Quadrajet Question
Thread Starter
Instructor
Joined: Jul 2001
Posts: 189
Likes: 0
From: Berkeley Heights New Jersey
Quadrajet Question
When I punch the accelerator the car down shifts but the carb seems to be starving for fuel. It makes a buammmm sound when the secondaries open but it goes no-where. I know its only an L48 but it should have more get up than it has now. Checked the linkage and found that the secondary throttle was not opening at all! Changed the hole on the linkage and now they open. The secondary lockout is working and the secondary air valves are opening. I don't know how to check if the secondaries are getting fuel.
I would appreciate any help from the forum. Thanks much!!
I would appreciate any help from the forum. Thanks much!!
Racer
Joined: Jul 2000
Posts: 289
Likes: 0
From: Norfolk, CT
Re: Quadrajet Question (bl75vette)
If the engine bogs down right after you floor it the air valve on top of the secondaries may be opening too soon. This will give the engine more air than it can use. Many of the criticisms of the Q-jet (like quadrabog) are a result of improper setting of the air valve spring. Check your engine specs or the spec sheet out of a carb rebuild kit. It will give the number of turns required on the screw that preloads the air valve spring. It should be in the neighborhood of 3/4 turn.
Try pushing on the airvalve with your finger (engine off). If it flops open with very little pressure there isn't enough preload on the valve.
Try pushing on the airvalve with your finger (engine off). If it flops open with very little pressure there isn't enough preload on the valve.
Racer
Joined: Feb 2001
Posts: 405
Likes: 15
From: Minneapolis
Re: Quadrajet Question (bl75vette)
I would also check the ignition timing. Had a similar problem once on a Poncho that did the same thing. Thought it was a Q-Jet problem, but turned out to be retarded timing.
Good luck!
Good luck!
