Another fuel pressure question

[Jeffrey Moore]

So, my (new to me) 2004 Ford explorer sport trac v6 4.0L SOHC, 2 wheel drive, automatic transmission truck has what I'm guessing to be a fuel delivery issue...in a nut shell, it's idling somewhat fairly decent (a little rough, but not terrible) and by the way, I use Forscan paid version, both windows and android, with an elm327 bluetooth adapter mostly on my phone...ok, issue is the ole hesitation with acceleration , from a dead stop, going up inclines or while at full speed when releasing the throttle and re applying it to maintain speed however, whenever this occurs in any of the aforementioned scenarios, I simply let off the gas pedal and re apply throttle but a little slower and steadier and that helps significantly Also. In the case that I am on the highway (full speed scenario) I can turn the od off and I don't have to baby it as much. With all that being said, let's go to truck in park, engine running and recording live data stream with forscan (android).. so watching the fuel rail pressure as per the sensor I am getting from 49.5 to 50.3 without applying throttle, whenever I apply throttle and depending on how aggressively I apply it, FRP may jump up to as close as 55.0 psi or drop as low as 47.0 psi ( oh and I'm not sure if this is a safety precaution or a problem, but when I try to rev my engine while in park, just revs up and down like its being governed or something) ok, back to FRP. So when ever I turn my engine off key on (ignition on) my FRP goes to around 72.0 psi and maintains that pressure as long as the key is on. I have not replaced anything as of yet because I want to pinpoint the problem and I have not physically checked the FRP with a fuel pressure gauge because I don't have a test port or shrader valve on my fuel rail. My first line of action no matter what the issue is to replace my fuel filter, as I don't know how old it is and that is a cheap and worthy cause.. I did notice while I was under my truck on one of my many investigational inspections that the RUBBER line from the tank to the in port on the existing filter is attached and secured to the filter via a hose clamp and not the normal fuel line attachment method requiring the special tool to remove, but the output side of the filter has the standard line and clip. Also at this location there is what I am assuming is another fuel related line
(Not attached to my fuel filter) that has a fitting with a 90 in the line right there at the filter location and is made of the hard plastic. At the point where the 90 is, it appears as if a critter or something has chewed the plastic and it has chew mark indentations there which I am almost positive go all the way through the line. So I am assuming that being that line is not connecting to the filter, but goes from my purge valve in the engine bay located on the driver side fender wall to a T at the bed of the truck then to the gas fill line ant to the canister above the spair tire, that it should have NO EFFECT on my fuel pressure or fuel delivery....but I don't know this for sure. Ok, one more thing. There is a hard plastic fuel line what comes from the driver's side of a T fitting to my fuel rail and its routing takes it down the side of the engine and apparently to close to the exterior manifold at some point in the past because there is a c shaped indentation on that line about even with the valve cover for location purposes, and it appears as this indentation was caused by extreme heat therefore burning a spot on that line with looks to be the half of that line. I'm not positive if this is a reliable method to check this line for leaks, but I sprayed soapy water on the afflicted area while the truck was running and could not see any bubbles revealing any leaks but then again, I'm not sure If that line is under vacuum, pressure, or if it even matters but I will say "If it's not leaking, it's missing a great chance to" nevertheless, there is definitely a weakness in the line at that point and could even be causing that line to collapse when throwing down on the accelerator so I will be replacing it no matter what. Anyhow, very sorry for the extremely long novel of a post but I'm just trying to be thorough. Also, I have gotten a code for random misfires at startup and a once I got a code for misfire on cylinder 3 after I floored it from around 45 mph and didn't let off until about 65 mph . It was stuttering a little and ofcourse not performing at its best although it was trying really hard, I can definitely see its potential. Anyhow, I'm going to post this now and I can answer more direct questions as needed.

Thanks so much, Jeff Moore

 

[Jeffrey Moore]

So, my (new to me) 2004 Ford explorer sport trac v6 4.0L SOHC, 2 wheel drive, automatic transmission truck has what I'm guessing to be a fuel delivery issue...in a nut shell, it's idling somewhat fairly decent (a little rough, but not terrible) and by the way, I use Forscan paid version, both windows and android, with an elm327 bluetooth adapter mostly on my phone...ok, issue is the ole hesitation with acceleration , from a dead stop, going up inclines or while at full speed when releasing the throttle and re applying it to maintain speed however, whenever this occurs in any of the aforementioned scenarios, I simply let off the gas pedal and re apply throttle but a little slower and steadier and that helps significantly Also. In the case that I am on the highway (full speed scenario) I can turn the od off and I don't have to baby it as much. With all that being said, let's go to truck in park, engine running and recording live data stream with forscan (android).. so watching the fuel rail pressure as per the sensor I am getting from 49.5 to 50.3 without applying throttle, whenever I apply throttle and depending on how aggressively I apply it, FRP may jump up to as close as 55.0 psi or drop as low as 47.0 psi ( oh and I'm not sure if this is a safety precaution or a problem, but when I try to rev my engine while in park, just revs up and down like its being governed or something) ok, back to FRP. So when ever I turn my engine off key on (ignition on) my FRP goes to around 72.0 psi and maintains that pressure as long as the key is on. I have not replaced anything as of yet because I want to pinpoint the problem and I have not physically checked the FRP with a fuel pressure gauge because I don't have a test port or shrader valve on my fuel rail. My first line of action no matter what the issue is to replace my fuel filter, as I don't know how old it is and that is a cheap and worthy cause.. I did notice while I was under my truck on one of my many investigational inspections that the RUBBER line from the tank to the in port on the existing filter is attached and secured to the filter via a hose clamp and not the normal fuel line attachment method requiring the special tool to remove, but the output side of the filter has the standard line and clip. Also at this location there is what I am assuming is another fuel related line
(Not attached to my fuel filter) that has a fitting with a 90 in the line right there at the filter location and is made of the hard plastic. At the point where the 90 is, it appears as if a critter or something has chewed the plastic and it has chew mark indentations there which I am almost positive go all the way through the line. So I am assuming that being that line is not connecting to the filter, but goes from my purge valve in the engine bay located on the driver side fender wall to a T at the bed of the truck then to the gas fill line ant to the canister above the spair tire, that it should have NO EFFECT on my fuel pressure or fuel delivery....but I don't know this for sure. Ok, one more thing. There is a hard plastic fuel line what comes from the driver's side of a T fitting to my fuel rail and its routing takes it down the side of the engine and apparently to close to the exterior manifold at some point in the past because there is a c shaped indentation on that line about even with the valve cover for location purposes, and it appears as this indentation was caused by extreme heat therefore burning a spot on that line with looks to be the half of that line. I'm not positive if this is a reliable method to check this line for leaks, but I sprayed soapy water on the afflicted area while the truck was running and could not see any bubbles revealing any leaks but then again, I'm not sure If that line is under vacuum, pressure, or if it even matters but I will say "If it's not leaking, it's missing a great chance to" nevertheless, there is definitely a weakness in the line at that point and could even be causing that line to collapse when throwing down on the accelerator so I will be replacing it no matter what. Anyhow, very sorry for the extremely long novel of a post but I'm just trying to be thorough. Also, I have gotten a code for random misfires at startup and a once I got a code for misfire on cylinder 3 after I floored it from around 45 mph and didn't let off until about 65 mph . It was stuttering a little and ofcourse not performing at its best although it was trying really hard, I can definitely see its potential. Anyhow, I'm going to post this now and I can answer more direct questions as needed.

Thanks so much, Jeff Moore

So, did I make my post to long for anybody to read? I kind of overkill things alot of times!

 

[Mr. Alligator]

So, did I make my post to long for anybody to read? I kind of overkill things alot of times!

Yes.

 

[Mr. Alligator]

There are wiser wizards on this Forum, but here are some thoughts:

*. Remove and replace the rubber hose patch in your high pressure fuel system, for safety.

*. Remove and replace the “critter chewed” lines.

*. Remove and replace the heat damages lines.

Does not sound like a fuel pump issue to me.

Is your engine throwing any other codes?

 

[Jeffrey Moore]

There are wiser wizards on this Forum, but here are some thoughts:

*. Remove and replace the rubber hose patch in your high pressure fuel system, for safety.

*. Remove and replace the “critter chewed” lines.

*. Remove and replace the heat damages lines.

Does not sound like a fuel pump issue to me.

Is your engine throwing any other codes?

It just started throwing s code suggesting that there is a small leak in th evap system which could be the critter chewed line

 

[Mr. Alligator]

When was the last time you changed spark plugs and wires?

 

[Jeffrey Moore]

When was the last time you changed spark plugs and wires?

I just bought the truck, so I haven't changed anything as of yet, however I did look at a couple of the plugs and they looked good and it looks like the spark plug wires are fairly new but I'm not really comfortable with them and the way they fit and routed

 

[Mr. Alligator]

I would probably change plugs and wires, just to give a maintenance starting point. Check and pay careful attention to plug gaps and firing sequence (it is easy to make an error on firing order, but that probably makes the engine run worse than yours). Although I think I have heard of engines run on wrong firing order for lengthy periods.

Still guessing that it sounds electrical. Throttle position sensor? Don’t know.

If none of these simple things resolve it, one option would be to take to a Ford Dealer for $90 diagnose ONLY. Then decide what to do with the repair.

 

[Mr. Alligator]

just saw this Firing order comment from the Forum....

..... the same mistake everyone here makes over and over again. (Me included.)

Recheck your spark plug wire firing order, and do it again. seriously. driver side is the side of coilpack where most of the confusion is

FRONT OF ENGINE