Erratic Tachometer on 2003 Contessa

[William Harmon]

Tachometer sometimes reads accurately at low RPM's but as RPM's increase the tachometer will peg out or become jumpy and erratic.  Turning on the lights helps somewhat but not the answer.  I appreciate any suggestions for this problem as it is quite annoying and possibly damaging to the gauge.  Thanks in advance.  William
2003 Contessa
Cummings 370 ISL
3 Slides 40 ft.

[Edward Buker]

William,

I think the tach may be fed by a small wire on the alternator T terminal, or a sensor on the engine. It would seem that you are getting noise on the line (extra pulses) that diminish with load on the alternator. I would try and find out what sensor feeds the tach, check the connections to see that they are tight and clean and that the tach has a good chassis ground. If there is a tach manufacturer they may have trouble shooting help. Sometimes a filter capacitor may help pass electrical noise to ground at the tach but I would hope the cap value and recommendation would come from the tach manufacturer.

Later Ed

[Gerald Farris]

William,
I believe that the problem you described is fairly common on you model coach, and I think that BCS (Beaver Coach Sales) has a cure for the condition. So I would call Ken Carpenter or Sean at BCS service department tomorrow and see if they can lead you in the direction of a quick fix.

Gerald

[Jim Houghton]

Had the same issue when we purchased or Contessa. This is what fixed it for me it was about $40 two years ago. Got it off of ebay but is also available elsewhere. SIEMENS VDO AUTOMOTIVE Part # V9999502490 Carin FMXX Signal Coupler RV Motorhome.

Jim

[Jim Houghton]

Just looked it up and it is now $46 with free shipping from the same distributor I purchased from 2 years ago.

Jim

[William Harmon]

Thanks ED, Gerald and Jim for your input on my Tachometer problem.  I made a call to Ken Carptener (BCS) today but have not heard back from him on a quick fix.  Depending on what Ken has to say, I will probably order the Carin Signal Coupler.  I will advise you as soon as I get it working.  Thanks again, William

[William Harmon]

Jim,
Did you install your Carin/FMXX signal Coupler yourself or have it installed.  I just received mine from Siemens VDO Automotive but with limited instructions.  I need to know where it is located on your coach and some step by step installation instructions would be very much appreciated.
Thanks,
William

2003 Beaver Contessa
40 ft. 3 Slides
Cummings 370 hp

[Jim Houghton]

I did the install myself. I will try and shoot a few photo's where I mounted it and see if I still have the instructions. I should have them but may have just used the label on it to hook it up. It was about two years ago and was the first thing I fixed after purchasing the coach.

[William Harmon]

If you would prefer, you can send pics and any other info to my email address (brylar@swbell.net).  I think my Contessa is a Tuscanny also.  I'm glad to correspond with another owner whom has the same year and model Beaver.  Maybe I can help you in the future.
Thanks for your assistance,
William Harmon

[Jim Houghton]

William,

Been a busy weekend working on our new Beaver House so it will be taken care of when not using. Still working so unfortunately we don't get to just take off regularly. I sent you my description of the install to your email you provided.

Jim

[William Harmon]

Update on progress of tach.  I did hear back from Ken Carpenter (BAS) and he advised no quick fix for my tach problem but he did switch me to the Parts Dept. and they advised they have fabricated a filter for most coaches.  Since Jim has a like coach to mine I went with the filter he installed with good results.  Jim provided photos of the installation and excellent comments which made the installation straight forward.  Only the Signal wire had to be cut and spliced into the filter.  The filter's ground and power wires were connected to the tach. All seemed to be going well until I turned the key on and observed no response from the Volt meter and the row of lights above the Volt meter and fuel gage.  Also a buzzer continues to sound.  Checked the air pressure and both the red and green hands on the gage show 110 PSI.  Also, verified all slides are closed and Levers are all in up position.  Diagnostics with engine running shows 14.3 volts.  Tachometer is now rock solid up to 2200 RPM's but with the coach stationary.  I'm not going to drive coach until I can get the above problems corrected.  All help appreciated.  Special thanks to Jim and each of you for your advise.

[Edward Buker]

William,

A good start would be to disconnect the filter and hitch back up the way you were temporarily and see if this is an interaction with that filter and the dash items that are not working. If so I would try the BCS filter given they have probably already been there and through trial and error have found a solution.

If someone has already put the effort in to invent the wheel, no sense in you spending your time chipping away stone on the Flinstone Mobile when you could be out having fun....

Later Ed

[William Harmon]

I have disconnected the filter at power,ground and signal but buzzer continues to go off and volt meter and lights above volt meter inop.  Is there possibility a fuse or reset responsible for what is going on??
Thanks,
William

[Jim Houghton]

Upon studying the owners manual there may actually be a fuse that is affecting the indicator lights and may also be why the buzzer and volt meter are not working. The panel is located in the battery compartment its called a chassis fuse panel and the fuse that may be the problem is FH1. Its a 15amp and provides the power to the service center indicators. I am quite sure the filter is not the issue. I will say that after owning my coach the voltmeter did quit and has been replaced but 1 1/2 years after my filter install. If you have the owners manual it is on page 353. If you don't I have it on digits and can send to your email.

[Edward Buker]

William,

What Jim is saying makes sense, for some reason you seem to have lost some power to the dash and that can also cause an alarm condition, just because the proper voltage is not present where it is needed to be to satisfy the alarm limits.

Assuming you find the source of the voltage loss and it is a fuse, then replace it and check and see if everything is working. You will still have the tach issue.

If so, then remove the fuse and install the filter as before, double checking that the wiring was/is correct given for some reason you blew a fuse with the install. Then replace the fuse and see if all is well. If the fuse blows just with the filter in place, then it is miswired or it is defective. Your choice would be to get a second replacement filter and try it or try the BCS version.

Later Ed