Can't Seem to Find Air Leak

[Doakster]

For the life of me I can't find my air leak. The truck does the typical start then stall then a long crank to restart. This is after replacing the caps and return lines which I thought what the issue.

Anything else I can look at?

 

[91f2504x4]

I am not sure what kind of filter head yours has on it, but have you checked there for leaks?

 

[Doakster]

This truck has a screw on filter head, supply line in, supply out and return line,

 

[howards@howard]

dam air leaks

there can be about 25 different leaks. you can try to locate them by putting temporary clear tubing on the supply and the return. Most people including myself install an electric pump to purge you lines every morning.

 

[RLDSL]

Could possibly be a slobbering injector leaking down. Went through that a while back... on a set of * rebuilt* injectors with only about 5k miles on them.
Junked them and got a set of new ones.

 

[allczns]

off topic but...

...is that an Arps kit on the tractor in your avatar? Ford? Fergie?

 

[Doakster]

...is that an Arps kit on the tractor in your avatar? Ford? Fergie?

Yup ARPS, it's an 8n

 

[Doakster]

there can be about 25 different leaks. you can try to locate them by putting temporary clear tubing on the supply and the return. Most people including myself install an electric pump to purge you lines every morning.

I think I'm going to have to get some clear tubing for all the return lines. Will any clear tubing hold up to the fuel. It's 3/8s correct?

 

[Doakster]

Alright did some more troubleshooting today and have some questions. I installed all clear tubing on all the return lines as you can see below.

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After I installed the tubing I fired the truck and let it run for awhile until all the lines were purged of air bubbles. I shut the truck off and watched for any air bubbles that would form and go back to the fuel filter. Nothing really significant was present, the only bubble was at line going from the driver side bank to the tee fitting, the tee fitting then goes back to the fuel tank.

I then noticed that my fuel filter o-ring/seal was looking a little unhealthy and i don't know when the filters were last changed so I replace both filters.

I went through the same deal, fired the truck and purged the air. But this time when I shut the truck off the rear tee line that I mentioned before instantly looses it's fuel and half of the line emptys as seen in the photo.

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I'm waiting it out right now to see if the fuel drops more in this line. I'm trying to figure out if this is normal or not. Obviously the fuel is draining back to the tank, but I would think if the system is tight it would more or less hydro lock the fuel in the lines and keep it in the line.

Or what exactly keeps the fuel from dumping all back into the tank?

 

[Mat J]

Is it leaking from the filter anywhere? Maybe the bowl drain.

 

[Doakster]

Is it leaking from the filter anywhere? Maybe the bowl drain.

Drain bowl? Not sure where that is, this truck is set up a little different than a Ford because it's an international truck. I replace both filters today, they are good and snug, not worried about them being the issue.

But after about an hour of watching the clear lines this is what I found:

The tee return line that I posted a pic of above eventually drained all of it's fuel down toward the injectors. After that air bubbles started to accumulate in the lines between the injectors and eventually of course made there way to the filter.

So what that tells me is that since there are no visible fuel leaks and the lines emptied back toward the injector, I'm pointing my finger at an injector that is leaking down.

Anyone agree?

 

[icanfixall]

That large return line fitting nut has a flat washer in it. Try tightening it.... On my injection pump return line its hard steel and runs down the drivers side head. At the back of itthere is a three way fitting made from brass. It has an o ring in it just like the filter to injection pump supply line. They are square or flat o-rings and some injection pump installation kits have all three of them. Any injection pump rebuild shop will sell you any amount you need.

 

[Doakster]

That large return line fitting nut has a flat washer in it. Try tightening it.... On my injection pump return line its hard steel and runs down the drivers side head. At the back of itthere is a three way fitting made from brass. It has an o ring in it just like the filter to injection pump supply line. They are square or flat o-rings and some injection pump installation kits have all three of them. Any injection pump rebuild shop will sell you any amount you need.

Good thought, it'll put a wrench on the fittings. But i think it's an injector. Mainly because I watched the line out of the tee fitting (my second picture I posted) drain itself back toward the injectors.

That tells me that fuel is leaking/draining down in an injector.

Plus the return lines going into the filters and the IP held like a rock, didn't develop any air bubbles by the fittings, so i think it's safe to say they are good and tight. Also the entire passenger side holds like a rock.

 

[Mat J]

pull the injectors on that bank and see is one is wet and dribbling.

 

[Doakster]

pull the injectors on that bank and see is one is wet and dribbling.

I think i might just get a set of 8, I have no idea when they were last changed out, truck has 292k on it. She does smoke real good for awhile on start up, more than you would expect and even a little when running.

Whats the torque spec on the injectors, for when i go to reinstall one if i pull that bank out?