Volvo Penta D2 MDI failure - what are the typical symptoms?

[Samwise2111]

I'm above the artic circle in Norway at the moment, with a failed MDI

Nice. Uhm, not the failed MDI of course.
I am on 63 degrees north right now.

Do you know why it failed? Does anything smell burnt? Have you opened the box and checked the PCB?
I am still trying to get my hands on another MDI that failed without obvious symptoms in order to continue the research. (We will also repair the unit, if possible.)
Woodstock37s appears to have got his fixed. At least he hasn't come back here any more...

 

[madabouttheboat]

I have purchased a push button for a byepass switch to start the engine in event of MD1 failure. However, I am not sure where exactly to fit the 2 wires.
Can anyone describe EXACTLY which terminal on the md1 unit I should connect to & where the other wire should go please
Thx

Late reply but maybe useful to others, if not you.

On the bottom there are three wires going onto three terminals. The orange wire is for the glow plugs. The red wire is main power into the MDI and the red/yellow wire is the starter wire. To bypass the MDI and get the engine running, if it won't start on the panel, you short the red and the red/yellow wires.

You can wire a momentary action switch between these two terminals and mount somewhere accessible before failure for peace of mind. This will. allow you to start the engine quickly if the MDI, and the panel start facility, fails.

You won't have any panel info, ie revs, engine hours etc, nor will the stop button work.

You will need to stop the engine by either cutting fuel supply or manually activating the stop lever.

The wires to the temporary action switch do not need to be huge. Maybe 2.5mm2.

If I had an MDI on my boat, I would not go to sea without this arrangement in place. Trying to short the two wires without a switch and with the MDI mounted will usually be quite tricky, sometimes almost impossible without removing the MDI unit first, which is not something you want to be doing out at sea or when trying to enter a harbour..

 

[Daydream believer]

So does one not need TWO intermittent switches. One to turn the starter over & one to warm the glow plugs.
If so , how does one wire the second switch to excite the glow plugs?
I have put the switch in to start the engine & that turns the engine over. I have not gone further than just a very short burst.

 

[madabouttheboat]

So does one not need TWO intermittent switches. One to turn the starter over & one to warm the glow plugs.
If so , how does one wire the second switch to excite the glow plugs?
I have put the switch in to start the engine & that turns the engine over. I have not gone further than just a very short burst.

Glow plugs are not needed in my experience.

 

[Samwise2111]

So does one not need TWO intermittent switches. One to turn the starter over & one to warm the glow plugs.
If so , how does one wire the second switch to excite the glow plugs?

In the Med you won't need the glow plugs. Maybe you will need them where it is really cold - if these are the conditions you like for sailing. ;-)
I use an ignition lock like this:
6JB 003 959-001 - Ignition-/Starter Switch
and switch them on anyway, for the sake of good order.
Please have a look at the circuit diagram I posted above.

 

[Samwise2111]

Will check the Unit by re-installing it, again. and after that re-check the PCBs.

@woodstock37s: Did you manage to get your MDI box repaired?

 

[Daydream believer]

In the Med you won't need the glow plugs. Maybe you will need them where it is really cold - if these are the conditions you like for sailing. ;-)

Please have a look at the circuit diagram I posted above.

Unfortunately there are two issues:-
I absolutely love sailing in the UK & Near Xchannel- What is not to like?
Then 2- Your sketch is total gobblegook to me.
Is it not posible just to have another push button for the glows - a bit like my old volvo- then I push the starter push button?

 

[Samwise2111]

Is it not posible just to have another push button for the glows - a bit like my old volvo- then I push the starter push button?

Yes, no problem at all. A push button to trigger the relay is fine. Just don't use a latching push button. ;-)

 

[Daydream believer]

Yes, no problem at all. A push button to trigger the relay is fine. Just don't use a latching push button. ;-)

This is like getting blood out of a stone
So where does one take those 2 wires to?

 

[Samwise2111]

So where does one take those wires to?

Does this help?

 

[madabouttheboat]

This is like getting blood out of a stone
So where does one take those 2 wires to?

Between the red and the orange, but unless you are sailing when there is frost and snow I don't think you'll need need them. Even then, I'm not convinced they are needed on the D1

 

[Daydream believer]

Between the red and the orange, but unless you are sailing when there is frost and snow I don't think you'll need need them. Even then, I'm not convinced they are needed on the D1

Thanks for that.
But the normal unit- when working as intended- does go through a cycle of using the glows. So they must have a use.
I know that my earlier MD2020 would not start if the glow relay failed.- which it did a number of times during its 5000 hour life- I accept that being a different engine of course, but it was always the same from new.

 

[madabouttheboat]

Thanks for that.
But the normal unit- when working as intended- does go through a cycle of using the glows. So they must have a use.
I know that my earlier MD2020 would not start if the glow relay failed.- which it did a number of times during its 5000 hour life- I accept that being a different engine of course, but it was always the same from new.

If you wanted to be clever you could wire this through a separate ignition switch mounted somewhere outside of the engine box and easily accessible with a spring back position on the anticlockwise turn of the key to arm the glow plugs and a spring forward clockwise for engine start. Just don't wire anything to the 'ignition on' terminal.

 

[Daydream believer]

If you wanted to be clever you could wire this through a separate ignition switch mounted somewhere outside of the engine box and easily accessible with a spring back position on the anticlockwise turn of the key to arm the glow plugs and a spring forward clockwise for engine start. Just don't wire anything to the 'ignition on' terminal.

I am far from a bright spark. A couple of press for contact switches will do perfectly. Bear in mid that One would not actually expect to use them except in exceptional circumstances. So it is not an everyday event - Says he with fingers crossed

 

[allendick]

> On the bottom there are three wires going onto three terminals. The orange wire is for the glow plugs. The red wire is main power into the MDI and the red/yellow wire is the starter wire. To bypass the MDI and get the engine running, if it won't start on the panel, you short the red and the red/yellow wires.

In a pinch a coin of your favourite currency will jump the red and orange, then the red and red/yellow terminals on the MDI. No need for anything fancy.

And, yes, a D2-75 (mine anyhow) will crank convincingly, but not start without some glow first.

 

[Daydream believer]

> On the bottom there are three wires going onto three terminals. The orange wire is for the glow plugs. The red wire is main power into the MDI and the red/yellow wire is the starter wire. To bypass the MDI and get the engine running, if it won't start on the panel, you short the red and the red/yellow wires.

In a pinch a coin of your favourite currency will jump the red and orange, then the red and red/yellow terminals on the MDI. No need for anything fancy.

And, yes, a D2-75 (mine anyhow) will crank convincingly, but not start without some glow first.

So one really needs 2 momentary switches. That way one can give it 10 seconds on the glow side & then press the starter switch.
I have installed a starter switch & purchased another momentary switch ready to install. I have been told that as my D1-30 is almost new, it will not need the glow.
When I am able to get aboard at the start of the season I will test that theory.

 

[Slowtack]

I connected two spring loaded starter buttons as per one of madabouttheboat's posts above... Available from most car accessory shops....

 

[Beneteau381]

I connected two spring loaded starter buttons as per one of madabouttheboat's posts above... Available from most car accessory shops....

Volvo Penta dealer from Portimao fitted a custom push button to my mates under guarantee engine! They fitted three boxes! I made enough noise with him that VP sent too techs from Sweden with a computer and Scope to confirm what I had seen on my multimeter, a flicker as the engine was shut down. Turned out that the relay operating coils were giving flicks of voltage, much as an ignition coil does, when it was switched off. This was destroying the boxes. The former Editor from PBO at the time got it. flyback diodes we’re the answer and that’s what the Swede techs fitted to one relay to fix the issue completely.

 

[Slowtack]

I read elsewhere that the culprit is a back emf from the fuel stop solenoid.... Have you a spec for the diodes please?... And where fitted?

 

[Baggywrinkle]

My MDI failed yesterday. Symptoms were the control panel beeping and switching on/off randomly ... it's been doing this on and off for a few months. I disconnected it to shut it up. When I reconnected everything the control panel was dead and none of the buttons worked. Had to short to the starter solenoid and use the stop lever today to move the boat. Part no is 23195776. Not a happy bunny.