Air in Fuel Line?
10-12-03, 06:42 PM
#1
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Air in Fuel Line?
I have been having some problems with my gls-se lately. I thought i pinned the problems down to a faulty fuel pump.
I also have a leaky gastank and it was leakin pretty bad today, so to remove some of the gas my dad pulled off the line going to the fuel rail and a blast of air and a mist of gas came out. Almost all air came out, and some gas misted in the air.
Now could air in the gas line be causing my car to die when idling for a period of time and die for no reason while driving?
I also have a leaky gastank and it was leakin pretty bad today, so to remove some of the gas my dad pulled off the line going to the fuel rail and a blast of air and a mist of gas came out. Almost all air came out, and some gas misted in the air.
Now could air in the gas line be causing my car to die when idling for a period of time and die for no reason while driving?
10-13-03, 08:45 AM
#7
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The vapor lock could be a possible reason. That would explain the blast of air out of the fuel line when it got popped off. I guess the struggling fuel pump could be getting hot causing the vapor to create. Anyone else had this problem with their RX-7?
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10-13-03, 05:04 PM
#8
84SE-EGI helpy-helperton
On SE's, it's not unusual to have a burst of air when removing any of the fuel injector hoses that lead to the fuel rail. This is because the lines going to the engine are the 'high point' of the fuel system, and when you let it sit over time, the bubbles will find their way to the high point. When you go to remove the hoses, there is residual pressure in the lines, and the air and fuel quickly vent. This is what you're describing.
If you're familiar with your SE, you'll know that there is a connector plug by your air filter box which must be shunted to run the fuel pump without the engine running. The SE is designed so that the fuel pump only pumps when the engine is cranking or running. It will not run when you switch the ignition on unless you are actively cranking or the engine is running.
When you shunt this connector, it will allow the fuel pump to run without the engine running which allows you to hear the fuel going through the rail - and to test for leaks prior to reinstalling the upper intake manifold (learned this the hard way...). If you notice, when you have the ignition 'hot' (not cranking) and the plug shunted, you can hear a 'hissing' of the fuel going through the feed line, the fuel rail, and the return lines. These lines will be very hard to the touch, as you're running quite a bit of pressure through them when the engine is running.
Any air bubbles are quickly forced back through the return line and to the tank where they are vented out into the atmosphere inside the fuel tank. This prevents any air bubbles in the fuel line which is an extremely unlikely cause of your engine dying when idling or when cruising. Vapor lock is when the fuel boils in the lines due to excessive heat - SE's are not known for having this condition due to the remote location of the fuel lines to the exhaust.
Some questions to help you diagnose the true cause:
1) Does the engine lack power at all? You mention it dying - when and how does this happen?
2) Have you changed injectors, are these originals?
3) Does the engine run roughly before it dies?
4) With the engine running, can you induce it to die like you've described? Like moving the wiring harness around (bad connection to an/both injectors), or possibly a bad ground cable?
5) What other work have you done on it lately? When did this start? Has it always done this?
6) Do you have any fuel leaks anywhere under the upper intake manifold?
7) What kind of fuel mileage are you getting? (Indicative of poor fuel management, rich idle, etc.)
8) Does the engine idle surge at all? Does it idle higher than 900 RPM (Stock SE idle speed)?
9) Have you replaced your fuel pump recently? Could it be caused by an intermittent fuel pump relay? Blown fuse (Main engine electrical inside, or the fusible link at the drivers-side shock tower)?
10) Tell us more. HTH,
If you're familiar with your SE, you'll know that there is a connector plug by your air filter box which must be shunted to run the fuel pump without the engine running. The SE is designed so that the fuel pump only pumps when the engine is cranking or running. It will not run when you switch the ignition on unless you are actively cranking or the engine is running.
When you shunt this connector, it will allow the fuel pump to run without the engine running which allows you to hear the fuel going through the rail - and to test for leaks prior to reinstalling the upper intake manifold (learned this the hard way...). If you notice, when you have the ignition 'hot' (not cranking) and the plug shunted, you can hear a 'hissing' of the fuel going through the feed line, the fuel rail, and the return lines. These lines will be very hard to the touch, as you're running quite a bit of pressure through them when the engine is running.
Any air bubbles are quickly forced back through the return line and to the tank where they are vented out into the atmosphere inside the fuel tank. This prevents any air bubbles in the fuel line which is an extremely unlikely cause of your engine dying when idling or when cruising. Vapor lock is when the fuel boils in the lines due to excessive heat - SE's are not known for having this condition due to the remote location of the fuel lines to the exhaust.
Some questions to help you diagnose the true cause:
1) Does the engine lack power at all? You mention it dying - when and how does this happen?
2) Have you changed injectors, are these originals?
3) Does the engine run roughly before it dies?
4) With the engine running, can you induce it to die like you've described? Like moving the wiring harness around (bad connection to an/both injectors), or possibly a bad ground cable?
5) What other work have you done on it lately? When did this start? Has it always done this?
6) Do you have any fuel leaks anywhere under the upper intake manifold?
7) What kind of fuel mileage are you getting? (Indicative of poor fuel management, rich idle, etc.)
8) Does the engine idle surge at all? Does it idle higher than 900 RPM (Stock SE idle speed)?
9) Have you replaced your fuel pump recently? Could it be caused by an intermittent fuel pump relay? Blown fuse (Main engine electrical inside, or the fusible link at the drivers-side shock tower)?
10) Tell us more. HTH,
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