marvelouzone
New member
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
5) did fuel system pressure test, only getting 50 psi needle bouncing like crazy
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..
so I did a little further testing and noticed that fuel pressure relief/check valve at the return line on the back of head does not hold pressure as I believe it's supposed to, if I hand prime system to 40 - 45 psi the check valve on return gives a steady stream of diesel to the return, at 15 psi it becomes a thin stream and starts to taper of. if I remove return line while engine is running with fuel system 50psi it seams the return valve is wide open.. So i'm thinking my problem maybe the return valve, but I'm not sure,,
Does anyone know the correct name for this pressure valve, or even better a part number, my searches only turn up ipr valves
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.
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
5) did fuel system pressure test, only getting 50 psi needle bouncing like crazy
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..
so I did a little further testing and noticed that fuel pressure relief/check valve at the return line on the back of head does not hold pressure as I believe it's supposed to, if I hand prime system to 40 - 45 psi the check valve on return gives a steady stream of diesel to the return, at 15 psi it becomes a thin stream and starts to taper of. if I remove return line while engine is running with fuel system 50psi it seams the return valve is wide open.. So i'm thinking my problem maybe the return valve, but I'm not sure,,
Does anyone know the correct name for this pressure valve, or even better a part number, my searches only turn up ipr valves
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.