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1994 6.5 turbo diesel has fuel running out of the hole in the inspection cover

Whiplash123

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Please help ! I have only owned Chevy Trucks but this is my first diesel and I'm lost
I can't see fuel leaking anywhere on top of rear of the engine but its running
Out of the inspection cover
 

Will L.

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First, welcome. Dont sweat it, tons of guys here that know these engines amazingly well. We can walk you through any issue.
Stick around after this problem is solved to learn from our mistakes, and know that most diesel shops do not understand this engine and will do things the way newer diesels are designed and that will cost you big money to learn their mistakes.

Originally On top of the engine is a plastic cover that says hides the middle of the engine. Get that out there- most never reinstall it.
in the rear center of the engine you will find the FFM (fuel filter manager) it has a cartridge fuel filter, in it and a few fuel hoses going through it. Take a look if fuel is leaking from it, or the hoses coming off of it.
Fuel leak obviously danger for fire, but also can keep the engine from running properly. Something different about diesels is if a hoseclamp or something is loose and that line has suction rather than pressure, it can suck in air and not let the engine run right even if it isn’t dripping fuel. So consider the easier to fund fuel leak a good thing because they are easier to find

A recently replaced fuel filter is a common source of fuel leaking when the large nut on top didn’t get screwed in staight.

There is a valve by the thermostat for draining out water from the fuel filter that could be slightly open. Follow the hose from FFM to it and check valve closed fully and hose condition to it.

If you get to replacing fuel line because you find defective hose- a couple things to consider.
Only buy sae30r9 hose to handle the modern fuel. The old hose doesn’t stand up long term to the new fuel - so deteriorating hose could be your issue.
It is 3/8 line feeding to the ffm, and 5/16 line coming out going to the drain and another 5/16 line coming out going to the ip (injection pump). -however many people upgrade that ip line to a 3/8 for better flow helping with longer parts life & drive ability.
then there is a 1/4” line that comes out the ip to return to tank. There are 1/8” lines on each injector thatconnect to each other then to the same return line as the ip return. If the 1/8 lines leak, they usually leak down the side of the engine. If the 1/4” part is leaking, or any of the 5/16 line, the ffm, or it’s connections - They leak into the center of the engine which has a valley. The fuel goes to the back of the valley where a hole is drilled that lets it leak down onto the flywheel and clutch or flexplate and torque converter if auto trans. Then it gets to the flywheel inspection cover on the bottom and comes out that hole.

Take pictures and post here by using the button below this box when typing that says “attach files” and choose “full image”. Or a video to YouTube, bitchute, etc and post the link here for us to watch. Ask tons of questions- we all had to start learning some where.

Depending where you live- a few guys here can meet up to help. I am in the Las Vegas Nv area.
 

Jaryd

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Look in the engine valley with a flashlight for fuel puddled there. At the back right hand side of the valley is the valley drain hole and a lot of these engines have a tube that goes down and makes whatever is leaking in the valley come out of the inspection cover like what your seeing.

Since you know it’s diesel fuel that you are seeing. I would bet that the fuel filter housing or the lines connecting to it is leaking. If it’s the filter housing leaking it’s not a hard job or expensive to reseal. Leroy Diesel is a site vendor and sells good stuff for these rigs. https://leroydiesel.com/products/fuel-filter-manager-oring-set/

You could raise the filter housing up for better access and checking for leaks using 10 x 1.5 mm all thread rod.
 
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Stoney

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Welcome to TTS. Looks like the guys already have you covered..
Side note I just learned something from this thread. Thanks to @Will L . Didn't know about the fuel hose issue, was considering changing all my fuel lines going from tank to lift pump to engine and back cause there in poor condition...(metal ones are rusted pretty bad) gonna replace with rubber. Now I know which type to get.
 

Whiplash123

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First, welcome. Dont sweat it, tons of guys here that know these engines amazingly well. We can walk you through any issue.
Stick around after this problem is solved to learn from our mistakes, and know that most diesel shops do not understand this engine and will do things the way newer diesels are designed and that will cost you big money to learn their mistakes.

Originally On top of the engine is a plastic cover that says hides the middle of the engine. Get that out there- most never reinstall it.
in the rear center of the engine you will find the FFM (fuel filter manager) it has a cartridge fuel filter, in it and a few fuel hoses going through it. Take a look if fuel is leaking from it, or the hoses coming off of it.
Fuel leak obviously danger for fire, but also can keep the engine from running properly. Something different about diesels is if a hoseclamp or something is loose and that line has suction rather than pressure, it can suck in air and not let the engine run right even if it isn’t dripping fuel. So consider the easier to fund fuel leak a good thing because they are easier to find

A recently replaced fuel filter is a common source of fuel leaking when the large nut on top didn’t get screwed in staight.

There is a valve by the thermostat for draining out water from the fuel filter that could be slightly open. Follow the hose from FFM to it and check valve closed fully and hose condition to it.

If you get to replacing fuel line because you find defective hose- a couple things to consider.
Only buy sae30r9 hose to handle the modern fuel. The old hose doesn’t stand up long term to the new fuel - so deteriorating hose could be your issue.
It is 3/8 line feeding to the ffm, and 5/16 line coming out going to the drain and another 5/16 line coming out going to the ip (injection pump). -however many people upgrade that ip line to a 3/8 for better flow helping with longer parts life & drive ability.
then there is a 1/4” line that comes out the ip to return to tank. There are 1/8” lines on each injector thatconnect to each other then to the same return line as the ip return. If the 1/8 lines leak, they usually leak down the side of the engine. If the 1/4” part is leaking, or any of the 5/16 line, the ffm, or it’s connections - They leak into the center of the engine which has a valley. The fuel goes to the back of the valley where a hole is drilled that lets it leak down onto the flywheel and clutch or flexplate and torque converter if auto trans. Then it gets to the flywheel inspection cover on the bottom and comes out that hole.

Take pictures and post here by using the button below this box when typing that says “attach files” and choose “full image”. Or a video to YouTube, bitchute, etc and post the link here for us to watch. Ask tons of questions- we all had to start learning some where.

Depending where you live- a few guys here can meet up to help. I am in the Las Vegas Nv area.
 

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Whiplash123

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Ok so I'm not sure if I did all that right !
I did find it leaking at the hose in back of filter housing I put new on and cut hose back
I checked the valve in front by thermostat housing it seemed good I've been checking all the little return lines etc and just still can't see the leak ! I did find a little critter nest under the top of intake and cleaned that out !
Then I asked you guys for help that's about all I figured out so far

I haven't even had a chance to touch it today but if the mosquitoes dont carry me away I plan on working on it yet tonight ! Thanks for any and all info !

Much appreciated !!!
 

Stoney

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This may sound dumb. But wouldn't it have to be a return line if it's a hose leak?? The lines going in would suck in air not blow out fuel Wouldn't they?
 

Will L.

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Pics posted ok, but not as full image- they posted as thumbnail. Unfortunately on iphones, when we click it- the pic only gets a little bigger and can not zoom in to see details well. So maybe one of the guys on a desktop can zoom in and look around to spot things.

I see what may be fuel around the ffm on the intake manifold y where it is mounted. That could indicate a leak in that area.

If you run a jumper wire to the lift pump, it can pressurize that line and help you find the leak.
 

emmott

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All lines downstream of the FFM and lift pump should be above atmospheric pressure if the lift pump is functioning
 

Whiplash123

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I found it easiest to remove the intake manifold and replace all the fuel hoses under there.
Welcome to the forum.
Sorry guys I finally
All lines downstream of the FFM and lift pump should be above atmospheric pressure if the lift pump is functioning
I finally. Had time to get into it a little deeper ! Upon a little more inspection I found the fuel is coming out of the filter housing itself where the wires go in. I appreciate all the info shared on the site it was very helpful.

Thanks again !
 

Will L.

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Fuel heater is probably bad. It could be loose or just bad seal, but that is unlikely to just start leaking there. Usually after having messed with it and accidentally leaving it loose is when that happens. If you see it coming out right where the wires are- definitely bad.

So, while you have it out of the truck to replace the heated, this is the time to replace the 3 rubber fuel lines going from the ffm (fuel filter manager). All diesel now days has alcohol in it (ethanol/ methanol). It didn’t used to when these trucks were built and the fuel line doesn’t stand up to it. And the amount of the alcohol is being increased in many areas. So don’t just buy regular fuel line. Get sae30r9. I suggest new hose clamps at same time.

Next things to consider:

Many learned that larger size line and fittings from the ffm to the ip helps the truck run better, especially because of the under powered lift pumps we have. This is known as the FTB mod (Feed The Beast). Drilling and tapping the ffm, 3/8” line going out to match incoming and the fitting on the ip (injection pump). If you dont want to drill and tap yourself, there is a ready made kit with brand new ffm including new heater and filter. This isn’t needed, but can be an improvement.

Heater:
FTB fittings and hose kit:
Complete ffm with FTB done already:


Next thing to consider in this area is a fuel pressure gauge. Read why before dismissal. This might have you not buy any of the above parts.
A new injection pump will cost you about $2,000 if you diy AND have the computer to time the new one, or you have to buy that also.
There are 3 reasons an injection pump die -
1.worn out at 250,000 mile range.
2.Water/ fuel bugs in the fuel- can happen anytime.
3.low incoming fuel pressure.

On the water: used to be if your water in fuel light came on, you would drain it, then second time drain and replace filter- but with the alcohol in the fuel now- drain and replace filter every time now. There are better water separators available.

The factory style lift pumps are not great, but the great ones cost a ton of money. Some like Fass have an amazing water filter that will hold a lot more water than than the tiny amount ours will, has a better filter, better pump, and a screw in better heater as an option. If you are not afraid to invest in the truck because you know you will stick with a diesel long term- this is a better option.
This fits the buy once/cry on e lifestyle rather than replacing the cheaper ones every hear or so, or the medium price ones every 5-6 years.

The pressure. Your incoming fuel pressure should be 8-14 psi. Leroy sells an affordable tap fitting that goes on top of the ffm if you stay that route. It measures fuel pressure coming into the filter. This is an ok option and way better than nothing. I prefer using a metal T fitting at the ip that you can attach the gauge to via sending unit or metal line.

You need to buy the gauge itself and mount in the dash so you can see it while driving. In diagnostics in the shops, we have to run the gauge against the windshield under the wiper blade to see it gets ok pressure while under hard acceleration, so just under the hood gauge doesn’t help. I used to use mechanical gauge with a metal fuel line feeding it- but now would recommend an electric unit for ease and safety.
You will spend a couple hundred bucks doing this probably. But knowing you are distressing the expensive injection pump before you ruin it is huge. Also, at some point in the future you will have engine troubles. There are 2 things that are always checked first in diagnostics on these. What is the fuel pressure to the ip, and is the return line clear of bubbles and contamination.

The $5 and 5 minute improvement.
That clear line- is the last part of this book of recommendations (for today anyways). Go to any hardware store and get 1/4” clear tubing. It is sold by the foot, usually made of perfectly clear pvc. Get 2 screw style hose clamps to fit it. Cut the line in half, and save one half (out of the sunlight, heat, and cold) to be used in a few years. Replace the existing return line coming out of the front of the ip near the thermostat housing. It is like an upside down ‘U’ shape and is the only 1/4” fuel line at the front of the engine.
This is so you can see fuel flow whenever the key is, watch for debris in The fuel, and for bubbles. Bubbles indicate air is getting in the line and can cause all kinds of crazy running issues.

So if you are driving and ever have anything funky going on- you just look at temp and oil pressure gauges like normal, then at the fuel pressure gauge. If all that is ok- pop the hood and look at the clear line. I can’t begin to tell you how many times in diagnostics the first thing that has to be done is add a fuel pressure gauge and clear line- then drive the truck and watch for it to happen again.
These diesels are old and diagnostics is different than new ones that 99% is done through the computer. Doing these two things- gauge and clear line are well worth it imo.

Let us know how the fix goes and if you have any other questions or issues.

Also once this repair is done- come back to learn what stuff to check to keep it alive longer - especially if you have not read the library info yet.
 
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