Replacing some fuel lines...guidance pls

[Franks89-911]

89 911 3.2L.

Hi all, yesterday while out for a joyride with my 7 yo son, we smelled a distinct odor of gas in the cabin while the car was moving. Definitely seemed to be coming from the front of the car, smell seemed constant even while top up and lots of wind coming thru cabin. We immediately returned home. Opened up the frunk and sniffed around, but couldn't pinpoint it. Felt along the lines in the front near the plastic rectangular expansion tank; nothing. Opened up the engine and felt around fuel filter, fuel lines etc. for wetness - Nothing. And no gas smell coming from the engine bay, which I guess is the best news.

Today, I went out again, sniffed around and smelled no gas, so took her out to see if I could replicate the issue (prob stupid, I know) and did my usual 20 min run to get to operating temp. She ran great, no smell of any kind, also good news. Same thing, no wetness or smell anywhere, frunk or rear.

But my luck can't last forever, so I figure my best option right now is start replacing some fuel components & hoses to be safe, and hope I catch it. Car is 27 yrs old and that stuff was never replaced by Dad (previous owner) may he RIP. Couple of the hoses on plastic expansion tank look pretty old. Figured I'd start with stuff in the frunk.

Having a hard time locating all of the right parts on our host (user error, surely), so here's what I need in a nutshell, if you can help:

• The black rubber connector/sleeve that mates up the gas tank with the metal gas tank fill line
• The 1 hose coming out of the top (Facing towards driver) of the plastic expansion tank
• The 2 hoses coming out of the bottom (Facing towards front bumper) of the plastic expansion tank
• The gasket for the gas cap
• The gasket for the fuel level sensor (assuming that's the round thing on top of the fuel tank with the wire coming out?)

Anyway, thanks all for your help. Also if you know of alternatives for such parts that work as well/better as the "Genuine Porsche $$$" brand I would appreciate that too.

[Tremelune]

Sometimes I smell fuel, but I'm unable to reproduce it consistently. I'm interested to hear responses.

[aigel]

You should not replace hoses that are not under pressure. Those are the last suspect. You should look first at pressurized lines. You have not checked around the fuel pump. The pump is behind the gas tank on the bottom side of the car, between the front wheels under a splash shield. If there is a slow leak, you can sometimes see dried on fuel or areas where the fuel washed away gunk.

You should look at a fuel system diagram. Hopefully you will see that it will be a BIG job to throw parts at this guessing. If the leak is not in the engine compartment, it is relatively safe to wait for it to come back strong enough where you can find the offending part.

G

[Ayles]

That black sleeve is not easy to replace. I changed mine while the tank was out. I dont see any other way since each end of the pipe inserts an inch or two into that sleave and it was SNUG. Our host has the part. The other lines in the frunk can replaced easily using braided fuel hose of the same length/diameter. Tank sender and cap are easy.

I bought the Porsche sleeve, but the rest I replaced with commonly available german braided fuel hose.

[wrxnofx]

Jack up the front of the car and remove the "belly pan" just behind the fuel tank. It covers the fuel pump, and perhaps there is a leak in the small line from the pump to the tank. The pan is 4 fasteners: 2 17mm nuts and 2 head head bolts.

There are also 3 lines in the engine compartment that should probably be replaced if they are 27 years old. I just went through this last year on my '87. One is shaped like a "J", the second runs behind the engine, and the 3rd is a T shape that runs under the intake manifold and connects to both fuel rails. There is a guy on here that makes them, BoxterGT. Search for his posts for them. Here are the part numbers:


The lines in your front compartment should be found here:


Finally, download the PET for your '89 located here. It's where I got these images.

[Techno Duck]

If you dont know the history of them, i would also suggest replacing the 3 pressurized lines on the engine also.

[kuba_kuba]

I had same the exact same issue as you describe on my '88 when I first got it. Intermittent fuel smell from front - nothing obvious in the frunk. Ended up being the fuel pump housing that was leaking onto the pan that protects it. Most of the time it would evaporate before I'd see anything.
I'd second the suggestions above to start with the pressurized items.

[chris_seven]

Originally Posted by aigel

You should not replace hoses that are not under pressure. Those are the last suspect. You should look first at pressurized lines.

We have been having nothing but problems with Cohline Textile Braided Hoses on cars with carbs for about 3-4 years now and this is fuel lines operating at 3psi.

The same problem occurs even with very low mileage cars, and I am sad to say, despite Cohline's claim that their NBR hose is E10 compatible. Cohline's insistence is that the problem is due to excessive temperature in the engine bay despite the fact this hose was used successfully in the 70's and 80's.

I just don't believe them and do think the issue is Ethanol Related.

One of our customers lives in France and has to use E85 fuel and his hoses last 3-4 months and have been a complete disaster. All you need is a 1967 911S Soft Window Targa bursting into flames due to leaking fuel lines.

The following thread shows the manner in which the hose fails and shows we are not alone in having this problem.

Cotton Braided Fuel Hose

We were changing hoses on an annual basis but we are now using Aeroquip Startlite which claims to the E85 compliant but is very, very costly. It is black textile braided and apart form the markings look relatively authentic.

We installed the first hose sets about 6 months ago and we will leave it another 6 months before we check in detail.

I sad to say that it appears that Ethanol increases NBR sensitivity to percolation with or without pressure and there are some SAE articles which seem to confirm this problem.

I don't think you can assume low pressure hoses will be free from defects.

[Tremelune]

So like, while we're on the subject...Why bother with braided fuel lines when the modern world uses something else?

Why Do Braided Fuel Lines Suck So Much? Am I Missing Something?

[Bergo]

if you don't care if it's stock (some people do, my car isn;t numbers matching, so whatever) There are tons of stuff available in the aftermarket. I went all -6AN fittings front to back, made things easy. you can just walk up and down the aisle of your local speed shop and have everything without having to track down obscure NLA part numbers.

[pdtweeks]

I had similar "where's that fuel smell coming from" on my SC, in the frunk....All of my fuel lines were new and properly tightened, but I just figured I had left one loose or...

turned out to be the fuel sending unit gasket.....dried from sitting and "shrank" (is that a word ? ). Replaced and tightened and smell went away.

I'm not saying that it isn't a good idea to replace those old fuel lines, just sayin' there may be other places to check as well

[steely]

I did the engine lines with AN (wrxnofx's post above) as soon as I bought her home, and I did the tunnel lines (OEM) and FP a couple years later when I got up the money and nerve - no smells anymore and a lot of peace of mind. I used to detect the odor of gas, but not anymore, and I'd heard it was a good thing to replace the old original lines to reduce any risk. My vapor recovery stuff is all original and maybe due, but I can afford to wait.

[steely]

Originally Posted by pdtweeks

I had similar "where's that fuel smell coming from" on my SC, in the frunk....All of my fuel lines were new and properly tightened, but I just figured I had left one loose or...

turned out to be the fuel sending unit gasket.....dried from sitting and "shrank" (is that a word ? ). Replaced and tightened and smell went away.

I'm not saying that it isn't a good idea to replace those old fuel lines, just sayin' there may be other places to check as well

Great suggestion!

[Lake Guy]

I had a few fuel smells last summer before I started the overall. Found two problems around the fuel pump. The hoes fitting brazed to the fuel tank was leaking at the weld and the hose connecting to the pump inlet looked suspect. The pump rubber isolator that mount the pump bracket to the chassis had failed and the pump was hanging on the hoses.

I'd definitely pull off that cover under the car and take a real good look around.

Mark