It seems like everytime I reach a higher RPM in my car the engine bogs out and it stops pulling. I was wondering if anyone knew of any possible problems, I was thinking it was the carb because there just seems like there is something wrong with it. Also we had a electric fuel pump in it and I was thinking it was too small. I was thinking about just running a second in line fuel pump on the car, or would it be a better idea to just replace the other one, I will eventually spray the car so I want to make sure there is enough fuel. I was wondering if the carb or fuel pump or maybe both would cause this problem. This summer I'm going to put a new carb and intake on it. The motor is rebuilt and has about 3000-4000 miles on it, the motor is .030 over, has slightly ported heads, and a small cam in it. Any information would be appreciated, thanks.
What kind of carb are you running? CFM? Timing? I'm certain that unless your fuel pump is about ready to take crap on you it isn't the problem. So long as you have a steady 6-7 psi you should be good unless you're using a forced induction method. When you say upper RPM, what are you talking about? 2k-3k, 4k-5k? Is this from a steady acceleration or a full out WOT? Any hesitation off the line? What year/ model car is this on? A hesitation off of the line usually indicates a lean condition. On a Holley carb your best bet is to go to a larger accelarator pump discharge nozel. That's with a heavy foot. If a hesitation from a steady, slow acceleration is what's occuring, you're most likely running too small of primary jets. THe possibility that you're secondarries are opening up too early (too light a spring) also exists. Let us know more about your car and we can help more. I'm not as familure with Q-jets as I am Holley's. But their are plenty on here who are. What's your name, where you from? Aubrey
Its running the stock carb rebuilt, 750 CFM if I am correct, on a '70 Riviera. It is fine off the line, not really sure what RPM range but its at a higher RPM 4-5K I would guess, usually right before it shifts into the next gear. It only happens WOT, if I back off the gas it shifts into the next gear and pulls without hesitation until it hits that same RPM range. My name is Dave and I live in the Chicago area.
DUUUUUUUDE!!!!!!! If you still have your original in-tank electric fuel pump (Yup, the 69/70 Rivs had 'em!) then you are running out of gas! Even with the higher output Ford Ranger pump I still fell flat on my face. The only cure in an in-line electric pump. With our "X" frame a location is very difficult to find back there. But now I pull right to the top in every gear! (Or you can run all new hard line across the engine bay and use a S1 mechanical pump.)
Yep What Jeff said.... And after you increase your fuel delivery, a larger carb will help too. :bglasses:
ou: I totally forgot that the car had a in-tank pump stock, it has been replaced, but I think that I will try to run a in-line pump and see if that helps the problem out any. Thanks for a lot for the information.
