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I want to perform an injector balance test with the OTC tester. I need to monitor the fuel pressure and its not easy to put the pressure gauge on. Can I get an accurate pressure reading from the data pid with the scan tool? Thanks
I have no codes and the pressure sensor appears to be reading correctly. The only problem I have is bank one long term fuel trim is at 12 and the idle is a little rough I'm interested in doing an injector balance test and want to know if you ever use the pid to do that. I can hook a gauge at the filter if necessary. Thanks
With the 5.4 liter engine and ruff idle issues i would look at the cam phaser to see if it is sticking (the metal part bolted to the camshafts) or a small vacuum leak if you have the plastic upper manifold.
As long as you find that the sensor is reading rationally? :huh: Lots of Ford products use the FRPS for the automated injector balance test.
I can't speak to the FRPS accuracy compared to a gauge on the rail. On a test where 1 PSI more or less is a pass/fail, it's kinda an important question.
Maybe i need to clarify why i say to use a mechanical gauge. Just for your info.
In cases of rich or lean conditions i dont rely on the fuel pressure sensor because they can misreport fuel pressure and not set a code. The pcm can only self test for short to ground, short to voltage, open in circuit, ohm test sensor circuit. It does not have a redundant backup for the fuel pressure reading. For instance with a lean condition like what you have i would put mechanical gauge on and compare that to what the frps says. If it matches then i would trust it for the remaining tests. But believing its good when not certain can send you down a rabbit hole. So if sensor reports 55 psi but really only has 40 psi you will be running lean because less fuel pressure =less injected into engine to maintain speed/accelerate. This would be because the fuel pump is being cycled on and off by frps to pcm to fpdm.
I am not saying you cant trust it but would verify its accuracy before putting complete trust in it. Plus with putting a mechanical gauge on you verify in one test the condition of 4 components. (The frps for accuracy, the fuel pressure regulator for regulating proper fuel pressure, fuel pump function and injector pressure drop test (balance test).
Now i am not certain if you have four o2 sensors or three with your truck but if it has three this is where i would definitely hook a mechanical gauge up. If it has four then maybe just to check accuracy. But would focus on the one bank and test o2 sensors and injectors and maybe smoke intake and look for side specific leaks.
This is some great info. Thanks! I am going to follow all your advice. I have borrowed a fuel pressure test kit from autozone and will be installing at the fuel filter. I will let you know the results.
Check the fuel Pump Module too. These trucks have a lot of issues. the Fuel pump module is up near spare tire (needs to be removed) they have a cast body and will split caising moisture and all kinds of funky issues with fuel idle run conditions you name it. Fuel injectors were extended warranty to 130000 cause they are junk. i have a lot of experience with that piece of shit
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