Deuce keeps getting air in fuel system

[Jeepsinker]

Nope.

Open the bleed screw on the filter housing and the fuel will bleed back down to the tank. I'm not convinced there actually is a check valve in the pump. I feel like the fuel stays up via static suction.

 

[ivbeenrokd]

Nope.

Open the bleed screw on the filter housing and the fuel will bleed back down to the tank. I'm not convinced there actually is a check valve in the pump. I feel like the fuel stays up via static suction.

Hmmm, interesting. I see what you're saying. Looks like I'll be sliding the fuel tank out Monday to check it all over in the inside. I'll still run it tomorrow and look it over really good, but it's making more and more sense that the problem may be in the tank.

 

[Jeepsinker]

When you plug the return and turn on your lift pump, if the leak is outside the tank it will show itself. Otherwise it most likely is inside the tank. You do need to fix those other small leaks anyway though. A lot of air can get in where only a small amount of liquid can get out. That should only make it get air in the system when sitting and not running though.

 

[rustystud]

Nope.

Open the bleed screw on the filter housing and the fuel will bleed back down to the tank. I'm not convinced there actually is a check valve in the pump. I feel like the fuel stays up via static suction.

I believe your right Garrett. I thought for quite sometime that there was a check-valve like most in-tank fuel pumps have,
but looking at the cut-away of the pump I see no mention of a check valve.

 

[DieselBob]

I believe your right Garrett. I thought for quite sometime that there was a check-valve like most in-tank fuel pumps have,
but looking at the cut-away of the pump I see no mention of a check valve.

Correct. There is no check valve of any type in the original Olympic pumps. Can't say about the newer Parker pumps.

 

[daytonatrbo]

Correct. There is no check valve of any type in the original Olympic pumps. Can't say about the newer Parker pumps.

Somebody at REO had a vendetta against check valves. The fuel system and oil system could have benefitted.

 

[Jeepsinker]

On the oil system, sure. On the A3, they did put a check valve in the fuel system, and all it did was cause problems.

 

[ivbeenrokd]

So here is some additional feedback as of now:
By the time I made it to the end of the Veteran's Day Parade I had a little more than 1/4 tank of fuel. The next time I started it was last Friday when working on it and then Monday so then around a 1/4 tank of fuel or maybe less after the Friday/Monday testing. Monday: Was having plenty of problems staying running. Went to the gas station, filled it up to a hefty 3/4 tank+ and still plenty of problems on the way home. Yesterday I bled the air out and went to start it and the batteries were too weak after all the cranking from the parade, Friday, and Monday. Charged batteries, did the "plug the return line" test, and found nothing new. Went by there this morning and started out by hooking the batteries back up and bleeding the air out again, but this time I found not much air at all. Started it up, let it idle, drove down the road, let it idle more. I ran it a total of about an hour and it never died. I did see that no2 line on top of the IP was still leaking a little, but nothing like it was before last Friday.

My conclusion here is that it performed significantly better with 3/4 tank rather than 1/4 tank which gives me more confidence the problem is likely in the tank as suggested.

 

[Jeepsinker]

Sounds promising. Fix that leak on the injector pump though. That is letting it bleed down while it sits.

 

[ivbeenrokd]

Here are some pictures after it running an hour.

 

[Jeepsinker]

Hard to see anything in the pics. Loosen the injector lines and snug them back down, that should stop those leaks. Otherwise, all I can see from the pics is that you have a flame heater to delete, and an FDC to bypass...

 

[ivbeenrokd]

When I worked on that number two line before that's basically all I did. I totally brought the nut out, wiggled the line around a little bit, and then tightened it back up. It seemed to fix it at first, but then the next time it was leaking a little again. What is the benefit in getting rid of the heater and bypassing the FDC?

 

[Blackbear]

When I had a similar issue it was the pump in the fuel tank itself, it would cut out on the road, I replaced it and all is well, however I still need to do the thirty second wait, then three cranks to start, it may be my hose so I'm going to check it now. Thanks for the thread.

 

[Jeepsinker]

Man, you've been on here since late 09' and you don't know? It gets rid of problem areas. The FDC can leak gallons of fuel into the crankcase in a very short time. The flame heaters also are very prone to leaking, can cause an engine fire, and are not needed at all.

 

[ivbeenrokd]

Man, you've been on here since late 09' and you don't know? It gets rid of problem areas. The FDC can leak gallons of fuel into the crankcase in a very short time. The flame heaters also are very prone to leaking, can cause an engine fire, and are not needed at all.

Hmmm, I guess I better get rid of them then. I must be a slow learner! LOL

 

[ivbeenrokd]

Okay, here's an update. I cracked the bleeder on the secondary filters this morning and got almost no air at all. I started the truck up and backed it out, let it run at varying RPMs for 45 minutes, pulled it back in, and shut it off. I'm going to try the same thing tomorrow but I'm not going to even open the bleeder valve before starting it. If it proves to work really well at 3/4+ tank of fuel then I may just keep it really full for the next few weeks to make it through the parades and then run it down and slide the tank out. We'll see....

 

[Jeepsinker]

Ok, you know every time it sucks air and stumbles or dies, it is potentially causing injector pump damage right? Air and water kills injector pumps. I would advise draining or siphoning off the fuel and fixing the problem now that you know where it is. All you need is some buckets or fuel cans, and maybe some hose.

 

[ivbeenrokd]

No I didn't realize that (I'm definitely not a diesel mechanic so I'm learning as I go/need to). I will round up fuel cans/buckets tomorrow and get to work.

Thanks,
John

 

[Jeepsinker]

The important part is that you are learning.

 

[rustystud]

Ok, you know every time it sucks air and stumbles or dies, it is potentially causing injector pump damage right? Air and water kills injector pumps. I would advise draining or siphoning off the fuel and fixing the problem now that you know where it is. All you need is some buckets or fuel cans, and maybe some hose.

Air and water in a system that pressurizes oil (hydraulic) or in our case fuel (for the injectors) can cause "microbursts" (cavitation) . These bursts are actually small detonations of heated water or air (gas) that actually destroy the pumps themselves. That is one reason why the injector pump has a continuous supply of fuel going through it to help bleed out the small air pockets that can get in normally. It was "not" made to handle large leaks caused by leaking fuel hoses.