wana12v

When my truck sits for a long period of time it has to crank a while to start, I looked under the hood and found that the fuel line that goes down by the starter is wet. So can somone give me the part number, or what size and length line i need. thanks

infidel

You need to clean it up down there and find exactly where it's leaking otherwise you'll just be throwing parts at it.
The return line (in red below) is most often the one that leaks and will drip down on the starter.
Return and intake hose kit availible here http://www.fostertruck.com/dodge/default.htm

Jeremy Cusick

Yeah, that's the FUN one to get to, too.

TRCM

OK.

I have read in several posts that a leaking return line will cause hard starting. Can someone explain to me how ?? I fail to see it.

Now, a leaking supply line, which lets the fuel/pressure in the line go away, yes, I can see that.

But how the return line affects the supply...I can't.

Is there a check valve or something in the lift pump that holds pressure for the next start-up ? I have noticed on my truck that it takes a bit longer to start, and the fuel pressure comes up slowly, like the supply line is draining back to the tank.

I have good pressure, so I really don't think I have any leaks.

Rrloren

I can't answer why it happens but I can tell you it affects starting, it happened to me on a trip earlier this year. Started to crank several times before firing up then in a few days was spewing fuel all over the engine and bottom of truck. Turned out to be the metal line was cracked.

infidel

Think of it as holding water in a straw with your finger over the end. If the return line leaks air is sucked in as the feed line drains back to the tank. This air most often ends up in the injection pump and causes an airlock that must be overcome with extended cranking in order to start. If there are no leaks it's like your finger on the end of the straw, no air will be sucked in and the fuel won't drain back to the tank. A leak anywhere in the system, supply or return can cause this. This is also the reason the return line can suck air but not leak fuel, looking for a leak can be fruitless.
Supply line leaks before the lift pump suck air when the engine is running and cause poor performance, leaks after the pump spew fuel.

I've heard several theories on why the return lines are so prone to leaking.
I believe it's just too hot strapped to the block with the cheap hose Dodge uses. Had heard that some think the engine paint attacks the hose.

TRCM

I understand your analogy, but if the overflow valve is sealing correctly, there is no way for air that is sucked into the return line to get past it to the injection pump. That is what I can't figure out. If the overflow valve is bad or missing, then yeah, it will work like that.

I have a brand new overflow valve, and it has been shimmed, so I know it isn't letting air past, or shouldn't be anyways.


I'm wondering if their is a check valve or something in the lift pump that is letting it drain down. If not, then the only other explanation is the preheater/screen assembly.

ticki2

Regardless of why , change the line. Mine started an engine fire , not very pretty.

TRCM

I am going to change it, but I like to understand why things happen also, not just do it because.

infidel

The reason air can get by the over flow is because it isn't designed to be a check valve. It's pressure relief valve and doesn't make a complete seal unless under pressure.

TRCM

um....guess I'm still missing something. The overflow valve spring is what keeps it sealing (spring presure holds the ball against the seat).....and pressure overcomes the spring to let it pass fuel.

how can it not seal ? if it is a pressure relief valve (which by design it is), then it better seal when not under pressure, or it will be the 1st pressure relief valve I have ever seen that doesn't (and I have worked on too many style relief valves to count).

Now, if it is a pressure regulating valve, then yes, it's design may allow a constant minute flow of fuel past it, and when the pressure builds, the ball moves to allow MORE flow past it. It didn't appear to be a regulating valve when I had the old one apart.

Even if it is a pressure regulating valve by desgin more so than a relief valve, I still can't see how it can bleed down and give the problems it supposedly does. On my engine, the fuel would have to flow up against gravity to do that.


Yeah, I am probably coming across as being difficult, but I am trying to understand why this supposedly happens, cuz logically, it shouldn't. I'm not trying to be difficult.

infidel

Guess you'll just have to accept the fact that's how it works.
Been proven who knows how many thousands of times that a leak in the return line allows air into the injection pump.

ccmckee

The rubber hose itself gets pinholes in it from the fuel,the air gets sucked into these pinholes and allows the fuel to leak down. Thus usually you get the hard start symptom with no visible leak anywhere. Most guys reccomned buying marine grade diesel rated hose to replace all the rubber fuel lines, which i beleive the fosters kit is.

Baja

Is there a test that one can do to see if the line is pulling air? Also, can this line pull air and not have fuel leak out? I have been pulling a lot of air and have found a few problems that I have fixed, but I am still pulling air. I do not want to throw parts at the truck, but I am running out of ideas. One problem I did not have is hard start, it starts instantly. Thanks.

infidel

If you pressurize the fuel system to about 10psi though the fuel fill with with compressed air you can usually find leaks.
I use an old fuel cap drilled and tapped with a tire chuck to do this but you can also wrap an air blow gun with a rag wrapped around it. The rag method will take two people though because the pressure leaks down fast.