passing gear on 350

[joebuick]

Hey Guys,,,,I scored a quadrajet in unmolested condition and went thru it just to look at the insides and looks like a new one. I installed this morning and the engine ran just great after the pump had give it some gas. I adjusted the air mixture screws with my new autozone carb adjuster screwdriver and man,,she just settled down and just patting its foot. I am real anxious to take a short trip and check the milage as the other carb was a guzzler as i never could get it to smooth out and would always run rich. Last time we went to the mountains I got 6-7 mpg,,!! whoa!!!! I'm betting 12-14 now, but will settle for 18-19.
The reason for this post is I need somebody to tell me how to adjust the cable coming from the tranny to carb. It was disconnected when we bought the truck and it must control the "passing gear" as it will not downshift no matter how hard you hit the go pedal. It is a turbo 350. thanks

[benoit454]

yea if it's no donwshifting no matter how hard you hit it, it's not going to without a kickdown cable hooked up, but you could do it manually by pulling down the shifter.

As for adjustment there's a tab on it behind the bracket near the big spring, usually right in front of it that you pull or pry up and that lets the cable slide in and out of the big bulb to adjust it. Once done you push the tab back down to lock it in place.

Now the one that was on our 84 chevy's th350 had a d shaped button to push and hold down and slide the cable in and out just like a 700r4 but it was a th350 non lock up long tail.

[mooseknuckles]

What did you set your mixture srews at?

[benoit454]

you need a vacuum gauage to set the screws right or at least a tach hooked up. There's no one set place for them to be right for anything each carb and each motor is different, thus why you need a vac. gauage hooked to it or at least a tach.

[joebuick]

Hey Mosseknuckles,,, you know what was funny is that this "unmolested" carb still had the factory metal plugs covering the adjusting screws (what a PITA to get them out) when I did get the plugs out, I was surprised that the right hand screw was only screwed out 1 turn,,,and the left one was out only 3/4 turn! This carb was on a 1982 Chevy van with 47,000 miles before it was wrecked and a 350 CI W/auto and had never been off the engine. What I did was start out at 2 turns OUT each side and adjusted IN while counting the number of turns, til engine stumbled a little, then slowly screwed OUT again counting til it stumbled again then screwed IN HALF of the turns. It idles great and is very responsive when I goose it.
Hey benoit454,,, how do you set a carb with a vacuum gauge? Is this one of the tools that Autozone loans? I know they are real good about their tool loaner program.
I just thought of something,,,,,if the engine will run better by adjusting the carb with a vacuum gauge,,,,,I might have to settle for 20-22 MPG,,!!

[benoit454]

you can use the hand pumps like they sell for testing or brake bleeding by yourself, they are failr cheap like probably under $20 maybe under 10 or you might get a loaner deal.

You hook it into a vac. source on the carb like one of the big ones for pcv(hose going to valve cover) or brake booster line, then you start it up and watch the gauge, in some cases it might jump around due to a vac. leak, valves, big cam etc. but basically you turn the screws all the way in one at a time thenback it out until you get the highest possible vac reading, then you do the other and you're set. here's the link I read...

http://www.centuryperformance.com/tu...e-spg-148.html

[joebuick]

Hey Chris,,, I'm glad you chimed in on the vacuum thing as I got to thinking ( I sometimes get dangerous when I start thinking) about my power brakes problem that I have not got to to figure out yet. I had swapped out the booster cause the brake pedal never felt right and was kinda hard to push the last inch or so. The new booster did not make a difference so we just put that one on the back burner to attack other items.
After you brought up about the vacuum thing, it mad a lot of sense so first I started to look for any leaks and the second thing I look at is the power brake booster. When I pulled the hose off it, the engine reved up, but when I plugged w/ my thumb,,,the engine really ran smoother than before,,,!!!! I plugged the hose back to the booster and it started to run a little rough. Pull it out and cap the end and like night and day,,!!! You cannot hear a vacuum leak at the booster but there has to be one there,huh? 2 bad boosters?
I checked w/ autozone and they do not have a loaner vacuum gauge so guess I'm gonna have to buy one.

[benoit454]

cool, glad it helped some but yea when you let more air in the engine revs up, but if you plugged it with your thumb and got it completely plugged off by doing so and it made a difference then you might have a problem but have you checked the little check valve that the vac. line plugs into? Them could maybe go bad or be messed up. Most of the time I think when the booster is messed up or whatever it makes for a hard brake pedal, but yea bad booster from new, it's definately possible, alot of new things come out of the box bad nowadays.