Hello I have a 1972 Skylark, it was originally a 350 two barrel car. Long story short I have dropped in a 455 running basically just a little better then stock, 10 to 1 pistons slightly hotter cam. Still running original intake and a quadrjet. Thought I might have been running it a little out of gas at the track in high gear. Upgraded to a stage 1 fuel pump from TA . Seemed OK when I first put it in. This year I think I'm almost vacumm locking the fuel system. Seems to be choking out. Runs better with the gas cap only on at first step. Anyone ever have any similiar issues. Still running original gas tank and fuel lines. Plugged off return line on pump. Appreciate any and all feedback!!
Sounds like the tank isn't venting. Could also be a collapsing fuel line, or the sock is clogged. You'll have to check everything. The nice thing about the Stage1 pump is you can easily tee in an electric pusher pump near the tank. That will take care of any fuel delivery problem you may be having if everything else checks out.
In addition to what Larry said, try putting in a restriction in the return line. I put a short piece of 5/16 rod in the return line in Sandy's X, solved the issue. Drill a 1/16 hole in the "pill" before you install it to relieve the pressure when the motor is off.
When I was running the Stage1 pump, I installed a ball valve in the return line. You can turn it on and off.
I just put a Q-Jet main jet in the return line by the pump, still can return a little fuel or vapor then. I had to try 3 stage one pumps before I found one that would keep up, they are not all the same.
Thinking about getting a rebuilt carb. What does it take to set up for an electric choke carb. Currently have NO choke set up on this carb.
Be careful on plugging the return on that pump... I did that one time on my run stand, just playing around, I was shocked to see the static fuel pressure went to 12psi.. Not sure if that will happen on every stage 1 pump, just sharing an experience. Q-jets have strong floats, so it might hold that pressure, you might not notice. Be interested to hear from others who have done this, and had a fuel pressure gauge installed.. maybe it was just that one pump I was using. Never did it in a street car, that I can recall. JW
I don’t recall seeing 12 psi but I did see 9. My gauge is just a cheapie but it’s in the ballpark. What I’ve seen from blocking the return is fuel seeping out around the accelerator pump.
I had some fuel delivery issues at high rpm even with a great mechanical fuel system. I’m making a lot more hp than stock, so it may not apply to your situation, but I just updated my thread with a successful solution, which was to convert to an in-tank electric pump. Having a fuel pressure gauge was critical to diagnosing the situation. http://www.v8buick.com/index.php?threads/qj-major-stumble-at-high-rpm.325770/
So if I 'm reading some these replies correctly, it is very possible I have screwed up the float in my carb and possibly the accelerator pump. With some of the way the car has been acting lately I think that may be what happened in my case. Has anyone every bought a JET Performance 32002 - JET Streetmaster Quadrajet Stage 2 Carburetors ? And if so what were you experience with them??
I just thought of a symptom the car had. After cruising for about eight or nine miles dow a local highway I took the exit and was crossing under teh road to make a return trip when the car sputtered then stalled out. After a minute I was able to restart it, but it ran like garbage on the trip back to my house. When I was a couple of block from my house it seemed to have cleared up/. When I hit the accelator it ran fine. Could this have been a symptom of too much pressure building up, then slowly working its way back down?? Any feedback on that ??
Other that seepage, I've never seen high pressure hurt anything. I think you have multiple carb problems. An Olds buddy has a Jet QJ and I can say that it is completely wrong. There are a couple of guys on the board who can fix you up icludimg myself but I don't advertise.
Possibly vapor lock too since it seemed to act up after running at higher speed for awhile.Try a insulating gasket under the carb to test for this option. gary
If you have the original Quadrajet on the 455, it is the best quadrajet option to work with, or one just like it. If you want to go to electric choke, Ken at Everyday Performance on here has a conversion that you can do on that carb. Several of us could either build your carb correctly, build you a replacement carb, or supply the parts if you want to build it yourself. As mentioned above, the Jet carb is a generic Chevy carb. It will start and run on many engines, but isn't built specific for anything, just a generic.
My buddy's carb will gas foul the plugs in no time. Fresh plugs, burnout, 1/4 pass, pits, fouled. Turns out Jet has the wrong jet to primary metering rods combination. Idle is decent, WOT is good, part throttle is a mess. I haven't dug into it yet but I will, curious to see what else they did.
Revision on previous post. Just pulled the gas tank to put in a new pickup and gauge float. Previous pick up had only a single tube, this one has two lines. I assume one is a return line. Car was originally a 350 two barrel could all of that been part of my issue??
https://www.rockauto.com/en/moreinfo.php?pk=872359&cc=1023028&jsn=413 Single line what was in car. Replacement I ordered before taking tank out https://www.rockauto.com/en/moreinfo.php?pk=872365&cc=1023028&jsn=412 Do I need to run a return line if there was not one originally??
No, A/C cars typically got the return line to combat vapor lock. You don't have to run a return. It wouldn't be hard to run one though, now that you have a fuel pump and sending unit with one. Color doesn't matter, is it clogged?
