Flickering gas gauge W124 - Page 2 - PeachParts Mercedes-Benz Forum

emerydc8 · #16 07-02-2010, 07:24 AM

Both times on my 400E, the flickering didn't start until it got down to less than one-half tank. Also, on my E420, last year I noticed that it started to flicker with less than one-half tank, but rather than replace the fuel quantity transmitter, I just never let it get that low. I know it's lazy, but I can live with it for now.

400Eric · #17 07-02-2010, 08:01 AM

Quote:

Originally Posted by macdrone

Also on the back of the instrument cluster is a potentiometer that is set from factory. You dont adjust it but if you do a search here or at benzworld you may find an article like I did that said to get a dielectric compond from radioshack and pour it on it and will stabilize the low currect that is coming from the tank which causes this condition. I actually havent heard anyone say the sending unit ever fixed this problem to my knowledge.

Maybe this is my issue then because my gauge flickers at all tank volumes, not just from half a tank on down. Any other opinions? I'd like to have a consensus before I start tearing into things and "effing them up".

lsmalley · #18 07-02-2010, 08:05 AM

as one of the forum members once told me.....it would probably ber cheaper for you to take it to a mechanic

mlozzi200478 · #19 07-02-2010, 08:17 AM

im s glad i read this post,i had the same issue last week,this was the first time it apened to me,the tank was about half ful,it was spiking up and down,then sowing a lower reading,i noticed if i shook the car it got worse,then i shut the key started it back upgot gas and i have yet to see the issue come back,plus i know the average miles per tank i get,so i can wath my miles if it happened long term. i get 260-270 miles per tank on a car that isnt running right.

400Eric · #20 07-03-2010, 01:19 AM

Quote:

Originally Posted by lsmalley

as one of the forum members once told me.....it would probably ber cheaper for you to take it to a mechanic

I haven't hired a mechanic in over 30 years (when I was still in my teens).... I'm not about to start now.

Stay tuned.....
Any more opinions are still welcome!
Regards, Eric

pifcat2 · #21 07-03-2010, 02:54 AM

Quote:

Originally Posted by 400Eric

(That was just me being silly. You knew that right?)

OK, all kidding aside, I'd like to have a replacement sending unit or two in my hand from my favorite U-Pull-It before I take this apart so I won't have to do it twice. So I'll have to wait till I can hit that yard first. If it turns out that I don't need a sending unit after all, well then I'll have spares instead which is always a good thing.

I do appreciate all the help!

In the meantime, are there any other possible culprits that I should be aware of?
Regards, Eric

When I was in England I was told a Birmingham screwdriver is a hammer.

While you're at the PNP, you may want to "pick n pull" a left gauge if you don't want to buy the whole cluster. They will let you exchange it if it doesn't work. I've accumulated several so I can test and exchange parts that work. Coincidentally, my gas gauge occasionally jumps when it should be steady and linear. The low gas light also comes on when the needle isn't all the way to the left. It's likely bad contacts either at the gauge or the tank sender...

Cal Learner · #22 07-03-2010, 08:11 AM

I have replaced the fuel sending unit for just this sort of a problem. In my case, the gauge seemed to get jumpy as fuel level got low. Since the sending unit is a float-mounted sensor that rides up and down along a wire and changes resistance with its position, there's some sort of electrical anomaly that begins to happen as the sending unit ages and wears. Someone else may know if there's some other easy fix, but I simply replaced the unit to correct the problem. Someone else mentioned a cluster potentiometer. The only pot I know of in the cluster has nothing to do with the gauges, only controls cluster lighting.

mlozzi200478 · #23 07-04-2010, 01:34 PM

time to call inspector gadget.go go gadget arms!!!!!

silversleeves · #24 07-04-2010, 02:01 PM

I fixed mine by fluke, I pulled the instrument panel after I determined the sender in the tank was clean. When I pulled the panel I moved the needle a few times from the back and when I reconnected everything I changed the location of my brown ground wire off of the back of the gas gauge and connected it to either the temp gauge or the oil pressure gauge, can't remember which. Probably pure fluke but my fuel gauge is very steady now.

400Eric · #25 07-05-2010, 05:02 AM

And GSXR posted on another thread that in his case it was the gauge too.
Does anybody know if a gauge from a W124 diesel will work? (Face not withstanding.) I already happen to have one of those.
Regards, Eric

emerydc8 · #26 07-05-2010, 07:39 AM

Have you considered testing it?

http://www.ps2cho.net/downloads/MB%20CD/W124/w124CD2/Program/Chassis/54-0257.pdf

If the transmitter turns out to be bad, they are $156.11 from Fastlane.

http://catalog.peachparts.com/ShopByVehicle.epc?q=1993-Mercedes--Benz-400e-Fuel--Delivery&yearid=1993%40%401993&makeid=63%40%40MERCEDES+BENZ%40%40X&modelid=6259%3AMBC|1530%3AED|10000072%40%40400E&catid=240737%40%40Fuel+Delivery&subcatid=240761@@Fuel+Level+Sending+Unit&mode=PA

400Eric · #27 07-05-2010, 09:07 AM

Thanks for the link but my computer won't open it.... it's just a blank white page. GSXR's already told me what I need to do I just need to do it. I'd rather fix my car than to have to fix my computer! It's something I'm just not good at!

If a gauge from an 87 diesel W124 will work then maybe I won't need to go any farther. Anybody?
Regards, Eric

timmyr · #28 07-07-2010, 07:43 AM

hey guys,

my 93 300e's fuel gauge has also been going crazy as of late. i wonder if the prob. is temperature related?

i filled up the car with a full tank of gas the other day, and have now noticed that the fuel gauge seems to be working normally. in my case, i guess that rules out the fuel gauge in the instrument panel, and means that there is a problem with the fuel sender unit?

what i do know for sure is that the low fuel lamp, still works, which is good news.

there is a nice DIY which a fellow poster put up, in it he explains how to take apart the sender unit, how to clean it, and test it.
http://www.peachparts.com/Wikka/W124FuelSender

for those of you who believe that the problem lies in the actual gauge in the instrument cluster, the second poster in the folowing thread claims to have found a possible solution.
https://www.peachparts.com/shopforum/showthread.php?p=482776

the haynes manual also claims that inaccurate/erratic instrument readings may be caused by a Faulty voltage regulator(if instrument readings increase with engine speed)

good luck

EricSilver · #29 07-07-2010, 11:35 AM

Walmart
+ 1 can Berryman B12
+ 1 fill-up
= removal of crud on float sensor wires and end of problem.

May be necessary to repeat Berryman application, but after 2 or 3 the issue should be resolved.

400Eric · #30 07-08-2010, 01:42 AM

Thanks for all the info and links guys!
When I hit that second link though, I got this:"This Connection is Untrusted" and it won't let me continue. I hate to ask, but could you please copy and then paste his post here?
Regards, Eric