I have a 12hp Westerbeke Diesel. Last week when I energized the glow plugs it would pop the 20AMP circuit breaker. I checked all the wiring and replaced the glow plugs. Same thing happened.. I then replaced the circuit breaker and was able to energize the glow plugs and start the engine one time. I shut the engine down waited a hour or so and tried to start again. Same thing happened, when energizing the glow plugs the 20AMP circuit breaker pops. Any help would be appreciated.
Engine electrical problem
- Thread starter Tom23400
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You have an intermittent short
The key thing to note is you where messing around near the glow plugs, the system then worked until you ran the engine a while and now the problem is back. I'd start my search for burned or frayed wires near the glow plugs. you probably moved the bad wire while replacing the glow plugs and then if vibrated back into place while the engine ran.
The key thing to note is you where messing around near the glow plugs, the system then worked until you ran the engine a while and now the problem is back. I'd start my search for burned or frayed wires near the glow plugs. you probably moved the bad wire while replacing the glow plugs and then if vibrated back into place while the engine ran.
Disconnect all of them, and
test the current for each one individually. They should all draw the same amount of current. If one draws significantly more current (or trips the breaker), that is the defective one. And if one draws no current, that one may be the intermittent one that Bill has suggested.
test the current for each one individually. They should all draw the same amount of current. If one draws significantly more current (or trips the breaker), that is the defective one. And if one draws no current, that one may be the intermittent one that Bill has suggested.
How do you test?
Guy - Just curious - How would one measure the current? My digital multimeter only measures up to 10A DC.
Guy - Just curious - How would one measure the current? My digital multimeter only measures up to 10A DC.
A clamp on amp-meter is what I use.
Otherwise, you will have to use a shunt and measure the voltage across it to get a corresponding current value. A shunt would go in series with the circuit. If the shunt is 50mV at 50 amps, then every amp produces 1 mV across it. So, put your voltmeter on the DC milli-volt scale and read the voltage across the shunt. So Rick, you would take off the wire from the Glow Plugs to the breaker and insert the shunt in-line with that circuit. One end of the shunt goes to the breaker, the other end of the shunt goes to the wire that you took off of the breaker. Your volt/amp meter uses this same concept. The meters internal shunt may only have a 10 amp max current because it is protected by a fuse.
Otherwise, you will have to use a shunt and measure the voltage across it to get a corresponding current value. A shunt would go in series with the circuit. If the shunt is 50mV at 50 amps, then every amp produces 1 mV across it. So, put your voltmeter on the DC milli-volt scale and read the voltage across the shunt. So Rick, you would take off the wire from the Glow Plugs to the breaker and insert the shunt in-line with that circuit. One end of the shunt goes to the breaker, the other end of the shunt goes to the wire that you took off of the breaker. Your volt/amp meter uses this same concept. The meters internal shunt may only have a 10 amp max current because it is protected by a fuse.
Did you check...
...the glow plug relay? If all the glow plugs are new you may well have a dead short in the relay. Use your ohm meter and check each glow plug resistance to ground. If they are all the same there is no issue with them. You say you 'checked the wiring' what exactly did you do to check it?
...the glow plug relay? If all the glow plugs are new you may well have a dead short in the relay. Use your ohm meter and check each glow plug resistance to ground. If they are all the same there is no issue with them. You say you 'checked the wiring' what exactly did you do to check it?
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