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Discussion Starter · #1 ·
This thread is mostly me just venting, in the 6 months I've had my truck so far, it's spent about 4 of them torn apart in my driveway. My most recent replacement/upgrade may have turned into the biggest fiasco yet.
My misfortunes going back a few months:
-Went to replace FFM and fuel hoses under the intake, only to discover broken tabs and missing bolts on the intake manifold. After acquiring a replacement manifold, I broke off the heater hose fitting in the process of replacing it. Overall what should have been a 1 day job turned into 3 weeks.
-I bought a stainless braided oil cooler line replacement kit from a popular vendor, and spent the last 4 weeks chasing an oil leak from the brand new fittings/hoses. Turned out I apparently had a defective hose end/fitting, the only defective one that the vendor has ever seen. If you have done this job you know what a pain it is to get to those fittings on the block and replace the hoses. I got to do it twice!
-While upgrading the glow plug harness with a new one from PT Wiring Solutions I broke the terminals off 2 new glow plugs, had to order replacements. Also discovered one broken off in the block which I have been unable to extract. I'll just live with 7, doesn't seem to affect startup much.
-Not knowing if the lift pump had ever been replaced, at 200k miles, I also bought the lift pump and harness upgrade kit from PT Wiring Solutions. Comes with a Carter pump and a relay harness. Lots of reviews saying what an easy bolt-in upgrade this was, worked perfectly, etc. LOL. After a very difficult time installing the pump, and getting diesel everywhere, I then had a terminal snap off of my glow plug relay while I was trying to loosen it to hook up the wire to the new harness. Had to order a new one and wait a day before I could try to finish getting it back together.

That brings me to today, I got everything buttoned back up fired it up and looked for leaks. Didn't see any so I decided to go around the block, about a 5 mile loop, to test it out. The engine is running great, but about 2 miles from the house I noticed a lot of smoke behind me. Since the engine was still running fine I just took it easy back to the house, and when I exited the truck I discovered fuel pouring onto the ground underneat. The entire under carriage and engine bay is completely soaked in diesel, and I've left a trail of it for who knows how far down the road, plus soaking the soil up my driveway and in front of my garage. I'll probably be lucky if it doesn't contaminate my well water. Given that the engine was running well, and I first noticed the smoke while decelerating off-throttle, the only thing I can figure is the return line popped off due to the additional fuel pressure with the new pump. I'm not sure how the engine would have kept running for a couple more miles if it was a feeder line.
On the plus side, I may have dumped gallons of diesel fuel across the county, but hey at least the second set of oil lines doesn't appear to be leaking now!:rolleyes:

I'll probably let it sit a couple of days just out of disgust until I can get in the right mindset to work on it again, and I suppose I'll be pull the intake yet again to see what the heck is going on. Stay tuned for the next episode of "what else can go wrong"...
 

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Discussion Starter · #2 ·
I have a 'weed dragon' torch at the house, gonna try to see if I can use that to burn off some of the diesel that is all over the ground in front of my garage :(. I was astounded at how much was pouring out of it.
 
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I have had days like this and more times than I like to remember. Sounds like you had several in a row. I feel your pain. Let us know the source of the fuel leak. Good luck, bud.
 
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Possible the water in fuel drain hose broke or popped off the FFM fitting. Might check that before pulling the manifold. The engine would still run with it leaking bad and fuel would go everywhere. Look on the bright side. At least you know your lift pump is working good.
 

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Discussion Starter · #5 ·
Yeah maybe I can unbolt the FFM from its mounts and see whatever is wrong before having to pull the whole thing again. Yeah the new lift pump certainly works! lol
 
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Discussion Starter · #6 ·
The comedy of errors continues... can't make this stuff up folks!
I ended up pulling the whole intake to try and find the leak, couldn't find any sign of a hose that was loose or anything. The lifter valley was full of fuel though. I decided to fire up the lift pump to see if I could see it leak, and fuel started pouring out from around the the ring securing the filter on the FFM! This is a brand new OEM FFM mind you, that came fully assembled. I've never had the filter out of it. When I got it apart the rubber seal appeared to be deformed in one tiny spot. Hard to believe that much fuel could come pouring out of such a small area. Apparently the old stock lift pump didn't produce enough pressure or volume to make it leak (maybe it wasn't pumping at all?).
I happened to have a new filter with the one-piece plastic top in the garage, so I replaced that and put everything back together. Cycled the lift pump a couple of times to check for leaks, and then fired it up. After about 20 seconds of running, now I have coolant spraying all over the place!
I don't know for certain if the fuel leak is resolved, I expect so, but apparently I removed the heater line and flexed that stupid bracket that bolts to the manifold one too many times, and it now has a little hole in the aluminum hard line where it is brazed/welded to the bracket. I've already broken the the fitting off in the water pump manifold once, and replaced that. Now looks like I'll be replacing the heater hose. I can't wait to try and access the bottom end of it where it connects to the nipple on the firewall! We'll see what else breaks in the process.
 

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Discussion Starter · #8 ·
^^yeah I'm probably going to do something like that, you posted that in my old thread where I broke that fitting off. MUCH cheaper and faster than getting a new metal hose.
 

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Discussion Starter · #9 ·
well, $6 worth of 5/8" heater hose has solved the last issue for now :). Need to do some test drives and see what blows up next!
 
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Sorry to hear your problems ; but, it does reinforce my philosophy of not upgrading my well running truck. I did do one popular upgrade when I first bought it, and did not notice any performance improvement. 90,000 miles later, I was thinking of installing a lift pump recently after reading many recommendations, and having a Carter fuel pump from some long ago project on a car I have since sold. Your post has convinced me to let well enough alone. Thanks for that, at least.
 

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Sorry to hear your problems ; but, it does reinforce my philosophy of not upgrading my well running truck. I did do one popular upgrade when I first bought it, and did not notice any performance improvement. 90,000 miles later, I was thinking of installing a lift pump recently after reading many recommendations, and having a Carter fuel pump from some long ago project on a car I have since sold. Your post has convinced me to let well enough alone. Thanks for that, at least.
A lift pump is highly recommended for a Duramax truck like you have.....
 
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Discussion Starter · #12 ·
To be fair, the only thing I've done that was purely an 'upgrade' was the lift pump, although I'm not so sure that my factory lift pump was even functioning, or at the least it wasn't producing enough volume/pressure to expose the faulty FFM ring seal.
My original saga started with another fuel leak though from the original FFM which was cracked and leaking at the bottom where the sensors connect. I also had rotten fuel lines under the manifold. My oil cooler line upgrade was also prompted by leaky and cracked factory lines, although I wasn't expecting the brand new SS braided lines to also leak out of the box!

I also did the Fluidampr upgrade (one of the only ones that didn't go sideways on me yet!) because the truck has 200k miles and I did not know if the original damper had ever been replaced. Since I hope to get another 100k out of this truck without major engine work, it behooved me to replace the damper.

My wiring harness upgrades were sort of just upgrades, but the original factory cables and various harness bits were definitely corroding and aged. I can say with the new stuff the truck fires up much faster. When it is warm it only takes barely a blip of the starter to fire up.

My philosophy is preventative maintenance rather than waiting on a problem to happen, and if I'm going to replace a part I'm going to put the best parts I can afford in their place. I'd rather discover a problem on my own terms in my driveway than have it break down while towing, hours from home.
 

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That brings me to today, I got everything buttoned back up fired it up and looked for leaks. Didn't see any so I decided to go around the block, about a 5 mile loop, to test it out. The engine is running great, but about 2 miles from the house I noticed a lot of smoke behind me. Since the engine was still running fine I just took it easy back to the house, and when I exited the truck I discovered fuel pouring onto the ground underneat. The entire under carriage and engine bay is completely soaked in diesel, and I've left a trail of it for who knows how far down the road, plus soaking the soil up my driveway and in front of my garage. I'll probably be lucky if it doesn't contaminate my well water. Given that the engine was running well, and I first noticed the smoke while decelerating off-throttle, the only thing I can figure is the return line popped off due to the additional fuel pressure with the new pump. I'm not sure how the engine would have kept running for a couple more miles if it was a feeder line.
I had a similar problem. There is a hose coming from the water seperator that goes to a small valve on top of the thermostat housing. Mine wasn't shutting all the way and caused it to leak fuel everywhere. I replaced the valve and problem solved.
 

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I also did the Fluidampr upgrade (one of the only ones that didn't go sideways on me yet!) because the truck has 200k miles and I did not know if the original damper had ever been replaced. Since I hope to get another 100k out of this truck without major engine work, it behooved me to replace the damper.
Identical decision I made with nearly identical circumstances and outlook.

Purchased my burb in 2012 w/ 200k. Fluidampr was one of the first upgrades I put on it, I don't remember at what milage but within the first year for sure.
Its an expensive upgrade thats completely invisible, but excellent peace of mind insurance if you intend on keeping and driving it long term.
Fast forward me 9 years and I just turned 328k this weekend and have yet to have any ENGINE issues. (Not for a second am I trying to claim the vehicle as a whole has been completely trouble free haha) Motor still fires up fast on cold starts, and still has no visible blowby (I also change my oil every 2500 miles. Early, I know, but aiming for engine longevity)

Be sure to STILL keep a close eye on the crank pulley! Mine displays enough wear in 1 year time to justify replacing it annually (sometimes sooner). Buy the Dorman brand once at a local parts counter (~$70) and enjoy free replacements w/ it's lifetime warranty.
I think I'm on my 10th or 11th one, and my local AutoZone still keep giving them to me no questions asked.

OR
You can go OEM route for nearly twice the cost (repeatedly). They seem to last UP TO twice as long, however no free replacements.

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Discussion Starter · #15 ·
Good to know about the crank pulley, thanks! My pulley looked OK so I didn't replace it.

I thought I finally had this thing mostly sorted out, but the curse has struck yet again! :mad:I had made a couple of short errand runs and everything looked good, so my wife put about 80 miles on it yesterday going to a farm in another county. When she got back I noticed some liquid wetting most of the area around the driver's side inner fender well, and some on the outer part of the fender behind the tire. I don't think it is oil or diesel fuel. My best guess is PS fluid or brake fluid, although neither fluid level is visibly low. The PS pump is not coated, so I don't think it was coming out of the cap on the pump (which I have seen happen if the pump overheats or is too full). Probably a new hole/leak in a line somewhere spewing out under pressure. Looks like the truck is parked again until I can figure this one out :(
 

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Good to know about the crank pulley, thanks! My pulley looked OK so I didn't replace it.

I thought I finally had this thing mostly sorted out, but the curse has struck yet again! :mad:I had made a couple of short errand runs and everything looked good, so my wife put about 80 miles on it yesterday going to a farm in another county. When she got back I noticed some liquid wetting most of the area around the driver's side inner fender well, and some on the outer part of the fender behind the tire. I don't think it is oil or diesel fuel. My best guess is PS fluid or brake fluid, although neither fluid level is visibly low. The PS pump is not coated, so I don't think it was coming out of the cap on the pump (which I have seen happen if the pump overheats or is too full). Probably a new hole/leak in a line somewhere spewing out under pressure. Looks like the truck is parked again until I can figure this one out :(
Check your hydroboost for leaks. Typically when you see a leak like that it points to the Hydroboost
 
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Discussion Starter · #17 ·
Turns out it is the high pressure line going from the hydroboost to the steering box, same kind of crimps as the factory oil cooler lines, and it is leaking right at the crimp between the hard line and the flexible hose. Why it would just suddenly start leaking out of the blue, I can only guess that this truck hates me!
 

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Turns out it is the high pressure line going from the hydroboost to the steering box, same kind of crimps as the factory oil cooler lines, and it is leaking right at the crimp between the hard line and the flexible hose. Why it would just suddenly start leaking out of the blue, I can only guess that this truck hates me!
GM parts quality scores again...(n)
 

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Turns out it is the high pressure line going from the hydroboost to the steering box, same kind of crimps as the factory oil cooler lines, and it is leaking right at the crimp between the hard line and the flexible hose. Why it would just suddenly start leaking out of the blue, I can only guess that this truck hates me!
It is called "AGING". LOL!!!

That crimp is done for High Pressure Hydraulic hose.
If you can find a local hydraulic or race shop, they can remake those with new high pressure hose and pressure test the crimp. They are used in AC, brakes, any high pressure lines.
 

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Turns out it is the high pressure line going from the hydroboost to the steering box, same kind of crimps as the factory oil cooler lines, and it is leaking right at the crimp between the hard line and the flexible hose. Why it would just suddenly start leaking out of the blue, I can only guess that this truck hates me!
That's probably the most common point of failure for factory style lines.

Wouldn't most of you guys agree?

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