KAD32 Help required!

[RIN]

I hope its nothing I have done.

I fitted a relay to the red/purple wire behind the port helm control panel (through an inline fuse) so the instruments on the helm switch on when the engine is started. I turned on the ignition and the log (only device attached so far) lit up ok

Tried to start the port engine and nothing - no sound from solenoid but a large voltage drop visible on the control panel.

Removed fuse to Solenoid I had installed and tried again - still nothing. Tried stbd engine it started fine.

Batteries are all in good condition.

Not sure what to do so took the control box relay from the port engine smeared with Vaseline and put it in the stbd engine. This worked fine. Put the stbd relay into the port engine after Vaseline treatment and it now decided to start.

Went over to the IOW Thursday but when leaving IOW, the port engine would not start. Opened the control box, waggled the relay - nothing. took off the multi pin loom and squirted WD40 - nothing. Opened the small plastic connector inside the control box (which leads to a compressor sensor), sprayed WD40 and the engine started.

Got back to the Hamble, tried port engine again - would not start.

Tried all of the above again, repeatedly for 3/4 hour - nothing.

Took out the relay again from the port control box cleaned up terminals and put back in - Engine started.


Now I don't think the relay I put behind the helm control panel caused this but I stand to be corrected.

It sounds like a dodgy connection in the control box but where?

If there is a dodgy connection in the control box, why would the helm show an immediate voltage drop?Could it be a short circuit rather than a bad connection?

So really what action can I take to pin this problem down

Any suggestions greatly appreciated

 

[AdeOlly]

If you're getting a big voltage drop then there must be a short somwhere.

For starters I'd try swapping the control box relay(s) from the working engine to see if that made any difference. If not then I'd remove the relay you fitted behind the helm to validate it defo isn't that, though if wired through a fuse it seems somewhat unlikely. I'd also check connections to the starter motor are intact and dry.

 

[[2068]]

"Big voltage drop" can be if you try and start an engine in gear.

Check that the little switches that check you aren't trying to start in gear haven't been disturbed or gone sticky. If waggling the control levers around a bit "fixes" the problem, you know you're on the right lines. The little switches are in the throttle/gear lever assembly.

dv.

 

[aquatom]

The big voltage drop may not be a big voltage drop. Most of the Volvo ignition switches cut the power to the instruments when the key is turned to start.

Try squeezing up the spade connectors in the start relay plug and check the 16 pin connector.

 

[gimmesunshine]

when you try to start the engine does anything happen, does the starter solenoid operate...?
if it does then you could have knackered commuatator segments
or the fault could lie with the ignition key, easy to swap over, worth a try

 

[RIN]

when you try to start the engine does anything happen, does the starter solenoid operate...?
if it does then you could have knackered commuatator segments
or the fault could lie with the ignition key, easy to swap over, worth a try

Nothing happens at all. I have put my hand on the solenoid whilst the ignition switch was turned and I felt nothing.

I was interested in Aquatom's comment about the voltage drop as that was that was the bit that was making me think there was a short somewhere. But if the ignition switch cuts the power to the instruments, then this might still be a duff connection or wire somewhere either in the relay socket or the 16 pin loom. But I am still not sure how to progress it.

 

[aquatom]

How did you connect the wire behind the dash?

 

[dragoon]

I saw something similar myself once with our Volvos on board. I wired in lights for the ignition circuit (so I could see if the batteries were charging). After I put them in the circuit, the engine wouldn't start (absolutely nothing happened when turning the switch.

My conclusion was that the indicator circuit actually provided the power for the start relay. I suspect this to prevent the starter being engaged when the engine is running. With the lamps in place, there was too bigger voltage drop to actuate the relays.

When I removed the lamps, everything worked again. You may be facing a very similar scenario.

I hope this helps.

Cheers,
Paul

 

[RIN]

How did you connect the wire behind the dash?

I scraped off some insulation on the red/blue wire from the ignition switch connected one end of an inline fuse to that via soldering, the other to the new relay. Connected the -ve straight to the new relay.

I also fused the new wiring that I put in to give power from the new relay to the log.

The easy check was to remove the inline fuse to the new relay and I still get the failure to start.

Its only seems to start after I have moved something in the control box

 

[volvopaul]

Sounds like a bad connection in the 16pin plug to me, or you may have dislodged something at the ignition switch, connect a multimeter to the red and white wire out from the ignition switch turn key to start if 12v there test then at start relay,if power there test at starter sol, if power there its starter.

Do both engines start from same battery, if so then not batter but maybe bad earth to engine, maybe earth is linked from 1 engine to the next with 1 cable from battery, check that out too.

 

[RIN]

Both engines do start from the same battery.

One thing - should the stater relay be pushed right in so it is flush with the socket, or should you be able to see a little bit of the blades? Not on the boat now but I do recall when I pushed the relay back in that I did see a little bit of the blades

 

[Elza_Skip]

Hi,

I have had something similar on my single installation.

Firstly I thought it was the microswitch in the throttle to confirm neutral. Simple switch but costs a fortune from Volvo so got one from RS.

Sypmtom was all power cut from instruments so looked like a short or jammed solenoid but in fact was the switch bypassing all power. No click from the solenoid and was annoyingly random

In the end this did not fix it but it seemed in the end to be slightly corroded connectors behind the ignition switch where the loop breaks out to go the the neutral relay. Cleaning these fixed it.

Then last year a new similar problem, but now I did hear the relay click. Oddly the voltmeter would start reading 13v then after trying to start the engine would drop right down and not recover. This turned out to be the master battery switch. If I opperated it a couple of times all was fine. It turned out there was about 0.5 ohm resistances which as soon as you tried to draw the larger current for the starter would then (IMHO) create heat and go open circuit. A new battery switch fixed this and when I took the old one apart I could see some corrosion on the contacts.

Good luck