The Diesel Garage banner

1 - 8 of 8 Posts

·
Junior Member
Joined
·
13 Posts
Discussion Starter #1
So I recently purchased a tow truck for a new business venture. It's a 2002 international 4300. When I purchased it I knew it would need a little work, it sat for a year, steel tank had rust, so the tank was replaced with a aluminum one. the truck ran, but was slugish on hills and had a shake/miss.. here's the list of what I did..

1) cleaned pre-filter "rock catcher"
2) replaced fuel filter
3)removed, tested, and had injectors rebuilt(5 out of 6 tested bad, 3 no fire)
4) replaced cam sensor

The problem I'm trouble shooting now is that truck still has a miss, and has less power than before injector rebuild. when I go in drive, it pulls very slow, in park rpms wont go pass 2000, and it rises very slow whe pressing accelerator, sometimes when it gets to 2000 rpms it slowly starts to fall back to about 17 - 1800 while holding pedal steady, other times it'll hold steady at 2000 rpms but missed and shakes..

I am new to medium duty trucks, but have worked on plenty 1 ton motors 6.0, 5.9's etc..

unfortunately I dont have access to any to a heavy duty scanner, so I'm stuck doing things manually and the hard way, but the budget doesnt allow for one. Just wondering if anyone has any ideas of what might cause the symptoms I'm experiencing.

Side note: truck does hold prime, and starts right up, even after sitting for days
 

·
Junior Member
Joined
·
93 Posts
Is the engine light on? What is the fuel pressure?
There is a schrader valve on the filter head.
If I remember correctly you should have 75 psi.
If it's low it could be the transfer pump or the pressure
regulator at the back of the rail.

Terry
 

·
Junior Member
Joined
·
13 Posts
Discussion Starter #3
Is the engine light on? What is the fuel pressure?
There is a schrader valve on the filter head.
If I remember correctly you should have 75 psi.
If it's low it could be the transfer pump or the pressure
regulator at the back of the rail.

Terry
Engine light is not on
fuel pressure is right around 60 psi, which is in spec from what i have reasearched
 

·
Junior Member
Joined
·
13 Posts
Discussion Starter #4
Is the engine light on? What is the fuel pressure?
There is a schrader valve on the filter head.
If I remember correctly you should have 75 psi.
If it's low it could be the transfer pump or the pressure
regulator at the back of the rail.

Terry
just checked again and the fuel pressure is 50 psi but bouncing , pulled return line while motor was running and it's returning diesel with the gauge only at 50 psi, is the pressure supposed to rise while reving the engine , because it does not while checking from schrader valve
 

·
Senior Member
Joined
·
2,555 Posts
I did a HEUI troubleshooting thread, based on a 466E, but the system is very similar to the 6.0 HEUI , most of the pressures are close and the procedures should be very similar.
Low power usually means low HPOP either via pump weakness or electronic signal.
 

·
Junior Member
Joined
·
13 Posts
Discussion Starter #7
Have you bled the air out of the schrader valve? Only fuel should come out.
yes everytime I did anything to the fuel system i bled it, even bled it when I hooked the gauge up, it has a button on the side with tube attached to allow air out of gauge..
 

·
Junior Member
Joined
·
13 Posts
Discussion Starter #8 (Edited)
I did a HEUI troubleshooting thread, based on a 466E, but the system is very similar to the 6.0 HEUI , most of the pressures are close and the procedures should be very similar.
Low power usually means low HPOP either via pump weakness or electronic signal.
thats what I was thinking, but what i noticed a little while ago is that when pressing the primer with the fuel pressure gauge still attached, I noticed the relief valve is leaking a thin steady stream as soon as the system gets to 10-15psi, once I prime the system up to 40 - 45 psi, which is the highest it'll let me prime, there's a more steady/thicker stream of diesel coming out of the regulator.. I dont believe this is correct operation of the relief valve is it?

anyone know the correct name for relief valve or better yet a part # mines is a 2002, it's located at the back of the head/fuel rail

edit: I guess I should clarify I checked the relief valve with the return hose off, and engine of pressurizing system from primer, and then started engine and checked relief valve while running also, pressure never got above 50 psi, but valve was open and returning diesel
 
1 - 8 of 8 Posts
Top