Quadrajet Choke Issues

[pontiacgp]

It's that time of the year again where a choke is that is not operating properly will cause noticable problems that will irritate you. Axisg posted the below in "what did you do to your G body today" ....so we don't hijack that thread trying to help him I started this thread and I suspect there are more of you that are having a problem with the choke......

"drove it to work today. With the colder weather I started messing with the choke. If I set the spring tight enough to almost close at cold then it doesn't want to kick off the high idle cam when warm ! If I set it just a couple degrees back then the choke flap stays open and it wont idle cold.

It did this last year as well so I changed the choke spring, now seems I am having the same issues. :/"

" I was getting fluctuating readings from the choke wire last year so I jumped off a switched 12v+ power lead instead."

 

[pontiacgp]

I would remove the coil and bench test it so you know it's working

 

[Opie Knievel]

It's problems like this that remind me of how convenient the TBI on my 4.3 is.

 

[pontiacgp]

It's problems like this that remind me of how convenient the TBI on my 4.3 is.

quadrajets are not difficult to work on and work great when tuned. And a quadrajet makes it easier to find an problem and repair than a computer run TBI when it breaks. Plus if a problem comes up with a quadrajet it usually won't leave you on the side of the road like a TBI will

 

[Oldsmoletick]

Could be as simple as the counter weight sticking ever so slightly too.

 

[Opie Knievel]

quadrajets are not difficult to work on and work great when tuned. And a quadrajet makes it easier to find an problem and repair than a computer run TBI when it breaks. Plus if a problem comes up with a quadrajet it usually won't leave you on the side of the road like a TBI will

Yeah but TBI's never break!! Lol 😛

Seriously though, I had a perfect working Quadrajet on an '83 Cutlass 4 door I had years ago. I agree, they are awesome when they're right. I should have kept that car.

 

[axisg]

Well this mornings setting was NFG. Had to two foot drive it for the first block leaving work or else it would stall

I assume the coil is OK as I can see the choke flap slowly opening whilst fiddling with the carb trying to keep it running. Spring doesn't seem strong enough to pull it off high idle cam though until its 100% warmed up. If I really mash the throttle the vacuum pull off will drop it down. It drops will little resistance when I put my finger on the cam and blip the throttle ( so I don't think its hanging up ).

Its been an ongoing issue with this carb since I put it on the car. Third choke coil now ( from my parts carbs ). The linkage is free. The only mod I have done is removing the secondary lockout tang ( like I always do with my qjets ). There is a rough spot when rotating the coil into position so I think it may be losing ground and messing with the spring.

Carb is 100% when warm. The parts that sucks is that you can only tune the choke when stone cold. Typically I am on the road most days so I get one chance in the morning to set it up correct.

I have been really lucky over the years tuning the qjet. Usually after a couple days tinkering its almost as good as FI. When cold the slightest movement of the throttle sets the choke. 2 pumps and it starts at high idle. Depending on the temp a minute or so at high idle ( 1200 rpms or so ) then with a throttle movement it should drop it down to cam 2 setting ( 1000 rpms ) where it will stay until warm. Then I like a 900 rpm winter setting. This one is not playing nice LOL

 

[Bonnewagon]

Here is a time lapse of the choke working down the fast idle steps. Clean everything with carb cleaner and verify all is loose. Make sure the secondary lockout is not hanging up. Check that the unloader tab is not interfering. If you have a secondary pulloff, make sure it is working right and not interfering. Then when everything is cold, ignore the hash marks on the choke housing, and adjust the choke so it closes smartly. Then adjust your vacuum pulloff so that when the motor starts it opens the flap to the specs. If you don't know the spec, 1/4" will work for now. You check it with a drill bit at the air horn where the butterfly opens. Later you can fine tune it so it doesn't stumble. If there are no other parts failing then that should do it.

 

[SupremeSpeed]

Mine is computerized No problems with my quadrajet! E4MC I love this carb!

 

[pontiacgp]

Here is a time lapse of the choke working down the fast idle steps. Clean everything with carb cleaner and verify all is loose. Make sure the secondary lockout is not hanging up. Check that the unloader tab is not interfering. If you have a secondary pulloff, make sure it is working right and not interfering. Then when everything is cold, ignore the hash marks on the choke housing, and adjust the choke so it closes smartly. Then adjust your vacuum pulloff so that when the motor starts it opens the flap to the specs. If you don't know the spec, 1/4" will work for now. You check it with a drill bit at the air horn where the butterfly opens. Later you can fine tune it so it doesn't stumble. If there are no other parts failing then that should do it.

that's a great view with the front beaker removed...🙂