Engine/Transmission (1998.5 - 2002) Hard Starting; getting Air.

[Harlacher]

My truck stalled when I turned into a parking lot the other day. (24 valve second generation) Would not start until I bled a fuel injector line off. Now it will not start without bleeding it first. I have been having problems with it since my old FASS went bad. I put a new one on and it hasn't been right since. Thought I had it fixed when I tighteded a couple of lines on the FASS. Runs fine once started.



I am going to start tearing into it sometime this week; going to start on the check valve in the return line. I searched the post for others with this problem and it sounds like a lot of people are dealing with similar problems.



Couldn't find anyone who had to bleed off the air first.



FASS will not build any pressure until I bleed the system.



Any help on things to check would be great. I have taken notes from prior post, but again could use any and all help on what to check.



Paul

 

[DFerverda]

I would start with the fass, if that was the last thing you changed.
You could unhook the fuel line at the fuel filter,(if you left the stock one in place) and cycle the key, and watch the fuel flow for air, stick a extension hose in a gallon jug or 5 gallon bucket put it under the fuel and watch for bubbles. The most likley place air is being introduced is on the suck side of the fass/fass to tank. Just find the bubbles/air and chase it till you find the source.
A loose connection could introduce air on the pressure side, but it would also cause a leak... ... ... .

 

[Harlacher]

Thanks I will start with that.



When this first started I tightened all the fittings on the Fass and the problem went away.



Why doesn't the FASS build pressure until I bleed the system?

 

[LowFly]

Thanks I will start with that.



When this first started I tightened all the fittings on the Fass and the problem went away.

It sounds to me like you DO have an air leak somewhere... . Most likely in the tank or a loose fitting or something. Diesel fuel systems are closed systems and if there is any leak in the system at all the pump will lose prime.

Why doesn't the FASS build pressure until I bleed the system?

The reason your FASS will not build PSI is because the pump is losing prime to to that air leak somewhere. Once that is fixed you should be able to prime the FASS system and everything should be fine.

 

[JKinney]

Stalled?? Low on fuel sucked air in the tank. Guage not giving a true reading.



Ive been there

 

[Harlacher]

I was low on fuel. I was trying to burn up as much as I could in case I had to drop the tank. When it happened I thought that might have been it. Bled the system, it started and I drove it home which was about 15 miles. Started it just a little while ago. Started right up??? Damm if I can figure it out. I am going to pull the bed and go over each line. Taking the bumper off also, going to fix some boost leaks and check/change all the fuel lines in the engine compartment also. Like LowFly said; closed system, no air allowed... . I will find it. I really appreciate all the suggestions. I want my truck back; dependable, fast, strong like it was before I changed the FASS.

 

[DFerverda]

When you drive several miles, stop and open the fuel cap and see if you are pulling a vacuum in the tank, it will make a sucking noise if that is the case. I had the valve stick in my fuel module. It can be pulled and cleaned while your bed is on or off, is easier. Do a search on air in fuel, lots of posts and ideas to look at.
The fuel line out to the fass is Known to rust and leak... ... .

 

[Harlacher]

Thanks DFeverda. I have started to pull the bumper off and I am pulling the bed to install some new springs plus check the fuel lines. I wish I would have tried the fuel cap test before I started tearing it apart. Do you think I can do it with it sitting and running? What valves in the fuel module are you talking about? The FASS?



What does the fuel solenoid switch (I think that is what it is called) located in the engine compartment do? It is the square switch that has a wire going back to the FASS. Two wires one from this and one power. I bought a new one; no difference. I want to get all the problems fixed with it this time.



Another question. My son has a 03 stick. When he is cruising down the road he shows a constant boost pressure. Mine never has. Is there a difference between the Auto and stick? 03 and 1999? I get a boost pressure as soon as I touch the accelerator pedal, go up a hill, or have a load change. I just do not keep a constant pressure.



Paul

 

[DFerverda]

The valve i spoke of is the pressure relief valve, it is on top of the fuel module on the fuel tank. It will cause vacuum in the tank if it is not working, you would need to drive for several miles for it to pull enough vacuum to hear it hiss when you take off the cap. That said i still think your air problem is from the tank side of the fass to the tank. Check the steel line that feeds the fass, they will rust and get a pin hole and you will get air, or a loose connection that is pulling air into the fuel, it could even be a hole in the pickup line inside the tank, but it is plastic and I would be looking from the top of the tank module to the fass... .

My truck will be about 10 lbs of boost at 60mph but will drop off also when i back off the go peddle, it is also an auto.


Quote" What does the fuel solenoid switch (I think that is what it is called) located in the engine compartment do?

That is a relay that powers the fass.
Dirk