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2001 Chevy c3500hd
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Discussion Starter · #1 ·
I have a fuel leak that appears to be coming from the rear of the engine. Seems to be dripping near the bell housing and starter. Any advice where to start?
 

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I have a fuel leak that appears to be coming from the rear of the engine. Seems to be dripping near the bell housing and starter. Any advice where to start?
The usual suspect is your FFM (Fuel Filter Manager).
There are 3 rubber hoses connected and a couple of O rings on the FFM that will leak
 

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Yep there is a drain hole that drains anything in the valley of the engine out the back. Its also possible that you have a return line on an injector on that side leaking but with the hot exhaust there also it would likely burn off before it actually caused puddles.

The FFM is the housing that holds the fuel filter. Could be the gasket at the top of the fuel filter element. Could be the O ring for the water in fuel sensor. Could be the o ring for the fuel heater. Could be any of the 3 hoses involved some of which run under the intake to get to the IP or water drain valve. If that all happens to be dry then it could be the injection pump itself is leaking which is a lot more complex and expensive to deal with.

Many of us relocate the FFM higher to make access and inspection easier. A popular method (which seems more complex to me) is to get threaded rod and just raise it up using its current mounts. My method is to hang it off one of the upper plenum bolts. This method doesn't require any new hardware other than hoses that you were likely there to replace in the first place. With both methods you don't need to have special hoses or run them under the intake. Raising it allows the use of normal (non pre bent) hoses.
 
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The FFM is the thing that holds the fuel filter. The top of it is visible on the top of the engine against the fire wall where the distributor would be on a classic Chev gas engine. Its either a silver metal cap or a black plastic one. Both styles have a big thumb screw with a spout on em for bleeding air out. Its really tucked down there and there isn't really any slack in the hoses so its a pain to work on in its factory location. You can fish new hoses under the intake if you attach a wire or new hose to the old one and snake it through. I didn't think it was worth the trouble so I just moved it so now its all easy to access if I ever need to again.
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2001 Chevy c3500hd
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Discussion Starter · #6 ·
I pulled the intake manifold and there doesn't seem to be a very obvious leak. The only place that looked a little bit suspicious was the bottom of the FFM. I ordered the seal from a GM Dealer and plan to replace most of the hoses and clamps since I am already in there. Do you just have one bolt holding the FFM up? Also is that sufficient enough or are there kits to help relocate it?
 

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There is no kit to relocate FFM.

I bought 1 meter (the selling unit length) of M10-1.50 threaded rod and cut it to around 9 to 9.25 inches.
Get a few washer nuts and use the existing bracket to hold it up above the intake.
The hoses can now go above the intake.
 

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Mine in the photo only uses one bolt. Its tight to the back of the intake so its not like its just hanging on that one ear. The hoses at the bottom are just about touching the intake too so its not miles in the air.either. Its been that way for a few years now with no issues related to the fuel manager.
 

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Discussion Starter · #9 ·
I pulled the FFM out, cleaned it, and replaced the heater seal on the bottom. Filled it back up with diesel, fired it up, ran for about 30 seconds then died. I attempted to bleed the air out through the filter but now it won't start at all. Do you think there could be debris clogged in the lines or just the air in the lines? If I have to bleed the air out through the injectors, do I have to crack all 8 lines?
 

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I pulled the FFM out, cleaned it, and replaced the heater seal on the bottom. Filled it back up with diesel, fired it up, ran for about 30 seconds then died. I attempted to bleed the air out through the filter but now it won't start at all. Do you think there could be debris clogged in the lines or just the air in the lines? If I have to bleed the air out through the injectors, do I have to crack all 8 lines?
Just open the bleed screw on top of the filter housing and let it bleed air till you see fuel come out from the bleed screw.
You can also apply a jumper wire to the lift pump to help force prime everything. Shown here- Question: - Help...Fuel pressure drops after several...
 

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Discussion Starter · #11 ·

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Thanks, I can hear the lift pump but I can't get any fuel to come out.
Apply the jumper wire to the lift pump connector. Open the T valve and let fuel flow into a container.
You should see 1/2 pint of fuel within 15 seconds in the container.
If you do not, replace the lift pump
 

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Discussion Starter · #13 ·
Apply the jumper wire to the lift pump connector. Open the T valve and let fuel flow into a container.
You should see 1/2 pint of fuel within 15 seconds in the container.
If you do not, replace the lift pump
The line from the lift pump to the ffm had a kink in it.
 

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