Fuel tank pressure

Would the fuel tank pressurising have anything to do with my engine backfiring,missing, fouling plugs and generally running like a bag of crap? the reason i ask is my car died at dubs by the pub, we managed to get it going again but it was running like crap. I put fuel in it before we left and forgot to put the petrol cap back on... stupid i know. but it didn't miss a beat the whole way home. 1.5 hr trip.

More likley that the the breather is blocked and the pump is struggling to pull fuel from the tank ie negetive presure in tank ???
Also what size jets are you running as it could be to rich and fueling up the plugs which will give you a host of problems when not knowing this as you'll blame every other item .
Also whats your points like??
And are you running a GOOD fuel filter as if not you'll be forever chasing shit in the carbs

Points are good, don't know jet size vw & volvo did the jetting. It is running rich for sure. If the pump was struggling it would be running lean yeah? Filter is ok i guess. I'm just gonna put my stock carb and manifold back on, i'm sick of pissing around with these webers! I really need bigger heads. It wont cost me anything to put my stock stuff back on but it would cost me about 1200 bucks to get big heads. I can't afford it at the moment. Just thought it might be an off chance of something simple like a blocked breather or something. cheers for your help.

if it ran good without the cap on check ya breathers my mate had in plastic tank suck in nearly scared him to death when it let go and went back to normal that was his crap running problem fixed

your tank needs to breath so check the plastic tube and blow it out with compressed air or poke a wire through it to clear but it must be free and allow the tank to vent otherwise you geth the problems you metioned above you should have come over to me i was about 10 meters behind you at Dubs packing the van to go home and watchin you trying to get the car going didnt relalise you were hqaving that much trouble

Yeah, it's trouble alright. I was in a real bad mood that day, Nothing was going my way. I had to push the car through the gates when we got there! i was quite happy to just leave the car there and go home in the splitty with a friend!

I'm not sure what model beetle you have...

most of the early beetles [before 1968]
had vented fuel caps
and no breather pipe...

so if the fuel cap really seals...
Your poor old fuel pump cannot suck fuel...

the other thing is to replace the fuel filter..
there is also a fuel filter in the bottom of the tank..

so maybe somthing is floating about and blocking the filter
most of the bottom filters would be original

I pulled Mine out and threw it away...
I have a filter under the tank which i replace every year..

cheers and best of luck

Lee

http://community.webshots.com/user/vw68autobug