Fuel leak

madmikeismad

madmikeismad

So mad
Joined
Dec 19, 2009
Messages
14,347
Figures this had to happen when it gets cold out.

I haven't run the truck in a couple weeks. Go to start it today and it takes forever to start, just attributed it to the cold. When it finally starts I notice a very fast drip on the ground behind the axle. I smell it, it's #2. I start rolling around on the ground and narrow it down to the lift pump.

If the leak is coming from lift pump/heater, what are my options? I know some people say bypass, and I already have a extra holley pump, should I just go ahead and do that?

PS: Also adding to my good luck, the belt literally fell off my other car last night. No pulleys broke or anything, the belt just fell off lol.
 
Also if I bypass the lift pump with the new pump, is it safe to just leave the lift pump in the block pumping air?

EDIT: used my brain for a minute, and realized that a fuel squirting must mean its after the lift pump. If it was before it would be sucking air, right?
 
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and i had the same prob and figured out that the seal around my primer button dried out and was causin it to leak..i could press the primer button and have my hand covered in fuel when i pulled it out so u may check that
 
You need to dig in there, get your hands dirty, and figure out where the leak is coming from.

Bypassing the stock pump is a bad idea unless you pony up and a buy a real 300 - $600 lift pump setup. A holley pump by itself does not create enough pressure for the injection pump. You would loose power running around with just 10-14 psi and it would probably hurt the injection pump over time.
 
I was gonna look more in depth at it tomorrow, it was too cold and snowing today. But I definitely think the leak is coming from somewhere in the pressurized part between the lift pump and main filter now. I'll let you guys know what I find. I'm hoping it's just a fitting or something that loosened up when it got cold.

I will also check that primer button. Thanks for the help guys.
 
Did you check the drain valve on the filter canister? I had that happen on my 24v, left a big puddle while I was wondering WTF? Just had to close it and was good to go. Simple and free possible solution.
 
I have it narrowed down to the rubber hose that runs behind the fuel filter. It's leaking and the fuel is running down the hose to the hose clamp where it joins the metal line.

What is that line? Is it the return line? If it is, why am I losing prime?
 
Your supply and return hoses connect behind the filter. Just swap the hose and call it good.
 
The only rubber hose behind the filter should be the stock supply line. Basically the stock supply line is a hard line from the tank to the firewall, from there it transitions into a 2 foot long combination of braided flex line and rubber line that is shaped like a rainbow and runs up behind the filter to a clamp and then down to the stock fuel bowl/heater/prescreen. From the bowl the line is a 3" long 1/2" 90* rubber elbow that feeds the suction side of the factory lift pump. The outlet on the factory lift pump goes straight up in hard line to the factory fuel filter/banjo bolt. Also connected to the banjo bolt is a 12mm smaller banjo bolt fitting that connects to the small injector overflow/return line. After the fuel is filtered, it exits the factory fuel filter via banjo bolt and hard line and runs about 1' to the injection pump inlet.

The return line from the back of the injection pump is a combination of hard line and flex braided line that runs behind the filter and down to the firewall where it transitions into hard line all the way back to the tank.

In short, if you leak is from a rubber line, it's the supply line that connects the factory hardline at the firewall to the the fuel bowl/prescreen/preheater.

You have two easy options to fix the leak and hard starting problem, buy 3' long piece of 3/8" rubber fuel line from local autoparts store and run it directly from the hard line at the firewall to the lift pump inlet and completely bypass the factory prescreen/fuel bowl/heater. To do this you will also need to buy a brass fitting to replace the 1/2" fitting at the lift pump inlet with a 3/8" barbed fitting. The threaded portion of this fitting would need to be 1/2" NPT.

Your second easy fix option is to buy a new factory fuel line and retain the stock fuel bowl heater/prescreen setup. Be advised, this line is a royal PITA to remove and reinstall, even on a truck with the inner fender removed. I personally would just bypass the factory preheater/prescreen bowl unless you live in Minnesota, Canada, or some other really cold climate.
 
Big Blue24 said:
The only rubber hose behind the filter should be the stock supply line. Basically the stock supply line is a hard line from the tank to the firewall, from there it transitions into a 2 foot long combination of braided flex line and rubber line that is shaped like a rainbow and runs up behind the filter to a clamp and then down to the stock fuel bowl/heater/prescreen. From the bowl the line is a 3" long 1/2" 90* rubber elbow that feeds the suction side of the factory lift pump. The outlet on the factory lift pump goes straight up in hard line to the factory fuel filter/banjo bolt. Also connected to the banjo bolt is a 12mm smaller banjo bolt fitting that connects to the small injector overflow/return line. After the fuel is filtered, it exits the factory fuel filter via banjo bolt and hard line and runs about 1' to the injection pump inlet.

The return line from the back of the injection pump is a combination of hard line and flex braided line that runs behind the filter and down to the firewall where it transitions into hard line all the way back to the tank.

In short, if you leak is from a rubber line, it's the supply line that connects the factory hardline at the firewall to the the fuel bowl/prescreen/preheater.

You have two easy options to fix the leak and hard starting problem, buy 3' long piece of 3/8" rubber fuel line from local autoparts store and run it directly from the hard line at the firewall to the lift pump inlet and completely bypass the factory prescreen/fuel bowl/heater. To do this you will also need to buy a brass fitting to replace the 1/2" fitting at the lift pump inlet with a 3/8" barbed fitting. The threaded portion of this fitting would need to be 1/2" NPT.

Your second easy fix option is to buy a new factory fuel line and retain the stock fuel bowl heater/prescreen setup. Be advised, this line is a royal PITA to remove and reinstall, even on a truck with the inner fender removed. I personally would just bypass the factory preheater/prescreen bowl unless you live in Minnesota, Canada, or some other really cold climate.
Click to expand...

Like North Dakota?
Its leaking at the red hose, somewhere behind the filter. Is that the hose you guys are talking about?
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Yes, and the other one beside it. One is 5/16 and other is 3/8. Both short maybe 15" long. Use good hose, marine quality.
 
It was that 5/16 hose. It looked like it was made of snake skin. Fuel was shooting out like a supersoaker by the time i got it to the garage. Took 2 hours with my big hands, but I could probably do it again in half hour now that I know exactly what to do.
 
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