Diesel stop solenoid problem

[KAL]

I have a Volvo Penta MD22 inboard diesel which was serviced by a Volvo Penta dealer a couple of weeks ago. He went to fire up the engine after the service and found that it would no longer stop when switched off at the ignition. We confirmed that the ignition switch seems to be functional (voltage sent to solenoid) so he diagnosed a faulty solenoid. Quoted cost for the solenoid alone was (wait for it) £192.84 + VAT. It's a Bosch EPVE injection pump, and I found a new solenoid online for £8.40, which I fitted. Engine starts fine but still will not switch off. I've confirmed that the solenoid is working (removed it and checked it operated when grounded). The old one also works! What next? Is anyone able to help with advice? Many thanks.

 

[DinghyMan]

Take your email out of the post as it will get harvested by spammers.

 

[scottie]

you will need to look at the wiring manual as this engine has a hybrid earth system
their are 2 solenoid and pos a relay as well

there is also a manual emergency stop on the pump which can be remotely opperatted
suggest that you start at the relay and trace what is and is not working

 

[oldsaltoz]

Sounds like crud in the shut off valve preventing it from closing tight.

 

[lyc]

We had same problem on a TAMD71B and it was the fuse holder to the stop solenoid that had a hairline crack, only found upon very close inspection!

 

[KAL]

Thanks for the email warning. Have taken out the link.

 

[KAL]

No crud apparent in the pump body, but when I removed the newly-fitted solenoid, it came out with a spring attached to the end of the plunger that could only have come off the old solenoid. I replaced it as it must have been there before the problem arose. The wierd thing is that I can't feel any clicking when I put a finger on the solenoid while it's operating. Am I right in thinking that the solenoid should get voltage when the ignition switch is turned to 'kill'? The solenoid gets 0v at all other times.

 

[KAL]

Thanks lc. Was it the fuse itself that was cracked and non-viable or the holder?

 

[scottie]

the earth for the solenoid on the pump is through the engine body but unless the earth return solenoid is opperating you can not complete the circuit

 

[KAL]

Thanks Scottie. If I'm managing to test the solenoid by earthing it on a bare metal part of the engine (and it's working) does that mean that the earth return solenoid is OK? Is there any way to test it?

 

[VicS]

[ QUOTE ]
unless the earth return solenoid is opperating you can not complete the circuit

[/ QUOTE ] But the earth return solenod is only energised, in parallel with the glowplug relay, during preheating and starting. So that can't come into the reckoning.

If the solenod is definitely operating if held against the engine while the key is turned to the stop position (yes that is when it is energised) then that proves the electrics are OK but I would have thought you'd feel and hear a click. If you can see the plunger move when the key is turned then fair enough.

I am not altogether surprised that you did not get a spring with the new one. I did not when I replaced the solenoid on the car (the spring goes inside that because it turns the fuel on when energised and the spring pushes it shut when the key is tuned off).

 

[KAL]

Hi Vic. I suppose I just don't understand how the solenoid is actually controlling the fuel supply. When it's activated, the solenoid pulls the plunger back into itself. I'd have thought it would do the opposite to cut off the fuel. I haven't seen an exploded view of the fuel injection pump though. At least you're confirming that the spring inside the pump body is necessary. Still, apart from the click of a solenoid in the main electrics box at the back of the engine bay, there's no feel of a click from the stop solenoid.

 

[beserksail]

Had same problem with a Bukh engine and on closing throttle the tickover was too fast, backing off cable solved it.

 

[VicS]

[ QUOTE ]
I suppose I just don't understand how the solenoid is actually controlling the fuel supply.

[/ QUOTE ] Now I don't either. I assumed it would work the same way as you did. I cant find any info on it in any of the manuals. I take it that you have compared the operation of the new one with the old one.

On the car it simply opens when energised and closes when the ignition is switched off.

 

[rhumlady]

Silly question but seeing as how the solenoid works when touched to the engine case (earth) while disconnected, could you not have a bad connection to earth when it is in it's working position?

 

[Hoolie]

Maybe you're already sorted, but I had exactly the same problem on our Perkins M50 (same engine). As has been pointed out by others the earth is isolated on this engine and is connected briefly when glowplugs or stop are activated. There is a heavy fuse/connector from the earth relay hanging free in the wiring loom and on our engine the cable had become brittle due to vibration and broken. Remade the connection and all was fine!