VOLVO TAMD74L-B EDC - Porthand engine doesn't crank

[sniffer]

Went to start boat to get her lifted out but the porthand engine will not crank so obviously wont start. The boat has twin TAMD74L-B and the starboard engine starts up as normal.

I tried the battery 'link' switch in case it was simply a dead battery but to no affect. I have never had to use the 'link' switch before so can't vouch that it would work. The boat is a flybridge and the issue is at both stations.

Switching on the ignition key brings on the three lights and the engine bay fans. The boat is in neutral, at both stations, and selecting the active station on the EDC control panel gives me a red light as normal and also a green neutral light. Turning the key to the start position causes all three lights to go out and the engine bay fans to stop. There are no solenoid or starter noises.

The voltmeter gives a good reading and all the battery voltages checkout (14v ish) with a fluke and the 7.5A fuse in the' ECU box' (if that's what it is) is good.

Anybody got any pointers?

 

[PaulRainbow]

Went to start boat to get her lifted out but the porthand engine will not crank so obviously wont start. The boat has twin TAMD74L-B and the starboard engine starts up as normal.

I tried the battery 'link' switch in case it was simply a dead battery but to no affect. I have never had to use the 'link' switch before so can't vouch that it would work. The boat is a flybridge and the issue is at both stations.

Switching on the ignition key brings on the three lights and the engine bay fans. The boat is in neutral, at both stations, and selecting the active station on the EDC control panel gives me a red light as normal and also a green neutral light. Turning the key to the start position causes all three lights to go out and the engine bay fans to stop. There are no solenoid or starter noises.

The voltmeter gives a good reading and all the battery voltages checkout (14v ish) with a fluke and the 7.5A fuse in the' ECU box' (if that's what it is) is good.

Anybody got any pointers?

Could be the battery, what does the battery voltage go to when you turn the key to start ? Can you swap the batteries over ?

Or a it could be a bad connection. If the battery checks out remove and clean all battery cables and all connections of the starter, plus the main engine negative connection (if it has one). Don't just look at them and/or wriggle them, take each one of and clean the cable lug and where it bolts.

 

[sniffer]

Could be the battery, what does the battery voltage go to when you turn the key to start ? Can you swap the batteries over ?

Could be but it doesn't feel like that. With the battery charger off I get voltages of 13v & 13.5v for the two pairs. The lower voltage reading of the two is for the starboard side and that cranks and fires up no problem.

Can't test any drop off as I'm on my own so can't hold/see the fluke and do the ignition at the same time. There is no 'feel' or sound of anything happening.

I've used jump leads now but no difference other than with the jump leads connecting the two pairs, the engine room fans remain on when turning the porthand ignition.

Tomorrow I'll test to see if there has been any voltage drop off and also disconnect the batteries and use a booster pack but I'm not optimistic.

Maybe a relay somewhere but specific info is proving hard to find.

 

[PaulRainbow]

Could be but it doesn't feel like that. With the battery charger off I get voltages of 13v & 13.5v for the two pairs. The lower voltage reading of the two is for the starboard side and that cranks and fires up no problem.

Can't test any drop off as I'm on my own so can't hold/see the fluke and do the ignition at the same time. There is no 'feel' or sound of anything happening.

I've used jump leads now but no difference other than with the jump leads connecting the two pairs, the engine room fans remain on when turning the porthand ignition.

Tomorrow I'll test to see if there has been any voltage drop off and also disconnect the batteries and use a booster pack but I'm not optimistic.

Maybe a relay somewhere but specific info is proving hard to find.

Given the battery voltages it's most likely a bad connection. The connection is good enough to pass the tiny current needed for the warning lights, but not enough to turn the starter over, hence the lights go out again.

Remove and clean all battery cables and all connections of the starter, plus the main engine negative connection (if it has one). Don't just look at them and/or wriggle them, take each one of and clean the cable lug and where it bolts.

 

[sniffer]

Disconnected the positive terminal, to confirm the battery bank was the correct one, wiped the terminal and refitted it. Tightened down the terminal connections. Removed and refitted the three starter relays in the engine control box (using the old relays, not new ones). The engine then cranked and started without problem.

Not sure which of the two actions did the trick .

Thank you for taking time to comment Paul.

 

[Sticky Fingers]

Excellent result!

 

[volvopaul]

Disconnected the positive terminal, to confirm the battery bank was the correct one, wiped the terminal and refitted it. Tightened down the terminal connections. Removed and refitted the three starter relays in the engine control box (using the old relays, not new ones). The engine then cranked and started without problem.

Not sure which of the two actions did the trick .

Thank you for taking time to comment Paul.

Dry joint on the main relay as everything is neutral ground

 

[sniffer]

Dry joint on the main relay as everything is neutral ground

Main relay as in one of the three relay units, as opposed to the start or stop relay or the board they plug into?

 

[sniffer]

Thinking more about this, there was/is, what I assume is dielectric grease of some description on the contacts of all three relays. I didn't clean that off, partly because the grease would be in the contact sockets anyway. Personally, I wouldn't put any sort of grease on contacts directly. Why now, I know not, but may be that was/is the issue?

 

[sniffer]

Bad news. Fired both up this morning, just to be sure, and no problem. However, forgot to open seacocks. So, switched off, opened seacocks but this time no go on port engine, same symptoms.. Didn't have time this morning to do anything so will return tomorrow, clean relay contacts as best I can and see what happens. Order some new relays too, just in case.