$10 for some wire and two connectors ?! .
Wow , PT Barnum really was right .
-Nate
Brian wrote:
>
> Thanks for the feedback, guys. It does sound electrical now that you've
> enlightened me. I found this site that sells a $8 supplemental ground:
> http://mbelectronicupgrades.com/Supplemental_Ground.html Has anyone used
> this? In any case, it looks like I'm going to use my new nifty instrument
> cluster puller tools from Mercedessource in the near future.
>
> Thanks again.
>
>
>
>
>
> ________________________________
> From: n61cm <jim@...>
> To: diesel_mercedes@yahoogroups.com
> Sent: Sun, January 29, 2012 6:56:41 AM
> Subject: [diesel_mercedes] Re: '81 240D wildly fluctuating fuel gauge
>
>
> Since it started with the new cluster install, perhaps the new cluster is
> defective. In that case, I'd send it back, wouldn't try to fix it myself. Does
> the temp gauge fart at the same time as the fuel gauge or at different times? I
> don't know if they share a common ground but the timing of the problems might
> tell you something. You can unplug the connection on the fuel sensor and jumper
> it so it will send full fuel signal to the gauge. Then if the gauge stops
> jumping, you will know its inside the fuel sender, a common issue on 123s. I
> guess you could do a similar test with temp gauge wiring as well, though I don't
> know which way the voltage (or ground) works on that system. It would be odd,
> though, to have both temp and fuel gauge sensor circuits crap out simultaneously
> and coincident with the swap-out of the cluster.
>
>
> Jim
>
> --- In diesel_mercedes@yahoogroups.com, audiolaw@ wrote:
> >
> > Brian,
> >
> > The oil pressure gauge is mechanical, I believe, just a tube from the
> > engine to the dash binnacle. So no electrical issues.
> >
> > The symptoms you describe are CLASSIC electrical connection issues.
> > Since they appear to affect more than one gauge, the problem is likely to be
> > the common ground connection for the binnacle, rather than the individual
> > feeds to the gauges. (Although, a fault affecting all the power to the
> > gauges MIGHT also explain the symptoms.)
> >
> > Check the binnacle ground connection. Check not only the wire
> > connection, but the base of the pin to which ground connects. The binnacle
> >has a
> >
> > printed circuit on the back, and the pin connects to this. Vibration or
> > pulling wrong when removing the binnacle might disrupt the pin-printed
> > circuit connection. Such a problem might appear only as a tiny crack in the
> > circuit trace, and a crack that can be intermittent, thus causing your
> >problem.
> >
> >
> >
> > This is not uncommon in any circuit that is subject to physical
> > activity. Examining the circuit traces and connections in VERY GOOD light is
>
> > important.
> >
> > IF you find a circuit discontinuity, it should be easy to handle with
> > a dab of solder. If you don't feel up to that task yourself, you are more
> > likely to get quality work at an electronics service shop than at a car
> > repair shop.
> >
> > Tom
> >
> >
> >
> > In a message dated 1/28/2012 5:20:47 P.M. Pacific Standard Time,
> > brianbarn@ writes:
> >
> >
> >
> >
> >
> > Since recently replacing the instrument cluster in my '81 240D so that I
> > would have the amazing luxury of a working odometer, I have a bizarre fuel
> > gauge. It flits around quite a bit, and sometimes flies back and forth from
> > full to empty and back. Sometimes the movement is less pronounced, say
> > from full to 3/4. This movement is not constant - sometimes the gauge is
> > just fine. The temp gauge also fluctuates sometimes, but not nearly as much.
>
> > The oil pressure gauge is rock steady all the time.
> >
> >
> > Is this a common situation, and is there a fix? I can estimate fuel usage
> > as long as the odometer is working, but it would be nice to have a steady
> > fuel gauge.
> >
> >
> > By the way, I got 28.5 mpg on the tank I filled today. Not bad for
> > around-town driving.
> >
> >
> > Thanks in advance for the feedback.
> >
>
