Q-Jet Questions.

[handloader90]

First off, what in the hell is that round thing? It has a cable coming from it that attaches to the throttle linkage. It connects to this little control unit thing in the right side of the second pic, the unit was mounted about dead center on top of the driver side inner fenderwell.

What purpose does all of this serve and is it necessary? I plan on removing everything non essential from the engine bay. I plan on only having the engine, brake booster, radiator and such. Just enough to make it run.

Is the choke on this electric or manual? No choke cable in the cab. I've got another Q-Jet sitting in the garage that supposedly came off of an El Camino and the choke is the exact same. If it is electric how do I get some current to it?

Another question, all of the HVAC and emission junk is still hooked up and running, I'm going to remove all of it and would like to know if I can just put rubber caps on all of the vacuum ports on the Q-Jet once all of the vac lines are removed.

Last question... what is hands down the best replacement intake for a Q-Jet? MFG and model info please.

 

[diesel4me]

That is the cruise control vacuum diaphram,it is what pulls on the throttle when you hit a hill,to maintain a set speed..those cables and wires are part of the cruise control too,they are teed into the speedometer cable,that "tells" the vacuum diaphram dewhickey when to kick in..

I'd either keep that setup and get it working,or put it on the "for sale" section here--you'll need a new non cruise speedometer cable that is one piece from the T-case or trans to the speedometer itself..

I cant really tell on the choke,I dont see a wire on the black cap so I'd assume it isn't electric,it's probably either a thermostatic spring type or one that draws hot air from an intake passage...

I think you can put an electric element on that type though,and just hook the wire to the fuse box,to a spot that only gets power with the key in "run" position only..make sure it gets no power with it on "accessory",otherwise the choke will be "on" then too,when your parked ,sitting with the radio on and the engine off..don't want that..

 

[Big Ray]

you have a "hot air" choke. what year is your rig?

If you're sticking with a carb I'd send it to these guys . they will rebuild it to your specs. a couple of guys here have done it and were happy.

I'd lose the hot air choke and install an electric unit. They can do it for ya. or sell you a new carb. (rebuilt).

as far as intakes go, if you're just using it off road I'd go with an Edelbrock Performer or an equivalent...

It's easy enough to put an electric choke on it, just run a switched wire to it. (hot only when key is on)

fwiw, I'd throw a matching cam while it's apart.

 

[handloader90]

you have a "hot air" choke. what year is your rig?

If you're sticking with a carb I'd send it to these guys . they will rebuild it to your specs. a couple of guys here have done it and were happy.

I'd lose the hot air choke and install an electric unit. They can do it for ya. or sell you a new carb. (rebuilt).

as far as intakes go, if you're just using it off road I'd go with an Edelbrock Performer or an equivalent...

It's easy enough to put an electric choke on it, just run a switched wire to it. (hot only when key is on)

fwiw, I'd throw a matching cam while it's apart.

Thanks for the info guys! The K5 is a '79.

I plan on pulling all of that stuff out as carefully as possible and will post it up once it's all out.

 

[handloader90]

I would really like to tear into the carb and rebuild it myself and install an electric choke on it myself. I've never paid anyone to fix anything for me yet and I love the learning aspect of it... having the know how to tear it down, maintain it, modify it and get it just perfect.

There's two books specific to the Q-Jet that I plan on buying soon. I think that between the books and the internet I'll have a finely tuned Q-Jet that performs well offroad.

So what about all of the vacuum fittings? Can they just be capped when I pull off all of the vac lines?

 

[diesel4me]

You should cap off any un-used vacuum fittings..keep the PCV valve too,don't be tempted to delete it,that causes a lot more problems than having it ever will..

The advice about doing a cam swap is not a bad idea,since many stock engines were designed with the cam "matched" to the factory emission equipment,and do not always respond well to having them removed..

 

[Big Ray]

Well, if you plan on working on it here's some links that will help you immensely...


in fact, here's my info stash, in no particular order:

tech and tips:

http://www.cliffshighperformance.com/

http://www.vetteprojects.com/kstyer/quadrajet.htm

http://www.73-87.com/7387garage/drivetrain/myqjet.htm

http://www.73-87.com/7387garage/drivetrain/qjetidle.htm


http://www.73-87.com/7387garage/drivetrain/damon.htm

http://www.73-87.com/7387garage/drivetrain/damon2.htm


part sources:

http://www.carburetion.com/quadrajet.asp

http://www.cliffshighperformance.com/

http://quadrajetparts.com/pigtail-connector-electric-choke-p-56.html

after all of these, you may think you know something about the venerable q-jet. all this info is just a pre-requisite for the grand daddy of all q-jet info by one Mr. Lars Grimsrud.

I present Q-jet info by Lars.

enjoy!