⚠️ Warning: Any Fuel or Coolant leak can Strand you on the Highway or cause Fires. "Slow" Fuel Leaking often evaporate before can even get under the car to look...

1. Many Fiero have Fuel Filters Under the Car, All V6 and 87-88 Dukes. I fix the F-pump recently then has this leaking...

Many instant think the Filter or line ends is the Problem but No...
Look closer to see Return Line and Clamp Bolt Wet?
That line is "sandwich" in same clamp holding the SS Filter allowing the tube to rust.
Was likely leaking way before this but very slowly so can't tell easy. Dropping the tank makes you to upset the lines etc to pull soft lines etc. result in a bigger leak after done w/ tank job.

Look at out of car just look wet in one spot...


But just careful poking open a big obvious hole...


I sanded more to see how bad and "just" soldered a patch to close for now. Will get 5/16" compression fitting(s) and tube for final repair.

Notes:
While the Return line has "0 pressure," the line can have enough pressure to leak instead of exiting properly. If you have Gas Smell, look at Return and Vent lines.
Currently Many Auto Part and Other Stores have "supply chain" problems and do not have long length of any Fuel hoses. Can't even order this. Even if you replace w/ hose, the filter clamp and "weak" bracket (not shown here) is only thing support the flex lines to the engine and have to make sure that's supported/protected. That's why I patched the line.

2. Heater Pipes have similar leaks where passes thru support clamps and tank "cross member." Same problem here leaking a bit way before now because pressure from "rust" and clamp stopped most of this...


After some cleaning...


The "brown" area and more is bad and don't have more picture but the pipe "Caved in" about ½ of the diameter so cut the rest and used hose and clamps to fix. I used 5" of hose to clear the support clamp part welded to car.
No longer have front support clamp. And added thin Polypropylene as guard between Aluminum Tube and Steel in other areas. Cut up Frozen "TV" food containers are good source of this plastic.

Notes:
This is 3/4" OD Tube. Many auto parts stores Don't have 3/4" ID hose in stock even when many Web Site say they do. Lowes has it but need to "buy a real" (10 Feet I think) costing $20+
OE setup had plastic/rubber to protect this happening but often doesn't work. Replace that with 1 or more layers of PP. If use old food containers etc is marked as...

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

quote Originally posted by theogre: If you have Gas Smell, look at Return and Vent lines.

For Fieros that have the gas expansion tank in the passenger side rear fender area, the vent lines that run below the battery tray are definitely in the line of fire from spilled/leaking battery acid. Really poor design. I discovered that these vent lines in my Formula were corroded from exposure to battery acid over the years and were subsequently leaking gas fumes.

That for 87-88 w/ bigger fuel tanks.

Fill and Vent lines to Fill port on the D-side of car for all years.
Many of those can rust out from iffy or missing inner fender and "mud" shield below that.

If you can find a shop for smoke test or make one, that saves a lot of time looking for fume leaks. Will Fail E-inspection in states EVAP testing but that doesn't show where the leak is.

Smoke test works for many vacuum leaks too.
But Often won't detect leaks on fuel output or return line because doesn't use enough pressure to push out gas.

E2A--> Do Not let smoke go into the EVAP "can" itself. Pinch off the vent or purge line while testing for fumes or vac leaks.
Smoke is Polypropylene Glycol and other chemicals can "poison" the carbon in the "can."

[This message has been edited by theogre (edited 06-22-2022).]

ME TOO! I had to replace the fuel lines twice due to battery fumes. My 86 2.8 also went thru 2 battery trays in its lifetime. Another time I smelled gas odor while sitting at traffic light. Crawled under to investigate and saw what appeared to be a brand new shiny starter. A tiny pin hole in pressure line was spraying a fine mist of fuel directly towards the starter. The mist could not be seen with the eye but when placing the back of my hand in it's path I could feel it. Be sure to check everywhere. Eventually I moved the battery to the front after a 3800sc swap.

Spoon

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"Kilgore Trout once wrote a short story which was a dialogue between two pieces of yeast. They were discussing the possible purposes of life as they ate sugar and suffocated in their own excrement. Because of their limited intelligence, they never came close to guessing that they were making champagne." - Kurt Vonnegut

Found another Fuel leak yesterday...

Actually 2...
1st part I filled the tank full recently because was going to drive 1+ Hrs each way and leaked some when totally full. (W/ gas prices going going nuts I don't buy a full tank w/0 reason.)
That was mainly because big O-ring for pump and line assembly moved when replacing the pump and can't see most of that ring when installed.

Remember 87-88 has the aux tank and main tank often see near total volume of it w/ liquid. But w/ this problem, many others vehicles will dump gas on the ground because can't trip the Station Pump Nozzle auto shutoff right w/ large leak at the top of tank or the line(s).

So drop the tank to fix the leak and test by closing or capping all lines/ports and blow very hand into one vent line w/ bubble soap on the tank assembly.

Fix the first but had a "new" problem...
The return/vent line (Can't remember which right now) was leaking where its soldered going thru the plate where the big O-ring seals.
I excepted this Maybe the above leak and bought somethings to fix but not the "plug" for the wiring.
So can't use a torch to heat or risk big problem.
Is very hard to clean so rules out "Fuel Safe" epoxies and glues in this case.
So I used a back up plan to solder it but w/ Solder Gun instead of Touch to heat but the Solder isn't normal types you get at most places.
I used "old school" Weller 8200 100/140w solder gun and New Tip and Low Temp Solder Paste use for soldering SMD parts in electronic work. (Solder Available on Amazon and others.) The gun heats in a very focus way and barely handles the job because so much metal But that also protects the plug. If the leak is on the line right next to the plug then not sure if the plug will seal even w/o "melting" because so close.

I filled the whole "indent" w/ paste and heated and slowly moves to heat and melt the solder and wait a bit more to heat the steel. Now no more air/fuel leaks even when tank isn't full.

Area fixed is more then just bright solder but dross etc flooding on top and not cleaned.

Again you don't want any leaks that dumps liquid fuel but:
● Any Gas w/ Ethanol can pull water from Air causing "Ethanol problems" so you still want any "fumes" leak fix even if never leak liquid fuel.
● Important in States and other places when Inspections require you to pass Emissions test and pressure the system and wait to see any leak. EVAP Test machines uses < 1 PSI of air. ~ 10in of water max

Note: While Many shops have Smoke testers for this... But may see leak at the top, fix the O-ring, and not see the line leak depending on how and where the test is done. Small leaks need no air from wind fans etc.

[This message has been edited by theogre (edited 09-16-2022).]

Update: (happened a couple weeks later then above posts but forgot to update this...)
I had to take out the fuel return line again...
Was working w/ small torch to solder the patch but melted too much solder and left a solder blob inside then plug return enough to cause fake O2 code and run rich because part block the return making high system pressure.

So heat the tube to melt the blob to flow out the end then had to re solder the patch.
This time I use the low temp solder and same gun and car been working w/ 13psi on Duke engine.

I also installed Permatex Brake Grease and some heat shrink tube over the return line for the area between bends where run against the filter and bracket.
Grease is "plastic friendly" to keep out water between return and shrink tubes.

I used 3/8" 50% heat shrink slipped on starting at tank hose end. Then some heat to shrink.

Suggest all Fiero w/ gas filter under the car has this done when replacing or other work w/ the filter.

Sorry, I had pictures but 1 flash died and lost many pictures. it died before copied for backups.

E2A--> I didn't use "Water proof" shrink w/ "glue" inside. This is thicker when shrunk and maybe harder to fit the filter and R-line in the band. Cost more and harder to install before shrinking for this use too.

[This message has been edited by theogre (edited 04-04-2023).]

Note: I used pinch tools on the hoses at each end to remove leaking pipe above so don't have to drain the whole system.
I have old KD ones but still can get from many sources...

Example: to find web search KD or GearWrench 145

pic from https://www.toolsource.com/...-pliers-p-71053.html

Handles most coolant and other hoses in cars and light trucks. Do not use on wire-reinforced hose or hoses w/ "spring" in them.

Other ways to pinch a line/hose but make sure whatever don't have shape edges or crush hose beyond stopping flow.