Engine stalls after refilling
07-21-2010, 08:25 AM
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Engine stalls after refilling
For the past few months the engine on my 98 A6 2.8L (91K miles) seems to stall or sputter immediately after filling up at the gas station. I've also experienced on and off P0455 EVAP System: Large Leak Detected. The two are likely connected, but does anyone know what on the EVAP system could be causing these symptoms? Only thing replaced thus far is gas cap, but the problems persist.
07-21-2010, 06:05 PM
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BTSOM. Evap has to do with capture of polluting fumes. Unless the tank is pressurized, and to the best of my knowledge its not, it should not affect drivability.
Water?
Contaminants?
Fuel filter?
G
Water?
Contaminants?
Fuel filter?
G
07-22-2010, 05:38 AM
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For the past few months the engine on my 98 A6 2.8L (91K miles) seems to stall or sputter immediately after filling up at the gas station. I've also experienced on and off P0455 EVAP System: Large Leak Detected. The two are likely connected, but does anyone know what on the EVAP system could be causing these symptoms? Only thing replaced thus far is gas cap, but the problems persist.
08-11-2010, 06:03 AM
#4
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Problem Likely Solved!
Checked as many vac lines as possible - all appear in great shape
Charcoal cannister - like new
Gas cap - replaced as mentioned before
Ran tests using VAG-COM (070 and 071)
- 070 - Purge valve tested SAT
- 071 - Tank leak tested UNSAT - Large Leak Detected..could hear the LDP cycle open/close and could see that happen on VAG-COM display.
Removed Purge valve - I was able to blow through it with my mouth!
Purge vavle is a normally-closed valve, thus I should not be able to blow through it at all when it is de-energized. Therfore the valve is stuck open.
When filling the tank with gas, the fuel vapors existing in the tank are displaced by the liquid entering the tank. Therefore, the vapors are forced into the charcoal cannister. Since the purge valve is stuck open, those vapors are now allowed to pass through the cannister, through the open purge valve, and into the intake manifold. These vapors in the intake manifold create an extremely rich combustion mixture upon engine start effectivley flooding the engine. Several cranks later with the pedal fully depressed gets the engine started and gives the ECU time to compensate to keep the engine running. After a minute or two, the vapor throughput stablizes and the ECU can now maintain proper combustion ratios.
Got new purge valve (cannot blow through it like I could with the old vavle) and installed it.
After several drive cycles, CEL has yet to come on.
Ran same tests using VAG-COM as before and all tests are SAT.
Have yet to refill the tank, but expect no problems on next fill up.
Checked as many vac lines as possible - all appear in great shape
Charcoal cannister - like new
Gas cap - replaced as mentioned before
Ran tests using VAG-COM (070 and 071)
- 070 - Purge valve tested SAT
- 071 - Tank leak tested UNSAT - Large Leak Detected..could hear the LDP cycle open/close and could see that happen on VAG-COM display.
Removed Purge valve - I was able to blow through it with my mouth!
Purge vavle is a normally-closed valve, thus I should not be able to blow through it at all when it is de-energized. Therfore the valve is stuck open.
When filling the tank with gas, the fuel vapors existing in the tank are displaced by the liquid entering the tank. Therefore, the vapors are forced into the charcoal cannister. Since the purge valve is stuck open, those vapors are now allowed to pass through the cannister, through the open purge valve, and into the intake manifold. These vapors in the intake manifold create an extremely rich combustion mixture upon engine start effectivley flooding the engine. Several cranks later with the pedal fully depressed gets the engine started and gives the ECU time to compensate to keep the engine running. After a minute or two, the vapor throughput stablizes and the ECU can now maintain proper combustion ratios.
Got new purge valve (cannot blow through it like I could with the old vavle) and installed it.
After several drive cycles, CEL has yet to come on.
Ran same tests using VAG-COM as before and all tests are SAT.
Have yet to refill the tank, but expect no problems on next fill up.
12-13-2015, 09:08 PM
#6
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Problem Likely Solved!
Checked as many vac lines as possible - all appear in great shape
Charcoal cannister - like new
Gas cap - replaced as mentioned before
Ran tests using VAG-COM (070 and 071)
- 070 - Purge valve tested SAT
- 071 - Tank leak tested UNSAT - Large Leak Detected..could hear the LDP cycle open/close and could see that happen on VAG-COM display.
Removed Purge valve - I was able to blow through it with my mouth!
Purge vavle is a normally-closed valve, thus I should not be able to blow through it at all when it is de-energized. Therfore the valve is stuck open.
When filling the tank with gas, the fuel vapors existing in the tank are displaced by the liquid entering the tank. Therefore, the vapors are forced into the charcoal cannister. Since the purge valve is stuck open, those vapors are now allowed to pass through the cannister, through the open purge valve, and into the intake manifold. These vapors in the intake manifold create an extremely rich combustion mixture upon engine start effectivley flooding the engine. Several cranks later with the pedal fully depressed gets the engine started and gives the ECU time to compensate to keep the engine running. After a minute or two, the vapor throughput stablizes and the ECU can now maintain proper combustion ratios.
Got new purge valve (cannot blow through it like I could with the old vavle) and installed it.
After several drive cycles, CEL has yet to come on.
Ran same tests using VAG-COM as before and all tests are SAT.
Have yet to refill the tank, but expect no problems on next fill up.
Checked as many vac lines as possible - all appear in great shape
Charcoal cannister - like new
Gas cap - replaced as mentioned before
Ran tests using VAG-COM (070 and 071)
- 070 - Purge valve tested SAT
- 071 - Tank leak tested UNSAT - Large Leak Detected..could hear the LDP cycle open/close and could see that happen on VAG-COM display.
Removed Purge valve - I was able to blow through it with my mouth!
Purge vavle is a normally-closed valve, thus I should not be able to blow through it at all when it is de-energized. Therfore the valve is stuck open.
When filling the tank with gas, the fuel vapors existing in the tank are displaced by the liquid entering the tank. Therefore, the vapors are forced into the charcoal cannister. Since the purge valve is stuck open, those vapors are now allowed to pass through the cannister, through the open purge valve, and into the intake manifold. These vapors in the intake manifold create an extremely rich combustion mixture upon engine start effectivley flooding the engine. Several cranks later with the pedal fully depressed gets the engine started and gives the ECU time to compensate to keep the engine running. After a minute or two, the vapor throughput stablizes and the ECU can now maintain proper combustion ratios.
Got new purge valve (cannot blow through it like I could with the old vavle) and installed it.
After several drive cycles, CEL has yet to come on.
Ran same tests using VAG-COM as before and all tests are SAT.
Have yet to refill the tank, but expect no problems on next fill up.
12-14-2015, 02:02 AM
#7
AudiWorld Super User
There is a nice diagram showing the location in this thread:
https://www.audiworld.com/forums/a6-...valve-1702853/
And, yes, it is also called the N80.
https://www.audiworld.com/forums/a6-...valve-1702853/
And, yes, it is also called the N80.
Trending Topics
12-14-2015, 09:04 AM
#8
AudiWorld Super User
12-14-2015, 12:01 PM
#9
12-14-2015, 12:07 PM
#10
AudiWorld Super User
Thats the passenger side, right?
My eBahn doesn't show the N80 for the 2.7T but it's near there. The pic sure looks like a V6 though…
Try this: illustration #44:
Audi Vacuum system activated carbon filter system 2,7ltr.
p/n 078133517H
Try this: illustration #44:
Audi Vacuum system activated carbon filter system 2,7ltr.
p/n 078133517H
Last edited by SloopJohnB@mac.com; 12-14-2015 at 12:23 PM.