Warm up transmission

[Blake Sherwin]

I had a thought last night as I was going to sleep. I know that back when I had a shop working on this I had them tie the choke fully open.

I was entertaining a "what if" scenario in my head last night and thought "what if" as I increase the thottle the choke plate is falling down to the closed position until I back off the gas and press it again to raise it back open?

I recall them telling me the auto-choke wasnt working, and when it was zip tied it simply wouldnt run. BUT I'm thinking what if I zip tied the choke, not so its fully open, but only so it cant fully close, say tie it so it can only get 1/4 closed or so.

I figured once I get good and warmed up, I can shut off and apply the ziptie with some slack, then drive around a bit.

This way if my issue changes from complete choking to just a loss of power due to it only partially closing I can isolate for sure if its choke related.

Granted I'm no expert yet with the carb, but its something I was thinking about, this is something I can test first without having to dismantle anything.

If this test is unfruitful then I can take off that switch and have a look (probably want to do that either way though).

Does this make any sense or am I talking nonsense?

[Paul Steinberg]

You clearly have a carburetor problem, and it is only a guess on my part, however, if the choke isn't working properly, and is flopping around, it needs to be fixed properly. By using the word "it", I am referring to the complete and whole carburetor. Anything less isn't going to result in favorable results. In fact, once you have the carburetor fixed, that doesn't mean that the engine is going to be better at all, since the defective carburetor could be masking other engine issues. You fix that which is an obvious problem first, and if some other issue is then identified, you either fix that one, or do a comprehensive examination of the engine as a whole, and determine how you want to attack the problem or problems. There are 3 things that are needed for a working engine... i.e. Fuel, Air & Combustion. You have a fuel problem, and once you correct that, the air issue will correct itself, since it is infinitely variable by the carburetor. The next is combustion... i.e. Spark plugs, spark plug wires, distributor and its associated parts, and finally, compression of the engine and its associated parts. By this, I am referring to piston rings, valves, cam to crankshaft relationship, etc.. If any of these are a problem, which you can't tell without a comprehensive examination, you will never resolve your problem(s).
You need a good working carburetor no matter what else has to be repaired, so that should be your starting point. It doesn't take a lot of expertise to remove it from the engine, and once repaired, to reinstall it. Many carburetor remanufacturers will do all the preliminary settings, so it should work properly right out of the box. It may require some fine tuning, and you can have that done by a professional once you have the car running properly.

[Blake Sherwin]

I learned today that apparently many shops believe quadrajets are all the same and part of my problem may be that I have the wrong QJet. I'm going to check the number tonight and see if it matches what is correct, and also run some tests on the choke with it warm.

A paste from the cadillac/lasalle forum:

My thought has been, and is, that you have a carburetor problem. Now that you have mentioned that a "repair shop" put a rebuilt Q-Jet on your engine, I am even more suspicious of the carburetor. GM used Q-jets pretty much across the board on their engines for many years starting in 1967 (on Cadillacs, other GM lines earlier), there are those that think they are all the same (or close enough) that any old replacement Q-Jet will do --- absolutely not so! Do you have any idea if the shop put on a NUMBERS CORRECT replacement Q-Jet for your 1968 Cadillac engine? Every Q-Jet I am familiar with has a number sequence on the carburetor body that identifies the year and division make engine (Cadillac, Olds, Chevy, etc.) that that particular carburetor was designed and calibrated for, as well as what transmission it had. Many Q-Jets may FIT on your engine and work to some extent, but they may well not work properly.


On our older cars, owner knowledge and education is most important! Many shops and so-called mechanics these days are as lost looking at and working on 1968 Cadillac as I would be working on a modern fuel injected engine.

http://www.carburetion.com/quadnumber.htm

Note that it points out at the early Q-Jets up until the early '68 models had a stamped, round disc with identifying numbers attached to the carburetor while all later models had the numbers stamped into the carb body. With your '68 the original carb could have had the separate attached tag OR the numbers stamped into the body. My experience with Q-Jets is that it is often (maybe always) better to have the original one off your engine rebuilt by a good carb overhaul shop --- there are plenty around and many of us here can recommend a good one.

Check the numbers on your present carb using the link I posted above and see what it is really for.

[Paul Steinberg]

If you feel that your carburetor has incorrect parts in it, then I suggest that you contact a fellow in Arizona that has shelves full of correct carburetor cores that he can rebuild for you. He specializes in the Quadrajet carburetor. Without his permission, I will not post his information on line, however, you can contact me for his contact information.
You could also send him your old one, and have him restore it with correct parts as necessary.
Just keep in mind, not to remove the large fuel nut, because 99% if the people that do, that don't understand that it is a very fine thread, will ruin the threads in the carburetor. That can be a very expensive mistake.

[Blake Sherwin]

I called him in January and i do plan on using him. I just need to gather the funds. Old carb is in a box ready to go.

This evening i tested if my choke was closing, by using a series of zipties to "block" the plate from fully closing but still allow movement. Drove around the block and issue didnt change. So that rules out the possibility of the choke closing while driving. I removed all the ties afterward

Tomorrow i will try to find and trace wires from the starter.

For that ignition switch i need to figure out if it comes out the bottom or i need to remove the dash panels.

[John ED Renstrom]

that book off e-bay will help you take this apart and fix them right. it save you more money then it costs. there is a screwed on plate under the steering column. take it off and the universal one is held on by that knurled outer ring. it will drop out the threw that hole you uncovered. caution do one thing at a time don't have a lot of this apart at the same time.

you can read the number off your carb and go to the carb shop web site and see if it is the right one for your car. it should be left hand rear if it's stamped

[Blake Sherwin]

Also it was pointed out that I have a hose missing from my carb dashpot. i need to get a T hose for it

[John ED Renstrom]

the one that goes to it is the outside right one it will be ported and that not the dash pot that is the vacuum pull off for the choke. it's function is to crack the chock open when it fires. the dash pot is one the other side it's function is the prevent it from stalling when you return it to idle. once again I tell buy that book. it would look like you have a few things mixed up there. any one set will. give you problems.

[Blake Sherwin]

Originally Posted by John ED Renstrom

the one that goes to it is the outside right one it will be ported and that not the dash pot that is the vacuum pull off for the choke. it's function is to crack the chock open when it fires. the dash pot is one the other side it's function is the prevent it from stalling when you return it to idle. once again I tell buy that book. it would look like you have a few things mixed up there. any one set will. give you problems.

You say its the right-most hose? the one that is on top of the other? I just want to make sure because my initial though was it was the lower one, the left one.

not doubting you, I just want to make sure I understand you correctly.

That book is on my list. I am going to buy a copy very soon.

[John ED Renstrom]

When you get it look things up. The far right port. Right on a car is passengers side no matter were you are standing or direction you are looking. Wondering what they plugged it into? Each one of those ports went some were. One of the problems with the rebuilt is some times you get a body that has more ports then you need.your to cap them off. If the people that replaced that carb didn't know enough to hook the choke pull off what else did they miss? Had you gotten the book most of this would have been behind you.