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Discussion Starter #1 (Edited)
2000 7.3 auto trans 4x4
How much is too much?
Can excessive fuel pressure cause problems, or damage components like injectors?

I have an “oil leaks” thread up, would have posted this there but the tread doesn’t appear to be getting interest any longer.

While chasing down leaks, I did my fuel bowl. There was an obvious small leak at the drain valve.
I pretty much rebuilt the entire fuel bowl w/exception of the “heater”, I pulled it out and tossed it. I live in the area of Houston Texas.

I purchased all my of my parts from RiffRaff or CNC fab, I’m confident that I didn’t get any junk.
I did rebuild the pressure relief with a kit from RiffRaff.

Prior to these changes, my fuel pressure ran between 50-60 but stayed mostly at 55.

Yesterday I finally got things back together, and the truck fired right up.
I was actually a bit surprised because I was expecting problems (it’s my nature).

Anyway, I cycled the ignition a few times as recommended, cranked it 1 time for about 15-20 seconds and the old 7.3 came to life.

I let it idle for a couple of mins while checking for any obvious leaks, didn’t see any. I put it into “high idle” for another 15 mins or so. After the truck warmed up a bit I drove it. Seemed to run fine, I noticed two things however.

1)a different sound from the turbo, not alarming but different. I’ll address this later with y’all.


2) fuel pressure is now about 90 psi.
It fluctuates between 82-92 even at regular idle.

Is this too much fuel pressure?
Will it damage anything?

Do you think I did something wrong while rebuilding the fuel bowl, if so what should I look at?


Edit:
BTW, my gauges are “glowshift”, I purchased and installed them before I knew any better.
I’ll replace them when I need to but they’ve held up ok so far. I mention this because I know they may not be 100% accurate but they do give me an idea of what’s going on (relatively speaking)
 

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The fuel pump has an internal relief at 100 psi -- the only thing I can see is undue pressure on that relief and wear on the pump

Do you have the fluctuation all the time or only when the engine is running?

I would get an actual gauge on there to test against the setup you have

Not sure there is anything wrong with Glowshift -- sometimes a bad rep is based on a small amount of feedback, with no basis in actual facts
- I suggested using an actual gauge to test, but most buy the cheapest gauge they can find, and rely on that as an accurate representation
- that's why I have general purpose gauges, and my "good" gauges ...well devolves here into a long rant with much hand waving about care and use of gauges ...LoL
 

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Discussion Starter #3
Little extra information.

Drove the truck a bit further today.

Still have 90 psi @ idle

While accelerating the pressure will drop to about 70, while maintaining highway speeds 60-75 MPH the pressure is steady at 80 psi.

Any additional acceleration, psi drops to 70, returns to 80 when holding throttle steady.

At idle, psi returns to 90-92.

Never saw the fluctuation prior to the rebuilding of fuel bowl.
 

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Discussion Starter #4
The fuel pump has an internal relief at 100 psi -- the only thing I can see is undue pressure on that relief and wear on the pump



Do you have the fluctuation all the time or only when the engine is running?



I would get an actual gauge on there to test against the setup you have



Not sure there is anything wrong with Glowshift -- sometimes a bad rep is based on a small amount of feedback, with no basis in actual facts

- I suggested using an actual gauge to test, but most buy the cheapest gauge they can find, and rely on that as an accurate representation

- that's why I have general purpose gauges, and my "good" gauges ...well devolves here into a long rant with much hand waving about care and use of gauges ...LoL


I appreciate your response but I’m a little confused by it.

I don’t understand your question about the fluctuations.
I wasn’t aware that you could have fuel pressure when the engine wasn’t running. Could you elaborate?

As far as gauges.
I’m also not sure what you mean by an “actual gauge”.
The fuel pressure gauge I have is an “actual” gauge as far as my knowledge goes.
It has a sensor thats placed into a port on the fuel bowl, that sensor is read by the gauge on my pillar cluster.

Please pardon my ignorance.
 

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Maybe I'm wrong, but the 2000 model should have an electronic fuel pump that runs with the key on - so you would see fuel pressure soon as you turn the key

What you have is an electronic sensor, I was suggesting a standard gauge to test the accuracy of the sensor -- sensors while convenient to use, can get damaged and read 'off'

I like electronic gauges, but always verify with an analog gauge, if a reading is in question
 

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Discussion Starter #6 (Edited)
Maybe I'm wrong, but the 2000 model should have an electronic fuel pump that runs with the key on - so you would see fuel pressure soon as you turn the key



What you have is an electronic sensor, I was suggesting a standard gauge to test the accuracy of the sensor -- sensors while convenient to use, can get damaged and read 'off'



I like electronic gauges, but always verify with an analog gauge, if a reading is in question


You’re not wrong, I just didn’t grasp the concept when I first read your reply.

When I turn the key on but don’t start the engine, I’m getting 82psi.
When I start the engine and it runs 20-30 seconds it jumps up to the 90-92 psi range.

It’s still fluctuates while idling between 92- 82.

I’ve never seen the fluctuation like this.
I’m concerned that I did something wrong, I’ve considered that maybe it’s just some air in the system that needs to work it’s way out.

The truck seems to be running fine, my main concern it that this level of fuel pressure may be bad and cause some damage in places that I don’t want to go.
 

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Discussion Starter #7
I did change brand of fuel filter while doing this work.

Is it possible that the new fuel filter is effecting fuel pressure.

I made the change because my cap was buggered up and I needed a new cap and filter.

I bought a filter that came with a cap already in place.


This is what I’m currently using.
 

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There are two ports to take pressure readings from, one is before the filter and the other is after -- the lower plug, more toward the rear is post filter and proper in my opinion

Also the small screen between the fuel bowl and regulator valve may be plugged
 

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Discussion Starter #10
No need to be over 65psi. 100psi and you run the risk of cracking the fuel bowl.

Sent from my Pixel 4 XL using Tapatalk


Thanks for responding.

My dilemma is, that I don’t know what what caused the increased fuel pressure, and I’m worried that 90 psi is to much.
 

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Discussion Starter #11
There are two ports to take pressure readings from, one is before the filter and the other is after -- the lower plug, more toward the rear is post filter and proper in my opinion



Also the small screen between the fuel bowl and regulator valve may be plugged


I don’t recall seeing a “small screen” when I did the work.
Guess it’s possible that I lost it, could that be the reason for increased fuel pressure?
 

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Discussion Starter #12
Is it possible that the old spring was worn, and replacing the spring that was included in the kit caused the increase?
 

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Lemme check my crystal ball ...LoL
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Pull the regulator back off and check -- there are vids that show the screen
 
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