Volvo 2023d, Rev Counter stops working

[D&T]

Asking for help again.

My rev counter stopped working today on our Volvo 2030. The engine starts perfectly and the rev counter was working fine, then it slowly returned to zero. I stopped the engine and re-started, the rev counter climbed to idling revs, then after a second or two retuned to zero. Sometimes the rev counter will start working after a few seconds (around 20), but other times either the oil or battery lamp will light and bleep and then the rev counter will immediately restart.The alternator is only about 4 years old.

The 2nd problem, which I suspect is linked, on the few occasions when starting the boat, when turning the key all the red lamps light, then with a further turn, the glow plug lamp lit (all as per usual), but one further turn of the key to start the engine causes all lights to go out and no noise from the starter or relay at all. Anyone has this problem? Leave it a while and all works fine, very frustrating and not good whilst at sea.

Thinking it may be a wiring problem, but have no idea which wires

Can anyone offer any advise, thank you?

 

[Moonbeam]

Can you get to the rear of the rev counter and check the spade to horseshoe connections (if you have those on that rev counter)? And all other connections in that area... and then the engine end, that's where I would start. Follow wires as best you can, never hurts to remove a horseshoe connection and re-sit it on the spade to freshen the connection and remove dirt/corrosion.

 

[gregcope]

Also check your main neg/ground connections.

This sounds familar. If it affects multiple parts then it is probably related to the shared neg/ground.

As @Moonbeam points out, check the connections on the back of the pannel and its multi-connector. Also check the black box this loom connects in on the engine side and the engines main net connection back to the battery.

I had a similar issue on a 2030B until I replaced the main cable. It was internally corroded (non-tinned). So even though the main lug looked fine, the issue was in the cable. Took ages to find ...

I will soon be selling Volvo 20x0 spares as I no longer have a Volvo...

As its a Volvo 2030 I assume the install could be quite "old" as in 15+ years old and hence hidden corrosion could be a thing ...

 

[D&T]

Also check your main neg/ground connections.

This sounds familar. If it affects multiple parts then it is probably related to the shared neg/ground.

As @Moonbeam points out, check the connections on the back of the pannel and its multi-connector. Also check the black box this loom connects in on the engine side and the engines main net connection back to the battery.

I had a similar issue on a 2030B until I replaced the main cable. It was internally corroded (non-tinned). So even though the main lug looked fine, the issue was in the cable. Took ages to find ...

I will soon be selling Volvo 20x0 spares as I no longer have a Volvo...

As its a Volvo 2030 I assume the install could be quite "old" as in 15+ years old and hence hidden corrosion could be a thing ...

Thank you for your views. Its very strange that it is intermittent

 

[gregcope]

Mine was just as you describe. Starts okay. Random drop outs. Sometimes the instrument warning lights too. Sometimes fine. Sometimes not.

Mine was corrosion hidden in the cable. On stripping the cable it was corroded for the first metre. I did not strip any more so it could have been worse.

 

[D&T]

Mine was just as you describe. Starts okay. Random drop outs. Sometimes the instrument warning lights too. Sometimes fine. Sometimes not.

Mine was corrosion hidden in the cable. On stripping the cable it was corroded for the first metre. I did not strip any more so it could have been worse.

Thank you for your reply. Which cable had corroded?

 

[gregcope]

The main engine negative/ground attached to the block. Under the starter on mine.

However it could be any as my post above, but I suspect a negative. Either in the panel, the loom to the engine, the black box and or/its connection to the block. Or the connection from the block back to the battery.

 

[D&T]

As a follow up.

I cleaned up the main ground on the engine block (which did have some corrosion) and all has been good since

I still have my fingers crossed!

Thank you everyone for your input, your advise has been brilliant (again). Thanks