Have a question regarding the tach/hourmeter gauge. Engines have the Cummins gauge panel with the older VDO gauges with square bezels. Tachs have built in hour meters, and neither of the hour meters are working. Tach part works. Find it strange that both would be broken at what appears to be about the same time hour wise. I am thinking they may be disconnected - any way to check or tell?
Thanks
Cummins 250hp
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In Memory of Vicroy
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I have the same tachs on my 250s. The hour meter function works off the 12 volt + from each ignition switch - i.e. when the switch is "on", the hour meter runs. I'm not positive whether there is one 12v+ to the whole tach (pretty sure there is) or two, one for the tach function and one for the hour meter function. It could be that the tach 12v+ feed is not switched thru the ignition, but that would be a long shot - and there is a fuse for the hour meters that is blown and/or corroded.
UV
UV
If they are the standard VDO 333-205 series with the analog hour meter, front has the square bezel, there is a lite circuit at the top of the guage and at the bottom 3 connections, 4 spaces.
Looking AT the back of the guage the far left is the tach sensor gray wire. Next is a blank space then the ground - black wire, last on the right is the ignition + purple wire.
No seperate connection for the hour meter as it is internal.
Standard tach drive is altenator driven with flywheel sensor being an option for better accuracy.
I've encountered numerous issues over the years with VDO hour meters within the tachs both analog and digital. Analog tend freeze up if they sit for a period especialy in large swinging climates or real humid climates. The digital ones usualy bleed to where you can't read it.
Yes all 4 hour meters not working at one time is a strange issue, but if the tachs work while the engine is running, its internal.
If any of the tachs above do not fit the description, then it could be a similar series VDO but different operation.
Unless I see the back, I'm going by Cummins wiring to determine style.
Looking AT the back of the guage the far left is the tach sensor gray wire. Next is a blank space then the ground - black wire, last on the right is the ignition + purple wire.
No seperate connection for the hour meter as it is internal.
Standard tach drive is altenator driven with flywheel sensor being an option for better accuracy.
I've encountered numerous issues over the years with VDO hour meters within the tachs both analog and digital. Analog tend freeze up if they sit for a period especialy in large swinging climates or real humid climates. The digital ones usualy bleed to where you can't read it.
Yes all 4 hour meters not working at one time is a strange issue, but if the tachs work while the engine is running, its internal.
If any of the tachs above do not fit the description, then it could be a similar series VDO but different operation.
Unless I see the back, I'm going by Cummins wiring to determine style.
Last edited by Michael on Jul 23rd, '11, 19:52, edited 1 time in total.
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Tony Meola
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Thanks Bruce, I think you are correct, in my case the engines were bought new from Cummins by the previous owner in 1992 ironically for a Bahia Mar like mine (which I also bought from him) that he was redoing. He never got round to finishing the boat and never installed the engines. They were kept in a container until I bout them 2 months ago. I fired them up for the very first time 2 weeks ago. So guess after sitting in the container for such a long period the analog meters froze up. I guess I will just add some others to keep track of hours.
That looks like them.
BTW those alarm panels can be sprayed with most anti corrosion sprays to keep from greening up. We recommend CX. You don't have to soak, just spray every few months.
The important thing for any of that is to make sure the instrument panels are well sealed to the dash and the gugaes are sealed to the panel to prevent any water leakage below them then your only dealing with humidity and not direct water soaking.
You can move the panels, but you'd have to extend all those wires. If they are clean and you keep them sprayed, they'll be fine. The issue is once corrosion starts and gets below the solder tracks or the clear coat they spray on them, its just a matter of time before they die.
BTW,
Those gauges do come apart not too difficult and I have fixed the counters before. I'd say someone has to have at least a medium or higher mechanical ability.
The issues was, it was always cheaper putting in a 20 dollar new hour meter than spending a couple of labor hours trying to fix the counters.
I'd say if you were in the states, send em to me and I'd see if I can get them going, but just the shipping doesn't make it cost effective for two hour meters.
BTW those alarm panels can be sprayed with most anti corrosion sprays to keep from greening up. We recommend CX. You don't have to soak, just spray every few months.
The important thing for any of that is to make sure the instrument panels are well sealed to the dash and the gugaes are sealed to the panel to prevent any water leakage below them then your only dealing with humidity and not direct water soaking.
You can move the panels, but you'd have to extend all those wires. If they are clean and you keep them sprayed, they'll be fine. The issue is once corrosion starts and gets below the solder tracks or the clear coat they spray on them, its just a matter of time before they die.
BTW,
Those gauges do come apart not too difficult and I have fixed the counters before. I'd say someone has to have at least a medium or higher mechanical ability.
The issues was, it was always cheaper putting in a 20 dollar new hour meter than spending a couple of labor hours trying to fix the counters.
I'd say if you were in the states, send em to me and I'd see if I can get them going, but just the shipping doesn't make it cost effective for two hour meters.
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