2nd Gen Non-Engine/Transmission Air in Fuel Line

[JCreer]

I just wiped out an injection pump on a 2002 2500 with 78K miles because air was getting in the fuel line with no apparent affect on fuel economy or power while pulling a 9K trailer! After traveling ~150 miles when braking to turn a corner the engine just quit. Would not start until front injection line was bled of air. Reached my destination 12 miles away by running smoothly between 800 and 1500 rpm at what seemed to be full power, but every time I let up on the throttle, the engine would die and need bleeding to start. Would not run smooth at any other rpm than 800 to 1500. This all happened with an Edge at #3 setting. After cooling off for a few hours the engine would start by turning the key and running the transfer pump twice (only got 2 or 3 psi on the pressure readout each time), then turning the engine over for 3 or 4 seconds, then turning the key back but keeping the transfer pump on for 3 or 4 more seconds to get normal 13 psi fuel pressure at inlet to injector pump, then engaging the starter to start engine. The engine would run, but not run smooth at any rpm!

Replaced the injection pump and engine started and ran fine until stopping using brakes which resulted in engine dying and air in fuel line. Engine will start using above procedure when worm and when cold, will start almost normal with the exception the engine must be turned over 6 or 7 times instead of 1 or 2 times. Every time the truck is stopped with the brakes the engine dies and air somehow gets in the fuel line! I'm thinking of putting clear temporary fuel lines between the fuel tank and rear, frame mounted stock transfer pump and if needed, between the transfer pump and fuel filter to try to determine where the air is getting in the fuel line.

Has anyone got any ideas relative to what's going on or other diagnostic suggestions??

 

[JR]

I would say your definitely sucking air somewhere, gonna have to follow the fuel line from the tank up to the lift pump and check for any signs of dampness. I have seen the O ring leak at the connection at the top of the tank on the sending unit. There is also a banjo bolt on the return line at the back of the head that is well known for leaking. Also make sure the lift pump itself isn't leaking at any of the fittings or has sprung a leak at a seal and check over the fuel filter canister as well. These are just some of the main areas to check, like I said your going to have to do a thorough inspection from front to back.

Do you by chance have a CEL? If you've got any codes pertaining to this, post them up as they may be relevant.

 

[MLee]

Check the fuel heater and the plug, this has been a problem in the past and might be the culprit. Fuel filter top tight and drain is full off. Take a few wrenches and make sure all fittings are tight.

 

[JCreer]

Rechecked all the connections from the tank o-ring to the IP and everything is tight; no leaks of any kind! I didn't pull the fuel level sensing/strainer assembly out of the tank to see if the draw tube has a leak at the flange joint or near the top. CEL indicated no codes when engine died after braking stops. When brakes are applied, engine dies immediately like fuel or air is cut off. It's like the brake being depressed either cuts fuel or air off. Is there any relationship between the braking system and the air or fuel supply systems like maybe the vacuum system? Is there anything else that could be telling the engine to stop during braking?

Will replace fuel lines with clear tubing tonight to see if air is in the line before or after the fuel transfer pump.

This is weird!

Thanks in advance.

 

[JCreer]

Do you mean the air intake heater? Do I have a fuel heater on my 2002? Other than starting, does the intake air heater keep operating when running down the road? It's hard to connect anything causing the engine to die instantly when you come to a braking stop! Something has to shut the fuel off or stop the air flow to shut a diesel engine of instantly like is occurring when you come to a braking stop doesn't it?

How do I check the fuel heater and plug?

Thanks in advance!

 

[JCreer]

JR, could it be a bad ground from the brake system is stacked with a fuel system ground that makes the PCM tell the IP to quit pumping fuel?

 

[JR]

I've never heard of such a thing, but I suppose anything is possible. If you don't touch the brakes, will the truck remain running? If you are on the throttle and simply let off and coast? If it is strictly brake related you need to track down the main chassis grounds and ensure they are all corrosion free and tight, that is the only thing I can think of that would cause a phenomenon like you are describing, unless you are having some funky ECM issue but generally there will be either a CEL or an erratic wait to start light, or something similar.

You do have a fuel heater, it is on the side of your OEM fuel filter canister.

When you were inspecting your fuel lines, did you find the fuel return line with the banjo fitting on the back of the head? Most people don't even realize it is there until they start having problems similar to yours, but the brake pedal thingy is def a little strange.

 

[JCreer]

Using the clear fuel lines confirmed that no air is being introduced in the fuel line before or after the lift pump, so that wasn't the culprit after all. Yes the banjo fitting you indicated was checked and did not leak, but thanks for alerting me to the possibility. I'm still suspecting the lift pump is not quite right, so we're watching it.

Luckily, the brake thing did not exist after all, so the grounds should be okay! The engine will not die every time you push on the brakes. However, the engine will die more often and quicker if you are braking to a stop, but it will coast to a stop and idle for a minute or two and then die. The tac gets a little erratic before it dies, so we're on to the MAP, ECM, or Edge now. We're going to completely disconnect the Edge and see if things don't become normal or we get a MAP or ECM CEL. When/if things become normal we'll hook the Edge back up to verify it is or is not functioning normal.

Can you think of anything else we should be trying?

Thanks again!

 

[JR]

Definitely disconnect the Edge before you get too involved in anything else.They are known to fail as they age and cause all kinds of funky issues. A faulty MAP sensor will not keep the truck from running the worst it will do is keep you down on power And generally throws a CEL.

 

[JCreer]

Edge disconnected and out of the picture. Truck runs the same as with the Edge i.e. runs okay until the rpms are reduced to less than 800 and then engine will die. Without the Edge it is much harder to restart and you may have to use my starting procedure presented in my initial message a few times before engine will start. When it does start a little blue smoke comes out, but it doesn't really miss or cough. Will idle, but will eventually die if throttle isn't depressed. All of this with clear fuel lines connected which don't show any air at all! No CELs are indicated at any time with analyzer or show up on dash indicator when use that procedure.

The throttle position sensor was changed a few months ago, so going to check the calibration of it, but don't expect anything because it doesn't really do anything to the idle rpm. The new cam position sensor is a suspect, but with no code I'm not sure what good it would do to change it again. The stock lift pump has always been a suspect, but fuel pressure to the IP is normal regardless of what you are doing with the rpms. What let's the engine go below idle speed and die is the question??

Essentially out of ideas of any substance. Do you have any suggestions of what to try next?

Thanks for the help!

 

[JR]

Is this a standard or auto truck? Are you sure the timing on the injection pump was set correctly?

 

[JCreer]

It's an auto and I'll check with the guy that did the IP replacement!

Here's some other thoughts I had/read about for your consideration:

1) Could the banjo bolt/overflow valve be bad?
2) Lift pump pressure okay, but volume is not?
3) ECM problem or wiring/connectors to lift pump or VP44 bad?
4) MAP or CPS bad and not providing CELs which can happen?

Thanks again!

 

[dknoch]

Worth a try, had mine die a couple years ago and found a relay to be bad. In the box under the hood, it was the fuel system relay. Swapped it with the horn relay and didn't have a horn that worked consistently. How is the oil level. Had a loss of prime issue on mine and the injector orings were bad, no leak visible anywhere. Doesn't sound like your case though. Issue with the draw straw in the tank maybe? Will it die if it is at idle and you hit the brake? Any codes? Key on-off-on-off-on and look at the odometer. Good luck!!!

 

[MLee]

Do you mean the air intake heater? Do I have a fuel heater on my 2002? Other than starting, does the intake air heater keep operating when running down the road? It's hard to connect anything causing the engine to die instantly when you come to a braking stop! Something has to shut the fuel off or stop the air flow to shut a diesel engine of instantly like is occurring when you come to a braking stop doesn't it?

How do I check the fuel heater and plug?

Sorry I missed your reply. Just remove it out of the fuel system. Because this has been a problem on other owners trucks (leakage at the plug, and some air) there is instructions on the removal procedure. If this is not the problem, replace the removed parts when you have yours running again.

 

[JR]

If the overflow valve was malfunctioning I don't believe your OEM lift pump could put out the kind of pressure your seeing. I'm actually surprised it does as well as it does, generally 10-12 at idle and 6-8psi under load is all the better I've seen them do. If you have doubts about it, they are fairly cheap to replace.

Does the engine feel like it's being pulled down? Sometimes a failing torque convertor will drag an engine down and cause it to stall at idle, but I'm not so sure this pertains to you as the truck should start right back up.

Truck will idle without any input from the MAP sensor. Where you will notice a problem with a failed MAP sensor is under load because the MAP takes the boost pressure it is seeing and feeds that information to the ECM. Idle will not be affected.

I'm not familiar with the Cam Sensor operation but I believe it to be the same as the Crank sensor on the older trucks. If a crank sensor fails the truck will not start. You also tend to lose the tach or at a minimum get a fluctuating tach that doesn't correspond with the engine rpm. The altenator also needs to see proper Crank sensor operation for charging purposes so a non charging issue is a good indication of a failed crank sensor.