new exhaust on van when ya go down the road below 55 its fine but 60 to 75 it chugs spits and sputters backfires loses speed ya let off and its good to go again also some bad smell from exhaust not form being new but like a carbon or something smell has me stumped fuel filter is good all vac lines fine what coould be the problem and how do I fix it ?
2007-07-10 06:48:05 · 8 answers · asked by Anonymous in Cars & Transportation ➔ Car Makes ➔ Chevrolet
I like the quadrajet, have had it on several 350's and it has always worked fine for me. Despite what many of these people say
It sounds like your secondaries are too rich - those are the larger bore barrels in the back. You will have to disassemble the carburetor again and work on the item that has two needle valves dangling from it and it is connected to a piston that goes through the center of the carb. They are probably adjusted too high by the piston not being fully inserted or by the holders being slightly bent up. The recommendation that I received from my daddy was to lean the secondaries out a little by bending the holders SLIGHTLY down (sent my mpg from 8 to 13, and it has not hurt the engines at all).
The main thing is to make sure the piston moves them up and down freely within their seats. The wider open you hold the throttle the lower your vacuum is and the higher the piston will be opening the needle valves wider and flowing more fuel - and that sounds like your problem, too much fuel.
2007-07-10 08:51:54 · answer #1 · answered by startrektosnewenterpriselovethem 6 · 0⤊ 0⤋
It could be a couple of things so some more checking is required. I would first check to ensure the motor is not misfiring electrically under load which it doesn't sound like it is, but you never know. Then you will have to check fuel supply to the carb as in available vacuum that the pump can produce while the motor is running. You just have to install a fuel pressure guage onto the pump's inlet and run the motor until the gas level in the carb gets low and you will see how much it can produce, 11-13" of vacuum is considered good. If too low, you will need a new pump. There can be pluggage in the line leading from the tank also. Things like a plugged in-tank fuel strainer, rusted fuel pipe, or even someone installed an in-line filter being plugged can cause this. If all this is okay, you will have a problem in the power circuit of the carb and that is a fuel delivery device inside the carb. What this is usually is a stuck piston that moves with vacuum supply just behind the gas bowl inside the carb. You have to remove the carb and disassemble and overhaul it to fix this right. Good luck.
2007-07-10 07:03:19 · answer #2 · answered by Deano 7 · 1⤊ 0⤋
Let's just try and tickle the problem @ hand, first.
Personally, I like the Qudrajet carb. if, it is workin correctly.
You say you have just replaced the exhaust system. My first question would be did yoou repl. w/ a more restrictive system? If so, than you might've richened up the mixer too much. If you feel that is the case(or even if it is not). Try re-adjustin the mixture screws on the front(bottom) of the carb. By, screwin 'em all the way in(do not force 'em on the seats!). Then, back the (2)screws out a turn and a half. This settin on the mixture is not exact but, it will get you in the ball play. Then, drive it around some and see how it acts.
Oh yea, you may want to note the # of turns you have to screw these two screws in while performin the re-adj. So, you can go back to that settin if, necessary later on.
Good luck!
2007-07-10 07:43:51 · answer #3 · answered by Don B 5 · 0⤊ 1⤋
Follow above advice on proper repair and diagnostic procedures. This so called JUNK is the most widely produced carburetor in the history of automobiles and for good reason, but like anything, can need maintenance. I also vote for secondary problems.
Good Luck,
2007-07-10 10:05:56 · answer #4 · answered by Anonymous · 0⤊ 0⤋
The carb is dumping too much fuel in the engine and it can't burn it all. Try wiring the back flapper on the carb shut. Or get a good carb we always called those Quadrajunk carbs because they are always screwed up. Hope this fix works for you...Good Luck
2007-07-10 06:58:24 · answer #5 · answered by Big Deall 4 · 1⤊ 2⤋
check the shafts and make sure there is no play in them. If there is the carburator is pulling air in there and not threw the throat of the carburator and it will cause it to have heritation or a flt spot in it and can also cause sputtering
2007-07-10 08:26:10 · answer #6 · answered by Bill R 2 · 0⤊ 0⤋
sounds like running out of gas. or sticky valve train . lobe off cam. change fuel pump . when changing fuel pump remove gas cap blow out fuel line strainer in fuel tank is probably plugged up.change fuel filter. try drive
2007-07-10 11:11:22 · answer #7 · answered by chris d 3 · 0⤊ 0⤋
qudra jet carbs are junk
get a different carb and it will run better
why do you think they call them qudra junk
2007-07-10 06:57:51 · answer #8 · answered by alleykhad607 5 · 1⤊ 3⤋