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Discussion Starter · #1 · (Edited)
i've gone thru most of the fuel leak posts and mine seems pretty much the same as most of the others; a fairly heavy leak dripping from the center-rear of the engine. from reading, naturally i suspect the leaks are somewhere around the ffm but i can't see anything at all with all that wiring and plumbing in the way.

i think the best thing to do is make jmjnet's mod repositioning the ffm and remove the upper intake manifold to easily get to the ip. at least i should be able to see things much better.

can i just remove the 6 bolts and the turbo hose connection and lay it to the side without taking the 2 sensors off? and can i run the engine for short periods with the upper intake removed? and is there a gasket involved?

thanks,

peyton
 
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i've gone thru most of the fuel leak posts and mine seems pretty much the same as most of the others; a fairly heavy leak dripping from the center-rear of the engine. from reading, naturally i suspect the leaks are somewhere around the ffm but i can't see anything at all with all that wiring and plumbing in the way.

i think the best thing to do is make jmjnet's mod repositioning the ffm and remove the upper intake manifold to easily get to the ip. at least i should be able to see things much better.

can i just remove the 6 bolts and the turbo hose connection and lay it to the side without taking the 2 sensors off? and can i run the engine for short periods with the upper intake removed? and is there a gasket involved?

thanks,

peyton
You need to unbolt the FFM and lift it up to be able to view the fuel heater on the bottom, the water in fuel sensor on the side and inspect the 3 hoses.
You can unbolt the upper intake and get a little more room if needed.
 
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I don't know how accessible the whole assembly is if you just extend it up in is original location but if you hang it off the middle of those 6 bolts you can get your hand around it to feel for leaks and easily see the 3 hose connections.
 

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Discussion Starter · #4 ·
You need to unbolt the FFM and lift it up to be able to view the fuel heater on the bottom, the water in fuel sensor on the side and inspect the 3 hoses.
You can unbolt the upper intake and get a little more room if needed.
thanks okdually.

i can't lift the ffm high enough (approx 1" max) to see the bottom of the ffm and hose connections ... i was hoping i could lift it up without removing hoses and wiring but looks like i will have to remove them. no connections that i can now see (injector return lines, ip hoses, t-valve hose, etc) appear to be leaking. hopefully taking the upper intake off will open things up for me.

can i safely run the engine for short periods with the upper intake removed? and when remounting the upper intake, do i need a real gasket or will "permatex rtv high temp gasket maker" suffice?

thanks again for your help,

peyton
 

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thanks okdually.

i can't lift the ffm high enough (approx 1" max) to see the bottom of the ffm and hose connections ... i was hoping i could lift it up without removing hoses and wiring but looks like i will have to remove them. no connections that i can now see (injector return lines, ip hoses, t-valve hose, etc) appear to be leaking. hopefully taking the upper intake off will open things up for me.

can i safely run the engine for short periods with the upper intake removed? and when remounting the upper intake, do i need a real gasket or will "permatex rtv high temp gasket maker" suffice?

thanks again for your help,

peyton
Yes you can run the engine. Just make sure no loose items are close or laying next to the intake( ie. nut, bolts, rags, paper towels, etc )

If you're careful enough you might be able to reuse that upper gasket.
If it tears, I would use another like gasket.
 
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Discussion Starter · #6 ·
Yes you can run the engine. Just make sure no loose items are close or laying next to the intake( ie. nut, bolts, rags, paper towels, etc )

If you're careful enough you might be able to reuse that upper gasket.
If it tears, I would use another like gasket.
thanks again,

i will only run it uncovered to check for leaks and will be careful. i already have a gasket that i found at autozone ... just curious about using "make a gasket".

peyton
 

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Discussion Starter · #7 · (Edited)
man, this thing is killing me. it is leaking like crazy to the point of making me wonder about the chances of a fire.

i have replaced the three hoses to/from the ffm and raised the ffm a la jmjnet for a better view of things. now the only things i cannot see are the #6 injector return hose and, under the input manifold, the injector pump-to-injector connections and the metallic return line running front-to-back. i don't see how the injector return could leak into the valley so it looks like the next step has to be remove the intake manifold to check those two things. what am i overlooking? any other ideas? thanks,

peyton
 
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Injector return lines require a special type of hose that has heat shrink properties. There are no clamps and regular fuel hose will not work.
 

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Discussion Starter · #9 ·
Injector return lines require a special type of hose that has heat shrink properties. There are no clamps and regular fuel hose will not work.
i was aware of those and wondered what keeps them on.

my injector return lines are gm hoses and use clamps. they are still relatively soft and none of the ones i can see leak. thanks,

peyton
 

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i've gone thru most of the fuel leak posts and mine seems pretty much the same as most of the others; a fairly heavy leak dripping from the center-rear of the engine. from reading, naturally i suspect the leaks are somewhere around the ffm but i can't see anything at all with all that wiring and plumbing in the way.

i think the best thing to do is make jmjnet's mod repositioning the ffm and remove the upper intake manifold to easily get to the ip. at least i should be able to see things much better.

can i just remove the 6 bolts and the turbo hose connection and lay it to the side without taking the 2 sensors off? and can i run the engine for short periods with the upper intake removed? and is there a gasket involved?

thanks,

peyton
Is this leak on your '86 or the '99? If it's the '86, that would be a mech. inj. pump. Twice I've had the throttle shaft seal leak on the mech. inj. pumps. Both times, it was very hard to see, and would leak more after shutdown than when running. And the fuel will run right down the back of the valley through the drain hole in the block casting and drip off the torque converter dust cover. If I remember correctly, the repair for the shaft seal is covered in the GM factory service manual. First time the leak was on my '86 1/2 ton 6.2 mech. inj. pump. 2nd time on the '93, same pump. Both times, the pumps were so high time that I replaced them, so I can't help much in the seal replacement if that turns out to be the problem.
 
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Peyton wrote removing the turbo hose, so it's pretty safe to assume it's the 1999 model.
My FFM decided to leak everywhere a while ago, so I replaced everything that was rubber from the fuel hose at the metal fuel line from the tank, to the fuel inlet to the IP and the hose for the water seperator.(That I didn't use anyway for the racor upgrade.)
 

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Peyton wrote removing the turbo hose, so it's pretty safe to assume it's the 1999 model.
Missed that. Yeah, disregard any IP throttle shaft seal.
 

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Discussion Starter · #13 ·
Is this leak on your '86 or the '99? If it's the '86, that would be a mech. inj. pump. Twice I've had the throttle shaft seal leak on the mech. inj. pumps. Both times, it was very hard to see, and would leak more after shutdown than when running. And the fuel will run right down the back of the valley through the drain hole in the block casting and drip off the torque converter dust cover. If I remember correctly, the repair for the shaft seal is covered in the GM factory service manual. First time the leak was on my '86 1/2 ton 6.2 mech. inj. pump. 2nd time on the '93, same pump. Both times, the pumps were so high time that I replaced them, so I can't help much in the seal replacement if that turns out to be the problem.
dang, i didn't say which did i? it's the 99. my 86, which i'm in the process of getting inspected, has its leaks, just not fuel. thanks for the ip info for future reference.

peyton
 
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Had this same leak on my 2000 6.5l. I did the same thing and fiddled with the ffm and checked the hoses, ran it, leaked etc. turned out the be the seal of the ffm cap that holds the filter in. Changed the fuel filter with a new one and new rubber seal and no leaks. Worth a shot, at the very least you have a new fuel filter in her. Good luck
 
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Discussion Starter · #15 · (Edited)
thanks guys,

i replaced the filter when i raised the ffm ... that was one of the reasons i raised it. i cannot see any leak on the ffm and surely i would be able to see such a leak given the amount of fuel that is dripping from the weep hole.

there are three things i cannot see:
1. the #7 cylinder return lines. i dismiss this because i don't think it could leak fuel into the valley. please correct me if i'm wrong.
2. the injection pump and the injector lines connections ... requires removal of intake manifold
3. the metal return line running thru the valley ... requires removal of intake manifold

it looks like the next step is removal of the intake manifold. to that end i have cleaned up the 86, had it inspected, etc to use as my errand-vehicle while i do it. thanks for all the helpful comments and suggestions.

peyton
 

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Discussion Starter · #16 ·
thanks guys,

i replaced the filter when i raised the ffm ... that was one of the reasons i raised it. i cannot see any leak on the ffm and surely i would be able to see such a leak given the amount of fuel that is dripping from the weep hole.

there are three things i cannot see:
1. the #7 cylinder return lines. i dismiss this because i don't think it could leak fuel into the valley. please correct me if i'm wrong.
2. the injection pump and the injector lines connections ... requires removal of intake manifold
3. the metal return line running thru the valley ... requires removal of intake manifold

it looks like the next step is removal of the intake manifold. to that end i have cleaned up the 86, had it inspected, etc to use as my errand-vehicle while i do it. thanks for all the helpful comments and suggestions.

peyton
some times life gets in the way. in this case, a lady in a ford pickup got me. no injuries but damage to both vehicles.

after slowly fixing the damage, i am now ready to return to finding the leak and, to that end, i removed the lower intake manifold so i could see the ip and surroundings ... at least with a mirror and flashlight. and sure enough, after a short idle, there was a fairly fast drip coming off the bottom of the ip. i still can't determine the source but it appears on the pump between the 2 lowest hard lines. so the question is: aside from the line nuts, what else could be leaking from that area? thanks,

peyton

ps: i couldn't believe that tangled mess of wires over and around the ip is "as is" from factory. and, as it happens, the pmd is tagged gm and dated 2012.

the picture: because i was very concerned about dropping something down into the intake after removing the lower manifold, i installed some window screen over the intake using the old gaskets to hold it down. the engine started right up and ran smoothly.

injection pump-engine valley 20201123b.jpg
 

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Discussion Starter · #17 ·
after extended inactivity on 007 (the 1999 2500 suburban), it remains only to finish installing the grill, lights, etc. to complete fixing the accident damage. however, a major problem remains: the ip leak which began shortly prior to the accident.

i turned the ignition switch on, without starting the engine, and the pressure generated by the lift pump (i think) creates a pretty good fuel leak from the ip and voila: 1. there is a constant leak with fuel drops forming between the two bottom fuel line connections but without any fuel line connection leak that i can see. 2. there is also a slowly developing fuel drop on the bottom of the black boot covering the pmd connection. i suppose a leak at one of the top 4 injection lines might direct a small amount of fuel to the boot while also leaking between the lines at the bottom. this is as far as i've gotten with mirror and flashlight. i hope to get a better look and maybe some pics with an endoscope.

is there anything else to leak from that area except the injection line connections? thanks,

peyton
 

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There is a fuel "rubber" hose from the Filter to the IP and t-valve under the intake.
 

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Discussion Starter · #19 ·
There is a fuel "rubber" hose from the Filter to the IP and t-valve under the intake.
true, but i can see the drops dripping from the injection line area of the ip but can't yet identify their origin. do you think it is possible that the fuel could be spraying the bottom of the ip from a crack in the rubber hose? thanks for the help,

peyton
 

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A crack in the rubber hose is possible or one of the injection pump line fittings is not tight enough to stop the drip.
 
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