Engine leaking diesel

[Ken13559]

My 2gm20f is leaking diesel. I find a small pool of diesel on engine body top next to the high pressure pump for injector. I suppose it's the o-rings/gaskets of the tube connections at HP pump top that's leaking. Any idea/suggestions whereas this diesel could leak from?
Thanks.

KenY

 

[jssailem]

Check the fuel hose connections. A clamp that has come loose or a fuel line that is cracked or failing would be my first suspect.

 

[Ralph Johnstone]

Hi Ken,

Can you indicate on this photo where the pool of fuel is collecting :

And no, I don't usually run the engine without the valve cover. Or does this show the area any better :

The best way to locate the fuel leak is to wrap paper towel around each joint and tightly tape with masking tape. Check for wetness at each towel after running the engine at idle for a few minutes.

Let us know what you find because if you've got it, I may be coming up on the same thing as well.

I'll be pulling the SS mixing elbow this winter to see if my original corrosion problem has progressed since last year. I'll PM you to let you know.

 

[Ken13559]

Located the leaks to be at top of Fuel Injector Pump. Can see wet diesel around the connection. Yard said they replaced the O-ring but still it leaks. I'll do it myself and see what goes there.
Leak source as circle in red.

Ken Y

 

[Ralph Johnstone]

I'll do it myself and see what goes there.

Then you're sure it's done right.
Will check the top of my injector pump once I start running the engine next summer.

 

[Scott T-Bird]

Then you're sure it's done right.
Will check the top of my injector pump once I start running the engine next summer.

Me too ... I find a small accumulation in the pan under the engine after running for more than an hour. I wasn't able to locate any leak at the injectors or return feed. I once found some diesel around the fuel filter but wasn't able to replicate it. I can't say I've noticed any at the injection pump but I also think I haven't looked closely. That will be my first step next season.

@Ken13559 , @Ralph Johnstone did you ever notice any performance issue? I haven't, so I haven't been overly concerned when I find a small amount under the engine that I can wipe up with a paper towel. I did replace parts and the fuel line at that location when I replaced numerous engine parts and had the injectors pulled out 2 years ago. I don't remember any difficulties, but if this is the source, I'll be very happy to find it out!

 

[Ralph Johnstone]

@Ken13559 , @Ralph Johnstone did you ever notice any performance issue?

I think the amount of fuel that was discovered by @Ken13559 represents a very small % of the fuel being discharged by the injector pump on that power stroke. In addition, there is also a % of fuel that bypasses some of the fuel from the injector back to the fuel tank. The purpose of this small amount of fuel is to cool the injector. Cool is a relative term, more like keeping the injectors from melting.

There is enough fuel delivered through the injector to satisfy the needs of the governor speed control.

 

[Ken13559]

I don't think the leaks affects engine performance. There's enough fuel going to the injectors like @Ralph Johnstone said.

 

[Ken13559]

If anyone know the O-ring size do tell.
From internet I gather the Fuel Injection Pump outlet O-ring to be 15x20x2.5mm (IDxODxCS).
I'm preparing O-rings of various sizes and don't want to be surprised when I start the work.
Thanks in advance.

Ken Y

 

[Ken13559]

Glad to report that I finally managed to replace the O-ring on top of the Fuel Injector Pump and solved the diesel leaking issue. It's an easy job albeit in a little tight spot.
O-ring used was 20x15x2.5mm

Ken Y

 

[Ralph Johnstone]

I finally managed to replace the O-ring on top of the Fuel Injector Pump

Great minds sometimes do think alike. I was completing the replacement of all of the rubber fuel lines on the engine last week and was working over the injectors. That triggered me to think of how you were making out with your leak. Glad it's gone with the replacement "O" ring.