Gauges Erratic

rhfetc · **Joined:** 24 Jun 2007 20:30 **Posts:** 19

Hello all,

The gauges on my W50 (#203) have started jumping erratically. They seem to all do a little dance at the same time. Changing the engine speed will sometimes reset them to a steady reading. This has only started intermittently in the last engine hour of motoring in and out of the berth. I thought maybe it was a bad ground so I checked the big ground bus bar in the front of the engine and they were all tight. Anyone else had similar symptoms and potential solution before I dig further? The heat, oil, and amp are all affected but not the tach as near as I can tell. Thanks for any tips.

Richard Fasse
Invictus - #203

Down2TheC · **Posted:** 19 Aug 2008 19:11

I would imagine that the guages all feed off one line from the alternator. Perhaps you could check that connection for corrosion? Just spitballin' here. But if they do it in unison, I'd think you have to look at the power source of ground.

I assume everything else in the electrical system is doing fine? I could see bad alternator power causing that, but if your rectifier was crashing, your batts wouldn't charge well. So if you see further electrical problems with more engine hours, maybe check that.

jvoelxen · **Joined:** 21 Oct 2006 15:36 **Posts:** 268

If you have a 'keyless' ignition system, your problem may be related to the pressure switch in the fuel system that energizes the gage panel. In this type of system, there is a pressure switch located on top of the fuel injection pump. This happens to be located on the low pressure side of the ijection pump. When it senses pressure from the fuel lift pump ( i.e., when the engine is running) the contacts close energizing the gage panel. If that switch is sticking, its internal contacts, or its external contacts are bad/corroded, these could cause your problem.

I had to replace my pressure switch, which was not too hard, but air gets into the fuel system. I tried real hard to keep air out, but a small amount go in anyway, requiring that I bleed the fuel system from the fuel injection pump through the injectors - pretty time consuming, so be prepared for the worst.

Good luck.

Jim Voelxen
Odyssey #191

rhfetc · **Joined:** 24 Jun 2007 20:30 **Posts:** 19

Thanks for the tips you gugys! My boat is indeed a keyless version and I actually thought I could hear a slight difference in the start-up alarms (a little longer and weaker) so there may be a connection to the pressure switch. I will check all the contacts you both have suggested. It is only a few weeks before I haul here but I have one last short 3 day cruise next week and will fiddle around to see what I can and let you know. I haven't bled the system before and am a little intimidated by that possibility so may have to enlist a more experienced buddy to help with that if replacement of the switch is indicated. Thanks again!

Richard and Jeannie
Invictus #203

jvoelxen · **Joined:** 21 Oct 2006 15:36 **Posts:** 268

Richard-

To get you through the season, if your fuel pressure switch is the problem, you can make a 'jumper' to place between the wires connected to the pressure switch. You'll need some wire and two male type spade connectors on each end. When you want to run the engine connect the jumper and your gages will function are long as a battery is switched on. That's the good news. The bad news is that your low lube oil pressure alarm will continue to sound if the engine is not running, so you'll have to disconnect one side of the jumper when the engine is not running. It's a slight inconvenience, but you'll have your gages operating.

Jim Voelxen
Odyssey #191

DAEDALUSCAN · **Joined:** 09 Dec 2007 21:03 **Posts:** 114

I had similar trouble until I bypassed the rubber connector going to the instruments. It was heavily corroded and if I wiggled it my gauges behaved really strangely.

carl s · **Joined:** 31 Dec 2006 13:33 **Posts:** 90

this is exactly what happened to me. I ended up getting a new tach, the old one was so corroded i thought that was the problem. it ended up being a fuel pressure switch. about 15 bucks. be sure to fill it with diesel or wd 40 before you install. mine did not require bleeding after this technique.

rhfetc · **Joined:** 24 Jun 2007 20:30 **Posts:** 19

Hi all,

Sorry about the late follow-up post so here it is. For now I have bypassed the switch as suggested by Jim Voelxen on Odyssey #191. The switch was easily accessed by leaning over the front of the engine. There were two posts on the switch and one of them had a clever Y to accomodate two female electrical leads. I made up a jumper with two 1/4 inch spade connectors and then did some testing. I found that the alarm was associated with the black electrical conncection attached to the Y so I taped it off. The other two connectors I put together with the jumper I made and now I have power to my guages when the battery switch is on - great! And the alarm is off. Of course I would like to have the alarm too and it appears from the wiring diagram that came with the boat that the oil pressure and water temperature alarms may be disabled now too. But I like having the guages back over the alarms. I haven't ordered the fuel switch yet but saw it on the web for $17.95. I will tackle that just before haul out if I get my act together. Thanks to everyone for the great advice I find here on this discussion board.

Invictus - #203

Richard and Jeannie in Sodus Bay, NY on the south shore of Lake Ontario

Tartan37.com

Gauges Erratic

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