Volvo TAMD 75 EDC issue

R

rpfletcher2

New Member
Joined
22 Dec 2018
Messages
6
Visit site
Hello everyone, I am new to the forum here and was looking for some help with a Volvo TAMD 75. I am tracing down an intermittent problem with the EDC. The engine will start up run fine and then all the sudden starts sputtering. The green neutral light will blink in time with the engine sputtering and it will eventually die. Trouble code 5.4 is displayed. The engine is essentially getting a "run" and "stop" signal back and forth due to the fault which shows up as a short. To my knowledge when it looses a solenoid coil on the transmission it kills the engine. So it seems I have some type of intermittent open signal going to the EDC telling the computer it lost a coil on the transmission. I have gone through the solenoid coils on the transmission and they are both good, even swapped them with the other motor, with no change. Swapped the computers between both engines, no change. Checked the wiring from the solenoids back to the computer plug near the fuel injection pump, resistance checks looked good. checked the harness plug going back to the solenoids and it was full of corrosion so removed the harness and butt spliced the wires together for now just to rule it out as a short or open. Is there anything between the solenoids and computer I could be missing? Relay? fuses? other connections? The resistance checks I did were with the engine off/ ignition off. Does the key switch and EDC need to be on for those checks? Is there another module on these engines for this EDC system? Sometimes the engine can run for 2 hours with no issue then the problem appears, other times it runs 5 min at the dock and the problem appears. And sometimes will run it at the dock for 30 min or more and I don't see the problem. Ive wiggled harnesses and connectors and cant seem to force the engine into this fault. It just happens randomly.

Any help would be appreciated.

-Rob
 
Is there a micro switch in the throttle body at the helm to signal the stick(s) are in Neutral ?
Which the ECU needs to see before it’s allows the engine to run / start ?

If there is worth checking , as if it’s got an intermittent fault ( usual suspects corrosion etc ) it may be telling the ECU the wrong info .
So if there’s a break there intermittently that signal stops = sputtering or when completely open = stops .
 
I think Portofino is right.

I'm pretty sure the electronic EDC control head unit has switches / sensors that tell the the ECU when it's in neutral, ahead or astern. The ECU then sends the relevant signal to the trans solenoids to perform the action.

Do you have a wiring diagram or schematic for the system?
Andy
 
The engine won’t start if the plugs are off the forward or reverse solenoid as it can’t see a circuit .

Try a lever calibration .
If it’s a flybridge boat check the station unit that stores the upper helm control position setting.
Disconnect the SPM unit if it has one, you can run it without this fitted, again if it’s a twin helm boat .
Has the engine wiring harness had the modified loom where the 2. 8 pin plugs are, I’ve found them now with bad connectors corroded, chop of the connector and fit a new one , this is the wire to the solenoid so could explain your 5-4 error code .

Check the system for more codes you may have them .
 
Hi, without looking at the boat it’s almost impossible to say for certain what it is. If I remember correctly code 5.3/4 is a transmission connection failure. I have seen three times this summer the Bosch electronic diesel control unit fail and produce intermittent and very strange faults similar to the ones you described. It seems that the unit does not fail instantly and customers reported being able to use the boat initially and ending up with the boat non starting with a stuck gear actuator (and I have had them start in gear which was alarming). Just run the usual voltage drop tests and relay runs. Like I said the symptoms are very strange and seemingly unrelated to the edc unit (it’s the grey box attached on the filter housing). If you can get hold of an equivalent unit leave the old one on and just connect the new one on the clip, it will run rough due to having no manifold vacuum line but you will instantly know because the faults will be gone. Mechanics will usually change this last and perform a full diagnostic on the rest of the system because it’s a 3 grand part 3.200 euros here. So it’s a bit of a risk to start out with it. These have been on two 44’s and a kad 300 but it’s the same system. I have seen this trip experienced guys up a lot. I work at the main distributor/dealer in the area of the world I am in and I have seen engines come in on pallets out of the boat freighted to us because it’s was very difficult to diagnose.
 
hm, that is a good point. I am not sure about the micro switches but you may be right. Although if it did not see the engine in neutral wouldn't that prevent the engine from starting in the first place? It will start up every time. Never had it crank over without starting. Corrosion somewhere I agree.
 
I do not have the wiring schematic for the engine or control system. I have been trying to get the prints to help me troubleshoot this. The engine does shift properly, fwd, neutral, rev, back to neutral without issue. but maybe it could be loosing the signal for the position and the default is a shutdown for safety. I will look into that
 
single helm unit. I am not sure the boat had the wiring harness modification. Do you have any more info on this harness modification? I am familiar with those two 8 pin connectors by the fuel injection pump. I will pull them apart and see if we have corrosion. I did a resistance check through them but maybe I missed something. This is the only fault code popping up.
 
I swapped the EDU unit attached to the filter housing with the other engine, no change. I think i will need the schematics to continue the checks, right not i'm am kind of shooting blind. I went through the checks on the transmission coils up to the EDC plug, all normal resistances. Even wiggled the harnesses while taking the measurements. No change. I will keep digging.
 
update for anyone curious or following this thread. I figured out the issue. Unfortunately I am unable to upload an imagine for some reason.. maybe the file needs to be formatted for the forum? But anyway, opening up the black box near the fuel injection pump on the port side of the motor there are three relays. The bottom one has a red wire that goes to the relay and has a 7.5A fuse in a separate fuse holder (you will see dangling loose inside the cover). This spade connector in the relay board was loose. I pinched the spade connector to bite onto the relay tighter and now the fault is gone. Not really satisfied with this as a permanent fix though. It seems like that relay board needs to get changed out or re-pinned. anyone know if this is a common problem?
 
rpfletcher2 said:
update for anyone curious or following this thread. I figured out the issue. Unfortunately I am unable to upload an imagine for some reason.. maybe the file needs to be formatted for the forum? But anyway, opening up the black box near the fuel injection pump on the port side of the motor there are three relays. The bottom one has a red wire that goes to the relay and has a 7.5A fuse in a separate fuse holder (you will see dangling loose inside the cover). This spade connector in the relay board was loose. I pinched the spade connector to bite onto the relay tighter and now the fault is gone. Not really satisfied with this as a permanent fix though. It seems like that relay board needs to get changed out or re-pinned. anyone know if this is a common problem?
Click to expand...
That’s the edc fuse so the loose connection may be the issue though you don’t normally get the 5.4 fault code when it blows the engine won’t start
 
You must log in or register to reply here.

Share this page

Top