Fuel drainback or what?

[scotty-u]

2000, 2500, 4x4, 5spd, stock truck, 314,200 miles. Made a short mileage run to the trash station earlier today and had this happen. Started truck to warm up a bit before leaving. Drove 5-6 miles to trash station. Weighed in, and then parked truck and shut it off as the line was long ahead of me. Parked on an approximate 30 degree incline (front end higher) for maybe 5 minutes . Restarted to move in line, and immediately the truck begins to idle rough, like i have experienced in the past with ff changes. Got it up on the level, and even slightly nose down, still idling rough. Back in, shut it off. Unloaded. Got back in hoping it would start, and it did, ran like normal. No problems with power on the way home.

This is the first time that I can think of that the truck was parked on an incline as mentioned above. Everywhere I park is either level or slight nose down.

Details: full tank of fuel with 60 miles on it filled up last week). Reputable fuel supplier. (Don't fill up when they are unloading). Fuel filter was changed last fall, due again at next oil change, next month. No fuel pressure gauge ( I know...I know). Lift pump around 2 years old, hummed its usual 15 - 20 seconds at first startup (didn't pay attention to subsequent starts). Temperature around 30 degrees. No fuel is showing up on the ground.

Your thoughts? Thank you.

 

[Vaughn MacKenzie]

It could be your overflow valve is bad. It is on the side of your VP44, at the fitting for the fuel return line. Cummins 3941156. Buy the Cummins part, not an eBay knockoff.

 

[petersonj]

Fuel drainback or what?

Parked on an approximate 30 degree incline (front end higher) for maybe 5 minutes .

I think you are on the right track with your thinking. Just a small air leak into the fuel line can cause this. Fuel won't necessarily leak out, but air can leak in - especially when the truck is parked as you mentioned.

I would not be concerned with the overflow valve - they very rarely, if ever, fail. There is already a drilled orifice that bypasses around the overflow valve for automatic bleeding of air, so a faulty overflow valve would not cause your symptoms.

Check your fuel lines carefully for cracks, chafing, tears, etc. - suctions lines and return lines, including the return line from the back of the head.

- John

 

[gtwitch]

On my 99 2500, I had a similar problem and was and it was an air leak at the top of the fuel filter above the starter where I had put my fuel Pressure sensor and I found it by spraying soap water on the pipe fitting ( fuel pressure sensor) while cold or before starting and I think that what was happening was that after shutdown, air was being pulled back into the top of the fuel filter can as it cooled down and then at start up, I saw air coming out of the bottom of the sensor threads until air was gone and no fuel would leak at those threads, but this would still happen at the next cool start up so I carefully put teflon tape( yes I know) on the threads and carefully tightened and no more problems to this day (5 years or so) I have a newer 2017 2500 but this 99 2500 is still my daily driver at 20 + mpg but is a bucket of rust but I haven't lost any critical parts falling off yet!
gtwitch in wyoming