2003 ford f650 with a cat 3126e 21' aatac rollback - Diesel Forum

mobla890 · 10-17-2007, 10:01 PM

I am having problems with the fuel system. I replaced the fuel filters and changed the oil and filter, and it ran great for a week, now it is draining the fuel filter and choking out. I blew the lines from the tank forward and it goes all the way to the pump and then stops. I dont know where to go from here. Do i need a new injection pump?

31catdr26 · 11-05-2007, 10:54 PM

check your fuel psi at the outlet of the fuel filter base, there is a elbow with a plug on one end and a line going to the cyl head. remove the plug and check fuel psi at idle and wide open throttle. record records and send to me. If your fuel psi drops to zero, it is most likely getting air in the system. Ford has plastic fuel lines. Check all lines for rubbed through areas. Also, make sure your Primary(oem) fuel filter is the right one or may be bad acusing the system to suck air

Winkman · 03-12-2008, 10:27 PM

What is normal fuel psi ? I have 65 psi at idle and 68 psi under load . The reason im asking is because i have been getting a Low fuel pressure cranking code in my new F650. I did notice that on start up it does take about 5 to 7 seconds to reach 65 psi and thought that was way to long. This is the first time i had to check psi on a CAT C7. I haven't had time to hook up to another C7 to compare it yet.

31catdr26 · 03-18-2008, 11:50 AM

Take the fuel psi regulator off at the back of the cyl head and take it apart. 7/8 wrench and look for any debris in there probably part of an o-ring. if so buy a new one and put it in and re-check your fuel psi. that is the most common problem found with these

Winkman · 03-18-2008, 08:44 PM

We had a Tech from cat stop over and looks like you were right. He replaced the psi regulator on the back of the head [ told me they were VERY common ] and then One injector. he took it for a test drive then re ran the cly contribution test and told us he has to change the other 5 injectors which he did today. It runs Great now . This truck only had 8000 miles on it. God That's SAD. He said the low fuel psi caused by the regulator scored and damaged the injectors and also they have been having many problems with sticking injectors in general. He did a Great Job.