Okay, my car runs fine up until I pass about 3500rpm at WOT. However it will run jsut fine and keep pulling after 3500rpm if i dont have it wide open. When it is WOT I get a crack/snap kinda sound and you can feel the car stop pulling whenever it makes the noise. And it makes the noise alot once it starts, like it doesnt jsut do it once then go away, it keeps doing it, only when I let off the gas a bit it stops.

Any Help Would Be Great.

Thanks.

 

You're outrunning the fuel supply. Most common causes- clogged fuel filter (nose of the carb if it's a stock QJet carb) or insufficient/shot fuel pump. Of course, a kinked or clogged fuel line can cause the same problems.

Lastly, a formerly fuel injected car will have an electric fuel pump actually in the tank. Since it's not running any more to feed the carb'ed engine it can become a big restriction as well.

 

Okay that makes sense. The fuel filter is new so that musn't be it. Feul pump im not sure cause I dont know exactly how I would go about checking it. How do I do that?

This problem cannot be remedied by adjsuting the air mixture screws on the Q-Jet? I belive it did this before I used a vacuum guage to set it so I assume not.

I will check the lines tomorrow, that is definitely a possibility.

Thanks For The Help Man.

 

Couldn't it also be that his engine is missing? How are your plugs and wires?

 

That is actually what I thought originally, I changed the plugs, not new but they were only in my buddies truck for about a month, they are NGK or AC-Delco I dont remember, the wires are ACCEL super stock I believe but one of them got ruined so it is a no name thing for now. The wires have been on the car for about 8000km. The car did and still does the same thing before and after the plugs and wires were changed. I am going to changed the wires and plugs as soon as I get paid and see if that helps.

 

Hmm..oh well it was worth a shot.

 

what your describing kinda sounds like spark knock or pinging.. whatever ya wanna call it.. have you tried adjusting the timing? its possible that its too far advanced

 

Yeah the timing has been messed with quite a bit lately. It is advanced but it seemed no matter what we did with it it would still do it. It's not pinging, cause the car was pinging but I got rid of that.

Im going to check the fuel lines because i actaully have a suspision they may be damaged(kinked or dented).

 

also make sure ya check the float levels..

 

Wait wait wait wait wait!! You agree that it makes sense that it is a fuel problem but then we go wy off in the weeds with ignition problems and all sorts of other stuff. Check the fuel supply FIRST. My got and experience tell me you are outrunning the fuel supply. Hook up a fuel pressure gague in the fuel line right in front of the carb. Mount the gague somewhere you can see it while driving the car. Duck tape it to the windshield (temporarily!) if you have to- that's what I do. If you are outrunning the fuel supply it'll be obvious- fuel pressure will take a nosedive as RPMs climb under heavy throttle. It should hold 5-6 PSI throught the entire run regardless of RPM or throttle postion.

If it passes that test then go fter ignition and other stuff, but do this FIRST. There is absolutely no way to "tune around" an inadequate fuel supply.