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Discussion Starter #1
Good afternoon fellas,

My '95 has developed a slow but steady fuel leak from somewhere up along the side of the block. A few months back one of the braided steel fuel lines, just forward of where it was crimped onto the hard line, rubbed through on the bottom of the cab and was absolutely dumping fuel everywhere. Fixed that with the fancy marine-grade diesel fuel line that is recommended. Also, a few years back the rubber return line dry rotted and cracked, and was letting air into the system and making it hard to start. That was a royal pain but we got it swapped out.

My question is, does anyone have a mapped-out diagram of the entire fuel system on these trucks, from the tank to the P pump and injectors? I'd like to have an idea of where to start looking and what all may be questionable now at 315,000+ miles that I should go ahead and replace while I'm in there.

I'd also like to add a fuel pressure gauge while I'm in there; I know it's not nearly as important to have a gauge on a P7100 as it is a VP44 but it would still be nice to keep an eye on it. I understand you have to put a snubber in the sensor line to keep the gauge from being killed by the pump's spikes in pressure, where exactly does the gauge tie into on the pump?

Thanks in advance,
Lane
 

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Look in the stickies at the top of this forum: Beginners info, Free factory service manual download and Joe G'sFuel system writeup (referenced in the stickies and many, many times in this forum).

If you search for fuel pressure gauge, you'll also find lots of info on how to do that. You'll find that you can tie in at the banjo bolt exiting from the main filter or the banjo bolt on the P7100 inlet. Also, snubbers aren't sufficient - you'll want a needle valve.
 
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I BET I KNOW!!!!

Look at the hard line towards the front of the engine/head. There are mounts welded to the hard line so that the hard line can be bolted to the intake or pump, or whatever, that's not the point. Look at the first mount. I'll bet it is broken on the back side on the weld and spraying onto your block. I'm guessing you don't need to ask how I know this? It took me way too long to figure out where my leak was coming from, drove me crazy.
 
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Discussion Starter #4
I BET I KNOW!!!!

Look at the hard line towards the front of the engine/head. There are mounts welded to the hard line so that the hard line can be bolted to the intake or pump, or whatever, that's not the point. Look at the first mount. I'll bet it is broken on the back side on the weld and spraying onto your block. I'm guessing you don't need to ask how I know this? It took me way too long to figure out where my leak was coming from, drove me crazy.
I'll certainly look into that lol thanks fellas!
 

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Another place to look is the return line. Perhaps Torquewinsraces is referencing the same thing, if you stand on the driver side of the truck and look at the engine, directly behind the brake master cylinder and fuel filter there is a steel tube to rubber hose for your return fuel line. The rubber hose has been a culprit for me on several occasions, though I had some hard start issues along with it.
 

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Another place to look is the return line. Perhaps Torquewinsraces is referencing the same thing, if you stand on the driver side of the truck and look at the engine, directly behind the brake master cylinder and fuel filter there is a steel tube to rubber hose for your return fuel line. The rubber hose has been a culprit for me on several occasions, though I had some hard start issues along with it.
Yes, that's exactly what I'm talking about. It's after the overflow valve (is that what it's called?). Mine was broken at the first mounting point. I couldn't even see the fuel spraying without a flashlight shining down there. It was a pinhole leak that was spraying back and down so it was next to impossible to see unless you were looking right at it.
 
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