Rust in Fuel system:

[93PONY]

I recently bought a 2000 F250.

When swapping the fuel filter I noticed corrosion in the fuel bowl. (Rust)
I cleaned it all out at that time.

I've been modifying the truck much like my last 2001 and have noticed a few things.
1. This truck is louder than my 2001.
2. This truck does not make nearly as much power. New truck averages 275/540 RW on my chassis dyno with a Max of 295RWHP. My 2001 with LESS mods and the same tune made an average of 305/600 RW on my dyno with a maximum of 342/699 RW (stacked tunes).
3. On my 2001 I was able to add enough pulse width through the tune that the truck ran out of High Pressure oil which made TONS of noise through the injectors. (sounds similar to pinging) My 2000 has not ever made this noise with increased injector pulse width, as if it's not running out of oil, yet power does NOT increase at all with more injector time thru the tune.
4. My 2001 would throw the typical ICP tune codes assosiated with an agressive tune. My 2000 does not throw any codes with the same tune(s).
5. This 2000 takes much longer to start at all times than my old 2001. In fact, I've had to increase fuel at startup to get the 2000 to start up marginally faster.

I recently pulled the fuel feed/return line to/from the fuel bowl and replaced it. The old line was a bit rusty both inside & out.

Yesterday I pulled the fuel tank and dis-assembled the platic filter housing on the fuel pickup. Both stainless steel screen filters were completely full of rust.....so much so that rust was acumulating in other areas as the filters were full. I cleand the filters & re-installed. Fuel level rod assembly was very rusty, but did not have enough metal surface area to be the sole source of the rust. No rust in the bottom of the fuel tank.

My question:

Where is the rust coming from?
Fuel tank is plastic, steel fuel lines don't show enough corrosion on the inside to be the sole source. Fuel Bowl is aluminum. Can it be from the Iron heads (internal fuel rails)?
If so.....does this mean my injectors are excessively worn and need replacing since at that point there is no filter? Or does fuel never leave the heads due to the fuel return line being at the fuel bowl? In which case rust in the heads would never make it's way back to the fuel tank?

FWIW, the truck runs smoother than my 2001. No rough idle or anything.

[LBSRACING]

Man the only thing I can think of is its coming in with your fuel from the pump.

[93PONY]

Originally Posted by LBSRACING

Man the only thing I can think of is its coming in with your fuel from the pump.

Hmm..... I hadn't thought of that.

I guess it's a good thing I swapped the fuel pump out when I bought the truck 2 months ago.

So, lets assume I've gotten rid of all the rust and stopped it at the source (I run fuel treatment which sould stop the rusting).

What other parts in the system should I replace that are likely to be damaged?

[Hank]

I agree that the rust must have come from the fuel source. Did previous owner fill it up from a farm tank? I dropped my fuel tank a few weeks ago and it was perfectly clean in there except for a few flakes of what looked like black paint. I found the source to be the steel filler neck and vent tube sections. Are yours rusty?

[93PONY]

Originally Posted by Hank

I agree that the rust must have come from the fuel source. Did previous owner fill it up from a farm tank? I dropped my fuel tank a few weeks ago and it was perfectly clean in there except for a few flakes of what looked like black paint. I found the source to be the steel filler neck and vent tube sections. Are yours rusty?

Who knows what the previous owner did. I bought it from a Dealer. All I know is that it was a one owner truck and was local. Which does not explain the rust since we have very little corrosion problems here due to weather.

Did you remove the 2 filters in the plastic housing? Or were the flakes on the large screen on the bottom of the pickup assembly?

The pickup assembly screen (sits on the bottom of the tank) on this truck was 100% spotless, no clogs. The 2 internal small screen filters was were I found all the rust.

[LBSRACING]

Originally Posted by 93PONY

Hmm..... I hadn't thought of that.

I guess it's a good thing I swapped the fuel pump out when I bought the truck 2 months ago.

So, lets assume I've gotten rid of all the rust and stopped it at the source (I run fuel treatment which sould stop the rusting).

What other parts in the system should I replace that are likely to be damaged?

Well all that rust in the system is never good for injectors.

[93PONY]

Originally Posted by LBSRACING

Well all that rust in the system is never good for injectors.

Agreed.
But did it get to the injectors?
Rust was found in the fuel bowl and tank filters.
Since the Fuel return line is at the bowl, this indicates the rust, or at least the rust that I've found, was generated in either the feed line TO the bowl, or return line FROM the bowl. The fuel filter in the bowl *should* have stopped any rust from entering the rails in the heads, HOWEVER, that does not mean that the rails (in the heads) are not rusty as well. It makes perfect sense that rust in one section of the system would mean rust everwhere....
Although I do not know if rust can form IN diesel fuel. It does not form in gasoline, you must have no fuel in the lines for rust to form in a gasoline system.

I'm assuming the rust formed while the truck was sitting at the dealership waiting to be sold, with low fuel in the tank.

Of course, if rust CAN form in un-treated diesel, that throws that out the window, and then I should assume the internal rails in the heads are just as rusty as the rest of the fuel system. In which case the injectors might even be rusty.