260Z w/72 carbs sputtering, backfiring...

[thebluez]

So, my car made it from Long Island up to Syracuse with no problems at all. On the way home she started to buck, hesitate and backfire, sometimes very badly. I cannot figure out what is happening but I replaced the fuel filter and cleaned both carbs (‘72 SU’s) as best as I could. I recently replaced my water pump, radiator and it seems that the cooling system is working fine. The problem seems to be heat related as it will start and run fine when cool but as soon as it starts to heat up it starts to act like it is not getting fuel. It will sputter and backfire and eventually stall. If I let it cool it will go just fine again until it gets warm. Again these are 72 carbs and all the heat insulation wrap is still on the fuel lines so I don’t think it is vapor lock...

Somewhat recently installed MSA headers...maybe I need to install a larger heat shield?

Anyone with any thoughts or suggestions? I’d appreciate it very much.

Void

void@interzonestudios.com

PS My car did win 2nd place in the daily driver category...

[boostedz]

Well I can tell you this that a backfire is caused by an over rich condition, if it were backfiring threw the intake then you would have a lean condition. I would check your plugs to see where you are with your fuel issues to "VERIFY" first. Then you know where you need to start.

You might also want to check your timing as well, I hope this helps you a bit, but like I said before VERIFY what the problem is first then go from there.