Engine started surging coming home and then died.

[TNDRIVER]

OK
She started for me and I let it run for a couple minutes. Came back 20 minutes later and she started but started to serge and then killed. I did this a couple more times with the same results.
Ken

Remove and clean or discard the check valves in the fuel line also.

 

[Kenneth Cole]

Tndriver
Where are these check valves located ?
Ken

 

[Action]

Tndriver
Where are these check valves located ?
Ken

Find the metal fuel lines at front of tank. Follow about 6” in front of tank. If you have4 metal fuel lines, two will just have a loop of hose on the ends. Dont worry about those.

 

[TNDRIVER]

Tndriver
Where are these check valves located ?
Ken

Action covered the ones at the tank. They are a couple inches long in the fuel line. My trucks also have one just before the fuel filter also. Greater authority than me says they can be tossed. Now is a good time to replace all the fuel lines. They are under suction between the tank and the mechanical pump on the block and pressure from there to the IP .
Check your filter drain line (small hose out of the bottom of the filter housing) to make sure the valve is closed and not sucking air.

 

[Kenneth Cole]

Hi
I tried removing the fuel tank cap and it made no difference. Also the fuel filter drain valve is tight. She started for me yesterday. I had to crank her over for about 15 sec. with no smoke then she started puffing smoke and started but would kill. I did this a couple times and found out that if I held the gas down about half way it would keep running even though it's still surging. As soon as I let up on the gas it would kill.
It's confusing to me that if I can get good fuel flow out of the fuel filter when cranking it over I would think that everything up to that point would be ok.
That's just my own opinion.
Ken

 

[Action]

Hi
I tried removing the fuel tank cap and it made no difference. Also the fuel filter drain valve is tight. She started for me yesterday. I had to crank her over for about 15 sec. with no smoke then she started puffing smoke and started but would kill. I did this a couple times and found out that if I held the gas down about half way it would keep running even though it's still surging. As soon as I let up on the gas it would kill.
It's confusing to me that if I can get good fuel flow out of the fuel filter when cranking it over I would think that everything up to that point would be ok.
That's just my own opinion.
Ken

1 pint out of filter can for 30 seconds of cranking. Or 1/2 pint / 15 seconds, etc. is what should come out. If that is met, parts towards the tank should be ok.
clean gatorade bottle works well and you can pour fuel back in tank. Assuming good fuel is what is coming out.

 

[TNDRIVER]

Hi
I tried removing the fuel tank cap and it made no difference. Also the fuel filter drain valve is tight. She started for me yesterday. I had to crank her over for about 15 sec. with no smoke then she started puffing smoke and started but would kill. I did this a couple times and found out that if I held the gas down about half way it would keep running even though it's still surging. As soon as I let up on the gas it would kill.
It's confusing to me that if I can get good fuel flow out of the fuel filter when cranking it over I would think that everything up to that point would be ok.
That's just my own opinion.
Ken

Put a fuel line out of the filter into a clear container , submerge the end in the fuel while cranking and see if you are getting bubbles in the fuel, indicates you are sucking air into the line. If not, my guess its pump rebuild time or at least have it on a test stand to eliminate it from the equation. You have looked in the tank..... right?? If not look there first, it's easier than pulling the pump. Two trucks both had biology experiments in the tanks. Both tanks had to come off, just saying. It's almost snow time there got to get her going!

 

[Glider]

if you check for flow as mentioned also check to see if it spits any air with fuel.

 

[Kenneth Cole]

Hi
I did the fuel into the jar and it looked like I was getting air in the fuel. To make sure I added a two foot section of clear hose from the pump to the fuel filter and turned her over. It shows a lot of air in with the fuel. I took the fuel tank cap of and still the same. I'm not real smart on these things but I would think that I would have to be getting air in the line from the fuel pump back. Wouldn't It require the sucking of the pump to be drawing in the air along with the fuel?
Also can someone tell me about all the vent lines on the humvee?

Ken

 

[Glider]

Ok known facts. Air in fuel between fuel pump and filter. Check supply between tank and pump. If no air: suspect fuel pump. If air present check hoses for leak. There is a short section of rubber line between tank and hard fuel line. Chances are if it's letting air in it probably letting fuel out. Look for wet lines or wet parts.

 

[Kenneth Cole]

Glider
How would I check the line from the pump to the tank for air?
If the fuel pump diaphragm was bad would it just not pump fuel? Could it be something with the vent line on the pump?
Ken

 

[TNDRIVER]

Hi
I did the fuel into the jar and it looked like I was getting air in the fuel. To make sure I added a two foot section of clear hose from the pump to the fuel filter and turned her over. It shows a lot of air in with the fuel. I took the fuel tank cap of and still the same. I'm not real smart on these things but I would think that I would have to be getting air in the line from the fuel pump back. Wouldn't It require the sucking of the pump to be drawing in the air along with the fuel?
Also can someone tell me about all the vent lines on the humvee?

Ken

Pull the vent line (small line on the top of the pump) off the pump then crank it and watch for fuel from the top the pump or out of the vent line if you pulled it at the t on the frame rail. Should not be any fuel! No fuel, eliminates the pump. Cheap and easy, 3/8 inch line from the pump inlet to the metal line out of the tank....... watch for air at the filter again.... still got bubbles, my bet would be a broken/cracked metal line into/inside the tank...... if the line between the pump and tank is sucking air there should be a DAMP spot where its leaking ....... maybe.... and yes the pump is sucking air. I see a tank removal in your future..... and SNOW! Keep us advised, someone else is going to have this same problem.

 

[Action]

There may be 3 pieces of rubber hose between the tank and pump (inbound).
2 right in front of tank. You may have a one-way valve between them. This assembly connects the hard line on the tank to the hard line on the framerail.
then 1 hose from the framerail hard line to the pump.

 

[Kenneth Cole]

Hi
Well I hooked up a clear line from the input on the fuel pump to the line coming from the fuel tank. Had the wife crank her over for about 30 sec. with no air showing up in the line.
So the problem I think has to be between the fuel pump output and the input to the fuel filter. I cant see any leakage anywhere. I also pulled the hose off the vent on the fuel pump and saw nothing coming out as she was cranked over.

Ken

 

[TNDRIVER]

Hi
Well I hooked up a clear line from the input on the fuel pump to the line coming from the fuel tank. Had the wife crank her over for about 30 sec. with no air showing up in the line.
So the problem I think has to be between the fuel pump output and the input to the fuel filter. I cant see any leakage anywhere. I also pulled the hose off the vent on the fuel pump and saw nothing coming out as she was cranked over.

Ken

You may have the answer in front of you, read between the lines...............When you replaced the suction line between the pump and tank the problem disappeared????????? Between the pump and filter is under pressure, fuel out no air in??????? If the hose between the tank and pump is clear and the fuel at the filter still has air the only answer IMO is the pump. It's easier to replace than pulling the tank , ask me how I know. Any thing that sets this long needs a fuel system clean and replacement from end to end, especially diesel. I learned the hard way with the 998, tank was off twice. Pulled the 1123 apart from the git go. Do you know about "Power Service" ??? You will where you're at. Your determination is noted!

 

[TNDRIVER]

Hi
Well I hooked up a clear line from the input on the fuel pump to the line coming from the fuel tank. Had the wife crank her over for about 30 sec. with no air showing up in the line.
So the problem I think has to be between the fuel pump output and the input to the fuel filter. I cant see any leakage anywhere. I also pulled the hose off the vent on the fuel pump and saw nothing coming out as she was cranked over.

Ken

PS... put your clear line on the output side of the mech. pump and see what you get right out of the pump...... that should answer the pump question once and for all.....

 

[Milcommoguy]

As suggested you might look for one of these on the filter housing. A check valve. See picture.

I am not a fan of them as they are another moving part that can quit or clog up. They do stabilize the pulsing of weak or some fuel pumps, with the filter canister acting like an accumulator. That said, have good ones or take it out.

I read you had good delivery, good pressure. And NO bubbles to the input to the IP... Right ???

Be sure all hoses are rated diesel fuel, of high quality, tight clamps... All of them. Look in the book and find them ALL. Underneath between the tank and pump, at the pump, at the filter, at the IP input and to the purge /test valve. AND check that the purge / test valve closes OFF tight. No cheap ass, imported rubber hose from the ZONE. Name brand like Gates or....

Is the fuel canister sealing good? Might have a look there. But you say, NO bubbles...No troubles ? Did we ever LOOK into the fuel filter system ??

The small vent on fuel pump is a housing vent. If you found fuel there...the diaphragm is leaking with a good chance that fuel can find its way to the engine crankcase and oil. BAD.

One would like to get this under control as said. Stay focus. Step 1-2-3-4 from supply (tank) to IP input. IMO spend the small money, buy hose and clamps and make it all new and pretty. Don't forget return lines too. That fixed...no more worries, move on.

Another free guess. Are we...tiring to help, YOU sure the IP electrical connections are good ??

Riding along here with no real history make it hard to figure what's up. Trouble shooting is a logical approach, BUT not a real science, LOL.

Not looking to freeze my butt off, CAMO

 

[Action]

If you decide to get rid of that calve on the filter can, you can remove the insides and put it back. Then you wont have to buy anything.

 

[Kenneth Cole]

Solved the problem of air in the fuel line.
It ended up being the fuel pump. This surprised me seeing that the pump was only 2 years old. As I stated before I placed a clear section of tubing between the fuel filter output and the injector pump and cranked her over and there was air in the line. And then between the fuel pump and the fuel filter and there was air. Then from the fuel tank to the input of the fuel pump and no air.

Ken

 

[TNDRIVER]

Solved the problem of air in the fuel line.
It ended up being the fuel pump. This surprised me seeing that the pump was only 2 years old. As I stated before I placed a clear section of tubing between the fuel filter output and the injector pump and cranked her over and there was air in the line. And then between the fuel pump and the fuel filter and there was air. Then from the fuel tank to the input of the fuel pump and no air.

Ken

THANK YOU for the follow up!!! It's helpful when we see the problem fixed. If you are new to diesels you are going to have an interesting first winter where you are.
A J