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-   -   Gas leak at first spring start (http://forums.pelicanparts.com/porsche-911-technical-forum/1024435-gas-leak-first-spring-start.html)

OsoMoore 03-23-2019 08:56 AM

Gas leak at first spring start
 
I started my SC up for the first time this year, and after clearing the garage around it, spotted a 3-seconds-per-drip leak coming from just inside the front passenger wheel.
It is clear, and smells to be gas.
It only started when I started the engine. I haven't had a chance to get underneath yet, and I'm not sure I even want to start it again before fixing.
Any tips on what to look for and what it may be would be appreciated.
http://forums.pelicanparts.com/uploa...1553357224.jpg

7783911 03-23-2019 08:58 AM

fuel pump connection to hose..started up puts on flow pressure...gas running along a sill to the point it can drop to ground?

boyt911sc 03-23-2019 09:09 AM

Locating fuel leak........
 
OsoMoore,

Test run your FP and you will locate the source of your fuel leak. Keep the FP running and begin your investigation. The drip area will direct you close where the source is located. Do not start the engine until you fixed the leak.

Tony

OsoMoore 03-23-2019 09:14 AM

Quote:

Originally Posted by boyt911sc (Post 10401804)
OsoMoore,

Test run your FP and you will locate the source of your fuel leak. Keep the FP running and begin your investigation. The drip area will direct you close where the source is located. Do not start the engine until you fixed the leak.

Tony

Excellent plan! I already know how to start the fuel pump on its own, by lifting the air flow sensor plate with the key slightly turned.

Mark Salvetti 03-23-2019 09:17 AM

I wouldn't use the air flow sensor plate to run the pump. That will also squirt fuel into the cylinders. You need to pull the fuel pump relay and use a piece of wire to jumper across terminals 87a and 30.

You'll also need to jack up the front of the car and remove the skid plate to expose the fuel pump and the hose connections.

The easy one to fix is the rubber hose on the suction side of the fuel pump, but since the leak is on the pressure side (or it would be leaking without the car running), you may have some challenges. Hopefully it's just a loose connection. If it's a crimp between the rubber hoses and the tunnel lines, you'll have some work ahead of you.

Mark

OsoMoore 03-23-2019 09:28 AM

Quote:

Originally Posted by Mark Salvetti (Post 10401811)
I wouldn't use the air flow sensor plate to run the pump. That will also squirt fuel into the cylinders. You need to pull the fuel pump relay and use a piece of wire to jumper across terminals 87a and 30.

You'll also need to jack up the front of the car and remove the skid plate to expose the fuel pump and the hose connections.

The easy one to fix is the rubber hose on the suction side of the fuel pump, but since the leak is on the pressure side (or it would be leaking without the car running), you may have some challenges. Hopefully it's just a loose connection. If it's a crimp between the rubber hoses and the tunnel lines, you'll have some work ahead of you.

Mark

Oh right. I forgot about flooding the cylinders.
The fuel pump relay and I are old friends… I have the skid plate off now, I'll jumper it and see what we see.

SkiVT 03-23-2019 09:43 AM

I had a similar leak last summer and it was the clamps on the hose 7783911 mentioned. They had rusted/ broken leaving the hose too loose at the fuel tank connection. Easy fix and hopefully you find something similarly easy.

OsoMoore 03-23-2019 09:48 AM

I did the jumper dealio and located exactly where it is leaking from.
http://forums.pelicanparts.com/uploa...1553362998.jpg

I'm going to do some digging into where that line goes to next.

Also, for the benefit of those who come later, here's how you jumper your fuel pump relay. Do this thing, and then turn the key half a turn. Touch the wires together and she runs. The pin numbers should be written on the inside of the fuel pump relay itself, the order of the relays may vary, and the FP relay will generally be your only red relay.
http://forums.pelicanparts.com/uploa...1553363256.jpg

And always have your fire extinguisher nearby when messing with gasoline.
http://forums.pelicanparts.com/uploa...1553363403.jpg

7783911 03-23-2019 09:54 AM

could you observe the leak occuring? time for a new hose unless it can be recrimped which generally (i am told) doesnt work. or can you run hose direct to barb and clamp?

7783911 03-23-2019 09:54 AM

ps..is that a Klassic fuse panel?

OsoMoore 03-23-2019 10:03 AM

Here's a less disorienting photo:
http://forums.pelicanparts.com/uploa...1553364031.jpg

Quote:

Originally Posted by 7783911 (Post 10401855)
could you observe the leak occuring? time for a new hose unless it can be recrimped which generally (i am told) doesnt work. or can you run hose direct to barb and clamp?

I observed the leak coming directly from the circled spot, at the crimp.


Quote:

Originally Posted by 7783911 (Post 10401856)
ps..is that a Klassic fuse panel?

It is a fuse panel rebuild I did myself, with some help from the PP forum. Here's my thread on it.
http://forums.pelicanparts.com/porsche-911-technical-forum/810035-sick-time-update-my-sc-fusebox.html

OsoMoore 03-23-2019 10:13 AM

I found some good info on http://forums.pelicanparts.com/porsche-911-technical-forum/944055-ive-searched-but-still-need-help-fuel-leak.html#post9451779.
My leak is the high pressure feed line... oh boy.

EDIT: Collecting threads on how to do this... fun times ahead.
Top thread: http://forums.pelicanparts.com/porsche-911-technical-forum/792001-okay-so-i-am-going-replace-my-main-tunnel-fuel-lines-tomorrow-any-suggestions.html
Other Threads:
http://forums.pelicanparts.com/porsche-911-technical-forum/305740-how-hard-change-fuel-lines.html#post2826584
http://forums.pelicanparts.com/porsche-911-technical-forum/328178-should-i-replace-theses-brake-fuel-lines.html

manbridge 74 03-23-2019 10:29 AM

New lines have an upgraded double crimp. FYI

SkiVT 03-23-2019 10:30 AM

Ouch!! I am having both tunnel lines replaced in a couple weeks to avoid this exact issue. Lots if good words about replacement lines made by Len in NH (boxstergt)

7783911 03-23-2019 10:55 AM

I can vouch for Len...great guy to deal with!

beren 03-23-2019 01:29 PM

Happened to me 3 years ago on the first drive. Was a ruptured fuel line, which I had to partially drop the engine to get in there to replace it. It was a good excuse to replace them all and the sound dampening material. I basically changed out any rubber thing I could when I did that.

boyt911sc 03-23-2019 03:18 PM

Nope..........
 
Quote:

Originally Posted by OsoMoore (Post 10401808)
Excellent plan! I already know how to start the fuel pump on its own, by lifting the air flow sensor plate with the key slightly turned.


OsoMoore,

This is a bad procedure to use when you are looking for source/s of the fuel leak. Why would you dump fuel in the combustion chambers when you could run the FP without the fuel injectors delivering fuel. Using the FP socket’s terminals #30 & #87A would be a better option.

Tony

OsoMoore 03-26-2019 05:29 AM

After an analysis, I'm going to replace the full fuel line set. I've talked to Len and am sending him an order later today. In the meanwhile, I'm working on draining the fuel and getting set up to access all the tight areas.

I'm thinking about dropping the steering stuff out of the way. Has anyone who did Len's lines done it with that in?

OsoMoore 03-29-2019 07:03 AM

I've borrowed 3 gas cans and some very large jacks from a friend. New lines are on order from Len, hopefully arriving by next weekend. Tonight I'm going to go for a fuel drain.

The current plan is to tape the hell out of the leaky spot just after the fuel pump and put a pan under in case it leaks some more. Then I'll detach the fuel line in back at the accumulator. Then I can stick the line in a can back there, and lift the air flow sensor plate to activate the pump. That should allow me to control the dumping of fuel into the cans. I don't have to mess with hoses while on my back under the car, and I can stop easily to switch to new cans.

I'll report back tomorrow!

Jeff NJ 03-29-2019 08:03 AM

Quote:

Originally Posted by OsoMoore (Post 10404910)
After an analysis, I'm going to replace the full fuel line set. I've talked to Len and am sending him an order later today. In the meanwhile, I'm working on draining the fuel and getting set up to access all the tight areas.

I'm thinking about dropping the steering stuff out of the way. Has anyone who did Len's lines done it with that in?

I did Len's lines with the steering assy in. It was a pain and there was much cursing and gnashing of teeth, but I believe it was faster than removing the steering and maybe helped avoid a separate can of worms while removing/reinstalling the steering assy.

Be sure to get the grommets for the tunnel lines and his threaded coupler to help pull the tunnel lines through while removing the originals.


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