whitedevilTA

iTrader: (8)

I have a problem and I am almost certain it's my carb. I had the car running in the driveway for a while and it ran perfect. I lost power to the pump, so I ran a wire straight from the tank and now the pump works again. Well I go to start my car and now somehow it will not hold an idle and it runs like CRAP. Float levels are right where they should be, pressure is at 7 PSI.....a little high but shouldn't affect it, and I didn't touch the idle mixture screws. Smells like it's running REALLY rich, and the plugs are black, yet it wont idle and wont rev unless you give it full pedal. Timing is set to 20 degrees advanced at idle with the vacuum hooked up, and about 38 degrees total timing. Any ideas??

wrsjr

With the pump on, look down the carb and see if fuel is dripping out. Might want to pull down the fuel pressure, maybe the gauge is not reading right and its pushing fuel out. What kind of carb? Holley? If so try checking your power valve, it could have blew.

whitedevilTA

iTrader: (8)

Fuel isn't dripping out of the primaries, but it's wierd because the secondary flap stays cracked open at it's sorry attemp of an idle and fuel drips out. I know it's supposed to be closed at idle, but when I close it and stop the fuel flow, it stalls out imediately.

It is a Holley 4160 750cfm vacuum secondary. I have the regulator as low as it will go without the screw falling out, and it doesn't go any lower. The car has a 255 LPH in tank pump...not sure if that would matter.

whitedevilTA

iTrader: (8)

Bump......anybody have any ideas? I don't even know where to start or what to look for!

mcampau

WIth those symptoms you definately are running rich. It's either a blown power valve, bad floats causing flooding or incorrect fuel pressure causing flooding. Are you checking float level with the motor running? Have you pulled the metering block and checked the power valve?

whitedevilTA

iTrader: (8)

Havn't checked the power valve, but the floats are fine. Took out the sight plugs and you can see them moving freely, and the fuel level is right at the bottom of the sight plug. Will the power valve beeing bad affect idle? I didn't think it would but then again I'm no pro.

Could the carb be plugged on the primary side? It wont idle unless I hold the secondary flap open, and then it runs really rich. Also, the secondary flap never fully closes, so I think I may need a stiffer spring for it. My cam makes very good vacuum.

mcampau

Yes the power valve will dump unregulated fuel directly into the motor when it is bad.

If something was plugged on the carb it would be running lean instead of rich most likely. Are you running a good fuel filter on it? If not I would tear it down and clean everything.

The spring in the vacuum secondary housing doesnt actually close the throttle blades. It is closed by vacuum. The only thing that spring controls is the opening point and opening rate of the secondaries. The seconadary side should be open very slightly so allow some fuel to be used out of the secondary fuel bowl. If not the fuel would go bad and cause problems.

whitedevilTA

iTrader: (8)

The only fuel filter I have is the factory in-line one under the car, which I'm sure isn't all too great. When I was cutting the AN hoses, I didn't blow them out or clean them after they were cut, so I think there may have been rubber shavings that could have gotten into the carb. I'm going to tear it down and clean it out and see if the problem goes away. Thanks for all the help!