own an 81 olds regency

[kilrcady]

I have a problem with the carb.I had it rebuilt and new gas tank installed and a new fuel pump.The car runs great.When it sits for more than a day the carb loses all the fuel from the bowl.Like I said I tried everything I could think of.I even disconnected the charcoal filter.Still no difference.It starts right up if I spray starting fuid into the carb.HELP!!

[joe_padavano]

Have you actually removed the top of the carb after the car has sat for a few days to verify there is no fuel in the float bowl, or are you just assuming this? If you're pumping the accelerator and not seeing the accelerator pump squirting fuel, this could be due to a bad pump cup or plugged nozzles.

One easy way to check the fuel level without pulling the top off the carb is to use a level stick through the vent. There's actually a calibrated tool for checking float level, but in your case a piece of plastic works fine. Simply mark the float level right after you shut the car off then check it again in a few days. If it's the same, you aren't losing fuel.

If you're truly losing fuel, either the plugs in the bottom of the float bowl are leaking (not an uncommon thing for a Qjet), there's a bad check valve in the fuel pump, or there's some unusual evaporation going on.

One other slim possibility is that the evap system is plugged and there's pressure building up that forces fuel out of the jets when the car is sitting.

[Guest JRZYBOB442]

Another possibility. Did you replace the ball check when rebuilding? It could be missing, stuck or the wrong size. The ball check stops the fuel from siphoning out after the car is shut off. If this is missing or stuck, the fuel will just slowly run back out of the line once the fuel pressure abates.

[Guest pfloro]

Did this problem exist before the carb rebuild?

I have had this same problem with my '84 Toronado with the 307 V8 & the 4bbl QJet. I've rebuilt the carb myself & am pretty confident everything in

the fuel system is in order...

After doing some searching on the Net, I've discovered that vapor pressure of gasoline has been going up over the past few years. This causes it to

evaporate more quickly. With a carb, fuel can easily evaporate out of the

bowl in a day or two.

Are you living in a southern climate? I noticed the evaporation happened more quickly after moving to southern Arizona...

If your Olds runs well after it starts, everything is probably just fine.

Good Luck,

Paul

[kilrcady]

First off The carb was rebuilt by a major carb rebuilder .Not replaced but rebuilt.I live in New Jersey.I was told to check the carcoal canister that this could go bad and suck fuel back.I disconnected the the vaccumm hose and still had the problem.The latest news.On a whim,I lossened the gas cap and left it loose.The thinking is that the tank wasn't venting properly.So far this may be the fault.I didn't have this problem before the tank was replaced due to rust.When the weather warms again,i will get under the car and see if all is in order.

[Talarico8447]

First off I would like to know for sure if the bowl is empty, but it sounds like you might be assuming this. One thing you can check is ignition coil output, in the 80's G.M had an issue with weak coil output that was not strong enough for initial start but would run the engine fine once started, especialy when cold out. This is especially true w/ some aftermarket coils and ignition modules (if thats what you are using?). I recomend using AC/delco at all costs. Ether/starting fluid has a lower flash point therefore the coil can ignite it easier and start the car. I would like to know how it starts when it eventually does start ie.. rough for a few seconds, black smoke etc.... how much starting fluid does it need to fire off. If a Quadrabog(oops I mean Quadrajet) is hard to start, there is something wrong, it is not normal operational characteristics. Your car should start right up with one,maybee two pumps of the gas pedal and turn the key when the engine is cold and no pumps at all when it is warm. If you can supply any more info about the problem that also may help for diagnosis.

[kilrcady]

Ok the problem happens when its cold or hot outside.Once warmed up its good for two or three days and works properly.I assume no gas because if you pump the carb while looking down the carb no gas squirts.I remove the carb and turn it over and no gas comes out.Like I said the car starts,runs and drive beutifly but once it sits for few (3 or more days) it won't start without the assistance of fuel or starting fluid.I'm going to try a check valve in the fuel line next.I'm also going to check out the evap system more closely. Fuel is definity leaving the carb after it sits for a while.whether buy evaporation or drain back or waht might be a negative pressure on the fuel system.This is my Father in laws car and he feels i'm his personal mechanic.So I should have plenty of time to do all this for him.Its all stock including the pollution equipment.The car is in really fine shape with low miles.He won't tell me but I think it all started when they(others) put in a new tank due to rust.Which is also makeing me look to the pick up in the tank.I have 4 other cars of my own to matain and I really dread dropping the tank.

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[kilrcady]

UPDATE.I took the car to another repair guy that said he would take a look at it.He was going nuts too.He was about to install an electric pump.He was looking for a good location for it when he found an inline fuel filter (after market) installed in the system.I was under this car all over the place and saw nothing.He had it on a lift and it was in a spot where you wouldn't be able to see it on your back.I guess whent they put all new lines,tank,pump and carb they put some extra insurance and didn't tell anyone.Replaced the filter with a piece of line and so far all is great.There is a filter at the carb.Thanks guys for all your help.