Just wanted to post an article about rebuilding Q-Jets based on my many axperiences doing it. They're actually fairly easy to service when you know how to avoid some common mistakes.

Pull the carb:
Fuel line- Hold the big 1"nut while you loosen the 5/8" fitting, preferably with a flare wrench. Otherwise you will surely twist the fuel line.

Brake vacuum- Again hold the bigger nut while loosening the 5/8" fitting

Electrical Conn.- Remove the TPS, MCS and Choke harnesses

Vacuum hoses- Remove all the vacuum hoses. Label them if needed, but generally they will be formed in shape to they're locations.

Linkages- Remove the clips and disconnect the throttle, kickdown(if A/T), and cruise control cables. Also remove the return spring.

Bolts- Remove the 4 1/2" bolts holding down the carb. Remove the carb.

I built my own stand for the carb. Use a piece of plywood and put 4 bolts up through the bottom at the location of the 4 mounting holes. Thread nuts down from the top about 2" from the wood. This is important because if you just set the carb on a bench you can damage the throttle pivots. If you are new to the Q-jet you should find a multi-section container to seperate the parts as they come off. Organize them in order of removal to avoid confusion later on. After a few rebuilds you will see that most the parts can only go one way can just throw them all together in a cup.

Rebuild:

Air horn- This is the top plate of the carb. First remove the accelerator pump clip and rod from the lever. This is on the front driver side. Remove the secondary vacuum break and linkage. Remove the flathead screw from the choke shaft. Remove the 13 torx screws that hold the airhorn. As you remove the airhorn feedthe choke shaft through the hole.

Disassembly- Remove the MCS plunger and primary needles. Remove the gasket carefully. Pull the accelerator plunger piston. screw in the MCS adjustment screw all the way counting the number of turns, then remove it and the phillips screw for the electrical connector and remove the MCS assy. Remove the small spring from under it and also the spring from under the accelerator piston. Lift the float assembly out by the pin pivot. Remove the last spring at the bottom of the bowl. Unscrew the 2 primary jets. Remove the flathead screw and check ball. Unscrew the float jet and remove it along with it's washer. If not already done, remove the plugs covering the mixture screws. Drill a small hole in the center and pry them out with a pick or mini screwdriver. Again count the turns as you lightly seat the mixture screws before removing them. Now flip the carb over and unscrew the 3 torx screws and seperate the throttle plate assembly.

-You can stop here if everything looks clean. The important part of the rebuild is: replacing the rubber cup at the bottom of the accelerator pump; replacing float needle and jet; cleaning all orfices, jets, needles, and throttle bores; greasing all pivots; assebling correctly with new gaskets.

I'm stopping here cauase it's late and time for sleep. [damn 8-5!!] I'll continue soon about the extended disassembly as well as painting the Q-jet and modifying for performance soon.

 

that's quite handy. I'll have to remember this...
That's interesting about the stand, i'll have to try and make one of those, never thought of that...

I could add a few points about the power piston removal / installation... or setting the power piston minimum height.... if desired...

I *think* that the big nut on the fuel inlet is over 1"... 1 1/16"? I'm not sure, if 1" is right, disregard this, but for some reason I think there is a reason I leave my 1" wrench aside and use a crescent wrench....

Also, another tip from my personal experience (boy, I could fill a few pages with what not to do...), is the "emulsion tubes".
When you remove the air horn, and you see 4 tubes sticking down from the air horn (hopefully 4), that's a good thing, don't bend or break them. Make sure they are open, ie. use a can of compressed air on it and make sure it blows through... If you only have 2 tubes, and 2 are sitting in the wells in the float bowl, then they fell out. No big deal, just find the holes that they belong in, and press them in and tap them SOFTLY with a hammer.

 

That is great stuff. I need to rebuild mine but I've been a bit afraid of it. I have been wrenching for ages but never rebuilt a carb. Any of the books I have are no help, seems like a $1000 worth of specialty tools are needed.

What can a carb newbie get by with as far as specialty tools?

 

I got by with:

carb cleaner
can of compressed air (or air compressor if you have it)
phillips screwdriver
flathead screwdriver
torx t8 & 15 & 20. I got the set, 8-30 for $5. you need those.
And I used a bent nail (1/16" or so) to pull out the throttle pin... (non-cc only)

The stand would be nice to have, i'll have to make one as per preloaders instructions

I made a gizmo to adjust the idle mixture screws, a 3" long piece of 3/8" ( I think ) solid round bar, then cut a slot in one end, about 1/4" deep, 1/8" wide. Other side I welded another 3" piece of rod to make a T
the slot can be made/modified with an angle grinder..

That's all I needed. The rebuild kit comes with a small paper square (like a carpenters square, for measuring.. not a [] square.)
that's to adjust the float level... aside from that... nothing else that I needed...

oh yea, assuming you have a vacuum gauge to set the mixture...

 

Just so there's no confusion (well, maybe just less confusion):

Preloader is talking about a computer controlled carb. Sonix is talking about a non-computer controlled carb.

If you have a CC carb, you'll need a couple of other tools to make the necessary adjustments. They are available at Pep Boys, Checker/Shucks/Kragen, NAPA, probably most any chain parts store, less than $10. You'll also need a high impedance volt/ohm meter (the typical digital from Radio Shack will do).

 

Actually, to performa a correct installation and adjustment of the E4ME, you only need about $15 worth of specialy tools:

 

Think I'll leave my carb in the car for now and pick up a carb at the scrap yard that is the same and rebuild that. That way I can take my time and if I mess it up, no big deal.

Is there a good place on line to buy those tools Vader? Or am I better off going some place like NAPA? Have everything else I need including an air compressor.

 

Any place that sells OTC tools should be able to supply the set. If not, they can be ordered online at Skyway Tools.

 

Pretty much every automotive tool manufacturer (K-D, Lisle, Snap-On, Kent-Moore, etc) has one for the purpose.

 

sorry for the delay in continuing this article---been too busy. just wanted to mention that occasionally addind Chevron Techron Fuel System Cleaner to the tank can sometimes perform small miracles. After using the tankful of gas I suggest replacing your fuel filter, or ditching the stock one and installing a clear glass one. I think they flow better and are very useful when diagnosing "no start" problems. AIR+FUEL+SPARK=COMBUSTION. You can easily confirm if your getting gas.

 

Is it difficult to set the throttle position sensor? I can rebuild the non computer q-jet but I been having problems with the electronic one. Well I dont mean trouble its a total disaster