Engine not turning off [Volvo Penta D2-40B]

[sailor_leo]

Since yesterday my Diesel engine is not turning off anymore when I push the "stop" button on the EVC and I have to turn it off directly on the engine.

Any ideas how to trace the defective component?



Thank you!


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[donradcliffe]

When you push the stop button, it is supposed to close a circuit and apply 12v to the stop solenoid, which pulls a plunger and stops the engine. Have someone help you and push the button while you are measuring the voltage across the solenoid terminals (the engine circuit should be on, but the engine doesn't have to be running. If the solenoid doesn't move and you have 12v across the terminals, its a solenoid problem. If you don't see the voltage jump up to 12v when the stop button is pushed, you have a wiring/switch problem.

[DougR]

There are three components to the stop system, not including the wiring. These are:
- the EVC button panel
- the MDI box mounted on the side of the exhaust manifold
- the stop solenoid mounted on the rear side of the high pressure injection pump

When the stop button is pushed, 12 volts is applied to the purple wire running from the button panel to the MDI box where it activates an internal relay. The relay in turn activates the stop solenoid by applying 12 volts to the purple wire which runs from the MDI box thru a two wire connector to the stop solenoid.

When the solenoid is energized a plunger extends from the relay and pushes the injection pump fuel rack to the " no fuel" position stopping the engine.

Most of the system can be checked fairly easily. Starting at the solenoid, unplug the two wire connector and unscrew the solenoid from the back of the injection
pump. With the solenoid removed you should see the plunger either flush with the body of the solenoid or protruding slightly. Momentarily connect the wiring to a 12v source...black is ground and purple is positive. When energized the plunger should extend about 17-18 mm and then spring load back into the body of the solenoid when the voltage is disconnected. If the solenoid reacts properly, check the wiring harness from the two wire connector back to the MDI box for any opens or shorts.

Next check the EVC button panel. Disconnect the panel from the system. The purple wire in the harness controls the stop function. You need to use an ohm meter to see if the stop button is functioning. Normally the circuit is open but pushing the stop button should close the circuit between the purple wire and the black wire. If this checks good, check the wiring harness between the button panel and the MDI box for any shorts or opens.

Unfortunately, checking the MDI box requires a special "break out box" to check functions, but in any event the relays within the box are not serviceable. If everything else checks out good the problem is almost certainly within the MDI box and it will have to be replaced.

DougR

[sailor_leo]

Thank you very much for the detailed description.

To turn the engine off using the lever on the engine body is exactly the same as pushing the button, right? (Both will cut the diesel)


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[DougR]

Yes, using the external lever to stop the engine is exactly the same as using the electrical stop button. Both actions move the injection pump to the "no fuel" position. Older series of the engines didn't have the electric solenoid and relied on the mechanical lever exclusively.

You could attach a simple pull cable to the lever so that the engine could be stopped remotely if you want, just as was done in the past.

DougR

[barnakiel]

Apply voltage directly to the solenoid. Listen for a click. If the solenoid clicks, then check the button with a bulb.


b.

[sailor_leo]

Now the on/off button (top left) stopped working too. So I guess the MDI box has troubles, since the "stop button" itself is working.

Is there a way to start the engine without using this panel?


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[sailor_leo]

Good news, everything is working again. It was a loose contact on the connectors on the mdi box.

But I still am very interested in how to turn the engine on without the EVC.


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[DougR]

All of the current Volvo Penta engines from the D1-13 thru the D2-75 are mechanically controlled engines based on the Perkins /ISM blocks.

The engines are fitted with a translator box ( MDI box) which controls the start/ stop functions, engine alarms, communicates with the instruments via CAN bus, receives and distributes info from the control panel, etc. This makes the engine appear to be complicated, but at heart they are simple engines. They have totally mechanical fuel systems that require no electricity to run.

In the event of a failure of the MDI system the engine can be started with a "remote" starter button which energizes the starter solenoid, just like most other mechanical engines. The stop solenoid is an " energize to stop" function so an electrical failure normally won't kill the engine, and the engine can always be shutdown with its mechanical stop lever.

Hope this helps.
DougR

[sailor_leo]

It surely helps a lot Doug. Thank you very much!


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[Eucherio]

I'm experiencing the same problem, but it happens afer a few minutes when the engine gets hot.

I unscrewed the black box and left is hanging. the engine started and stopped after 10 seconds, now it doesn't start anymore, even when cold.

my engine is 150 hours old.

[SY_Josefine]

I had problems starting my engine. Sometimes it worked, sometimes not. Finally I opened the control panel and the buttons are supposed to press against the electronic board but there was oxidation. Cleaned the board with alcohol, and voila - works as a charm.

[yuridds]

I have the same stopping problem on D6. Emergency button on engine would not work.
Is it the same system for engine stop as on D2 or different?
Where stop solenoid is located?

[Kiwi Dave]

Hi

I had a problem last year - it proved to be a disconnected wire. But I had to bypass the MDI Box until I figured it out

https://www.youtube.com/watch?v=jW47...5Uv2he&index=2

[yuridds]

Thanks for video, but I have Penta D6 370 and it completely different engine and layout.
I dont have lever or box like this. if anyone has D6 engine stop issue experience and how to diagnose it, please post reply. Stop engine problem is intermittent on my boat and it's only on starboard engine. One time it's stops another is not.