Cliff's Quadrajet Parts and Rebuild Kits

Quadrajet Problem Solving => Diagnose a Quadrajet carburetor problem => Topic started by: 77cruiser on May 28, 2009, 09:37:55 PM

Title: lean right off idle
Post by: 77cruiser on May 28, 2009, 09:37:55 PM

Lean right off idle 25-30 mph AFR go to about 16. Go just a bit more & good AFR goes to mid 14.
Do I need to open the down channels more or the idle feed restrictions?
down channels --.055
idle feed--.036


Jim

Title: Re: lean right off idle
Post by: Cliff Ruggles on June 01, 2009, 02:37:29 AM

What is the carburetor number?  If it has an APT system try raising the metering rods slightly....Cliff

Title: Re: lean right off idle
Post by: 77cruiser on June 01, 2009, 11:50:20 AM

17082292

When I go into the throttle just a bit more(I assume when the mains start up) it's fine.
I was thinking if I opened the down channel a little it would give more fuel to the transition slot & not upset the idle.
Is this right?

Title: Re: lean right off idle
Post by: Cliff Ruggles on June 02, 2009, 04:34:53 AM

Going into the throttle may be lowering the vacuum enough to raise the power piston?  I would leave the idle system as is, and raise the APT first.

What source (manifold or ported vacuum) are you using for the vacuum advance?.....Cliff

Title: Re: lean right off idle
Post by: 77cruiser on June 02, 2009, 11:59:23 AM

Manifold, I have about 10.5-11 in. vac @ idle.

Title: Re: lean right off idle
Post by: Cliff Ruggles on June 09, 2009, 05:25:55 AM

That should be enough to fully employ the vacuum unit, have you tested it with a timing light?....Cliff

Title: Re: lean right off idle
Post by: 77cruiser on June 10, 2009, 03:55:06 AM

I ended up going to .059 on the down channels & it seems to be OK now.