Thread: Engine cutting out

Tweet

Hello everyone, I'm new here and I have a question.

My Biscayne lacks power in the upper rpm band, in fact once you get above 3 grand it barely accelerates even with the throttle pressed all the way down. So I decided my car isn't getting enough fuel and my carb is probably dirty. I got a couple big cans of carb cleaner and sprayed a bunch down in there while the car was running.

Well when I went for a test drive instead of getting all this extra power I was expecting my car runs much much worse. It starts and idles just fine but once you give it gas it sputters and barely runs. It will get you down the road without dying, but it feels like I'm driving a riding lawnmower.

So help me out here...I'm wondering if I didn't get overzealous and put too much carb cleaner in and it hasn't evaporated yet, or if my car is just running super rich now? If it were too much carb cleaner I don't see why the car would even start and idle fine, but I thought I would ask anyway.

The other thing that makes me think running rich is that I changed out my fuel filter a little while back and I think it made the cutting out at full throttle I was experiencing worse. Could be my butt dyno playing tricks on me, but I would swear the car had just a little less power after changing the filter.

By the way the car is a 350/powerglide/quadrajet so no adjustment screws for me either.

Time to bite the bullet and get a carb kit and do it right.

Is the filter you put in dirty? Maybe picked up something from your gas tank. Another possiblity is your fuel pump is not working. Carb is getting enough gas at idle but when asking for more gas the pump is not supplying.

Which fuel filter did you change? Do you have an inline filter? If you have an inline and that is the one that you changed then there still might be a filter in your carb at the end of the fuel line. It could be clogged.

Put on a clear glass aftermarket inline filter (for test purposes only) and rev up your engine. see if the filter is running out of fuel. If it does then you should probably change your fuel pump as Chevy37 suggested. Change the filter back to one of the Fram white plastic or metal ones. The glass ones have been known to break and catch fire, hence the (for test purposes only) statement .

Also, Has this car been fine and just started this. What did you change BEFORE this started. How much fuel is in your gas tank. Does it still do this if your tank is full. If not, you night want to drop your tank and clean it.

Just some thoughts. Let us know what you find.

Dmac,
Spray carb cleaner is made for cleaning up deposits during a rebuild, or just for cleaning up exterior deposits. When you sprayed it down the carb while running the only thing you may have accomplished is cleaning up the air side venturi a little and maybe loosening some carbon deposits in the combustion chamber. You didn't do anything to the carb internals that would almost certainly be the side affecting performance, in the fuel metering internal to the carb. You might get lucky by putting a good cleaner like Sea Foam http://www.seafoamsales.com/how-to-u...treatment.html in the fuel tank, but it's not likely.

Like Bug said, you can see if it is starving for fuel, and if not then as R Pope says it's probably time for a carb kit and proper rebuild of the unit.

make sure your plugs are`nt gas fouled as well .. .. an old trick i used to do to check Quadrojets for flooding was to unhook the fuel line ( cap it off good ) then start the car and see how it runs with only the fuel sitting in the carb .. if it smooths out you def have a rich problem

I've changed plugs & wires and I changed the filter on the carb. I know my fuel system needs a good going through so after the fuel filter I was trying this to see if it was a dirty carb to blame or if I had a bad fuel pump, clogged line, whatever.

The thing is, whatever the carb cleaner did caused me a lot of problems. The car accelerated fine at low rpms but by the time I was in high gear and at about 3000 rpm the car felt like it had nothing left. So I thought it may have been a problem with the secondaries on the quadrajet being dirty or maybe not jetted properly. But besides that the car ran good.

Now, after adding the carb cleaner, it runs terrible. Sputters badly and hardly pulls. Whatever the carb cleaner did, it messed something up.

Taking the fuel line off is a good trick. I also do have a wideband AFR I could hook up when I get a chance and get a real reading to tell me what it is doing. But obviously that carb cleaner did something so I was trying to find out what.

Originally Posted by dmac

I've changed plugs & wires and I changed the filter on the carb. I know my fuel system needs a good going through so after the fuel filter I was trying this to see if it was a dirty carb to blame or if I had a bad fuel pump, clogged line, whatever.

The thing is, whatever the carb cleaner did caused me a lot of problems. The car accelerated fine at low rpms but by the time I was in high gear and at about 3000 rpm the car felt like it had nothing left. So I thought it may have been a problem with the secondaries on the quadrajet being dirty or maybe not jetted properly. But besides that the car ran good.

Now, after adding the carb cleaner, it runs terrible. Sputters badly and hardly pulls. Whatever the carb cleaner did, it messed something up.

Taking the fuel line off is a good trick. I also do have a wideband AFR I could hook up when I get a chance and get a real reading to tell me what it is doing. But obviously that carb cleaner did something so I was trying to find out what.

It may have knocked loose carbon in your combustion chambers and fouled plugs? Can't see how spray cleaner could do anything to the carb itself - it's only going through the air side. I do know that it's darned cold here in the KC area today to be messing with it outside!

Originally Posted by rspears

It may have knocked loose carbon in your combustion chambers and fouled plugs? Can't see how spray cleaner could do anything to the carb itself - it's only going through the air side. I do know that it's darned cold here in the KC area today to be messing with it outside!

Yeah that's why I'm here instead of in the garage messing with it. Way too cold for it today! I didn't notice your location earlier, I actually live in Gardner too. Small world. I usually just put KC since most people know where that is but I doubt many people know where Gardner is.

I will go out there a little later a check a couple of the plugs and see if that is the case. I hope not, I've only probably put about 50 miles on those plugs. If I fouled the plugs wouldn't I notice the miss at idle though? Like I said it idles perfectly and runs sort-of alright at minimum throttle.

take a full 5 gallon can of gasoline. mix in a bottle of gunk carb and injector cleaner ( not spray ), and a bit of seafoam. rig your fuel pump so it will suck out of the can ( open can with a hose stuck in it ). and run that thru and blip the throttle a bit.. that should clean up the carb pretty good. it's harsh but it won't hurt the motor. I have revived carbs with that process