00 Merc 5.7 w/B 3

[rnl]

Normally when I turn the key on there is an alarm, which I know to b the low oil pressure alarm. Start the engine and the alarm goes off in a few seconds. twice in the past week when i turn the key on the alarm does not sound, and the engine turns over but will not start no matter what. I then turn the key on and off until the alarm sounds and then the engine wil fire and run fine. Am i on the right track thinking this is oil pump related? Could it be a bad ground? Is there some sort of a safety that is retarding the spark(or something else) when the oil pump isn't working properly so as to not damage the engine?
If I have left any info out that would be useful just ask and I will get it.

Thanx in advance!

 

[Don S]

Re: 00 Merc 5.7 w/B 3

Am i on the right track thinking this is oil pump related?

No, the oil pump has nothing to do with the alarm, it's all electrical.
When the alarm doesn't sound, and the engine won't start, does the rest of the instruments work?

 

[rnl]

Re: 00 Merc 5.7 w/B 3

As far as I know everything else is working. Obviously some of the gauges only operate while running, but depth finder GPS etc are working.
Could the fact that it is intermitent mean a bad ground? If so where?

 

[jtybt]

Re: 00 Merc 5.7 w/B 3

Sometimes the neutral safety switch gets loose. Try jiggling throttle n neutral and see if that helps.

 

[rnl]

Re: 00 Merc 5.7 w/B 3

Interesting... I will check that out the next time it happens.

 

[rnl]

Re: 00 Merc 5.7 w/B 3

Don S .......anymore thoughts?

 

[Don S]

Re: 00 Merc 5.7 w/B 3

Obviously some of the gauges only operate while running, but depth finder GPS etc are working.

All the gauges should move a little when you first turn the key on. The needles will move a little bit. The GPS and other accessories aren't hooked to the ignition system.
Have you checked electrical connections? Fuses for corrosion? all wiring conntecitons.

Could the fact that it is intermitent mean a bad ground? If so where?

It could be a bad ground, bad hot wire or bad sensor wire, or a bad connection anywhere in the electrical system.
There is no single answer for your problem, and intermittant problems are the hardest to track down.

 

[rnl]

Re: 00 Merc 5.7 w/B 3

UPDATE: I believe I have found the problem. Loose/bad connections at the back of the safety lanyard switch.