1526 Pre-Start Noise

[rokit]

It doesn't bother me, and I'm not worried - but I am curious:

While the glow plugs are on before I start the tractor, there's a fluttering/clattering noise. It sounds exactly like an electric flapper/diaphragm-type fuel pump, but this thing is gravity-fed and has no fuel pump. After engine start, I can't hear it because either it's gone away or the engine is loud enough to drown it out.

Any ideas?

 

[oldpilgrim]

I never found out what it is, but it's normal. I was told it's a fuel pump, because there is one going to the injectors. But I don't know for sure.

 

[rokit]

I never found out what it is, but it's normal. I was told it's a fuel pump, because there is one going to the injectors. But I don't know for sure.

I did figure it's normal, I just wonder about this kind of stuff.

The injection pump which feeds the injectors is not electrical - it is driven by the engine itself via gears...thus it wouldn't make any noise until cranking. There is a fuel-shutoff solenoid on the inlet to the injection pump, but I've never heard a solenoid which sounded like anything other than a single click.

 

[RNeumann]

Do the dash gauges make some noise? I have a 1538 and can't say I ever noticed noise. But my Chevy definitely makes some noise when you turn the key to the on position.

 

[oldpilgrim]

Do the dash gauges make some noise? I have a 1538 and can't say I ever noticed noise. But my Chevy definitely makes some noise when you turn the key to the on position.

No noise from the cluster. It's apparently only on the Mitsubishi engines.

 

[arrow]

It's on my 3016 as well. Sort of sounds as if a "spark" is jumping going to the glow plugs. My dealer also made the "it's the fuel pump diaphragm clattering" which didn't make a whole lot of sense as I never heard of injectors having diaphragms. There are diaphragms on fuel pressure regulators. Perhaps the beast has one of these. It does sound more electrical to me however.

 

[mike69440]

I believe there is a small electric fuel pump to get fuel to the injector pump, looks like a filter.

 

[arrow]

It doesn't bother me, and I'm not worried - but I am curious:

While the glow plugs are on before I start the tractor, there's a fluttering/clattering noise. It sounds exactly like an electric flapper/diaphragm-type fuel pump, but this thing is gravity-fed and has no fuel pump. After engine start, I can't hear it because either it's gone away or the engine is loud enough to drown it out.

Any ideas?

I know the tank is above the engine negating the idea for a pump feed especially if it had a carb a la stationary engine.. Because there are injectors, there has to be some pump regulatory mechanism to pressure them. Wouldn't feed enough with just gravity being a pressure source for an injector to my way of thinking.

 

[rokit]

I know the tank is above the engine negating the idea for a pump feed especially if it had a carb a la stationary engine.. Because there are injectors, there has to be some pump regulatory mechanism to pressure them. Wouldn't feed enough with just gravity being a pressure source for an injector to my way of thinking.

Well, you're right. There is an injection pump on the side of the engine - it is a very high-pressure unit which feeds the injectors and controls injection timing. When I say "fuel pump," I really mean a feeder pump just to get the fuel to the injection pump (commonly called a "lift pump" in diesel trucks).

I believe that the 1526/3016 simply feed the injection pump via gravity. If there is a lift pump as mike69440 indicates, I certainly haven't seen it.

 

[DieselMonk]

It is a inline metal fuel pump. Mine has that too. If you have the hood open, looking from the front, it is mounted on the left side of the engine. The fuel gravity feeds the filter bowl. The fuel pump sucks from the bowl and force feeds the injector pump.