Engine gauges

[britinusa]

After enjoying a few hours sailing in the Ocean this weekend, we got down to testing the non-working engine gauges.

#1: Engine Temp Gauge.
Shorted the tip of the Sensor on the engine and the Gauge read max temp.  - Ordering a new temp sensor


#2: Engine high temp alarm.
Shorted the tip of the 2nd sensor on the engine and the alarm light lit up and the alarm sounded. - Ordering new high temp sendor.

#3: Fuel Gauge
Gained access to the fuel tank area by removing the cabinet just above the shower seat. Inside I found a wire with a terminal end that had been tie-wrapped to the fuel line and covered with electrical tape.
Shorted that line to the tank body and the fuel gauge read full. - Ordering a new fuel sensor (the one with the magnetic reed switches, not the swing arm type)

I think I lucked out on these items.

Paul

[Ron Hill]

Paul : You'll just have to install the new parts and see it that solves your problems.

BTW, the easiest way to get to the fuel tank is by taking the port side panel off in the aft cabin.

A thought

[KWKloeber]

After enjoying a few hours sailing in the Ocean this weekend, we got down to testing the non-working engine gauges.

#1: Engine Temp Gauge.
Shorted the tip of the Sensor on the engine and the Gauge read max temp.  - Ordering a new temp sensor


#2: Engine high temp alarm.
Shorted the tip of the 2nd sensor on the engine and the alarm light lit up and the alarm sounded. - Ordering new high temp sendor.

#3: Fuel Gauge
Gained access to the fuel tank area by removing the cabinet just above the shower seat. Inside I found a wire with a terminal end that had been tie-wrapped to the fuel line and covered with electrical tape.
Shorted that line to the tank body and the fuel gauge read full. - Ordering a new fuel sensor (the one with the magnetic reed switches, not the swing arm type)

I think I lucked out on these items.

Paul

Paul, what you have to make sure is that your temp sender and temp switch are properly grounded.  It could very well be that they are a-okay, but the threads are not grounded.   A VERY common problem.   You can use a wire with an alligator clip to temporarily ground them to a good engine ground to test the gauges again.  It would be rare for both the switch and the gauge sender to go bad.

What happens is corrosion on the bolts holding down the thermostat cap produces a poor ground.  That's the only way the ground is transferred to the temp units.   

I have been working on a little add-on to ground those units properly.  If you want to try one email me offline - I'm looking for a guinea pig to try it out on.  Even a slight corrosion will affect the accuracy of the temp gauge (which is only about +/- 15-20% anyway.)

Alternately you can remove the T cap, clean up everything, and reassemble using copper content never seize on the bolt and sender and switch threads -- then clean up the cap well, use a star lock washer under each bolt head to get a good BITE into the T cap.   Then paint over the bolt heads well to prevent corrosion from creeping under them.

Ken

[britinusa]

Good point Ken (no pun intended)

I'll go down to the boat and run a ohms test between the senders bodies (each of them) and the engine ground.

If high, I'll remove them, clean them up and reinstall as you suggested.

Thanks.

Paul

[Stu Jackson]

Gained access to the fuel tank area by removing the cabinet just above the shower seat.

In 17 years of owning our C34, and in reading Mainsheet magazine articles since 1987, this is the very first I have ever heard of this "route."

Got any pictures?

[chuck53]

Gained access to the fuel tank area by removing the cabinet just above the shower seat.

In 17 years of owning our C34, and in reading Mainsheet magazine articles since 1987, this is the very first I have ever heard of this "route."

Got any pictures?

While I know I can take the door off that cabinet opening, I'm pretty sure it is all one piece of fiberglass and no way to get behind it short of cutting a hole in the back of the cabinet.

[britinusa]

As we refer to it, the 'bog roll' holder is a wooden cabinet that is removed with just taking out 4 screws.
From the hole left after removing the cabinet box, I can reach the front end of the fuel tank and to top where the gauge is located.

I'm going down to the boat tomorrow (tueaday) night and will take a pic.

paul

[Noah]

To get to the fuel tank, remove the port aft cabin bulkhead/trim panel. To access the fuel tank gauge sender go through the beckson port in the port cockpit seat locker. To get to the shower sump pump, remove the teak toilet paper cabinet. To get to the engine gauges, remove the gauge panel and hopefully you have adaqute slack in the wiring harness and it is well supported to pull it out into the cockpit. That's the way it works on my 1990 C34.

[britinusa]

Didn't get to the boat last night, Nature demanded attention (mow the lawn), so I'm heading down there this evening.

Reading some posts that found me, I got this from Boating Magazine 2011

http://www.boatingmag.com/how-to/installing-fuel-water-separator

Step 1
First, you'll need the proper kit. For outboards, that'll generally mean a filter equipped with a clear plastic collection bowl. For inboards, use a filter fitted with an aluminum bowl for gas, or a clear glass or plastic inspection bowl for diesel. A disposable filter without a collection bowl can also be used.

Paul

[chuck53]

To access the fuel tank gauge sender go through the beckson port in the port cockpit seat locker.

My Beckson port is so deep in my locker, there is no way I could ever reach it.  If I cleaned out the locker, my 9 year old grandson could crawl in there and reach it but not me.

[Noah]

Not fun for you, but probably for him! Fortunately mine is well placed enabling access the sender and puck up tube assembly.

[britinusa]

Anyone know the temp/resistance steps of the Engine Temperature Sensor?

I'm seeing 74ohms at ambient temperature (80+ Degrees)

Thanks.

Paul

[KWKloeber]

Anyone know the temp/resistance steps of the Engine Temperature Sensor?

I'm seeing 74ohms at ambient temperature (80+ Degrees)

Thanks.

Paul

Always check the wiki first!!!  I had posted the complete gauge troubleshooting guide on there in the engines section. 
http://c34.org/wiki/index.php?title=Tachometer_Malfunction_Q%26A

Are you sure it's 74 and not 740?  600 - 800 ohms at 75F is normal.


Ken K

[britinusa]

Some success.

I was able to install the new Fuel level sensor (removed the aft berth panel to gain access to the tank area, removed the bekson access panel in the port cockpit locker to allow passing the new sensor Up into the locker and then down into the tank) Works great.

No luck with the engine temp and high temp sensors. Installed 2 new sensors, ran the engine for 30 minutes, still shows minimal temperature.
Shorted the new sensors to the body of the sensor housing and the temp gauge read full right, and the temp alarm sounded (pretty weak!) and the light flashed.

I shorted the temperature sensor housing to the arm of the alternator support.  Still no temp reading.

Is it possible that the engine earth is the problem?

Paul

[Ron Hill]

Paul : Check to make sure they sent you temp senders and not temp switches!!