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71InvaderGT
Samba Member
Joined: May 01, 2012
Posts: 62
Location: Ontario, Canada
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 Posted: Fri Aug 02, 2013 9:11 am Post subject: 1600cc engine - died while driving down a steep hill? |
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Hi,
I have a 1600cc engine that has had a fresh oil change, new spark plugs, timing done for premium fuel, and the valves adjusted. The Invader has been running great for weeks now.
The car fired up strong and I went to the gas station. They only had 91 Supreme, which is typically fine. I put in 10 litres and went on my way. It was about 23-degrees, which isn't too hot, but 2km down the street I went down a steep decline and the engine died! I immediately thought vapour lock, but am unsure (3 hours later and still won't fire).
The car STINKS of gas, all electrical systems work, and the engine rotates, but won't fire up. I can see the fuel creep up the line, but it doesn't go back down when the car shuts off.
I'm thinking clogged fuel filter or fuel pump? Does anyone else have an idea? Sorry for the long description! |
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LeeVW
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Joined: June 14, 2006
Posts: 1016
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| Posted: Fri Aug 02, 2013 9:32 am Post subject: |
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Do you have a mechanical or electric fuel pump? Where is the fuel filter in relation to the pump - before or after?
I would investigate the strong gas smell to see where the leak is. Be careful. |
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71InvaderGT
Samba Member
Joined: May 01, 2012
Posts: 62
Location: Ontario, Canada
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| Posted: Fri Aug 02, 2013 10:05 am Post subject: |
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| LeeVW wrote: |
Do you have a mechanical or electric fuel pump? Where is the fuel filter in relation to the pump - before or after?
I would investigate the strong gas smell to see where the leak is. Be careful. |
I have an electric fuel pump. The line comes from the gas tank, runs along the side of the engine bay, up to the fuel filter and immediately to the fuel pump (both are attached to the side of the engine bay). From there, it goes straight into the carb. Usually when I shut the car off, the fuel drops down the line and back toward the pump, but that isn't happening.
Regarding the gas leak, I am baffled because there are no spills under the vehicle on the garage floor. |
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surfnc
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Joined: September 29, 2006
Posts: 948
Location: OBX, NC
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| Posted: Fri Aug 02, 2013 10:29 am Post subject: |
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71InvaderGT
As Lee said be careful.
What kind of carbs/carb do you have? I have had something similar happen with a PICT34 carb where the fuel pump overcame the float and fuel was pouring out of the overflow tube right into the carb flooding it out. You could carefully check this by taking off the air filter and looking at the carb mouth while someone cranks the engine. You will see fuel pouring out immediately. Be careful while you do this.
The answer to this is to check float valve and possibly reduce fuel pressure. Electric pumps can put out a fair amount of pressure.
Vince
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71InvaderGT
Samba Member
Joined: May 01, 2012
Posts: 62
Location: Ontario, Canada
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| Posted: Fri Aug 02, 2013 10:39 am Post subject: |
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| surfnc wrote: |
71InvaderGT
As Lee said be careful.
What kind of carbs/carb do you have? I have had something similar happen with a PICT34 carb where the fuel pump overcame the float and fuel was pouring out of the overflow tube right into the carb flooding it out. You could carefully check this by taking off the air filter and looking at the carb mouth while someone cranks the engine. You will see fuel pouring out immediately. Be careful while you do this.
The answer to this is to check float valve and possibly reduce fuel pressure. Electric pumps can put out a fair amount of pressure.
Vince |
Thank you both for outlining the danger in this repair.
I have the PICT34 carb as well. I rebuilt it in March and have not yet had any issues. You are saying that an actual stream of liquid gas will pour into the carb? I will have to do this test when I am home from work. |
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71InvaderGT
Samba Member
Joined: May 01, 2012
Posts: 62
Location: Ontario, Canada
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| Posted: Fri Aug 02, 2013 10:40 am Post subject: |
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| I am going to replace the fuel filter as well, being as it has been on the car since I purchased it three years ago. |
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Letterman7
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Joined: March 14, 2004
Posts: 3230
Location: Downingtown, PA
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| Posted: Fri Aug 02, 2013 11:09 am Post subject: |
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| I have to agree with Vince on too much fuel pressure as well. It'll overwhelm the carb and flood it out in a heartbeat. Put a pressure regulator on it and turn it for about 3 pounds of pressure. As stated before... be careful! |
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surfnc
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Joined: September 29, 2006
Posts: 948
Location: OBX, NC
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| Posted: Fri Aug 02, 2013 11:11 am Post subject: |
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| 71InvaderGT wrote: |
| surfnc wrote: |
71InvaderGT
As Lee said be careful.
What kind of carbs/carb do you have? I have had something similar happen with a PICT34 carb where the fuel pump overcame the float and fuel was pouring out of the overflow tube right into the carb flooding it out. You could carefully check this by taking off the air filter and looking at the carb mouth while someone cranks the engine. You will see fuel pouring out immediately. Be careful while you do this.
The answer to this is to check float valve and possibly reduce fuel pressure. Electric pumps can put out a fair amount of pressure.
Vince |
Thank you both for outlining the danger in this repair.
I have the PICT34 carb as well. I rebuilt it in March and have not yet had any issues. You are saying that an actual stream of liquid gas will pour into the carb? I will have to do this test when I am home from work. |
The brass tube cut at an angle is the over flow tube.
If the float is overcome by the fuel pump, fuel will flow right out of the tube into the carb throat and flood the engine. This would also account for your fuel smell and the fact that you do not see any on the floor.
Vince
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kingq
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Joined: March 13, 2013
Posts: 56
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| Posted: Fri Aug 02, 2013 10:31 pm Post subject: |
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madmike
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Joined: July 11, 2005
Posts: 5300
Location: Atlanta,Michigan
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| Posted: Sat Aug 03, 2013 5:52 am Post subject: |
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lostinbaja
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Joined: December 19, 2004
Posts: 4036
Location: Frankfort, Illinois
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| Posted: Sat Aug 03, 2013 7:21 am Post subject: |
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Does it have spark?
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71InvaderGT
Samba Member
Joined: May 01, 2012
Posts: 62
Location: Ontario, Canada
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| Posted: Sat Aug 03, 2013 9:19 am Post subject: |
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| Letterman7 wrote: |
| I have to agree with Vince on too much fuel pressure as well. It'll overwhelm the carb and flood it out in a heartbeat. Put a pressure regulator on it and turn it for about 3 pounds of pressure. As stated before... be careful! |
I just took a look at some of the universal fuel pressure regulators. This is a great idea and thank you for the recommended pressure! |
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71InvaderGT
Samba Member
Joined: May 01, 2012
Posts: 62
Location: Ontario, Canada
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| Posted: Sat Aug 03, 2013 9:26 am Post subject: |
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Vince,
Thank you for your advice. I am waiting for the roommate to wake up so I can try this. I have installed the clear fuel filter, installed the pump so it is below the gas tank, and ran the car. The electric fuel pump is certainly working better, but the car still won't fire.
I have now eliminated a blocked line, clogged fuel filter, and broken fuel pump. I am now hoping that the fuel pump is overpowering the carb. How could this happen if the vehicle has been running great for 6 weeks?
| surfnc wrote: |
| 71InvaderGT wrote: |
| surfnc wrote: |
71InvaderGT
As Lee said be careful.
What kind of carbs/carb do you have? I have had something similar happen with a PICT34 carb where the fuel pump overcame the float and fuel was pouring out of the overflow tube right into the carb flooding it out. You could carefully check this by taking off the air filter and looking at the carb mouth while someone cranks the engine. You will see fuel pouring out immediately. Be careful while you do this.
The answer to this is to check float valve and possibly reduce fuel pressure. Electric pumps can put out a fair amount of pressure.
Vince |
Thank you both for outlining the danger in this repair.
I have the PICT34 carb as well. I rebuilt it in March and have not yet had any issues. You are saying that an actual stream of liquid gas will pour into the carb? I will have to do this test when I am home from work. |
The brass tube cut at an angle is the over flow tube.
If the float is overcome by the fuel pump, fuel will flow right out of the tube into the carb throat and flood the engine. This would also account for your fuel smell and the fact that you do not see any on the floor.
Vince |
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71InvaderGT
Samba Member
Joined: May 01, 2012
Posts: 62
Location: Ontario, Canada
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| Posted: Sat Aug 03, 2013 9:30 am Post subject: |
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I don't have that flashing gun to check if I have spark. Is there another way to check?
| lostinbaja wrote: |
| Does it have spark? |
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Letterman7
Samba Member
Joined: March 14, 2004
Posts: 3230
Location: Downingtown, PA
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| Posted: Sat Aug 03, 2013 9:57 am Post subject: |
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| 71InvaderGT wrote: |
I don't have that flashing gun to check if I have spark. Is there another way to check?
| lostinbaja wrote: |
| Does it have spark? |
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The flashing gun is a timing gun, it won't tell you if you have spark. The easiest way is to take an old spark plug and unplug one wire at a time and put it to your test plug. Just lay the plug on the block so it can be grounded and crank the engine. You'll see whether or not that wire has juice to it.
| 71InvaderGT wrote: |
| I have now eliminated a blocked line, clogged fuel filter, and broken fuel pump. I am now hoping that the fuel pump is overpowering the carb. How could this happen if the vehicle has been running great for 6 weeks? |
It's possible that the fuel pump busted the internal accelerator diaphragm on the carburetor (#24 here http://www.vw-resource.com/carb_41.html#general) or the float valve is stuck or the float itself isn't set right or damaged. You did check to see that you aren't getting gas into the oil, right? |
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