TAMD 75 EDC Problems

[simonjames]

Hoping for some help please. We have a Fairline Targa 43 with TAMD 75 EDC engines. Doing some boat handling basics ie astern, forward tight turns etc boat was fine. Then suddenly everytime you put the port engine into astern, the boat totally lost drive on the port engine, it didn't go into limp home mode just sat ticking over and wouldn't select forward or astern until turned off and re started. Took the boat back to marina on starboard engine, an engineer came and diagnosed it as the solenoid replaced it and the engine instantly selected forward and astern on port engine. However, the starboard engine then decides to enter limp home mode. Engineer arrives and diagnoses potentiometer fault, brings a spare new potentiometer and boat seems ok. Going out to do some more boat handling starboard engine drops out into limp home mode again, back to berth again on Port engine this time. Engineer duly arrives starts boat everything ok, advice of the engineer turn engine batteries off for 12 or so hours and fault would clear. He duly arrived next day turned the batteries on and declared the boat repaired. Later in the afternoon started up the engines removed the springs and the boat selected forward gear on starboard engine on its own while ticking over in neutral according to the controls. Engineer comes back and removes a very hot grey relay, changes it and no difference at all. Does anybody have any ideas as this is wrecking confidence of the boat to the point where my parents are really regretting buying it. Sorry the post is so long just wanted to get all the facts out.
Thanks in anticipation

 

[crazy4557]

Sorry to hear of your gremlins, very frustrating on a new boat to you.
I had similar problems last year and found corroded wires to the gearbox actuator pump which sits above the gearbox. I think there's about 3 or 4 wires and these can get corroded and play silly buggers with the controls.

Take a look but it's little tight around gearboxes on those.

 

[simonjames]

Sorry forgot to mention the port wires were very corroded above the solenoid have been cleaned up and port engine ok now. The baffling thing is that it's now the starboard engine that now has all the problems.

 

[crazy4557]

Sorry forgot to mention the port wires were very corroded above the solenoid have been cleaned up and port engine ok now. The baffling thing is that it's now the starboard engine that now has all the problems.

Does that mean that you have checked and cleaned those starboard terminals too? If not then worth checking but I doubt you would have not already checked the wires.

 

[volvopaul]

This rings a bell with me, where is the boat, what was it called when you bought it.

Was tech from a dealer ?
I'll add more later.

 

[LynnC]

I think you will find there is a bad connection on the wires to/from the potentiometer. Most likely at the connector block at the engine (circled in the picture). The suggested cure was to put a wire to bypass the connector block, for each potentiometer wire. I suspect your boat missed this modification.
The problem occures when the bad connection (usually at the -ve (0 volt)) causes an obberent voltage to show at the wiper of the potentiometer.

 

[volvopaul]

T

I think you will find there is a bad connection View attachment 52597 on the wires to/from the potentiometer. Most likely at the connector block at the engine (circled in the picture). The suggested cure was to put a wire to bypass the connector block, for each potentiometer wire. I suspect your boat missed this modification.
The problem occures when the bad connection (usually at the -ve (0 volt)) causes an obberent voltage to show at the wiper of the potentiometer.

Years back ther was a mid to the loom, we had to cut out the two wires to the solenoid and bypass with a connector , this was usually done on first service , the issue was that some engine gave a signal to both forward and reverse solenoid , the result was a blown to bits clutch pack which stalled the engine immediately.
The pot sensor sends a signal to the relays for forward and reverse .

 

[simonjames]

The boat is in Barcelona now it's been in Plymouth for about a year however, it came back from med to somewhere on the south coast about 18 mths ago I believe it was called Rayvonlee or something similar. No unfortunately tech was from a Yanmar agent who has experience with volvos as he used to work for a dealer.

 

[simonjames]

Just to add a bit more sometimes when you turn on the ignition the starboard red edc light flashes bringing diagnostic code 2. 7 , then turn it off and back on boat fires straight up and will select both forward and reverse ok however, if left for say 3-5 mins to warm up it will select forward on stbd engine on its own