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Pete, Auto Service Technician
Category: Ford
Satisfied Customers: 27884
Experience:  Over 17 years diagnosing and repairing automobiles various makes and models with some training and certifications.
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Just replaced air injection rail on 1996 f150 with 4.9

Customer Question

just replaced air injection rail on 1996 f150 with 4.9 .after reinstalling intake and putting everything back together it ran terrible for a few minutes now it wont start
Submitted: 1 year ago.
Category: Ford
Expert:  Pete replied 1 year ago.

My name is ***** ***** I am a professional here at Just Answer. I noticed that your question had not received a response and thought I would see if you still need help with this.I apologize for the delay and I hope I can still assist you with this here.

Just to be sure I assume this was the fuel injection rail that was replaced?If I am incorrect let me know.

If this issue of low fuel pressure only occured after the fuel injection rail was replaced this can indicate that one or more of the fuel injectors are leaking needing reseated or resealed to the rail or an individual injector leaking due to damage the injector affected would need replaced.I would check the injectors and make sure they are all seated and sealed to the fuel rail as well as fuel lines at the fuel rail for any issues needing repaired like a kinked fuel line or leaking fuel line connection.Usually one of these will be the cause here if this issue only occured after the fuel rail was replaced.

If this is not what is occuring here or if these were all already checked and found o.k. let me know so we can continue.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.

Thanks Pete

Customer: replied 1 year ago.
Thank you Pete for the response ,no it was not the fuel rail replaced ,it's the smog rail ,I was told it was called the air injection tube ,I didn't touch the fuel rail
Customer: replied 1 year ago.
I'm worried maybe I don't get all the vacum lines hooked up right
Expert:  Pete replied 1 year ago.

You have posted above that it has low fuel pressure,if the fuel pressure was tested what is the actual fuel pressure?

Customer: replied 1 year ago.
I don't the pressure I just pushed in on the valve on the end of the fuel rail and fuel just dribbled out
Expert:  Pete replied 1 year ago.

Just to be sure the engine did run properly before the rail was replaced am I correct?

If so have you double checked the work area to see if anything was bumped loose or damaged in any way needing repaired or reconnected?

Customer: replied 1 year ago.
it ran ok before ,I will just keep checking to make sure everything is hooked up right ,
Expert:  Pete replied 1 year ago.

O.k.,if you find that everything is connected properly let me know as well if you need anything else here.Feel free to rate my help here if you like.

Thanks Pete

Customer: replied 1 year ago.
Pete ,something just came to mind ,I did some welding on the truck ,I disconnected the neg side of the battery but I wonder if I fried something ,it has spark
Expert:  Pete replied 1 year ago.

Usually if you disconnect the battery like you did here this wont cause anything to short out or become damaged.But to be safe just in case a control unit or module was damaged I would have the fault codes checked in the engine/transmission computer(s) to see if any codes are set.If there are any codes set the codes will need to be diagnosed to locate and repair the fault here.I would start with having this done.

Your PCM (engine and transmission computer) monitors and controls the fuel pump.It turns on the fuel pump relay.The fuel pump relay receives a ground signal from the PCM.The relay has power in in two spots one from fusible link M which looks to be a 20 gauge blue wire and one from the power EEC relay.The relay then sends power to the pump through the IFS switch (which is the switch that opens with a collision with the vehicle) then powers the pump from there.

It is possible the PCM was damaged or the fusible link shorted needing replaced as well here.If you can get the codes read out this will help locate which is the cause here needing repaired or replaced.

Thanks Pete