Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor
Poor Fuel Mileage on 4.3 V6 with Quadrajet 17056250
Cliff Ruggles:
I can't see what you've done but the original set-up would have had a different intake and intake system, TPS, etc which the ECM would reference for timing/fuel delivery.
To effectively complete the conversion you may need to install a distributor with mechanical and vacuum advance or engine efficiency and fuel economy will suffer.....
don3194:
--- Quote from: Cliff Ruggles on January 20, 2021, 04:26:36 AM ---I can't see what you've done but the original set-up would have had a different intake and intake system, TPS, etc which the ECM would reference for timing/fuel delivery.
To effectively complete the conversion you may need to install a distributor with mechanical and vacuum advance or engine efficiency and fuel economy will suffer.....
--- End quote ---
Right now the ECM has enough input to properly advance the distributor, the vehicle drives and accelerates well enough, it just gets poor mileage.
I have noticed that when I go to start it, it smells like fuel and today I was just messing around with it, making sure I didn't have any vacuum leaks. Well, I pulled off one of the vacuum caps and the port was full of fuel. It was really only a dribble but I'm thinking this is related to my problem.
In the attached picture, my finger is under the port that the fuel dribbled out of.
If the image attachment doesn't work, I posted it here: https://imgur.com/a/O6Js6ki
EDIT: Keep in mind that I had just got done driving it when I pulled that cap off, so it was at operating temperature.
Cliff Ruggles:
Your problems could be fundamental, starting with a poor quality rebuild kit with the wrong parts in it. I'd go back in with one of my complete kits, correct float setting, check the PP hanger arms for being bent, leave access to the APT system for full control of part throttle A/F, etc......Cliff
don3194:
Thanks for your input, I was thinking it would be something basic. How do I know which one of your rebuild kits to purchase? It looks like I have to choose between the Basic, HP and SR kits.
Cliff Ruggles:
Get the SR rebuild kit. It is a complete kit with all the parts required to do a complete/correct rebuild.
I would check the jets and metering rods to make sure they haven't been changed, modified, or just slam worn out.
I don't even look at them here, all carbs I get involved with get new ones. One has to realize that these carbs have been out there for 50 years or so. It's actually pretty common to see jets that have been drilled out to HUGE sizes and you wouldn't even know it unless you pin gauged them to check for size.......
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