New Fuel Pump Has Gas Coming Out Exhaust

[John W]

Hello Everyone!

I picked up my first 911 a few weeks ago and I have been trying to get it running after sitting for about four years. The vehicle is a 1981 (October 1980) 911SC Targa. So far I have done the following:
-Drain old gas from gas tank
-Clear out the fuel line
-New Fuel Filter
-New Fuel Pump
-Installed pop off valve into the airbox
Installed fresh oil

The car wouldn't do anything when I first got it. Now when I turn on the ignition without engaging the starter I can hear the pump running. However when I try to start the car it will sputter a bit but not completely fire up. The times I try to run it when I shut the ignition off I will see gasoline come out the driver's side exhaust connection. (The forward downward exhaust pipe to muffler flange)

I am new to 911's and don't fully understand the workings. With 18 years air-cooled vw experience once I saw the raw gas I stopped and came here to consult for help. ANY HELP would be appreciated!!

-What could be causing so much gas to dump out that side?
-Is there a diaphragm or something that I should replace?

There isn't any gas leaking on the top side. From what I can see this looks internal.

Thank you!

[911SauCy]

If im gathering your description correctly, the fuel return line connection is all the way up near the firewall, directly above your described leak location, i'd put moneyon it pumping out of there and leaking down onto the exhaust.

went through almost exact scenario.

invest in a fire extinguisher

you'd need to be pumping A LOT of fuel through a completely or muliple completely dead cylinders to have fuel flowing outofthe exhaust...

[ossiblue]

You have a couple of issues, right off the top.

First, the pump shouldn't run with the ignition "on" and the engine not running. Could be a disconnected air flow sensor switch, a stuck intake plunger, a bad air flow sensor switch, or a bad fuel pump relay.

Second, when you tried to start the engine and the engine began to turn over, the intake plunger like lifted off its stop (as it should) and caused the injectors to squirt fuel, leading to flooding. Fuel leaking from an exhaust connection means raw fuel is being pumped through the engine.

Third, given the time the car was sitting, you likely have some air leaks in the system which leans the mixture enough to prevent starting--that's why you get the sputter but no running. Additionally, the cold start injector may be faulty which also would make a cold start difficult. Bottom line, the more you crank a non-starting engine, the more you will flood it.

There are more possible reasons for your situation, but the above are the most common. Start with one problem, fix it, then move to the next.

Let us know where you'd like to begin and we can ask more detailed questions. Nothing you've mentioned hasn't already been resolved for others.

[John W]

Originally Posted by 911SauCy

you have a gas leak which is dripping down onto your exhaust.

if im gathering your description correctly, the fuel return line connection is all the way up near the firewall, directly above your described leak location, i'd put moneyon it pumping out of there and leaking down onto the exhaust.

went through almost exact scenario.

invest in a fire extinguisher

you'd need to be pumping A LOT of fuel through a completely or muliple completely dead cylinders to have fuel flowing outofthe exhaust...

Thank you 911SauCy,
Is that return line regular fuel line or a pressed fitting line? Is the return line hard to change out?

I always have fire estiguisher ready when working with a "new to me car" or gasoline.

[John W]

Originally Posted by ossiblue

You have a couple of issues, right off the top.

First, the pump shouldn't run with the ignition "on" and the engine not running. Could be a disconnected air flow sensor switch, a stuck intake plunger, a bad air flow sensor switch, or a bad fuel pump relay.

Second, when you tried to start the engine and the engine began to turn over, the intake plunger like lifted off its stop (as it should) and caused the injectors to squirt fuel, leading to flooding. Fuel leaking from an exhaust connection means raw fuel is being pumped through the engine.

Third, given the time the car was sitting, you likely have some air leaks in the system which leans the mixture enough to prevent starting--that's why you get the sputter but no running. Additionally, the cold start injector may be faulty which also would make a cold start difficult. Bottom line, the more you crank a non-starting engine, the more you will flood it.

There are more possible reasons for your situation, but the above are the most common. Start with one problem, fix it, then move to the next.

Let us know where you'd like to begin and we can ask more detailed questions. Nothing you've mentioned hasn't already been resolved for others.

Ossiblue,

That is some great info!!

This makes the most sense to start with I think -"First, the pump shouldn't run with the ignition "on" and the engine not running. Could be a disconnected air flow sensor switch, a stuck intake plunger, a bad air flow sensor switch, or a bad fuel pump relay."

1. Disconnected air flow sensor switch - I will have to find where this is.
2. A stuck intake plunger - I will have to find where this is.
3. A bad air flow sensor switch - I will have to find where this is.
4. A bad fuel pump relay - I'm guessing this is near the fuse panel. I can check this.

I will dig on the internet to find all of these areas. Are there any members on here or does anyone know of a Porsche man in or around Kansas City? I hate to hassle everyone with questions.

[timmy2]

Nice looking car.
Google Jim's basement garage and then click on the CIS primer. It will really help you find things and identify them.
Then search here on the forum for the CIS for dummies thread.

[Das Schnell Ei]

The fuel head is going to have to come off and the plunger is going to have to be removed and cleaned. If it's been sitting for four years it's going to be gummed up and stuck. So when the fuel pump is running its dumping fuel all of the time ... Engine only sputters and raw fuel is spitting out the exhaust.

[boyt911sc]

John W,

There is really nothing new about your problems. We have seen, encountered, and fixed these problems many times before. So it is a matter of you doing it with help from these guys or bring the car to a shop that would probably cost you an arm and leg by the time you get your car out of the shop.

If you have the time and interest to do the troubleshooting and wanted to learn more about it, this is the right place to start. These are my suggestions to you:
1). Get a reference manual like Bentley.
2). Get a set of fuel pressure gauge kit.
3). Use a digital camera to show the section or part in question.
4). Read Tim Irwin's Thread about 'CIS Dummies'. And read more posts about CIS troubleshooting.
5). Don't hesitate to ask questions for clarification. There is no such thing as stupid questions. But there are stupid answers you'll get in this forum. So be prudent and careful who you listened too.
6). A timely feedback from you is what these people would expect. Nothing else.

And keep us posted.

Tony

[stormcrow]

John W

You could still have old gas in the lines that won't burn off. You need to be very careful if the fuel is coming out of the exhaust for you may damage your piston if the cylinder gets full of fuel.

Do a thorough check before you even try to start the engine again as a safety precaution. There is tons of information on this site that explains everything you need to know about the fuel system but were afraid to ask.

Just do a search - one other thing you need to have a thorough understanding of how the fuel system works with all other components and the pressures related to fuel pressure. That's very important when dealing with the fuel system.

[Gordo2]

Perfect timing on your post - I was preparing to post something similar.

I have a carb'd engine and noticed that the muffler spits drops of moisture on the deck right after I start it.

At first, I too thought it was unburned fuel - but today, I wiped some up with a finger and sniffed it - the smell wasn't strong enough to be fuel.

In my case, I first noticed the droplets coming out of the exhaust this spring - cool moist weather.

I believe mine is simply from moisture condensing within the exhaust - spitting out when I start it.

Good luck,

Gordo

[boyt911sc]

Originally Posted by John W

Ossiblue,

That is some great info!!

This makes the most sense to start with I think -"First, the pump shouldn't run with the ignition "on" and the engine not running. Could be a disconnected air flow sensor switch, a stuck intake plunger, a bad air flow sensor switch, or a bad fuel pump relay."

1. Disconnected air flow sensor switch - I will have to find where this is.
2. A stuck intake plunger - I will have to find where this is.
3. A bad air flow sensor switch - I will have to find where this is.
4. A bad fuel pump relay - I'm guessing this is near the fuse panel. I can check this.

I will dig on the internet to find all of these areas. Are there any members on here or does anyone know of a Porsche man in or around Kansas City? I hate to hassle everyone with questions.

John W,

A stuck Fuel Distributor plunger as in item #2 above would not cause a Fuel Pump to run. But the rest of the items above are spot on. LJ always delivers very clear and concise write ups that are easy to understand and follow. Wish I could write and explain like he does.

Tony

[porwolf]

Originally Posted by John W

Thank you 911SauCy,
Is that return line regular fuel line or a pressed fitting line? Is the return line hard to change out?

I always have fire estiguisher ready when working with a "new to me car" or gasoline.

Congratulations to your new Porsche membership.

Reading this thread reminds me of when I awakened mt '79SC from a 16 year hibernation. The gas in the tank was the big problem. I solidified to a hard brown gunk that plugged the fuel intake and especially the return line into the tank. If that line is plugged that could be the cause of you gas leak. Pressurized air would not go into my tank at the return line, it was solidly frozen. I would make sure that both metal tubes, outflow and return, at the tank are completely clear. Pay special attention to the return line tube it is only about 1/4 inch in diameter and needs to be clear.

[911SauCy]

Originally Posted by John W

Thank you 911SauCy,
Is that return line regular fuel line or a pressed fitting line? Is the return line hard to change out?

I always have fire estiguisher ready when working with a "new to me car" or gasoline.

It's a rubber line with screw-in press flare fitting. It's not easy as the fuel lines run through the center tunnel of the body. Which is why I decided to go with all aluminum braided AN racing style lines (mounted in place where A/C lines once were)

Ossiblue makes a number of good points. I went back to edit my original post and saw he beat me to a couple things.

Good luck

[T77911S]

i only read the title.

stuck fuel plunger in the head.

pull the head off and be careful not to let the plunger drop out.
pull the plunger out and clean it with carb cleaner. try to clean inside the sleeve the plunger came out of. i would not spray carb cleaner in there due to the rybber O rings.

[John W]

You are all AWESOME!!! Thank you for helping out this "Porsche Newbie". Many of you have suggested items that I always suggest to new vw guys like a Bentley Manual. Going from knowing a great deal to starting over has been a touch frustrating. I've found myself taking a step back and taking a few deep breaths so I don't feel like I'm in over my head! haha

So far this method has worked. I will get the car situated where I can tear into it and have it sit for a few days.

THANK YOU TO EVERYONE FOR THE WONDERFUL ADVICE!!!!!!! THANK YOU!