fuel injector help
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fuel injector help
I have an 2004 5.9L. I turned the truck off a couple of weeks ago and it will not start now. I have replaced the Inj pump and it started right up and I turned it off and attempted to start it again. It turned over several times and finally started. The third time it would not start. I have had the computer rebuilt, I have replaced the cam and crank sensors and still wont start. Fuel is flowing to the injector pump. The computer says im getting 1475 psi at start up and Im getting fuel pressure and there is no codes or history in the computer.
Read more: http://www.justanswer.com/questions/...xzz0HGfBj8DG&B
Read more: http://www.justanswer.com/questions/...xzz0HGfBj8DG&B
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Joined: Dec 2008
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From: East Alabama
Is that 1475 psi while the engine is running?........
If it is, it's WAAAAY too low.
At idle you should be around 6800 psi.
You've replaced a few of the things that will cause it not to start, but let me ask you this:
Are you running any programmers or boxes? Specifically one that ramps up rail pressure.
Did you mess with any of the high pressure fuel lines?
Did you mess with any of the conenctor tube nuts where the HP lines go into the head?
Have you replaced the fuel filter?
Have you checked the wiring harnesses going to the injectors?
If it is, it's WAAAAY too low.
At idle you should be around 6800 psi.
You've replaced a few of the things that will cause it not to start, but let me ask you this:
Are you running any programmers or boxes? Specifically one that ramps up rail pressure.
Did you mess with any of the high pressure fuel lines?
Did you mess with any of the conenctor tube nuts where the HP lines go into the head?
Have you replaced the fuel filter?
Have you checked the wiring harnesses going to the injectors?
Last edited by Coal Train; Jun 3, 2009 at 05:41 PM.
Thread Starter
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Registered User
Joined: Jun 2009
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Coal Train,
The 1450 psi is during starting only... I can't get the thing started long enough to check the idle pressure. I was using an EZ programmer up until I started having problems then I disconnected it. Fuel lines: only to check pressures.... I believe the lines to be good.
I am thinking computer. See, when I had the computer rebuilt, they said I was running lower voltage than normal to the injectors. They supposedly fixed that . Right now, I am waiting for a mechanic to check the wiring harness, that's the next step. Have you had experience or heard of this before?
Chris
The 1450 psi is during starting only... I can't get the thing started long enough to check the idle pressure. I was using an EZ programmer up until I started having problems then I disconnected it. Fuel lines: only to check pressures.... I believe the lines to be good.
I am thinking computer. See, when I had the computer rebuilt, they said I was running lower voltage than normal to the injectors. They supposedly fixed that . Right now, I am waiting for a mechanic to check the wiring harness, that's the next step. Have you had experience or heard of this before?
Chris
All Star
Joined: Dec 2008
Posts: 863
Likes: 0
From: East Alabama
Coal Train,
The 1450 psi is during starting only... I can't get the thing started long enough to check the idle pressure. I was using an EZ programmer up until I started having problems then I disconnected it. Fuel lines: only to check pressures.... I believe the lines to be good.
I am thinking computer. See, when I had the computer rebuilt, they said I was running lower voltage than normal to the injectors. They supposedly fixed that . Right now, I am waiting for a mechanic to check the wiring harness, that's the next step. Have you had experience or heard of this before?
Chris
The 1450 psi is during starting only... I can't get the thing started long enough to check the idle pressure. I was using an EZ programmer up until I started having problems then I disconnected it. Fuel lines: only to check pressures.... I believe the lines to be good.
I am thinking computer. See, when I had the computer rebuilt, they said I was running lower voltage than normal to the injectors. They supposedly fixed that . Right now, I am waiting for a mechanic to check the wiring harness, that's the next step. Have you had experience or heard of this before?
Chris
Fuel pressure (from tank to injection pump) should be 10 - 17 psi at idle.
Rail pressure (injection pump to injectors) should be approx 6800 at idle and up to 20K when running under a load.
There's a couple of things that could be causing the issue....
You replaced the cam / crank sensor so that's 2 of the big ones.
You have fuel pressure to the injection pump, so that's no problem.
That leaves the injection pump, fuel rail and injectors....
What would cause this with the injection pump is more than likely the FCA (fuel control actuator). This is where your actual pressure is controlled.
In the rail, the biggest thing that would cause this is the relief valve being popped. It's a one time item. If it pops, the truck may start, but more than likely will die if you tap the throttle.
Injectors.....at this point, I doubt it.
What you need to see is you requested and actual rail pressure. Basically the pressure that the ECM is ASKING for vs what is actually being GENERATED at the rail. Only way to do this is with a StarScan or other tool that can see the readings from the ECM.
