Gauges reading incorrect.

cashwowud

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Feb 10, 2016
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17
Hi guys, Can someone give me a clue as to my problem.

​I have a 2000 Four Winnns 205 and 4 of the gauges, fuel, volts, temp and trim have suddenly started reading about 30% lower than they should.
So far I have checked the battery when engine stopped and running, 12.5v and 14.5v and the alternator, 14.5v. I have not done anything else yet but I would like some help please before I go further. I have read Don's guide to using a DMM and I will run through his procedure but I can't understand why 4 gauges are wrong.

Thanks in advance,

cashwowud
 

GA_Boater

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May 24, 2011
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49,038
I would check voltage and grounds starting behind the dash.
 

cashwowud

Cadet
Joined
Feb 10, 2016
Messages
17
Thanks GA, Today I checked the earth on the multi-pin block that plugs into the instrument panel and it had 12.5 volts. Three days ago I fitted a new fuel cell (low and high pressure pumps and filter, Volvo 5.7gsi). It seems a strange coincidence that my gauge problem started when I started up first time after connecting up but for the life of me I cannot see what I may have disturbed. Any ideas please?

​Thanks in advance,

cashwowud
 

GA_Boater

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Cash - Did you disconnect the battery when working on the fuel pumps? The books always say to disconnect the battery for almost any work.

Maybe one of the connections is flaky?
 

cashwowud

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Feb 10, 2016
Messages
17
Yes GA I did disconnect but I think you must be right about a dodgy connection but where? If it's the battery then why does everything else work ok?. I'll check as many as I can this weekend.

​Thanks
 

cashwowud

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Joined
Feb 10, 2016
Messages
17
Did some more testing today and couldn't find any bad connections. The temperature sensor on the engine thermostat has a plug with two connections. The voltage across these is 5 volts with the ignition on and engine stopped. If I link the terminals the gauge does not move. Is this correct?.
​Any help much appreciated.

cashwowud
 

cashwowud

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Feb 10, 2016
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Hi again, Please ignore the last post. The sensor in the thermostat housing on my Volvo 5.7 gsi is in fact a coolant temperature sensor for the ecu and the 5 volts supplied to it is correct. Can anyone tell me where the sensor for the gauge is located please? I cannot find any refernce to it in the manual except in the wiring diagram.

Thanks in advance.

cashwowud
 

GA_Boater

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Yes GA I did disconnect but I think you must be right about a dodgy connection but where? If it's the battery then why does everything else work ok?. I'll check as many as I can this weekend.

​Thanks

Back to this a little late, Cash.

It's because of the added power routing to get to the front of the boat. The battery has a fairly direct path to the starter, solenoid and trim motor in the back. The front is fed through the harness to the remote control, through the key switch, probably a fuse/circuit breaker block to finally provide power to the instruments. So more connections going to the front. Not sure how your boat is wired, but sometimes the power feed off the battery is from a separate feed other than the large cables on the battery posts - One more connection to go flaky.

Hope that's clear.
 

cashwowud

Cadet
Joined
Feb 10, 2016
Messages
17
Hi GA and thanks. Now I know where the water temp sender is, I have earthed the feed and the gauge goes up about a third the way. Also put a voltmeter between the feed and earth and got 5.2 volts with ignition on and engine off. I will do more checks and come back when I can.

Thanks

cashwowud
 
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