TMD22A - Stop Solenoid

boatone

boatone

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Just a few cables from Boulters Lock
www.tmba.org.uk
Seem to remember a thread some time back about stop solenoids and not being able to switch off engine - think skipper stu and VicS may have been involved amongst others.

I now have same problem - starb'd engine will not switch off. I have rigged a temporary stop cable to the lever on the pump but need to sort the solenoid or electrics.

Volvo solenoid is over £200 but seem to remember mention of a VW Golf item being suitable at much lower bucks.

Can anyone identify the alternative part for me please? Difficult to get down into engine area to check all the electrics as cabin furniture has to be removed. Would hate to get down there and find it actually is the solenoid and then having to wait to obtain the replacement!
 
boatone said:
Volvo solenoid is over £200 but seem to remember mention of a VW Golf item being suitable at much lower bucks.

Can anyone identify the alternative part for me please? Difficult to get down into engine area to check all the electrics as cabin furniture has to be removed. Would hate to get down there and find it actually is the solenoid and then having to wait to obtain the replacement!
Click to expand...

But wouldn't it be annoying to buy a new solenoid and then find that it was only a poor connection? I'd have a look first.
 
pvb said:
But wouldn't it be annoying to buy a new solenoid and then find that it was only a poor connection? I'd have a look first.
Click to expand...

Cost of a second visit by engineer to complete if solenoid IS faulty has to be considered, as well as not being able to use the boat while cabin dismantled !
Either way, if it is the solenoid i still need the information I am looking for.
 
most marine diesel pump stop solenoids are wired so that when 12volts goes to the solenoid it stops the engine. The ones on cars work the opposite way round, they have a 12 volt feed as soon as you turn the ignition on, then when the voltage is removed (you switch ignition off) the engine stops. You can try pulling the connection off the stop solenoid on your port engine, and if it still starts and runs then you have the marine solenoid that requires 12volts to stop the engine, in which case a car one will not work(your engine would not start!). They are wired like this so the engine will continue to run even if all the electrics fail, common sense in a boat really. You should be able to buy one from a diesel specialist rather than volvo, but they are a lot more expensive than car ones.
 
black mercury said:
most marine diesel pump stop solenoids are wired so that when 12volts goes to the solenoid it stops the engine.
Click to expand...
Yes, I had sussed that out but thanks for info re cars being opposite!
This afternoon I have run a separate 12volt cable directly to the solenoid spade terminal and I get a good 12.6 volts between terminal and engine block earth but solenoid not being activated so I guess it's duff.
Interestingly , the supply from the ignition switch is only giving just 12volts so guess that needs looking into as well.
 
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I believe that you require an earth connection to be made as well
Checking if you get 12v on the solenoid lead would be wise
It's a b****** electrical system original engine based parts are temporary earth return other parts insulated return!
 
scottie said:
I believe that you require an earth connection to be made as well
Checking if you get 12v on the solenoid lead would be wise
It's a b****** electrical system original engine based parts are temporary earth return other parts insulated return!
Click to expand...

I think the wiring diagram indicates it's earthed through the engine block, rather than by a separate insulated return.
 
pvb said:
I think the wiring diagram indicates it's earthed through the engine block, rather than by a separate insulated return.
Click to expand...

Yes but the block is isolated from DC negative,

The bottom relay in the diagram closes to connect the DC negative to the block during "stop" (and "preheat") It is energised via the diodes in the wiring loom from the respective connections on the key switch

So Scottie is right.
 
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VicS said:
Yes but the block is isolated from DC negative,

The bottom relay in the diagram closes to connect the DC negative to the block during "stop" (and "preheat") It is energised via the diodes in the wiring loom from the respective connections on the key switch

So Scottie is right.
Click to expand...

In that case, the OP's wasting his time applying 12v to the solenoid unless he also connects the engine to negative. The fault, as I said earlier, might only be a poor connection (or a faulty relay perhaps).
 
Now I am getting thoroughly confused. Are we saying the 12v measured between the solenoid and the block is mo indicator that the solemoid itself is faulty?
I can hear the relays operating on both engines but whatever function they perform was not live when i tried the direct 12v to the solenoid terminal. I cannot feel or hear the solenoid itself actuating.
 
scottie said:
I believe that you require an earth connection to be made as well
Checking if you get 12v on the solenoid lead would be wise
It's a b****** electrical system original engine based parts are temporary earth return other parts insulated return!
Click to expand...
Checking for power on the lead to the solenoid would be first step if power is ther then checking the earthing would be next step
Looking at previous thread would give some more thoughts on md22 problems
 
scottie said:
Checking for power on the lead to the solenoid would be first step if power is ther then checking the earthing would be next step ...
Click to expand...
Get two leads, one to each battery terminal. With the engine running, connect the positive to the solenoid, the other to the block. If it stops, find out which of the two isn't working. If not, solenoid is faulty.
 
nigelmercier said:
Get two leads, one to each battery terminal. With the engine running, connect the positive to the solenoid, the other to the block. If it stops, find out which of the two isn't working. If not, solenoid is faulty.
Click to expand...
Exactly what I had decide to do, Nigel, and I did as soon as I woke up this morning!
Result - the solenoid is OK!
I connected direct 12v+ to the solenoid and also prepared a 12v- lead connected to an accessible -ve terminal block. Ensured clean 12v available across the two.
Started engine and touched -ve lead to engine block- engine immediately stopped so solenoid working ok.
Then tried switch off position with key which should apply earth connection. Relay could be heard but engine continued running so earth clearly not activated.
Finally tried using switch in conjunction with direct -12v and engine stopped so it looks as if +12v to solenoid via switch is ok and it is the earth side where the problem lies.
 
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