W124 - The legend of the dancing gauge and more electrical power...

26 Dec 2020: The fuel gauge has been dancing, and it has been annoying to see it like that, as sometimes, it is difficult to gauge the amount of fuel that I still have to drive. I am still getting used to knowing how much reserve the car has once it reaches the empty mark.


To begin with, the fuel tank float was replaced. It was replaced with one from VDO. Upon installing the float, the issue was not solved. It was further suspected that the fuel gauge could be faulty as it may be loose or even defective.


The mechanic has pulled the instrument cluster out and tighten the bolts but it did not fix the issue.


I decided to then have the instrument cluster to be reconditioned as I contacted Simon Top (his Facebook ID) who does restoration of the instrument cluster and also is a mechanic who works on Mercedes as well.


I removed the instrument cluster and had that replaced with a loaner. It is important to note that the 4 cylinders and 6 cylinder instruments are not the same.

Simon updated that there has been a few issues with the cluster:

  1. The casing has been bored with 2 holes where LED was inserted that made the lighting effect faulty
  2. The fuel gauge was faulty
  3. Speedo cable may need replacement soon

So what was done was that Simon looked for a donor casing where the gauges were transferred. He then tested and ensure that all lights are working and also cleaned it up in the process.


On the collection day, we tested the cluster and there was a clicking noise possibly from the speedo cable, it was oiled and reattached the cluster back in place and it all worked.


After monitoring the fix for some time, the issue is not completely resolved. There were new observations found that I hope would resolve the issue:

  1. The battery on Rhino was of DIN 55 previously and not DIN 66 which was the required standard. It was replaced and there was a difference in the behavior observed where power delivery is stronger (of course, it has a brand new battery fitted)
  2. The charging system may not be optimum causing the grounding to not be proper. The alternator was replaced with a stronger 120A replacement
  3. The fuel dial flickers on the new battery and the observation is that is mostly happening below 2000 rpm and beyond that, it sits straight and idle. I am guessing that below 2000, the electrical system may not be stable, and replacing the alternator will be a step closer to resolving this

The alternator was replaced with a Valeo 120a one which is Made in Germany, but it did not solve the issue. The fuel gauge was still flickering and I an unsure what else could cause it. I also noticed that when the engine is running and the headlamp is one, pressing on the power window switch is dimming the light a little. This should not be the case especially with a new battery and alternator installed properly.


On Saturday, 20th Mar, over the morning coffee, as I was speaking to a spare part dealer, I shared my challenge on the flickering fuel dial and what all has been done to sort the issue out. As a summary, till this point, all of these has been done to address the fuel dial flickering issue:

  1. Replaced fuel tank as the old one was rusted
  2. Replace fuel cap as the old one was not holding pressure
  3. Replaced battery as the old one was weak
  4. Replaced alternator as the old one was weak
  5. Tested 3 other instrument cluster and they were all the same
  6. Replaced the fuel float to VDO

I asked if it could be grounding where the grounding cable on this car may have been weak due to corrosion and what else can I check for a fix to this issue. He asked me to check the OVP (over-voltage protection) relay which could be bad. 


What does an OVP do? According to an article in pelicanparts.com, the overvoltage relay or OVP supplies power to the idle control and cold/warm start circuits. The relay does just what it says and protects these delicate systems from spikes in voltage.


I went to the mechanic and asked for the OVP to be checked, and as we pulled it out, one of the pins (mine is the 9 pin version) on the relay, the smaller pin to be precise had some electronic melting residue on it (in white). All the pins were stained with dirt. Before we got the relay replaced, he cleaned the relay socket and air blew any particle that could have been stuck. We got the relay replaced and there was an immediate difference. The first difference is that as I start the car, warm start, the RPM no longer shots up to 2200 rpm and gradually decreases to about 700rpm. It now starts at 1200 rpm and decreases to about 700 rpm gracefully.


When I flick the gas pedal, the rpm shot up, and then it drops to 1300 rpm (thereabout), before gracefully decreasing again to 700 rpm.


As for the fuel gauge, the fuel level was at 3/4 tank full and I have yet to see any flickering. The fuel gauge started flickering shortly after the fuel dropped below the 3/4 tank level back, this issue is not solved at the moment. I noticed that the flickering only happens during warm-up and when the car is idling stationary. While it was in motion, it wasn't there.


Revisit:

The gauge misbehaving has been traced to a few sources and the one that seems to be the weakest link in the equation is the fuel float sender.


After scouting around, I found one for sale in the US. Got it ordered and for some reason, the shipping manifest was marked with USD 0 shipping cost. That resulted in the Malaysian Customs assigning a cost for duties calculation, which is over 5 times the paid shipping cost.


Now the issue is being managed by the courier company who wants the sender to pay for the duties due to incorrect declaration. But I did ask the courier company, why wasn't the shipping invoice looked at as there is a cost to it but declared as zero.


A week later, and after some negotiation with the seller, the agreement was I would pay for what is taxable to me as per the tax amount and the rest will need to be absorbed by them. Reimbursement was made to my credit card account and I paid the courier to have the shipment delivered. 


To know if this episode solves, we will need to get the new float installed. 


Update:

August 2021: The replacement original fuel sender/float has been installed. I also took the opportunity to replace both the o-rings on the fuel sender flange. The old one needed replacement and most replacements out there are not properly replaced and old rubbers do not seal well.


From the initial observation of a full-filled tank, there has not been any dancing. Further to that, the fuel level is now below the 3/4 mark and no 'dancing' is observed at the moment. 


After monitoring over a couple of full tanks of fuel, the 'dancing' gauge has resolved, but a new issue was found. The dials springs up when the key is turned on the ignition, which should not be its behavior. Even the oil pressure gauge does not rest when the engine is turned off. It should rather gracefully rise up from its resting point.


The speedo is sent for a repair where the faulty gauges will either it will be repaired, if possible or replaced. I am also taking the opportunity to replace the bulbs to a brighter Amber ones while correcting the dial color as well.


More updates to be reported once the repairs are done.


Pictures:


The old alternator was one from Bosch

Replacement 120a Valeo alternator

The replacement alternator

Old OVP which was original in this 26-year-old car 

Another view of the old OVP - the original one that came with the car

Fuse at the top of the OVP relay

Replacement KAE (Made in Germany) and MB OVP repay side by side

Flue float - shipment box opened

Fuel float - Mercedes genuine

Lens cleaning in progress

Gauges being checked before repaired

Comments

Post a Comment

Popular posts from this blog

W124 - Engine Wiring Harness Replacement

Image
Mercedes built from the year 1992 to 1997 was installed with an eco-friendly (degradable) wiring harness. The issue with this type of harness is that the insulation disintegrates and crumbles especially when exposed to heat. For the W124 model, it is safe to say that all cars built from the year 1992 onwards were marred with this issue, both petrol and diesel models. What is baffling is that Mercedes is aware of the issue but a safety recall was never issued to have the wiring harness replaced with a non-eco version. The intention of going green badly backfired as this issue introduces an array of problems on the car. The reason why this happens is that the insulation upon crumbling exposes the bare wire and when two or more of the bare wire touches one another, it messes up the communication to and from the ECU causing strange behaviors and in more serious cases, it causes fire. This issue was covered in length in the following links: http://badmercedes.com/ http://www.mercedesdefects...
Read more

W124 - Transfer of Ownership using MySikap

Executive Summary: A short entry on documents needed to obtain a copy of the VOC (vehicle ownership certificate) from the JPJ. Details: I was out at the JPJ to get the registration card, I think its now called the VOC. I have completed the online transfer of ownership via the MySikap portal and thought that all I needed to do was show up and present my IC to obtain the VOC. The Shah Alam JPJ was packed and I decided to go to the Shah Alam UTC instead. After queuing for about 30 minutes, my turn came up. At the counter, I was declined because I did not have the receipt copy for the transfer and photocopy of my IC. I was under the pretext that all that is needed is my IC and they should be able to see the transactions and details but apparently I was wrong. I will have to return to the JPJ again, to get the VOC and prepare all the required documents. In summary: If the transfer of ownership is completed online via the MySikap portal, keep the receipt and print them out Have a photocopy o...
Read more

W124 - Rust... No More and Hello Accurate Facelift Look

Image
Executive Summary: This entry is about the rust repair on the Rhino and also correcting the external trim to the correct facelift version for 1994 onwards made W124s. Details: When I bought the car, I was a W124 newbie and wasn't aware of where the rust spots are and what I should I be checking for. I tried doing my due diligence by checking on the real condition with the person who sold me the car based in Kampung Melayu Subang, K*****T Auto, but as shared in my previous post, don't expect a conman to be honest (by the way, stay away from dealing with this guy, stay very far away!). I was told it was in good condition and there are no rust issues and the body is in very good condition bla bla bla... a bunch of bullshit! I have requested an inspection of the body condition which was fair. There were rust and the rust was observed to be on the front passenger footwell, both sides of the rear spare wheel wells, a little on the rear left quarter panel, and the battery tray among t...
Read more