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#1
posted to rec.boats.cruising
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Volvo Penta 2002B 18 HP Deluxe Panel Temp Gauge
On 06/04/2010 21:33, goofball_star_dot_etal wrote:
On 06/04/2010 21:04, Armond Perretta wrote: My 2002 (1993) has 3700 hours and runs well. The deluxe panel also was fine with all gauges except the tach performing properly. I have replaced the original tach with the latest (both wires removed from the old sender and one of these to "w" on the alternator, the hour meter wire removed and set aside, etc.). I just started up the engine for the upcoming season and the new tach is fine. However now I have a new issue with the temp gauge. Here are the symptoms. Prior to starting, when I turn the key one click, all gauges including the temp move a bit, indicating that the wiring is fine to all instruments. Nothing happens with the tach of course. When I then start up, all gauges including the new tach perform as designed, except that the old temp gauge (which ran perfectly last year) pegs to the left once the engine starts, giving what looks like reverse polarity connection symptoms. I did not change any wiring to this gauge when fitting the new tach. Next, when I shut down after running the engine under load and letting it come to temp, all the gauges including the temp show what appear to be correct readings, but only when the engine is NOT actually running. That is, it seems the temp sender is OK and sending correct info, the oil sender same, the voltage meter same, the tack off of course, etc. I think this means the temp sender is fine, but that running the engine is somehow sending the incorrect voltage to the meter. Only when I start up and the engine is actually running (and the tach showing the revs) does the temp gauge peg to the left. Is it possible I just picked the wrong one of the 2 old tach wires for the new tach to connect to "w"? No other wiring changed from the time the temp gauge was OK. Ideas welcomed. Check for voltage drops between various earth points when the alternator is charging. In particular, check the integrity of the alternator earth path (since it seems that the error is associated with charging current), the engine earth path (since, probably, the temperature sensor thermistor uses the engine as earth), and the instrument earth (since that is where you see the problem). In an ideal world one would have a single point earth but this is not always practical. |
#2
posted to rec.boats.cruising
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Volvo Penta 2002B 18 HP Deluxe Panel Temp Gauge
It is absolutely essential that DC return is isolated from the hull. There is no such thing as not practical. Failure here with
induce electrolytic corrosion throughout your boat as well as neighboring boats at your marina. There have been multiple threads here on this very subject. Engine installations are the number one source of this fault by amateurs and professionals alike. Boats are not automobiles and must not be wired in the same manner. The general cause is that many of these engine sensors use the engine block as the DC return. Steve "goofball_star_dot_etal" wrote in message o.uk... On 06/04/2010 21:33, goofball_star_dot_etal wrote: In particular, check the integrity of the alternator earth path (since it seems that the error is associated with charging current), the engine earth path (since, probably, the temperature sensor thermistor uses the engine as earth), and the instrument earth (since that is where you see the problem). In an ideal world one would have a single point earth but this is not always practical. |
#3
posted to rec.boats.cruising
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Volvo Penta 2002B 18 HP Deluxe Panel Temp Gauge
On Tue, 06 Apr 2010 23:49:41 +0100, goofball_star_dot_etal
wrote: On 06/04/2010 21:33, goofball_star_dot_etal wrote: On 06/04/2010 21:04, Armond Perretta wrote: My 2002 (1993) has 3700 hours and runs well. The deluxe panel also was fine with all gauges except the tach performing properly. I have replaced the original tach with the latest (both wires removed from the old sender and one of these to "w" on the alternator, the hour meter wire removed and set aside, etc.). I just started up the engine for the upcoming season and the new tach is fine. However now I have a new issue with the temp gauge. Here are the symptoms. Prior to starting, when I turn the key one click, all gauges including the temp move a bit, indicating that the wiring is fine to all instruments. Nothing happens with the tach of course. When I then start up, all gauges including the new tach perform as designed, except that the old temp gauge (which ran perfectly last year) pegs to the left once the engine starts, giving what looks like reverse polarity connection symptoms. I did not change any wiring to this gauge when fitting the new tach. Next, when I shut down after running the engine under load and letting it come to temp, all the gauges including the temp show what appear to be correct readings, but only when the engine is NOT actually running. That is, it seems the temp sender is OK and sending correct info, the oil sender same, the voltage meter same, the tack off of course, etc. I think this means the temp sender is fine, but that running the engine is somehow sending the incorrect voltage to the meter. Only when I start up and the engine is actually running (and the tach showing the revs) does the temp gauge peg to the left. Is it possible I just picked the wrong one of the 2 old tach wires for the new tach to connect to "w"? No other wiring changed from the time the temp gauge was OK. Ideas welcomed. Check for voltage drops between various earth points when the alternator is charging. In particular, check the integrity of the alternator earth path (since it seems that the error is associated with charging current), the engine earth path (since, probably, the temperature sensor thermistor uses the engine as earth), and the instrument earth (since that is where you see the problem). In an ideal world one would have a single point earth but this is not always practical. I'm a bit confused. Assuming a normal inboard engine installation, the alternator earth is normally either through the case to the engine block or through a separate earth connection to the same place. The engine is normally grounded/earthed by a direct connection back to the negative side of the battery. It almost has to be connected this way as the starter, which IS earthed through its case to the engine block will never develop its normal power without an adequate earth/ground path back to the power source; the battery. Cheers, Bruce (bruceinbangkokatgmaildotcom) |
#4
posted to rec.boats.cruising
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Volvo Penta 2002B 18 HP Deluxe Panel Temp Gauge
On 07/04/2010 14:14, Bruce wrote:
On Tue, 06 Apr 2010 23:49:41 +0100, goofball_star_dot_etal wrote: On 06/04/2010 21:33, goofball_star_dot_etal wrote: On 06/04/2010 21:04, Armond Perretta wrote: My 2002 (1993) has 3700 hours and runs well. The deluxe panel also was fine with all gauges except the tach performing properly. I have replaced the original tach with the latest (both wires removed from the old sender and one of these to "w" on the alternator, the hour meter wire removed and set aside, etc.). I just started up the engine for the upcoming season and the new tach is fine. However now I have a new issue with the temp gauge. Here are the symptoms. Prior to starting, when I turn the key one click, all gauges including the temp move a bit, indicating that the wiring is fine to all instruments. Nothing happens with the tach of course. When I then start up, all gauges including the new tach perform as designed, except that the old temp gauge (which ran perfectly last year) pegs to the left once the engine starts, giving what looks like reverse polarity connection symptoms. I did not change any wiring to this gauge when fitting the new tach. Next, when I shut down after running the engine under load and letting it come to temp, all the gauges including the temp show what appear to be correct readings, but only when the engine is NOT actually running. That is, it seems the temp sender is OK and sending correct info, the oil sender same, the voltage meter same, the tack off of course, etc. I think this means the temp sender is fine, but that running the engine is somehow sending the incorrect voltage to the meter. Only when I start up and the engine is actually running (and the tach showing the revs) does the temp gauge peg to the left. Is it possible I just picked the wrong one of the 2 old tach wires for the new tach to connect to "w"? No other wiring changed from the time the temp gauge was OK. Ideas welcomed. Check for voltage drops between various earth points when the alternator is charging. In particular, check the integrity of the alternator earth path (since it seems that the error is associated with charging current), the engine earth path (since, probably, the temperature sensor thermistor uses the engine as earth), and the instrument earth (since that is where you see the problem). In an ideal world one would have a single point earth but this is not always practical. I'm a bit confused. Assuming a normal inboard engine installation, the alternator earth is normally either through the case to the engine block or through a separate earth connection to the same place. The engine is normally grounded/earthed by a direct connection back to the negative side of the battery. It almost has to be connected this way as the starter, which IS earthed through its case to the engine block will never develop its normal power without an adequate earth/ground path back to the power source; the battery. Cheers, Bruce (bruceinbangkokatgmaildotcom) Fortunately the starter is not running, so does effectively does not exist during normal operations. I bet some meters kick when the starter is operated on many boats.. There comes a point when it is quicker to get a meter out and fix the problem rather than to speculate what should be, or might be. It stinks of a 'common mode' problem to me, and I would check the earth conections first. I look forward to hearing the result. |
#5
posted to rec.boats.cruising
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Volvo Penta 2002B 18 HP Deluxe Panel Temp Gauge
On Wed, 07 Apr 2010 14:59:02 +0100, goofball_star_dot_etal
wrote: On 07/04/2010 14:14, Bruce wrote: On Tue, 06 Apr 2010 23:49:41 +0100, goofball_star_dot_etal wrote: On 06/04/2010 21:33, goofball_star_dot_etal wrote: On 06/04/2010 21:04, Armond Perretta wrote: My 2002 (1993) has 3700 hours and runs well. The deluxe panel also was fine with all gauges except the tach performing properly. I have replaced the original tach with the latest (both wires removed from the old sender and one of these to "w" on the alternator, the hour meter wire removed and set aside, etc.). I just started up the engine for the upcoming season and the new tach is fine. However now I have a new issue with the temp gauge. Here are the symptoms. Prior to starting, when I turn the key one click, all gauges including the temp move a bit, indicating that the wiring is fine to all instruments. Nothing happens with the tach of course. When I then start up, all gauges including the new tach perform as designed, except that the old temp gauge (which ran perfectly last year) pegs to the left once the engine starts, giving what looks like reverse polarity connection symptoms. I did not change any wiring to this gauge when fitting the new tach. Next, when I shut down after running the engine under load and letting it come to temp, all the gauges including the temp show what appear to be correct readings, but only when the engine is NOT actually running. That is, it seems the temp sender is OK and sending correct info, the oil sender same, the voltage meter same, the tack off of course, etc. I think this means the temp sender is fine, but that running the engine is somehow sending the incorrect voltage to the meter. Only when I start up and the engine is actually running (and the tach showing the revs) does the temp gauge peg to the left. Is it possible I just picked the wrong one of the 2 old tach wires for the new tach to connect to "w"? No other wiring changed from the time the temp gauge was OK. Ideas welcomed. Check for voltage drops between various earth points when the alternator is charging. In particular, check the integrity of the alternator earth path (since it seems that the error is associated with charging current), the engine earth path (since, probably, the temperature sensor thermistor uses the engine as earth), and the instrument earth (since that is where you see the problem). In an ideal world one would have a single point earth but this is not always practical. I'm a bit confused. Assuming a normal inboard engine installation, the alternator earth is normally either through the case to the engine block or through a separate earth connection to the same place. The engine is normally grounded/earthed by a direct connection back to the negative side of the battery. It almost has to be connected this way as the starter, which IS earthed through its case to the engine block will never develop its normal power without an adequate earth/ground path back to the power source; the battery. Cheers, Bruce (bruceinbangkokatgmaildotcom) Fortunately the starter is not running, so does effectively does not exist during normal operations. I bet some meters kick when the starter is operated on many boats.. There comes a point when it is quicker to get a meter out and fix the problem rather than to speculate what should be, or might be. It stinks of a 'common mode' problem to me, and I would check the earth conections first. I look forward to hearing the result. I was commenting on the remark about multiple ground circuits, as there aren't any. The Temp and pressure senders are grounded through their case to the engine block. The alternator is grounded through its case to the engine block.The starter is grounded through its case to the engine block. If an electrical ignition engine the ignition is grounded to the engine block. The engine block is grounded through a big cable to the battery Neg. post. No multiple paths. As far as the instrument problem is concerned the logical plan would be to undo the last thing done, i.e., disconnect the Tach and see what happens? Hardly rocket science but if only one thing changes - the bloke connects a different tachometer - and all the instruments fail then ????. Cheers, Bruce (bruceinbangkokatgmaildotcom) |
#6
posted to rec.boats.cruising
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Volvo Penta 2002B 18 HP Deluxe Panel Temp Gauge
Bruce wrote:
As far as the instrument problem is concerned the logical plan would be to undo the last thing done, i.e., disconnect the Tach and see what happens? Hardly rocket science but if only one thing changes - the bloke connects a different tachometer - and all the instruments fail then Which I will of course try today. Yesterday I tried switching the old tach wires (see original post). That was a "no go" because the connectors allow only one proper connection on the new instrument. Note that only the temp gauge is acting up. All other gauges (oil, voltage, tach, alarms, lights, etc.) perform properly. -- Good luck and good sailing. s/v Kerry Deare of Barnegat http://home.comcast.net/~kerrydeare |
#7
posted to rec.boats.cruising
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Volvo Penta 2002B 18 HP Deluxe Panel Temp Gauge
On Thu, 8 Apr 2010 06:46:02 -0400, "Armond Perretta"
wrote: Bruce wrote: As far as the instrument problem is concerned the logical plan would be to undo the last thing done, i.e., disconnect the Tach and see what happens? Hardly rocket science but if only one thing changes - the bloke connects a different tachometer - and all the instruments fail then Which I will of course try today. Yesterday I tried switching the old tach wires (see original post). That was a "no go" because the connectors allow only one proper connection on the new instrument. Note that only the temp gauge is acting up. All other gauges (oil, voltage, tach, alarms, lights, etc.) perform properly. Still, I'd reverse my "repair" and see what happens. A heat gage going full scale indicates that somewhere between the instrument the temp. sender you have a short to ground and/or the sender in shorted to ground. You can isolate things a bit more by disconnecting the existing connections to the Temp. Gage and connecting a jumper from some known source of power to the proper terminal on the gage, then temporarily connect the wire from the temp sender, to the gage and see how it works.Try using a jumper of some sort, make a whole new connection from the gage to the sender and see what happens. This should give you a pretty good indication of what is working and what is not. If you find that isolated from everything else on the panel the Temp Gage works then you can investigate the "everything else". And yes, this is exactly, leaving out experience, how a professional instrumentation guy will do it - isolate the instrument and it's sender from everything else to determine whether it is the instruments themselves or "everything else", fix either the instrument or "everything else". Cheers, Bruce (bruceinbangkokatgmaildotcom) |
#8
posted to rec.boats.cruising
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Volvo Penta 2002B 18 HP Deluxe Panel Temp Gauge
Bruce wrote:
... I'd reverse my "repair" and see what happens. A heat gage going full scale indicates that somewhere between the instrument the temp. sender you have a short to ground and/or the sender in shorted to ground. ... ... this is exactly, leaving out experience, how a professional instrumentation guy will do it - isolate the instrument and it's sender from everything else to determine whether it is the instruments themselves or "everything else", fix either the instrument or "everything else". Thanks, Bruce. I think I am getting close to a solution for this issues thanks to many comments here, on the Volvo forums, and elsewhere. I am betting that I simply removed the wires from the temp sender when trying to remove the wires from the tach sender. My manuals and Volvo downloads give essentially no exact guidance, pictures, or diagrams on which sensor is which, and on top of that there is really no room in the engine compartment to look around and see the entire layout. This of course has been a problem from day one with small sailing boats. I just sent the following to the Volvo forum. Additional comments are of course welcome. BTW thanks to you all who are providing serious and detailed suggestions. I readily admit I am an amateur when it comes to marine diesels, despite having messed with them 30 or so years. Apparently some few readers believe it's necessary to remind me of my ignorance in these matters. Rest assured, friends and others, I am well aware of my limitations and have been humbled by the sea many times. Set to Volvo forums: "I think we're getting warm. Yesterday I tried various combinations, including just disconnecting the wire to the "w" lug. I had assumed that this wire, one of 2, belonged to the old tach. When I then tried the engine with this wire disconnected the tach still worked but the temp gauge was "dead." "In other words I suspect that my problem is that instead of disconnecting the wires I may have mistakenly assumed belonged to the old tach, I actually disconnected the wires from the temp sender, and then connected one of these to "w" on the alternator. This fits all the symptoms so far, and could easily have happened since I am not really sure which sender is temp and which is revs. My manual does not show the locations clearly. Another clue is that the pair I disconnected has 2 different sized lugs, fitting the description of the temp sender wires given to me by Richard Vosbury of Annapolis. I suspect the larger lug is the actual temp resistor and the smaller lug is the temp alarm. Today I will run down to the boatyard and try again, this time using the correct pair of wires (assuming I can locate them somewhere in the vicinity of the alternator on the starboard side of the engine). In he meantime, any more comments on these suppositions? Putting all the comments together so far is at least giving this confused amateur some ideas on how to proceed. Thanks, gentlemen." -- Good luck and good sailing. s/v Kerry Deare of Barnegat http://home.comcast.net/~kerrydeare |
#9
posted to rec.boats.cruising
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Volvo Penta 2002B 18 HP Deluxe Panel Temp Gauge
On Thu, 8 Apr 2010 06:46:02 -0400, "Armond Perretta"
wrote: Bruce wrote: As far as the instrument problem is concerned the logical plan would be to undo the last thing done, i.e., disconnect the Tach and see what happens? Hardly rocket science but if only one thing changes - the bloke connects a different tachometer - and all the instruments fail then Which I will of course try today. Yesterday I tried switching the old tach wires (see original post). That was a "no go" because the connectors allow only one proper connection on the new instrument. Note that only the temp gauge is acting up. All other gauges (oil, voltage, tach, alarms, lights, etc.) perform properly. Leave the tach unconnected and see whether the other instruments work. then connect the tach and see. should tell you something. The tach has three wires? Battery, or Ign., Ground, and Signal? Does it have a multitude of jumpers or micro switches to set RPM and number of poles on the alternator? Cheers, Bruce (bruceinbangkokatgmaildotcom) |
#10
posted to rec.boats.cruising
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Volvo Penta 2002B 18 HP Deluxe Panel Temp Gauge
On 08/04/2010 08:39, Bruce wrote:
On Wed, 07 Apr 2010 14:59:02 +0100, goofball_star_dot_etal wrote: On 07/04/2010 14:14, Bruce wrote: On Tue, 06 Apr 2010 23:49:41 +0100, goofball_star_dot_etal wrote: On 06/04/2010 21:33, goofball_star_dot_etal wrote: On 06/04/2010 21:04, Armond Perretta wrote: My 2002 (1993) has 3700 hours and runs well. The deluxe panel also was fine with all gauges except the tach performing properly. I have replaced the original tach with the latest (both wires removed from the old sender and one of these to "w" on the alternator, the hour meter wire removed and set aside, etc.). I just started up the engine for the upcoming season and the new tach is fine. However now I have a new issue with the temp gauge. Here are the symptoms. Prior to starting, when I turn the key one click, all gauges including the temp move a bit, indicating that the wiring is fine to all instruments. Nothing happens with the tach of course. When I then start up, all gauges including the new tach perform as designed, except that the old temp gauge (which ran perfectly last year) pegs to the left once the engine starts, giving what looks like reverse polarity connection symptoms. I did not change any wiring to this gauge when fitting the new tach. Next, when I shut down after running the engine under load and letting it come to temp, all the gauges including the temp show what appear to be correct readings, but only when the engine is NOT actually running. That is, it seems the temp sender is OK and sending correct info, the oil sender same, the voltage meter same, the tack off of course, etc. I think this means the temp sender is fine, but that running the engine is somehow sending the incorrect voltage to the meter. Only when I start up and the engine is actually running (and the tach showing the revs) does the temp gauge peg to the left. Is it possible I just picked the wrong one of the 2 old tach wires for the new tach to connect to "w"? No other wiring changed from the time the temp gauge was OK. Ideas welcomed. Check for voltage drops between various earth points when the alternator is charging. In particular, check the integrity of the alternator earth path (since it seems that the error is associated with charging current), the engine earth path (since, probably, the temperature sensor thermistor uses the engine as earth), and the instrument earth (since that is where you see the problem). In an ideal world one would have a single point earth but this is not always practical. I'm a bit confused. Assuming a normal inboard engine installation, the alternator earth is normally either through the case to the engine block or through a separate earth connection to the same place. The engine is normally grounded/earthed by a direct connection back to the negative side of the battery. It almost has to be connected this way as the starter, which IS earthed through its case to the engine block will never develop its normal power without an adequate earth/ground path back to the power source; the battery. Cheers, Bruce (bruceinbangkokatgmaildotcom) Fortunately the starter is not running, so does effectively does not exist during normal operations. I bet some meters kick when the starter is operated on many boats.. There comes a point when it is quicker to get a meter out and fix the problem rather than to speculate what should be, or might be. It stinks of a 'common mode' problem to me, and I would check the earth conections first. I look forward to hearing the result. I was commenting on the remark about multiple ground circuits, as there aren't any. The Temp and pressure senders are grounded through their case to the engine block. The alternator is grounded through its case to the engine block.The starter is grounded through its case to the engine block. If an electrical ignition engine the ignition is grounded to the engine block. The engine block is grounded through a big cable to the battery Neg. post. No multiple paths. Some common paths there, and the possibility of a connection not being as it should be. If there is a potential difference between the sender earth (ground) and the instrument earth, it might cause the observed problem if there are two legs of a bridge circuit which go to different 'earths'. There is no such thing as a single point (earth). Whether an engine block, terminal block, star washer, or other connection can be treated as electrically equivalent to one is what matters. It depends on the circumstances, such as the frequency and the currents involved etc. Mixing sensitive instruments with high current devices such as starter motors by sharing a common path (wire) is not a good idea for the poor instrument, but it well may be ok for two intruments to be connected through a shared supply wire. For RF interference issues, a low resistance is no guide to whether a connection is low impedance or can be regarded as a single point. As far as the instrument problem is concerned the logical plan would be to undo the last thing done, i.e., disconnect the Tach and see what happens? Can't do any harm. Hardly rocket science but if only one thing changes - the bloke connects a different tachometer - and all the instruments fail then ????. Then there is a fault. We knew that. Tachometers don't wreck temperature gauges all on their own. He may have inadvertently disturbed something or connected wires at random but I was trying to suggest something that he may not already have thought of, rather than the most likely cause (finger trouble..) |
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