40+ years they've been around. I got a bad tank of diesel last year and I think it gunked my sender back up again. Going to have to pull it out and clean it all back up again. Good reminder to buy diesel at stations that sell a good quantity of diesel, it'll grow nasty algae if it sits for a long time at a gas station that doesn't sell much!
Saved me completely with the wiring part. Man what a day even dropped a wrench 🔧 in the tank and had to mag it out.
Oh man that is a rough time. Glad it helped you out though! Hopefully you can get your gauge working!
One of the best w123 youtube channels on here. Learned so much by tacking these simple known issues you talk about
Thank you so much! I love knowing my efforts to make these videos are helpful to others!
Great video, good information, good use of visuals, and nice calm instructions on how to do the job, oh how I wish more youtubers would follow your lead.!! Many thanks from the UK.
Thank you very much! I've been frustrated by plenty of other how-tos myself.
Please overanalyze further down to molecules
@@mmm4638 This will prove challenging as diesel fuel is a combination of different molecules. However, A good approximation of the chemical formula of diesel is CnH2n, which leads to The reaction of diesel combustion being: 2CnH2n + 3nO2 ⇌ 2nCO2 + 2nH2O
🤣
You had me laughing at 3:23-4:11!!! haha That's Awesome you were able to go back and fix after testing the initial repair! thumpsup
I'm still wondering where all that gunk came from. Gauge has been working good until just recently it has begun hanging at about 1/2 full sometimes, I'm not sure if the center rod is rusty again, I'll need to pull it back out, but its been several years, I can't complain!
You gave me the guts to clean the sender on my '86 W201 myself. Thank you.
Awesome! So glad it helped you out, hopefully your fuel gauge works like new now!
Hilarious plot twist double ending. Had a good laugh while learning more helpful info about this old girl. Thanks man!
Testing the cable for the gauge, triangle, gauge triangle gauge needs to get a Nobel Prize for it. Remember the gauge is only measuring the resistance of the cable as that is how the gauge works - it monitors resistance. Also, the socket can be wired differently to the video with reference to the "blanks" and the guide pins, so need to find the ground first via continuity and then + and -.
Its sure a relief to know if the problem lies in the sending unit or if there is another issue up the line.
There could be an issue with the resistance being off and being inaccurate, I have seen that where connecting the wires directly like I did may make the gauge move but the resistance of the wire or ground source could cause the gauge to read inaccurately with the actual sending unit resistance.
@@trythistv Hi could you please help me with this sender unit question. I have a Mercedes 190e W201 1987. Is there a particular sender unit for my car or one fits all. I need to get a new sender unit but which one for my car.
@@siriperera6974 So from the quick research I did, Your sender is slightly different from on my car, that could be because it has a gas engine, or it is 5 years newer and a different body style, either way it looks like this is what you need according to everything I could find: amzn.to/3CAicZ7 It shows an earlier part number (2015420304) which has been discontinued and replaced with the one I linked (2015420504)
@@trythistv Thank you so much.
Im going to have to give this a go. Ran wvo/diesel for 10 years straight and its all over the place. Its completly sporadic , so due for a cleaning im sure. Thanks for the knowledge and confidence booster😅
I've had more trouble with pump diesel in my blue car than I have ever had with WVO in my grey car (I don't think the channel has seen the grey car yet, its due for an introduction soon though)
But it can certainly cause some gunk to build up and those tiny wires are very sensitive to any change in resistance
Thank you so much for your video!! I have a 1980 116 and my gage stopped working so this will help me a lot!
My very first Mercedes, and first car entirely was a 1980 300sd, I drove that car for years, loved it. Got me into Mercedes and I fell in love with the om617 engine. Almost identical to my w123 that I have now except for a few little odds and ends. I miss that w116. It was a great car.
You make the best videos. Going to follow your steps on my w123. Thanks again.
Thanks, I couldn't make videos like this without folks like you watching them! I hope your fuel sender repair goes well! Mine works much better than it did, it does still have a little quirkiness right at about 1/2 tank, I'm guessing I didn't get the wire quite clean enough when the float sits right there.
A brilliantly put together video. Top job man, helped me a lot.
Glad it helped!
The wire beside the contact was the best tip yet. I will have get into my sender and check if that is my problem as well. Thanks for this bit of information. JIM H
Thank you so much for this video. You saved me some good money. Took that flux capacitor out and cleaned it as you said. Only sacrificed my toothbrush and some contact spray! All works well again. Cheers
Probably best to retire that toothbrush. Or gift it to someone... Probably retire it lol. Glad the video was helpful, it sure is nice to have a functional fuel gauge, even if it is a bit depressing to watch it go down with the prices the way they are.
Haha your reaction to the gunk inside was priceless! Very cool video and awesome result overall! Totally rooting for you
Man that stuff was NASTY!!! My gauge worked great for a while, but has recently begun acting up again, not sure if its more gunk or if something else is up. Car has been running awesome tho! Just took about a 2000 mile road trip, never even skipped a beat.
@@trythistv Haha I actually enjoy nasty stuff when I dive into my cars myself. It means it's original and not tempered with (because most end up being serviced by noobs to save a few bucks). My r107 is fine but I'm addressing a '91 w124 4matic these days, and boy let me tell you, the parts bill is stacking up! I had a mechanic address a fuel smell from the rear, and after being unable to find culprit, he pulled the tank and cleaned it and patched it in a place or two, not only did that do NOTHING to the fuel smell (we now suspect its the entire tank), fuel gauge stopped working too. It's stuck at 1/4th mark. So just waiting on a big enough wrench to open the fuel sending unit with. I have to thank you for the follow up after the service, knowing whether it worked long term or not is a HUGE help!
@@shaazy you know that is a phenomenal way of looking at it. My gauge does still work, but it tends to flop around a bit once you're below 1/2 tank, which makes me suspect some gunk/algae in my diesel, it seems harder and harder for me to find good diesel in TN.
@@trythistv Haha thanks. I've actually not that much of an experience with old diesels for precisely that reason, bad fuel. Sticking it out with petrols. Ive been refraining from filling mine more than half cause of that darn fuel smell. It starts up and drives fine, but the smell makes me feel I'm wasting fuel when I don't drive it for a few days. Below half tank, needle's stuck. Couldn't get hold of a big wrench today, so the job's moved to tmrw.
Excellent! Been exactly there and done exactly that! Grabbed as many of these as i could from the local bone yard knowing that they were indeed VERY expensive to replace. Broke the fine wire like yourself but not sure I ever got to the point of figuring out the correct path for the wire on the float as I had enough in the garage to just grab another and keep moving on. I do love those diesels though! Especially the 5 cylinder Turbo Diesel venerations. I got pretty good at working with all the vacuum and getting those pesky transmissions to work flawlessly. Wonderful engineering, craftsmanship and materials that makes them so satisfying to own and operate given one is willing to take the time to figure things out like you do! Excellent video brother! This will be VERY helpful to the next guy doing the very same thing. Little chilly there, but you've got that beanie on so your good! Take care!
I have a 84 300d been sitting since 01. I hv had it couple weeks. Been driving it daily after going over and replacing dry rotted vacuum lines, Changing fuel and filters, alot of cleaning and freeing up windows and sunroof.. Still a work in progress.. Transmission was shifting through the gears way to soon before having time to gain enough rpms to accelerate with traffic without manually shifting up to drive as speed picks up. I adjusted the cable and helped some. Will pull out and keep up w traffic but still goes through the gears too quick. Any suggestions? Only had 92500 on it and was took e tremely good care of until it was parked on a carport and was just started and moved every on e in a while to keep it running. Any suggestions are appreciated this is my first mercedes to fix up.
@@bradleesykes8764 Hey Bradlee. I'd have numerous suggestions. TrythisTV is a wealth of knowledge as well, but I'm happy to share my vast experience with the 5 cylinder diesel if you'd like. How do we communicate outside of TH-cam? Happy to yak with you on the phone if we can figure that one out. Take care.
I just got an 80 240d ,and I'm learning.
I came from vws ,so at least I'm a little aware of European stuff.
Anyways ,it's been great ,I've put like 80mi on it in about a week here.
This thing gets great fuel mileage, the fuel gauge hasn't even moved yet!
Well, this morning it quit like 400' before work.
I know diesel,it felt like it ran outta fuel.
So I dumped in 5 gallons, and the gauge didn't move🤣🤣🤣
Primed it up and off I went to the station and filled it up.
Wow ,what a concept ,repair something!
I priced em at around 200$ or so, but if it'll "clean up" I'll give it a try!
Thanks for the vid!
6:24 AHA!
My warning triangle is on all the time and the gauge reads half.
Lol I was wondering what that light was.
I'm still not done going thru tht owners manual.
I debated replacing my fuel sender, but I'm of the ideology that if its already broke, and I'm planning on replacing it, what can I hurt by taking it apart?
Saved my old fuel sender, and saved some money that I can spend on some other project lol.
You'll grow to love that 240D, they aren't the fastest thing around, but comfortable, well built and full of personality.
Excellent vid, thanks man. I'll keep you posted on my fuel gauge progress.
You are very welcome! I hope you get your gauge working!
How did it go?
Good job. I'm going to work on it tomorrow. Thanks.
Hopefully you got it working!
Thank you very much trythistv, i was just looking for the dimension on the drive socket. 46 mm. You just made my day.
Also very nice to see the rest. How you fixed the sending unit. Fabolous!
Greetings from Norway and my -80 230E.
You are very welcome! Glad it helped you out, I do believe it is the same socket for the fuel level sender and the tank strainer on the bottom, at least on the diesels, I'm unsure if the fuel tanks are the same in that way on the gasoline models, but they're a great car either way!
Very useful video, I just did it with my
'85 300D, works! Many Thanks
Awesome! Its so nice to have a functional fuel gauge!
Was having issues with mine as well, your video was a huge help! Thanks!
Glad it helped! Seems like any bad fuel wreaks havoc on those fine little wires
Brilliant video! I’ll be fixing mine this weekend!
Watch those super thin wires! very easy to break if you get a little overzealous cleaning like I did
Great video thanks it’s worth replacing the o rings too 👌
Ok guys before you purchase a new fuel sending unit try and clean the electrical connection on top of the unit first. Don't make the same mistake I did, and purchase a new VDO sending unit which didn't solve the gauge Fluctuating issue.
I took the old one apart, and cleaned it up well put it back together and used a 220 grit sand paper to clean the electrical connection on the sending unit. It works perfectly fine now.BTW it's a 1995 E320
Excellent point, any connection along the signal path can cause issues, absolutely worth checking and cleaning the contacts!
Great effort , clear, honest and informative video.
Thank you very much! You've described the exact goal for making these videos!
May I know the type of ultra thin wire
? .. And what is his name if I want to buy it? Thank you very much for coming
I haven't tried it personally, but I have been told it is this: amzn.to/3rtps7q 37awg resistance wire.
@@trythistv thanks 💚
Very helpful!! Mine is a 73 450SLX, but same concept. Mine had sat outside for 16 years with no driving, so you can guess what the tank/sender looked like!
Phew yeah sitting doesn't do anything good that's for sure. Senders of this style were used on a ton of cars, I had no idea they were used on the gas engined cars too though. Thanks for the info!
@@trythistv The center rod had lots of corrosion, but cleaned up OK. But the contacts and washers and nut at the bottom were so rusty I didn't even recognize what they were. And I broke the ground wire, despite being VERY careful. I'll try soldering it tomorrow...
fine video. I have 2 W123 cars and the sending units don't send after the tank becomes half empty. Looking fwd to a fix. Yet another reason to own these cars which are FIXABLE in a home garage rather than the expensive junk being made today.
Most definitely! Being able to perform my own maintenance and repairs saves me a fortune, and is quite enjoyable too in my opinion.
I do need to pull my sending unit back out, fuel quality is horrible in the rural town I live in, even with fuel tank cleanings and multiple biocide treatments it always comes back and messes up my sender and stops it from reading properly after a few years.
I cleaned mine with Simple Green; then soaked in isopropyl alcohol for an hour; cleaned it with small brushes; lightly sanded the metal rod; sprayed silicone spray on the rod before installing; works great!
Very helpful video I am having the same problem. Will definitely give it a try
Excelente Maestro, ¿ De cuántos milímetros es la copa para esa tuerca del aforador ?
46mm if I recall correctly
@@trythistv Gracias Maestro por su respuesta, Saludos desde Centro América 🙂👍
The black nut at the bottom is threaded and turns like a normal nut. Left or counter-clockwise loosens it.
Yup, figured that out basically after the whole process lol
Great video. You're not going to believe it but my sender has no fill up hole, it only has a hole on the top. I'm driving crazy right now, I don't understand the reason, should I drill it and make the hole?
Could be that the bottom plastic thing does have a path that fuel could take to make it in that would make it less susceptible to sloshing causing erratic readings, but it could also be prone to any debris settling into that area.
I feel like a 1/8 inch hole near the bottom of the aluminum tube certainly wouldn't hurt anything, but I would be super careful drilling it, you can see how delicate the wires and everything is inside of it, don't accidentally nick one of those with the drill!
Thank you very much for the video, it helped me a lot to fix my problem, but I would like to replace the thin wire with a new one, and how it is tied or bent at the bottom because I do not know if I have placed it correctly or incorrectly.
Here is what I've read about replacing the wires: the thicker ones don't really matter at all, they just need to be a wire that conducts power for the low fuel light, some thin copper wire will be fine.
The teeny tiny silver wires are 37awg nichrome wire, here is a link (it's an affiliate link) to some that should be an exact replacement for those super fine resistance wires: amzn.to/37IpSLf
I do believe they get soldered onto the sender frame.
Very important that those are the right resistance, otherwise the readings will be skewed or it may not work at all.
With guitar string replace and resolder fix done
Did you find a type of guitar string that works for the resistance wire? I've heard that a 37AWG resistance wire (Like this: amzn.to/3yA3EHq) is the correct gauge and such, but have not tried it personally as my wire is still mostly ok
Just wondering if you would know, if on my 89 300ce Mercedes 2 door, if I can delete all the stock exaust mufflers and catalytic converter up to the Oxygen sensor or , even the sensor, with after market muffler and pipes, and not have issues!! Thanks for the vid on the sender unit?? Any idea the size of O ring on the sender unit??
I can't see any reason you couldn't, if there is no downstream o2 sensor, then it won't make any difference in how the car runs, other than you'll fail emissions tests if your location requires them.
I'm not sure on the O-ring size, I should measure mine though, I bet they tend to degrade on the gasoline cars!
Boa tarde amigo. Falo do Brasil . minha w116 300SD foi substituido o tanque por um de mitsubishi l200 . sensor diferente. Sei que neste sensor na parte superior tem um diodo retificador. Voce sabe me informar qual é?? Sem ele o ponteiro do marcador fica oscilando buscamente. Abraço
Also this thing is in 300d 1985
Able to pull out the sender and get it pretty well cleaned up and reinstalled. The gauge now works, mostly, but the indicator bounces down to E on occasion. Is this just an issue with one of the contacts? I also see you have a video on the tank screen, which I had replaced 2 yrs ago. Watching that next. Thanks.
For the most part I've found the weird twitchy gauge issues are all the sender.
I am certain someone somewhere has experienced a failed cluster needle thingy too but I personally have not. Often a little dirty patch on those crazy fine wires will be what's making it flail like a madman.
The tank strainer is a messy job for sure! Catches a lot of crud though so it's worth checking out with the amount of years we have on these cars now.
@@trythistv I tested the cluster and the gauge works fine. I may pull the sender back out to do additional sediment removal and when I do I will pay more attention to cleaning the wires with cotton balls with diesel or brake cleaner. I had someone change the strainer out for me a year ago. But after additional tank cleaning, I'll either replace again or look further into your upgrade of putting the goldenrod setup in the engine compartment.
Very helpful, thanks.
I have a short in my car and some mechanic told me it was due to the broken sending unit. Is this likely?
I would highly doubt it, the wires inside the sending unit are so tiny they wouldn't carry any current at all.
If the sending unit is to blame, its easy enough to test, just pull the connector off the top of the sending unit and leave it disconnected.
What is your car doing that you say it has a short?
Any idea what the green pin on the unit is for? Mine broke off.
If you're talking about the little plastic nub, it is just there to orient the plug in the correct direction, there is likely a cutout or hole in the plug that would sit on that plastic pin. Just make sure you've got the plug on facing the right way and it won't hurt anything to be missing.
Merci pour votre aide
De rien, merci d'avoir regardé! (Hope that says "you're welcome, thanks for watching", I had some help translating)
Great video
So the wire goes in between the two metal flaps or doing slalom (up and beneath)?
If I'm understanding correctly it zigzags so that it touches the inside of both flaps and holds a teeny tiny amount of pressure outward on each flap so that it makes a good connection, but be very gentle as that wire is extremely fragile
@@trythistv thanks. If it touches inside the flaps then how it is zig zag?
@@manuelmantilla4536 I'm struggling to explain it, the little flaps were ever so slightly offset on mine, so one was shaped like a < and the other like a > and the wire went in the middle so >|< like that, it puts just a tiny amount of pressure on the flaps due to the offset so that it makes a connection
@@trythistv understood! Thanks
Thanks great advice
What kind of battery did you test the wiring with?
No battery, just connect one plug to the other with a wire. It measures resistance not voltage, so connecting the 2 wires together should make the gauge flop from empty to full when the key is in the on position
Hello there I have tried two different 46mm sockets none worked, which do you have thx.
So the kit I've got is this one: amzn.to/3lySKfq But for some reason it is showing not available now.
I've also seen this: www.thingiverse.com/thing:2778966 if you know someone with a 3d printer they might be able to whip up one of those for you!
@@trythistv Ok thx for info
Very useful, thanks very much. 👍
Hey, nice tutorial! My Sending Unit Wires are broken (w123 300D), do you know wire specification? So, finally I can repair mine! Thanks a lot!
The thicker ones don't really matter at all, they just need to be a wire that conducts power, some thin copper wire will be fine, the teeny tiny silver wires are 37awg nichrome wire, here is a link to buy some: amzn.to/37IpSLf
(Affiliate link, I'll get a commission if you buy from that link, if you'd rather not, just search amazon for "uxcell 37awg hearing wire cr20ni80")
awesome video
Very useful indeed .thanks
Thank you very much.
Wow that is so cool
I did this to my 380sl, but found out my fuel sender is working good, can it be the cluster cause mine shows fuel when filled up, but delays when I lose more gas and goes back in forth to half full to sudden quarter tank
It could be the cluster itself, but before you look into that I'd check the grounds, It is quite common for the connections to corrode ever so slightly behind the cluster (Brown wires are ground) and with that little extra resistance from the corrosion it throws off the more sensitive gauges like the fuel gauge that is looking for slight resistance changes.
Can you do similar video about Jeep Cheroke 4x4 ?
if I can find someone with a jeep that'll let me tear it all apart lol. The fuel tank needs to be dropped, or a hole cut in the floor for sure, there is no access designed into the jeeps that I'm aware of, and then its an integrated unit, fuel pump, sending unit and such all comes out as one piece.
I have a 300 TD wagon, I need to tear down the sending unit and clean it up, it shows a half tank even when full up to the filler neck
I need to redo mine as well, I got some bad diesel and it gunked it up, if you ever get diesel in east TN, pay attention to where you see all the trucks and buses at, fill up there. these little stations with low fuel turnover have cost me more than I'd like to know about.
@@trythistv I usually carry a jug or two of fuel treatment or a few cans of seafoam
I love Seafoam. Biobor JF is good stuff too, kills off algae/bacteria or whatever stuff grows in diesel, I try to treat my tanks every so often now, then check the filters after a few drives.
this problem is also for w123 petrol ?
I do believe all the W123 used the same fuel sender, so yes. I also believe the W126, W124, W116 and possible others all used this sender, or at least one similar enough that the same steps to test and repair it would apply.
What's the part number , I might need to replace mine for my 1982 300sd chang can't find the part online
The sender for my car is 123-542-04-04, I suspect the w126 you've got should use the exact same part. I know the peachparts/pelicanparts site lists near everything available, or you can always try eBay, now and then there is a cheap used one on there
The nut is a security type
It sure is a goofy looking nut, probably not really meant to be "user serviceable", but we'll make due and keep our amazing old cars going as long as possible!
Is this thing is in 300d 1985 year
Yes indeed. This style sending unit has been used from some time ranging from the 70s up until at least the mid 90s. Possibly even longer!
so did this make your fuel gauge work?
It sure did! Been working great ever since. You can pop the connector off and test it with a jumper wire to see if it is the sender or something else before you pull it out of the tank
nice
Good job!!!
Thanks! its super nice to have a functional fuel gauge!
My wires have snapped , anyone know what kind of wires they are????
I have heard but have not personally confirmed that it is 37AWG resistance wire like this: amzn.to/3ZLaDtu
Probably should clean the tank as you have lots more algae in the strainer area
I did a video where I pulled the strainer, and ended up cutting the screen off because it was so clogged up with nast! (I have a massive water separator/prefilter screen that catches gunk very effectively, I wouldn't advise removing the tank strainer with the stock filtration)
Algae is an insane problem in the rural east TN area I live in. My wife took the car once, filled up at a different station than usual and got 2 miles down the road before the whole fuel system was gunked up with algae.
Another friend filled up his brand new truck, and didn't make it out of the station before the water in fuel light came on, and then the truck shut down, and it ruined some very expensive cp3/cp4/injectorey parts (I'm unsure what the modern bits are in diesels, I know my Bosch pumps and thats about the extent of my knowledge)
One of the contacts on one side of my float is weak and frail. Damnit!
Ah nuts! They are incredibly fragile. Mine was not terribly great but has held up well so far
Great Video - Any Ideas - I did every thing you suggested - circuits were OK - wires were OK - looping the wires through < & > contacts was OK - tried it outside the tank - IT STILL DOES NOT WORK - Desperate now , from the UK
Did you test it with a multimeter? There should be resistance that varies with float position on pins 1 and 2.
And did you test the gauge by jumpering the connector as I showed? They have a terrible habit of the ground wires behind the cluster getting a bad connection, and in some cases the gauge itself on the cluster decides to give up the magical smoke that makes it work.
@@trythistv Thanks very much for your prompt reply - This is used unit i got from a breakers yard . I opened it up & it looks OK & was fairly clean & slides well. I did the car test - fuel gauge & warning light both worked.
When I put my multimeter on the pins of the sender - I get NOTHING - on all pin combinations .Does it mean I will have to buy an OEM new one - but I can not see anything wrong with it. Thanks again.
That strikes me as something has internally failed, it is possible the connection between the inside where the wires are and the pins on the outside has failed seeing that the wires and slide are in good shape.
Knowing your wires and gauge/light are all functional basically tells you the problem is the sender, whether finding a good used replacement or if new senders are being produced how cost prohibitive it would be to procure one is ultimately the decision to be made.
It would also be possible to take a socket and multimeter and check cars in a junkyard until a functional unit was found, I understand that gas and diesel mercedes used this same sender for a very wide range of models and years so it shouldn't be awful to locate one.
@@trythistv Thanks very,very much for your help .I assumed it was a problem with this particular sender.But what I did not understand was - if the wires were soldered to the pins - How could I not be making a circuit - I do not understand - Looks like I will have to buy an OEM .
@@trythistv Just to let you know. Try as I might, I could not get my S/H sender unit to work .Even though it had all three wires in place ,clean, & the float slides easily ,BUT I could not get a ohms reading across the pins. I ended up buying a new OEM unit for £194 .It now works OK. - Albert
You're sure a nice likeable guy, and gave great info, but you should never go around a clock factory, clean such things very gently with Berryman, lacquer thinner, etc using fine brush, until spotless, put fine pumice on wires, slide up and down until wires are bright, and the slide contacors will be just so,, final wash it all, clean the plug-in contacts, barring trouble elsewhere, it will work. Thanks! No ridicule intended! 🌈lol
I've been told I'm a little heavy handed at times, If it gets the job done though... This sending unit is still working great! lol, I do appreciate some of the tips, I've been meaning to get some Berrymans stuff, I've heard it works wonders.
Dude! Great video.
Thank you very much! I hope it helps out some people!
Tell me you know a thing or two about the vacuum system.
I don't think you can own one of these cars without a mityvac and some printed out vacuum hose routing diagrams lol
Where can I get a routing diagram for my 1983 240D? I need to replace the whole thing. I think.
the hard plastic lines rarely ever break or have issues, but the rubber connectors are all usually at various stages of decomposition by now. an 83 will be nearly the same as my car, minus 1 cylinder and a turbo, but vacuum wise that shouldn't be a huge difference.
You can block off the central locking, if the issues are in that system this post has some excellent diagrams here: www.peachparts.com/shopforum/1247118-post5.html
Then there is some of the highest quality ones I've ever seen over here: www.justanswer.com/mercedes/7z9ow-mercedes-benz-1983-new-question-vacuum-schematic-240d.html
Thanks bud
Glad to help! Sure is nice having a working gauge again.
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I'm barely fluent in English, much less any other languages but I think you're referring to condensation? If so, you're exactly correct! The condensation inside the fuel tank can cause that algae to grow and it makes a right mess of the tank and fuel sender!
lol in my country its 20$
It would probably be costly for me to move there though :)