Diesel dies on startup

[yttrill]

Anyone like to take a stab at this one: diesel engine, fires up then immediately dies. Retry several times, it may run for 1-3 seconds then stop. When it finally goes it is up and down in bursts before stabilising. It runs well after operating for about 15 seconds. It starts properly if given some throttle. If stopped it restarts properly after 60 seconds operation and 60 seconds delay but the starting problem reappears after 5 minutes.

I had this problem before and it was a leaky air vent in the fuel filter. I have two fuel supplies, one in the keel and one at deck height. A serious leak will result in air in the lines if using the keel tank, and fuel leaking out if using the higher one.

I had a visible air problem before but now everything is tightened up I don't think the problem is air. I also found the engine very low on oil and topped it up.

Could be that the lack of lubrication on startup is stopping the engine. After operating for a short time the engine is better lubricated and so starts properly.

This behaviour only appear recently after a 50 hours operation. The last service was about 100 hours operation prior.

The engine is an old Nissan 4 cylinder ED33 of the kind found in a Nissan Patrol, it is keep cooled (no salt water involved).

[MBWhite]

It sounds to me like you still have some sort of air leak in your intake line somewhere. The scenario I visualize is when the engine is off, air bleeds back into the line so the fuel goes back into the tank. Then the engine starts with the residual fuel in the injector pump until it runs out and dies, then you have to crank it until the injector pump is primed again.

If you have a manual priming lever on the engine mounted fuel pump, try pumping that for a bit before the initial start and see if that makes the problem go away. If it does, then you have narrowed down where you need to inspect to find the actual cause of your problem.

If you do not have a manual priming lever on your pump, you can plumb in an inline electrical pump and just let that run for 20 seconds or so to get the same effect.

[Arthur Garfield]

Hi,
Are you in US? Australia?
Not common engine in US.

Ok,Obviously,this is fuel side issue.
You do know your fuel supply systems are fubar and should be entirely rectified in robust manor.
That said,it seems you will be well served by using a 5 gallon can with fuel line into your engine and see if your situ resolves.If not I would think bad mechanical lift pump or,bad seals in injection pump.Does this show leakages?


All the Best

[yttrill]

Originally Posted by MBWhite

If you have a manual priming lever on the engine mounted fuel pump, try pumping that for a bit before the initial start and see if that makes the problem go away. If it does, then you have narrowed down where you need to inspect to find the actual cause of your problem.

I do have a manual priming pump on the second filter, and also a second fuel supply which is above the engine (the keel tank fuel supply does not have a lift pump, the injector pump has to lift the fuel).

With the upper tank selected, an air leak shouldn't be possible: if there is a sealing problem fuel should leak out, rather than air in. Using that tank makes no difference.

Of course the manual priming pump won't expel any air unless the air vent on the filter is open (and the air is in the top of the filter). I have just replaced the filter cartridge, they're Delphi glass bowl type filters (really hard to assemble). The first stage fuel filter assembly is brand new.

There is some discolouration in the first fuel filter. I recently replaced the second filter cartridge after noticing some crud floating about in the fuel (the keep tank has some crap in it, nothing I can do about it at the moment).

[yttrill]

So I replaced the first stage fuel filter which had some crud in it and now it starts and doesn't stop. First test only, since engine is warm. It is running a bit rough though. I should probably change the oil and oil filter too.

It's possible as MBWhite said there is a tiny air leak and a partial blockage of the first stage fuel filter would encourage the injector pump to suck a bit more air than it would were it clean. Also when I installed the first stage assembly I had to swap the input/output port handedness, and the plugs supplied by the manufacturer were in so tight i had to put the whole thing in a vice to loosen them. I dented the filter cartridge in the process, so it may have been a tiny bit out of alignment.

Will report back on cold test. Thanks for help MBWhite!

[yttrill]

Originally Posted by Arthur Garfield

Hi,
Are you in US? Australia?
Not common engine in US.

Ok,Obviously,this is fuel side issue.
You do know your fuel supply systems are fubar and should be entirely rectified in robust manor.
That said,it seems you will be well served by using a 5 gallon can with fuel line into your engine and see if your situ resolves.If not I would think bad mechanical lift pump or,bad seals in injection pump.Does this show leakages?


All the Best

Hi, I'm in Australia, it's a Japanese engine.

The fuel filtration and management system has been rebuilt by me recently, and includes a fuel cleaning circuit. The main problem is that the keel tank is crap. It's a steel boat, fuel in the keel, but the top part of the tank is plywood fibreglassed onto the steel. This is a seriously bad idea! There has been enough crap in the tank to completely block the fuel uptake line so at the moment I just have a fuel hose thrown into the tank through the dip-stick hole (no fuel gauge, just a dip stick that doesn't reach the bottom of the tank and can't be lengthened: the tank is 6 feet deep).

There is no lift pump: the injector pump sucks the fuel out of the keel if that tank is selected. The second deck level tank gravity feeds the fuel system but it is only 30 litres and has to be refilled with jerry cans from the deck, so it is useful only for emergencies.

The injector pump recently got refurbished, but bad seals are possible. There was a lot of fuel on the engine room floor, however I have an ongoing problem with the in-keel tank leaking and I assume that is the source of the spillage. Just checked, no sign of a leak near the injector pump or injectors.

[markpierce]

Most likely there is air in the fuel line. Prime the engine using the finger/hand pump on the engine. Pump until there is little/no resistance. If the engine falters, repeat.

[Terra Nova]

Sounds like air leaks. This showcases the desirability and usefulness of a gravity-feed day tank.

[Rustic Charm]

Originally Posted by yttrill

Hi, I'm in Australia, it's a Japanese engine.

The fuel filtration and management system has been rebuilt by me recently, and includes a fuel cleaning circuit. The main problem is that the keel tank is crap. It's a steel boat, fuel in the keel, but the top part of the tank is plywood fibreglassed onto the steel. This is a seriously bad idea! There has been enough crap in the tank to completely block the fuel uptake line so at the moment I just have a fuel hose thrown into the tank through the dip-stick hole (no fuel gauge, just a dip stick that doesn't reach the bottom of the tank and can't be lengthened: the tank is 6 feet deep).

There is no lift pump: the injector pump sucks the fuel out of the keel if that tank is selected. The second deck level tank gravity feeds the fuel system but it is only 30 litres and has to be refilled with jerry cans from the deck, so it is useful only for emergencies.

The injector pump recently got refurbished, but bad seals are possible. There was a lot of fuel on the engine room floor, however I have an ongoing problem with the in-keel tank leaking and I assume that is the source of the spillage. Just checked, no sign of a leak near the injector pump or injectors.

I had this very same issue with my keel tank the first year I out it into operation. Initially it was sucking air at a joint on the tank. That was the reason for the starting well but the suddenly dying. By pass the tank to test it completely. That's what I did.

The next thing I discovered is the blocked filters which continued last year when I was in rougher weather, shaking up the tank in the heavy seas that would then go through the filters. This year I have done two things to address this. Firstly I'm using Fuel Right and secondly I've built my self a fuel cleaner /polisher. It's installed but havnt had a chance to operate it as yet.

[casual]

Has a like problem after installing a new engine .Went thru all the hoops as you have. Turned out to be a hairline crack in a 90 degree fitting from the main tank.

[Cadence]

Originally Posted by yttrill

Anyone like to take a stab at this one: diesel engine, fires up then immediately dies. Retry several times, it may run for 1-3 seconds then stop. When it finally goes it is up and down in bursts before stabilising. It runs well after operating for about 15 seconds. It starts properly if given some throttle. If stopped it restarts properly after 60 seconds operation and 60 seconds delay but the starting problem reappears after 5 minutes.

I had this problem before and it was a leaky air vent in the fuel filter. I have two fuel supplies, one in the keel and one at deck height. A serious leak will result in air in the lines if using the keel tank, and fuel leaking out if using the higher one.

I had a visible air problem before but now everything is tightened up I don't think the problem is air. I also found the engine very low on oil and topped it up.

Could be that the lack of lubrication on startup is stopping the engine. After operating for a short time the engine is better lubricated and so starts properly.

This behaviour only appear recently after a 50 hours operation. The last service was about 100 hours operation prior.

The engine is an old Nissan 4 cylinder ED33 of the kind found in a Nissan Patrol, it is keep cooled (no salt water involved).

Just a quick stab at it from your description. Sounds like a governor problem. The loping is indicative of that.

[CptLawrence]

Try blowing into the fuel line at a point right before it enters the injection pump(dont blow into the pump), plug or crimp the line right before the fuel tank. Listen for leaks or bubbles. Filters have o-rings that are easily lost or damaged and if something gets cross threaded it may never go back together air tight. An electric diesel pump should be installed to fill the day tank from the keel tank, use a push button switch so the pump cant be left on. Discoloration in the fuel filter bowl may be indicating water, if there is a drain in the bowl then use a small glass jar to check it out, a few drops is not going to cause the problems you have. Maybe bilge water is seeping into the keel tank and forcing fuel to rise into the bilge.

[h the boat]

It must be fuel starvation, from whatever cause. You say you recently replaced the filter system, the top of the last filter in line to the injection pump, MUST BE AT LEAST 6 inches above the injector pump. If it is not, any tiny amount of air in the system, will be trapped in the top of the filter and may be sufficient to give you the starting problem. When the engine is running normally, the return flow to the tank should be sufficient to clear the trapped air. But when the engine is stopped the whole problem starts again. The other posts give good advice regarding your fuel system. You should give serious consideration to fitting a permanent day tank above the level of the engine, with a direct feed to the filters. The return pipe from the injection pump may go back to one of the filters, (as it does in most vehicle installations of this engine), re route it back to the new day tank. Fit a small electric pump, to lift from keel tank to day tank, with overflow near top of day tank , back to keel. fit a manual switch for electric pump. Renault diesel cars and vans fitted an electric pump, from about 1992 to 2005, which is located under the right side on chassis frame near wheel arch. They rarely go wrong and must be in demolition yards.but beware they are only rated for 20 minutes continual running so dont leave one on permanently. It sound a lot but is not for good reliability. h the boat.

[h the boat]

Just an addition, the return pipe from injection pump or filter or both, should go back to the top of the day tank, it cannot suck in air through this pipe if the tank is above the level of the engine. h the boat

[Cheechako]

You might try an in line electric fuel pump... pretty cheap and if it works you at least have the problem figured out. Put it right after the tank before the filters.