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93 PAU Fuel Leak Fix Advice Needed!

GunnyP

A Regular
91
11
8
Cleveland, OH
Buick Ownership
Buick Park Ave Ultra 1993
93 PAU 90k miles.

A "no crank - no start" issue that seemed resolved as weak battery returned. First change was that pumping the gas pedal several times was necessary before achieving crank. Then, this too failed and smelt a strong gas odor. Had intended to measure the fuel pressure but found no smell of gas within the engine bay.

Inspection found a puddle of gas at the rear passenger door. Another attempt to crank with vigorous pedal depressions garnered no crank but nearly a 1/2 cup of gasoline in a catch pan. Jacked her up cautiously on slightly sloped driveway and found that the fuel lines are entirely nylon right back to the tank. So it appears the gas had dripped down the fuel line from the junction of the steel pipe and the nylon quick connector.

The three fingers of steel pipe visible at the tank appeared completely corroded through; however, upon rubbing the pipes, this corrosion flaked off. The pipes feel round and smooth to the touch and do not appear to be the issue. As it is difficult to inspect them visually, coaxed a neighbor to pump the gas pedal some more but for some reason no gas leaked or apparently was pumped. Not certain why. Could the fuel pump itself have died?

The only near certainty seems to be that the leak is between the tank and the lowest point of the fuel line run which is at the rear passenger wheel well.

Presuming these are all original 26 yr old fuel lines, how best to proceed?
1. Change out all the fuel lines. If so, is there a source?
2. Run just a new supply line to a new fuel filter near the front wheel
3. Your wiser approach

Can barely fit a hand into the space where the fuel tank pipes are located and can feel no clips for the supposed male end of a quick connector at the tank. Was expecting a simple squeeze to release mechanism, but actually this might be the Dorman model female connector that is offered as replacement on Amazon.

Thanks for your input!
 

torres7

Full Member
145
20
18
Lincoln Nebraska
Buick Ownership
Buick RMW
Have you tried spraying ether (starting fluid) in the throttle body and crank it to see if it would run for a few seconds? That would narrow it down to either spark or fuel problem.
 

Liver lips

New member
27
6
3
Minnesnowta
Buick Ownership
97 Riviera supercharged 01 Park Ave Ultra. Had 87&84 century 97 Park Ave Ultra 97 LeSabre
Did you check your ring that hold your fuel pump in the tank? Mine rusted off on my97 Riviera I ended up making my own ring closure assembly or whatever you want to call it wouldn't do any harm opening that little access door in your trunk and seeing how things look. I've replaced every line in a couple cars and be honest with you I wouldn't waste my time on that hard plastic line it's a pain to work with and it wants to kink when you try to pull it save yourself a headache pay the money and put in fuel injection hose you don't need to heat it up with the heat gun or boiling water to push on a fitting or buy special tool like you do with the hard plastic stuff
 

Waiex191

Active member
201
70
28
Poplar Grove, IL
Buick Ownership
2000 Century
I replaced the fuel line in my 2000 Century. It also has 3 lines that are nylon from the tank, and metal forward.

The lines may feel ok after you knocked off the rust, but I bet that is where your leak is. The line that goes through the filter is pressurized.
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GunnyP

A Regular
91
11
8
Cleveland, OH
Buick Ownership
Buick Park Ave Ultra 1993
Have you tried spraying ether (starting fluid) in the throttle body and crank it to see if it would run for a few seconds? That would narrow it down to either spark or fuel problem.
Hadn't any starting fluid at hand; however, deployed a fuel pressure gauge at the fuel rail and it was reading 0 psi. Turning the ignition key to run did result in a continual drip of gas from the quick connect that attaches the nylon hose to the fuel tank. So the fuel pump is still operable at least to some extent but either the leak is too great or the fuel pump to weak to pressurize the fuel rail.
 

GunnyP

A Regular
91
11
8
Cleveland, OH
Buick Ownership
Buick Park Ave Ultra 1993
Did you check your ring that hold your fuel pump in the tank? Mine rusted off on my97 Riviera I ended up making my own ring closure assembly or whatever you want to call it wouldn't do any harm opening that little access door in your trunk and seeing how things look. I've replaced every line in a couple cars and be honest with you I wouldn't waste my time on that hard plastic line it's a pain to work with and it wants to kink when you try to pull it save yourself a headache pay the money and put in fuel injection hose you don't need to heat it up with the heat gun or boiling water to push on a fitting or buy special tool like you do with the hard plastic stuff
On this 93 PAU there is no access from the trunk to the fuel pump so this is not possible to check AFAIK.
With the ignition key in the on position was able to determine that the fuel pump is still working although not audibly. That is to say, in several YouTube videos it was posited that the fuel pump engagement is quite audible once the ignition key is moved to the on position.

In my case, I heard nothing and have never noticed any fuel pump noise hitherto; but there was a continual drip of gas from an apparently faulty quick disconnect fitting right at the gas tank. So the current strategy is to stop the leak by replacing that quick disconnect fitting using a Dorman Quick Disconnect 800-058 Nylon Fuel Line Repair Kit and then splicing it to the remaining line with a Dorman 800-193 3/8" Nylon Fuel Line Press Fit Union.
 

GunnyP

A Regular
91
11
8
Cleveland, OH
Buick Ownership
Buick Park Ave Ultra 1993
I replaced the fuel line in my 2000 Century. It also has 3 lines that are nylon from the tank, and metal forward.

The lines may feel ok after you knocked off the rust, but I bet that is where your leak is. The line that goes through the filter is pressurized.

Quite right! The leak turned out to be right at the fuel tank quick disconnect.

Sadly, now in day 2 of trying to use the included fuel line quick disconnect tool to force the quick disconnect to release its leaking, woebegone hold from the metal fuel line so that it can be replaced. Managed to get the disconnect tool over the metal line but there is simply no room to properly manipulate the tool with ones fingers to press it into the quick disconnect fitting.

Ordered 3 days past and received yestereve a 3pc. Double-X Hose Grip Pliers set that are 13" in length. The circular nose 1/2"diameter allows yanking down on the plastic disconnect tool thereby forcing it theoretically into the quick disconnect fitting. However, it has yet to properly disengage and now the plastic lip of the disconnect tool on which ones fingers are meant to gain purchase to depress the device into said fitting appears considerably mangled. Apparently it is necessary to force the lip of the disconnect tool flush with the top of the disconnect fitting to achieve disengagement but at this rate the lip will disintegrate before that necessity is achieved.

So, reading "Zen & the Art of Quick Disconnect Tools" over lunch. Surely they come in metal, no?
 

GunnyP

A Regular
91
11
8
Cleveland, OH
Buick Ownership
Buick Park Ave Ultra 1993
Well, that ended badly...

The service manual suggested turning the quick disconnect 1/4 turn each way and pinching in the unreachable tabs at the apex of the quick disconnect. The rather rusted line broke when twisted, leaving a jagged distorted metal pipe end.

Had decided based on several still bright orange fuel line tags that the fuel line was too new in appearance to be original equipment. And that the disconnect did not seem to match the appearance in the PAU Service Manual. However, as the disconnect tool was not working thought it was worth a try.

The raised "barb" that is probably necessary for the replacement Dorman quick disconnect to work broke off inside the old quick disconnect end. So must find a different solution to repair the fuel line.
______________________________
 

Liver lips

New member
27
6
3
Minnesnowta
Buick Ownership
97 Riviera supercharged 01 Park Ave Ultra. Had 87&84 century 97 Park Ave Ultra 97 LeSabre
You could always eliminate the quick connects with a compression fitting I've done that before if you can get at them and get a clean cut compression fittings also work on the plastic lines but you need to buy one that has a sleeve that goes inside the line first where you put the fitting on so it doesn't Crush or distort the plastic line
 

GunnyP

A Regular
91
11
8
Cleveland, OH
Buick Ownership
Buick Park Ave Ultra 1993
You could always eliminate the quick connects with a compression fitting I've done that before if you can get at them and get a clean cut compression fittings also work on the plastic lines but you need to buy one that has a sleeve that goes inside the line first where you put the fitting on so it doesn't Crush or distort the plastic line
Great idea! Didn't realize there existed metal to nylon compression fittings. Just ordered precisely that: Dorman 800-223 Fuel Line Compression Union Nylon to Steel.
Fuel Injection line had been suggested earlier and will continue to look into that but a compression fitting on the metal should work after sandpapering smooth all the rust off the line. Also the jagged metal end will not be so great a concern as no reliance on an O-ring seal.
Thanks!
 

Liver lips

New member
27
6
3
Minnesnowta
Buick Ownership
97 Riviera supercharged 01 Park Ave Ultra. Had 87&84 century 97 Park Ave Ultra 97 LeSabre
And whatever you do don't pull your line out with a rope on the end thinking you can pull you new line up with the Rope Rope will take the shortest distance to the end and you will not be able to pull your line back through pull the new line with your old line I've made that mistake had to drop my return line then to pull both lines back through
 

GunnyP

A Regular
91
11
8
Cleveland, OH
Buick Ownership
Buick Park Ave Ultra 1993
Day 3 trying to secure fuel line compression union to the fuel sender assembly engine supply line. The fuel supply line was leaking high up in the crevice between the fuel tank and the rear passenger foot well and door frame. The fuel sender assembly is situated on top of the tank and has supply, return and fuel vapor lines that have grievously corroded. The metal line was connected to a nylon quick disconnect that had failed.

So far, simply not enough space to reach the line by hand or tools to securely tighten the compression fitting down. Also, in forcing the compression fitting on to the rusted pipe the pipe seems to have bent above where the compression nut sits and may leak from there even if secured at its present location.

I am so not gruntled.

Any special tools that might be helpful working in a very confined space?

If not, it appears that dropping the tank may be the only alternative in this instance. Which apparently means the exhaust system has to come down as well as the other fuel lines and perhaps the parking brake line to the rear passenger wheel.

Probably ought replace the fuel pump since the lines are not in good condition. Ah, apparently its not the fuel pump but rather the Fuel Sender Assembly that contains the rusted supply lines and connects to the pump which is the item of interest that needs replacing. Sadly, the tank was 1/3 full. Well, actually that means near empty given the eccentricities of the buick fuel gauge. Nevertheless, will have to be evacuated.

Begun PB Blasting the fuel tank strap bolts which are covered in rust. Service manual claims only the rear exhaust strap needs to be removed.
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Liver lips

New member
27
6
3
Minnesnowta
Buick Ownership
97 Riviera supercharged 01 Park Ave Ultra. Had 87&84 century 97 Park Ave Ultra 97 LeSabre
I got to go to work now but I'll send you pictures of what I had to do to the top of my tank in case your ring is Rusted off like mine was on my Riviera but yeah dropping the tank might be your only option or cutting a hole in your trunk and putting a piece of tin over it later
 

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GunnyP

A Regular
91
11
8
Cleveland, OH
Buick Ownership
Buick Park Ave Ultra 1993
Fully committed to dropping the tank. Efforts to secure the compression fitting with hose grip pliers proved the current metal fuel lines weak beyond hope.

One note of comfort is that the local garages all ask for just under $1000 to replace a fuel pump; whereas, RockAuto had this Fuel Hanger Assembly with Pump and Sending Unit for under $80. Fuel Hanger Assembly with Pump and Sending Unit.jpg

Was tempted to replace the fuel tank itself but it and the fuel filler hose seems to simply have a layer of surface rust but are otherwise intact. So this puppy should eliminate concerns about the fuel pump pressure and provide proper quick connects to easily attach and splice into the existing nylon fuel lines.

Believe the tank ring is included with the above unit but will double check to make certain. Don't remember the Service Manual making mention of the tank ring or dealing with the fuel filler hose for that matter but clearly it must.
 

Liver lips

New member
27
6
3
Minnesnowta
Buick Ownership
97 Riviera supercharged 01 Park Ave Ultra. Had 87&84 century 97 Park Ave Ultra 97 LeSabre
yeah I got a bunch of stuff I need to get done up so I'm going to be quick I should probably do a write-up on this damn thing but right now I just don't have the time so basically to put it simple I bought a I believe 6 inch stainless steel beauty ring from Plumbing or whatever at Menards or Home Depot. Laid out a bolt pattern on it cut out the center the same size is the hole in a regular retaining ring just to fit over the pump. Position the fuel pump where needs to go spun the ring so the holes won't be in the way of the lines and marked out the holes drilled and tapped em. I believe I used 5/16 stainless steel bolts but where I work I got access to any kind of bolt ever made. but yeah I'd probably go stainless anyway now comes the pain in the azz part you got to seal the threads I used Permatex number 2 it's gas resistant it never hardens and you gotta crawl in the trunk reach into the tank and try to thread the bolts up through the inside of the tank you could probably just screw it to the tank you still have to use sealant but I figured if I ever had to take it off again I wanted to be able to put it back on easy peasy lemon squeezy it took a while and there was a lot of cussing but I got it done. Then you just put your gasket on like you normally would do put your pump in the hole throw a couple washers on it and your nuts. Tighten it down like you do a tire in a star pattern. Now I had some Permatex high tack gasket sealer the purple stuff you know that had been sitting for about 6 years and I don't think the lid was on it tight so I took a screwdriver and Dug all that stuff up it was kind of like a sticky Play-Doe gooey whatever you want to call it and it was almost a full can so I kind of stretched it out and made a gasket out of it and put that on the top that's stuffs gas resistant too and it was stiffer than a three peckered billy goat and just as sticky. It's squeezed through the threads and nuts and through the gaps in lid and got all over my socket it's been on there for a month and a half and don't seem to be going nowhere anyhow that's what I did if you use my method you owe me beer when whenever you come to Minnesota. Oh yeah whatever you do don't use silicone there's been a million people that have tried it or more and still ain't one of them that got it to work on gas tanks also I've used regular compression fittings with the brass sleeves for nylon connections and have never had a problem as long as you put the there's a brass slide I guess for lack of better term that goes inside the hose so the hose doesn't collapse have a picture of compression fitting with the sleeves in it in my hand I've used to Steel to nylon fittings too picture0011.jpg picture0010.jpg picture0006.jpg 0921192309.jpg 0921192308a.jpg 0921192303.jpg 0921192302.jpg 0921192249.jpg 0921192246a.jpg 0921192246.jpg never had a problem with them just expensive then I guess you're supposed to use the special clamps if you use fuel pressure hose. you see my fuel pump I don't have them on it but I have them on the other side I ran out. you know it's kind of one of those do as I say not as I do things I've also used regular 37-degree jic flare fittings and haven't had no problem I used copper for my hard line from my gas just cuz I have it here and it doesn't rust. I've also been using small copper tubing for replacing vacuum lines and vacuum line from milkers it's way thicker and stretches more than car vacuum line and I've had no problems with temperature or collapsing or kinking under vacuum or boost like you sometimes do with cheap vacuum line. There now I should get an endorsement or at least free vacuum lines from The Surge milker company huh? And yes I know my fuel tank pressure switch isn't hooked up on my pump a 97 doesn't have one but the Park Avenue fuel pump with one is $50 cheaper and that's the only difference I seen between the pumps. If I'm wrong about anything feel free to correct me I'm a carpenter not a mechanic Ive just driven junk most of my life so I had to learn how to fix this stuff good luck bro 0921192302.jpg
 

Liver lips

New member
27
6
3
Minnesnowta
Buick Ownership
97 Riviera supercharged 01 Park Ave Ultra. Had 87&84 century 97 Park Ave Ultra 97 LeSabre
You get her going there? I got a head on out & finish my front suspension on my Riv. Hope she's in a Cooperative mood tonight cuz sometimes she's a real ------ . go ahead and fill the blank in with any word you can think of. it would probably work in this situation
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