Where is the fuel rail sensor located?

Hi,

First, could you provide me with the code that was retrieved? I have several different possible causes of problems based on codes.

Now, take a look at pic 1. I highlighted the fuel pressure regulator. If I recall, this was used prior to the electric pressure sensor. See if this is on the fuel rail.

Let me know.

Joe

See pic below.

Thank you for the reply. For some back info, I always get a "Camshaft Sensor" code even though the sensor is fine (replaced many times to be sure), my guess is I just don't drive the vehicle far enough for the computer to get set. It is not driven often and never far. Usually, after a long drive, it goes away.

The rail code I got was "P0193 Fuel Rail Pressure Sensor Circuit High Bank 1". After the stall, I get more codes, but I am guessing those are not important and just results of the stall.

I looked in that area of the diagram you sent and found this. It looks kind of like what I think the new part looks like?

Hi,

That looks like it's attached to the fuel rail. The regulator should be vacuum operated according to my manual. That has an electrical connector. If you look at pics 1 and 2 below, it shows the vacuum regulator location. If I recall, it will be partially under the upper intake manifold. See if it's there. If it isn't, then what you sent a pic of is either the fuel rail pressure sensor or fuel temperature sensor.

Possible causes related to the code are a bad sensor, open circuit or short to ground, sensor signal voltage shorted to reference voltage, or even a faulty PCM.

Pic 3 shows a schematic for the fuel system at the fuel rail. I highlighted the FRP sensor. Pic 4 is a pic from the schematic indicating the sensor will have three wires to it. The pic indicates wire colors as well, so we need to confirm they match.

Let me know what you find.

Joe

See pics below.

So here is my engine at that area in the diagram. I am unable to locate anything that looks like the right part here unless the diagram you gave is from under the engine looking up? The first picture I sent in the previous post does have a wire connected and is bolted with 2 small bolts to the engine and does have a small hose attached. That "nub" at the bottom is actually a small hose.

I feel like the part may be the first picture I sent you, although it is not in a very easy place to get at (under everything) so I am hoping it is not. It is in the area of the diagram you posted, just underneath everything.

In my case this part looks like: https://www.carparts.com/details/Mercury/Cougar/Replacement/Fuel_Pressure_Sensor/1999/V6/6_Cyl_2-dot-5L/RM54360002.html

Called a "fuel injection pressure sensor". Would the code I am getting go with that part?

Hi,

Looking at the pic, I'm not sure what you are referring to. The link you sent looks correct. The component will be connected to the fuel rail.

Could you circle the part you're referring to in the pic?

Joe

That is a tube even though in the photo it looks like a cap. It's just a 90-degree tube. And I have no idea what is connected to the "cone" part. Any "replace" videos I watched only had the 1 tube and the electric cable attached. but I could not find one for my vehicle.

Hi,

The cable is for the wiring, the tube is a vacuum port, and the cone appears to be where the fuel line would attach. That is where the pressure is identified.

Joe

Thanks, I will attempt to pull it out and replace it. I think I read I need a special tool to disconnect the fuel line.

Hi,

Yes, you do need a tool. When you look at where the line connects, there will first be a safety clip (usually metal) that you will remove by hand. Once that is removed, look closely where the two connect. You'll notice a spring going around the fitting.

At this point, select the correct size disconnect tool (same diameter as the spring). Next, push in on the fuel line, and using the tool, push the spring back at the same time you are gently removing the fuel line.

I attached an example of the tool below. You can get these at any parts store, and they aren't expensive.

Let me know if you have questions or if there is something I can do to help.

Take care,

Joe

See pic below.

Hey Jacob, I just want to thank you for all the help. I replaced the part but still have the exact same issue. I always had a feeling like maybe something was wrong with a circuit board somewhere, or because I drive it so infrequently, the computer is just no longer able to keep up with the limited data. As I said, my Camshaft sensor always went off until I drove for like 50 miles straight. I think the car is just not meant to be driven that infrequently and I guess I will bite the bullet and buy a new car. But I wanted to thank you for all the help, the replacement of that part went just as you described.

Tommy,

I'm sorry to hear it didn't take care of the problem. Is the vehicle the same as before? Also, you are very welcome, but I don't feel very helpful if it isn't fixed.

Let me know.

Joe

Yes, same as before. I was able to get it to run a little longer today than as of late, but that may have just been random. It still likes to rev up and almost stall out, rev up, stutter and then at some point just stalls. I was originally thinking "dirty gas" as the car is old and I did let the tank almost run dry before this started, but I don't feel like that would cause this problem and would not send the code for the vacuum pump. I will start it again tomorrow and see how long it runs and try to get a new set of codes. The codes today still sent the same code for the vacuum pump. But I have no idea if that was because the car would need to be driven a bit to turn it off. I did get a code that said I did not have enough data and the car needed to be driven more, but of course I cannot drive it.

Tommy,

I wasn't aware this started when nearly running out of fuel.

Have you removed the IAC to check for dirt, corrosion, or anything stuck to the panel? That can cause the idle issue you described.

Let me know.

Joe

See pic below for location. It's mounted on the throttle body.

I am still getting the original P0320 (camshaft sensor) and that has always been my problem. While most often it just went away after driving 50 or so miles, I do always see it and never bother fixing it until I need to get an inspection. The symptoms of this are supposed to be: The check engine light switch is on, Engine goes through a hard start or doesn’t start despite cranking up, Engine hesitates or stalls during acceleration, Engine dies and refuses to restart.

And I have all of those symptoms. I have replaced the sensor many times and that usually (after driving a while) shuts it off. But maybe it is not the sensor and I have a bad wire somewhere, or maybe just because it has been on for so long this time, the computer is too messed up to allow the engine to run long enough for me to reset it? It's been throwing that code for 2 years straight now. I just ignored it after replacing the sensor because the car ran perfect.

At any rate, it seems like a camshaft sensor is pretty hard to fix. Replacing is a snap, but that clearly is not what is wrong with it. Tracing the wiring or checking the circuit board or software is likely well beyond my means.

Tommy,

The P0320 isn't for the cam sensor. It's related to the ignition engine speed input. Do me a favor. When it stalls and won't restart, check to see if there is spark to the plugs. If there isn't, let me know. I don't want to overwhelm you with diagnostics unless that is the issue.

Here is a link that explains how to check for spark:

https://www.2carpros.com/articles/how-to-test-an-ignition-system

Let me know.

Joe

Sorry, I meant P0340.

The engine starts and purrs when it starts for a few seconds. But if I hit the gas, it goes crazy and stalls. And if I do nothing, after a few seconds the engine will rev up, and when it does it is like really chokey and then revs down and runs hard then stalls. But it purrs like a kitten for a few seconds, it just seems like it has no way to "adjust" the idle and has no idea what to do when I give it gas, it seems to get all confused. It seems like as soon as the car has to do any "thinking" it "Panics" and over corrects then under corrects then over then under then stall. And I get a lot of water from the tailpipe.

Hi,

The water could simply be condensation, especially if it is cold. The code makes sense to me now. LOL I attached a pic below which identifies possible causes.

That is the only code, correct? Also, could you record what it does and upload it for me to hear? If possible, do that for me. I will listen to it and share it with two other very good techs here and get their ideas as well.

Let me know.

Joe