924Board.org

[Legitimate Salvage]

When I got my 924, it had the common interior fuel smell. I had it sorted (or so I thought) by replacing the fuel sender seal and never filling it past 3/4 tank. Still got an occasional whiff after filling up, but no persistent fuel smell.

So last weekend after taking it for a drive, my wife had been out in the garage. When she came back in, she asked me if I'd spilled some gas working on the car. Nope. Went out into the garage and the smell was strong... like don't strike a match strong. I rolled the 924 out of the garage and got some fans going. I looked for puddles/drips where the 924 was parked and found nothing. 30 min later the smell was gone.

Car spent the week outside (under a proper cover). Never saw any fuel leaks.

Today I went on a hunt. Zero fuel smell under the hood. Some fuel smell in the back hatch near the filler neck/fuel sender. But it wasn't near strong enough to account for last weekend. Got up under the car on the passenger rear side (at the fuel pump and accumulator) and bingo, a very heavy gas smell. The smell was strongest at the well for the in tank pump. There's a round cover there held in place with five 8mm bolts. One of the 5 looked wet and the paint around it was bubbled. I took an 8mm wrench and was able to tighten each bolt by a 1/4 turn.

NGL, I don't think that is the source of the leak/smell. Looking around there were no visible leaks and no stains indicating a fuel leak. I touched each fuel line and clamp and found no wetness or residue. So I'm at a loss as to how to eliminate this phantom leak short of dropping the fuel tank and reworking the fuel system. Any thoughts?

[Fifty50Plus]

At the top of the tank there is a hose that vents fuel vapors to a charcoal canister elsewhere on the car. (Front left fenderwell???). Sometimes this hose breaks/leaks/wasn't reinstalled when tank was pulled before or cracks. Usually when the tank is filled you get the same conditions that you describe.
If you are lucky, it was the seal that you tightened above the fuel sender.
_________________
1979 924 NA race car H-Prod SCCA
1982 924 NA race car - Sold
1981 924 Turbo sold
1982 924 Turbo sold
1972 911 E race car - traded for Cayenne Diesel
1975 914 1.8 Building for H-Prod SCCA

[Legitimate Salvage]

Those top hoses, or splits in the tank can't be ruled out. But that means dropping the tank. At least, I have a snailshell tranny so I think the tank can come out without removing the transaxle.

But I'm highly inclined to put a new tank in if I have to go that far. Are the new production tanks I see on ebay or elsewhere any good?

[Raize]

Attach a piece of hose to the fuel breather and blow into it as hard as you can. Cover the end with your thumb and listen around for where the air is leaking out.

Mine was leaking at the filler hose where it connects to the tank, but only very slightly. Now I replaced the hose and the gas tank goes "whoosh" when I take off the cap, signalling that it is well sealed.

[Cedric]

[Raize]

[Legitimate Salvage]

[quote="Raize"]

[Mike9311]

Just went through all this on a '82 S2. Top hoses for sure

Obviously in this case the trans had to come out.

Also fixed the fuel sender while in there
_________________
1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car

[Legitimate Salvage]

Just spent another 20 min. under the car and in the rear hatch sniffing around. Based on my olfactory sensors, the strongest fuel smell by far is at one of the two hoses on the underside of the fuel tank. One hose goes to an inline filter and then to the fuel pump. Both look new (probably replaced a couple years ago by the PO). Some smell there but the worst of it is two inches over at the other fuel line.

This one is slightly smaller. The other end of this hose terminates in a factory crimp and attaches to a metal line. This hose appears to be original, and I can see some splitting at the screw type hose clamp. Any fuel leaking out of here would dribble down to the bolt I described in my initial post.

My guess is that this is a fuel return line. I was tempted to remove it and cut about a 1/4 inch off of it and reconnect it with a fresh clamp. But I'm betting I'd get a face full of petrol doing that.

Pics:






The other end of the Leaky Boi...



I'm off to see if I can find that hose somewhere...

[Legitimate Salvage]

The part I ordered: https://griffiths.com/product/477209071-porsche-924-fuel-line/

Replaced this end section of the return line today. I learned a few things.

FIRST AND MOST IMPORTANT: Run the car low on gas AND drain the tank by pulling the the old return line at the bottom of the tank. I thought I had run the tank low enough. I was wrong… horribly wrong. Draining the tank would have saved me a lot of trouble.

The nut on the end of the soft line (17 mm) DOES NOT swivel. It’s solid with the hose crimp. The nut on the hard line end (14 mm) is not a solid piece with the hard line. Given there isn’t much room to get two wrenches up there, use a crowfoot wrench to break the 14mm upper nut free (holding the 17mm as best you can with an open end wrench... using two crowfoot wrenches would be ideal). Once loose, you can just barely get your fingers up there and un-thread the 14mm from the 17mm nut. Installation is the reverse of removal.

Do this BEFORE you fit the hose onto the barb coming out of the tank. The return hose runs through a clamped bundle of lines just aft of the fuel pressure regulator. Pull the old hose out and slide in the new one. Then attach it to the barb and tighten the hose clamp.

I devised the above procedure based on the symphony of bad ideas I used for this repair.

I simply clamped the line with vise grips, then popped open the connection to the hard line. I spent the next 30 minutes trying to get the 17mm nut off, assuming it was swiveling. Nope… I was loosening it, but the hose was bouncing it back into place before I could get the wrench back on it. Stupid me finally looked at the new hose and figured out why it wasn’t unthreading. So I opted to cut the old line above where I clamped it and proceeded to try to spin the 17mm off by the remaining hose section. This step wasn't necessary since the upper 14mm nut isn't solid with the hard line. I was turning the 17mm nut, but the 14mm was turning right along with it. I could've just stuck my hand up there and undone the 14mm nut (without cutting anything) and been done in 15 minutes.

Then I removed the other clamped end of the return hose (the nipple on the bottom of the tank). At this juncture, it became abundantly clear there was more than a few gallons of gas left in the tank. So I got a face full of gas as I slid the new line on (while the tank was draining). I’d had a pan underneath the entire time so that caught most of the gas. My face caught the rest.

Moral of the Story: I’m an effing doughnut. I did ALL of the above with gas dripping/running down my right arm. Since the old line was hard and dry rotted, clamping with the vise grips caused the line to form some small splits. Hence, it was dripping gas the entire time I was working on the line. I have a lovely chemical burn on the upper right side of my back, shoulder, and down my right arm.

Did I mention I did this on my concrete driveway, mid-afternoon, in direct sunlight, on a 97*F day?

The only smart thing I did today was wear safety goggles.

Don’t be me. Don’t be an effing doughnut. Drain the tank first.

Thank you for coming to my TED Talk.