Hey Guys,
I have a 91 Firebird with a 68 Impala 350 sbc in it that has a Demon 650 carb on it. I bought the car maybe 2 months ago and it drove home problem free for 2hrs of highway. I registered it yesterday and today it started having stalling problems. It will be driving along (35ish) and start gargling as if it were sucking air or not getting enough fuel, the first couple times it did this then died. My brother and I figured out that when it did this (usually at steady mid throttle) you could let off to idle for a bit and it would recover and you could go another minute or so... When it starts dying, the oil pressure drops like crazy, is this caused by the dropped rpms or could this be a related problems? The fuel pressure at idle is about 3.5psi which seems solid for a mild street motor, the regulator and gauge are in the engine bay so i can not watch them while driving. After dying, the car will start right back up after a couple seconds of waiting but there will be little or no fuel in the sight glass on the carb. It seems that it just doesnt have enough fuel for constant throttle or there is an air leak. Where can I start? Fuel pump? Test for air leaks? The car seems to respond fine to heavy acceleration but not consistent pull of fuel.
Thanks in advance,
Tyler

 

Would setting a higher float height also be a good place to start seeing as the fuel in the sight glass is very low?

 

sounds like either a fuel filter plugged or the pickup sock in the tank clogged.

 

oh wow, those are two things I hadnt considered yet... where would the filter be located? Best bet to check it and replace completely? I would assume it needs one even if that isnt the problem.

 

bad fuel pump?

 

I raised the float height and have a new fuel filter for a carb setup that I am ready to put in but am limited by New England weather, don't feel like lying in mud/snow/ice in the dark to replace it so I am waiting to use a friends shop. It has been running much better and the raised float height and addition of a real exhaust (used to be true dual glasspack side pipes) have definitely helped it out. I plan on doing the filter and re-adjusting the fuel pressure and then i think it should be good to go. I don't think pump only because 1) no bad noises from it and 2) no hard-starts

 

Just FYI, the fuel level should be set half way in sight glass and fuel pressure at 6 LBS......

 

OK, I set it to half height in the sight glass earlier but the pressure is currently below 6. Will the filter affect the pressure or should I set the fuel pressure now even if I haven't done the filter yet?

 

NO, replace filter first. A restricted filter will effect pressure at the regulator, if it is restricted now......