Volvo Penta Di-30 Difficult Starting

[DameGravey]

My D1-30 suddenly decided that it would become a pain to start.

The first indication was after a twilight race a few weeks ago I started the engine, it idled poorly then stalled, started again same thing, a third time I gave it some throttle, it started but would not come off idle, ran as with it was on only 1 cylinder then eventually came good. Note that my normal starting procedure involves about 10 seconds of glow plug before cranking, as per the operators manual.

It was like that before the solution was found yesterday. I am writing about this because try as I might I could not find a reasonable description of my issue even after a number of different google searches and I thought that it may provide an answer for someone that has the same problem.

Googling and talking to a number of folk could only come up with the evergreens:
Water in the Fuel.
Dirty fuel.
Fuel block.
Blocked Air filter.
Further discussion went along the line that if for any of these reasons the engine was difficult to start then run roughly, why would it come good after a few minutes. Could it be that a warm engine could handle these difficulties better than a cold engine? Could it be the glow plugs?

Now the filters (all of them) are less than 50 hours old and while I run the fuel tank fairly low for racing I am paranoid about cleanliness and water, Fuel Doctor is used liberally and fuel is sourced from known high volume outlets. (Yes even in Sydney that can be an issue) We were back again at the Glow plugs, but why would all 3 fail at the same time?

The Glow plug indicator would light up on the instrument panel which sort of threw me off that line of thought, then a perusal of the wiring diagram in the workshop manual revealed that the instrument panel indicator light is illuminated on the same circuit as the low current relay coil activation. Not the high current switched circuit.

Yesterday a check of the two relays in the little black box on the side of the engine revealed one was open circuit in the coils, fortunately these relays a standard Bosch mini relays that are pretty universally and inexpensively available, replaced and problem solved.

As I said this is hopefully to assist anyone that suffers the same and cannot find an answer.

It is also interesting to note that the DI-30 loves its glow plugs, even in Sydney with the current water temperatures around 20 c and ambient air temperatures in the mid 20's it won't start properly without a 10 second fix of pre-heat.

[Lepke]

Your problem sounds like a fuel problem but could be more. Remotely, air in the fuel. A diesel needs 3 things to start. Fuel, temperature and compression. Most diesels compress the air about 20 times. That usually creates enough heat to raise the air temperature to well above the ignition temperature in weather down to about freezing. If you have to use glow plugs all the time, you're loosing compression. Either the rings, valves, bad head gasket or the engine is turning too slow.
To troubleshoot the injectors, after the engine starts but is not firing on all cylinders, loosen the nut on the top of an injector. The loss in pressure will keep that cylinder from firing. (Have a rag handy) If the engine runs rougher or dies, that was a good injector. If no change – possible bad injector. After going thru all three, move the injectors and see if the problem moves. If it does move – bad injector. If it doesn't move, possible bad injector pump, bad rings, bad valve or bad head gasket.
Sailboats seem to have a lot of fuel problems. I think that's because you refuel infrequently. You should use a fuel conditioner/biocide every fueling. Newly refined diesel comes with additives that stabilize the fuel, kill organisms and expel water. But they only last a couple months. If you leave your tanks low, you're drawing fuel from where water normally collects. Especially in a tank left near empty.
I'm near 70 and been on the water most of my life. My current boat holds 2000 gallons of fuel. I've never had a fuel contamination problem on this boat or any other. I use a fuel conditioner every time I fuel or if the fuel sits. I use a conditioner that also contains elements that make for a hotter, cleaner burn. That gives me better mileage and the real cost of the additive is zero.