Excessive Gas Tank Pressure & Hard Start when Hot
07-12-2004, 12:18 PM
#1
Nordschleife Master
Thread Starter
Excessive Gas Tank Pressure & Hard Start when Hot
My 84 -
Recently, Iv developed an irritating and dangerous problem with tank pressure. When I run low on gas, my tank developes so much pressure it physically expands the gas tank - to the point where it sounds like Im letting air out of compressor when Im removing the cap. {So much pressure that it's blowing by the tank seal for the fuel level float}
Also, when the car is Hot - she's a little hard to start. The only thing I havent replaced are the caps and rotors - Is it possible that the two issues are related?.
Any Ideas?.
Im going to research my manuals and trace it back but just thought I would ask anyway.
TIA
Recently, Iv developed an irritating and dangerous problem with tank pressure. When I run low on gas, my tank developes so much pressure it physically expands the gas tank - to the point where it sounds like Im letting air out of compressor when Im removing the cap. {So much pressure that it's blowing by the tank seal for the fuel level float}
Also, when the car is Hot - she's a little hard to start. The only thing I havent replaced are the caps and rotors - Is it possible that the two issues are related?.
Any Ideas?.
Im going to research my manuals and trace it back but just thought I would ask anyway.
TIA
07-12-2004, 12:21 PM
#2
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Drew,
The tank is supposed to vent through the carbon cartridge / vapor recovery system, I think... consult your WSM and check hoses for kinking, etc.
The tank is supposed to vent through the carbon cartridge / vapor recovery system, I think... consult your WSM and check hoses for kinking, etc.
07-12-2004, 12:42 PM
#3
Administrator - "Tyson"
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Not exactly the same, but worth talking about. I removed the gas vapor system from my car per Porken's instructions.
Driving my car for the first time since the removal, my air/fuel is very rich, pegged when full throttle. I didn't think much of this since I didn't have the gauge before the mod.
I was at Tim Murphy's house getting the IC test fitted and checking the fuel lines. I disconnected the return line, gas kept flowing, and flowing, and flowing. Tim and I were puzzled. Pulled the gas cap, sure enough, lots of pressure and the flow stopped. Put the cap back on and continued our work.
About an hour later, we notice gas spewing under the car. Sure enough, more gas coming out of that open line. Check the gas cap, more pressure. I could not figure out what was going on, the gas vapor system is gone, one open hose coming from the tank.
Then I noticed the vice grips on the vapor line dangling in the fender, sealing that line and my gas tank.
Driving my car for the first time since the removal, my air/fuel is very rich, pegged when full throttle. I didn't think much of this since I didn't have the gauge before the mod.
I was at Tim Murphy's house getting the IC test fitted and checking the fuel lines. I disconnected the return line, gas kept flowing, and flowing, and flowing. Tim and I were puzzled. Pulled the gas cap, sure enough, lots of pressure and the flow stopped. Put the cap back on and continued our work.
About an hour later, we notice gas spewing under the car. Sure enough, more gas coming out of that open line. Check the gas cap, more pressure. I could not figure out what was going on, the gas vapor system is gone, one open hose coming from the tank.
Then I noticed the vice grips on the vapor line dangling in the fender, sealing that line and my gas tank.
07-12-2004, 01:13 PM
#4
Burning Brakes
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Hi Drew,
Fuel pressure problems are notorious for warm start problems. I don’t know about tank swelling solutions. But, solve that and you probably will solve the starting problems.
Starting solutions can be as simple as a fuel filter replacement – always a good idea. The check valve on the fuel pump, the fuel pressure dampers or regulator. Again, fix the swelling before you try any starting solutions. Anyhow, here are some links about starting solutions:
http://www.928oc.org/tip/tip561.htm
http://www.928gt.com/928tips/Fuel.htm
https://rennlist.com/forums/showthre...hreadid=141554
Also, 928 Specialists has a fuel gauge to mount to the injector rail for about $30. This can help with analysis of starting problems.
Fuel pressure problems are notorious for warm start problems. I don’t know about tank swelling solutions. But, solve that and you probably will solve the starting problems.
Starting solutions can be as simple as a fuel filter replacement – always a good idea. The check valve on the fuel pump, the fuel pressure dampers or regulator. Again, fix the swelling before you try any starting solutions. Anyhow, here are some links about starting solutions:
http://www.928oc.org/tip/tip561.htm
http://www.928gt.com/928tips/Fuel.htm
https://rennlist.com/forums/showthre...hreadid=141554
Also, 928 Specialists has a fuel gauge to mount to the injector rail for about $30. This can help with analysis of starting problems.
