Trying to sort out some erratic and/or non functional gauges on '87 W124 wagon.

1. Odometer intermittent
2. Oil pressure gauge - jumping all around..from 0 to pegged, all place in between.
3. Tach not working.
4. Gas gauge doesn't work when it drops below 1/4 tank - pegs to 0 when it get's to 1/4.

Appreciate some tips on fixing these various problems.

Warren C.

1. Pot metal gear is slipping. Do a search for odometer repair. There was a good write up on dieselgiants page.... http://dieselgiant.com/repairyourodometer.htm

2. Sending unit is on the way out. Replace or clean sending unit to see if that alleviates it.

3. Check fuses and wiring. Not sure if 124s had tach amps.

4. Treat your tank with a biocide, and/or remove the sending unit and clean, make sure wires are ok.

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91 350SD
14 F150 Eco
19 Fusion Hybrid
11 GT500

Thanks for the reply...

Re Odometer....the Dieselgiant write up is for a 123 unit...is a 124 essentially the same functionally?

Re: The tank sender - never heard of a biocide for the fuel tank.. What brand/name and where is it available?

Warren

Th

Dont know a product name, but know it is typically available at boat supply stores. Should be easy for YOU to find locally.

Ask for biocide fuel treatment.

A tankful of B99 would do about the same thing.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

ahhhhhhh this isnt going to be much help buttttttttt My Sdl will have intermitten problems of the same sort instead of treating the problems indivually I would think it is an electrical issue in the cluster that needs soldering Someone more experienced then I should be able to help there
Personally i slap my dash and it all goes back where it is suppose to which then leads me to think it might be a ground issue to the electrical 35 years of electricity in the marine enviorment you learn to slap the @@@@ out of stuff

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commercial fisherman diesel in my blood in my boats trucks and Dear old Dad has had me drivin them since i got my first license in 1968
1986 300 SDL 427654
1999 Chevy Crew Cab Dually 225423
1986 300 SDL 287000 Dad's
1987 190 Turbo 158000 Mom's (my inheritance)

Re: Odometer, yes, 123, 124, and 126 can use dieselgiants fix

Re: Tank Sender people like Startron. I bought something else online, red stuff, stopped the tourettes in my fuel gauge. I dunno if B99 will kill fungus, but I run a B50 mix in my 87 SDL. My 86 SDL will never read full, I may get some biocide and treat her....

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91 350SD
14 F150 Eco
19 Fusion Hybrid
11 GT500

I use/used Startron Tank cleaner. I bought it online at www.westmarine.com.

My fuel gauge is behaving better now. It is still not 100%, but it is much better. It is accurate from 1/4 tank to full. It never seems to go below 1/4 tank. Of course, I'm paranoid about running below 1/4. I drove it to empty when it read 1/4 tank once. I don't want to do that again. Luckily I ended a 490 mile trip a block from my house when the engine finally died from lack of fuel. That was before I treated the tank so it may work now. I really don't want to find out the hard way.

The gauge on mine is not all that accurate down there and my Odometer does not work. I just don't like to run out of fuel, so soon after 1/4 tank is when I fill back up again.

-Jim

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1995 S350D, Green with black leather interior.
Bought January 2008 w/ 233,xxx miles.
I did 22,000 miles during the first year of ownership.

Warren,

There is a west marine down in sausalito. They should have 4 or 5 biocides for diesels on the shelf. I have been using startron as well (which I got at west marine) and I don't think that it is a conventional biocide but rather works to disrupt the water source for the critters. Running a tank of B99 will work great as well and in Mill Valley you should have no trouble with gelling.

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1987 300TD 231,000
#22, afterglow, plastic fan, euro lights, alternator upgrade, cluster housing update

The PO of this car ran biodiesel in it mostly..... obtained from a co-op in Ukiah, CA (not sure what "B rating")....don't yet understand all the ratings for biodiesel yet ...I'm new to this diesel thing....

Anyway....the fuel gauge hasn't been corrected by using biodiesel. It's fine from 1/4 to full...but really flaky below 1/4 tank....the reserve light comes on at different times in the fall from 1/4 ...so can't depend on that.

Like to fix it...so I'll try one of the biocides...before pulling the sender out.

Are the biocides just a fuel addititive....pour in and keep driving...or do you have to drain the tank after using them.

Warren

Just add the recommended amount of Biostat and drive. I suggest carrying spare fuel filters in case it dislodges algae that might be in the tank. If the car had been non-op for a long period algae can start growing but from what I read the PO was using Bio so that may have left some deposits on the level sender and if that is the case Biostat won't help at all. I would add a bottle of RedLine fuel catalyst also and see if the gauge improves. In my experience once you have a flaky gauge the only solution is a new sender. I've cleaned them before but had poor luck in a few cases (one fell apart in the tank!) so with all the labor involved installing a new sender might be the best way to get the gauge reading properly again.

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!

My 87 TD also has a crazy (jumping up and down) gauge, but only when it's below a 1/2 tank. Even a hair above a half tank and suddenly the gauge is perfect.

I was thinking about just pulling the sender, cleaning and putting it back in, but after that last post about "replacing the sender is the best route", I think I might just do that.

I've been running biodiesel (b99) for a few weeks, hasn't changed anything. I mixed in some petrodiesel though, so maybe it was too diluted to properly clean up the tank.

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-justin

1987 300TD, 1987 300TD
2008 R32, 2000 Passat Wagon