still electric choke question

No. The only thing choke related on that carb that is vacuum controlled is the choke pull off.

No, not right. Vacuum doesn't "build."

The fast idle cam doesn't hold the choke closed. The bi-metal spring in the choke thermostat holds the choke closed, the fast idle cam changes position because it's moved by the action of the bi-metal spring.

If there isn't enough engine vacuum, you have other more serious mechanical problems with the engine. Vacuum (via the choke pull off) is used to slightly open the choke from its fully closed position once the engine starts, this allows the needed air into the engine for it to run properly when cold.

As a GM dealership mechanic, I've worked on literally thousands of Rochester carburetors, the choke coil only needs to be tight enough to -just- close the choke at room temperature, by nature, the bi-metal spring will add the necessary tension when conditions are colder than room temperature. 3-5 minutes is the normal opening time for an electrically assisted choke coil.

This all assumes that the fast idle speed is set correctly, the choke pull-off is set correctly, the fast idle cam position is set correctly, the choke coil (thermostat) is the correct one for the application, the electric choke circuit is functioning correctly, the ignition timing is set correctly, the vacuum and mechanical ignition advance devices are functioning correctly, the heat riser (EFE) is functioning correctly, the EGR valve is functioning correctly, the intake manifold isn't cracked and allowing a vacuum leak or exhaust gas to dilute the air-fuel charge, the cam is timed correctly, the fuel pump is supplying enough fuel, the float level in the carburetor is set correctly, there are no -other- carburetor problems, the ignition system is functioning correctly, the engine has the correct spark plugs, the PCV system is functioning correctly and has the correct PCV valve, all vacuum hoses are serviceable and connected correctly, The oil isn't molasses and that the vehicle operator knows that they need to press the accelerator pedal half way down in order for the choke to move closed (set) when cold.

The choke spring -doesn't- need to be as tight as it can go. It has a proper setting and that where it needs to be. Tightening the shit out of it will not solve your problem.

Even a Chiltons manual should show the proper choke adjustment specifications and give adequate descriptions of how they are performed.

On Sun, 08 Apr 2007 06:44:57 GMT, "Craig" wrote: how about putting manually operated choke on it ?

Easy to do but a pain to deal with in cold weather. If this is a QudraJet, it's so easy to get the choke to work it's not worth the aggravation of dealing with a manual conversion.

Al

The age of this truck and being two a wheel drive and where it's located and this guy is wanting better control over choke / idle speed / time NOW , suggests the truck doesn't get used as a daily driver , to me the pain and aggravation of having to deal with any carbs ' automatic ' "issuses" time after time is the problem, not having to adjust the choke manually.

I agree, if there is a GOOD reason to swap to a manual I would. But usually they are drop dead easy to get working. Most libraries will have a decent manual for older cars and parts are still easy to get.

Al

"Craig" wrote in news:Jb0Sh.2227$Uf7.1075@edtnps89:

you should not have to overtighten the choke cap for any reason...the bi metal spring inside the cap does wear out at the age you describe. it still works but not to specs. = has to be way to tight AND releases to early. really sounds like you need to find a good quadrajunk tech. or buy a F/I vehicle. the second option is best, it keeps our braindead presidents economy flitering on.................kjun

Sounds like you've got a Rochester M4ME with an automatic choke coil. In my opinion, you definitely shouldn't have the spring set all the way back towards the firewall, as this will make the setting way too rich (might even do some fuel wash damage to your engine if you let it go too long). Is it hard to start when it's cold, but fires right up when the engine's hot? Also, when you cold start, do you have to pump the pedal several times, and then see gas spit out the exhaust pipe? If so, you definitely need to readjust that coil.

Here's the method that worked for me: loosen the three screws on the choke housing, and then start from a too lean position--i.e. turn that coil cover back to the right quite a bit. From there rotate the coil cover too the left until the choke plate just starts to close. Keep turning the coil cover until you can see a little slot mark cut into the side of the coil cover, then rotate the cover back to the right so that the slot mark is aligned with the middle index dot on the choke housing. Tighten the cover screws, and it should be set correctly.

Thanks alot of critisizing me! Everybody else in this group responded with good tips and suggestions, except for you.

You say you worked at a GM dealership for over 20 years! We'll I haven't, and I'm learning this as I go. If you have a problem with people learning your trade, the f*ck off. I said I'm a newbie, and all you did was flex your muscle.

This is the last time I post to the newsgroups, just because of this dick.

I find that the old saying, "trade secrets", is so true. This guy is so obviously pissed off that someone besides a mechanic, is trying to learn what he does, because he thinks he's so superior, then he can go to hell.

I'm only aiming this at the jerk who wrote the original message.

Thnx to everybody else, who posted suggestions that actually helped, rather than criticised!

I have just reread aarcuda's response several times and all I can find is a very factual answer. He didn't sugar coat it nor did he hold your hand. I was trained by GM to work on Delco Rochester carburetors many years ago and found his explanation very factual, brief, and to the point. If there was personal criticism there I failed to see it.

You must have had a very bad day, sorry about that. Remember that this is a newsgroup and there is much wisdom passed on here, though, unfortunately a lot that falls much short of wisdom too.

Don't read into a digital message what isn't actually there, just seek information and you will find it, just discard the junk, it usually isn't too had to determine the difference.

Don't give up on newsgroups this easily, keep reading and learning. One day you will be the one offering answers to other newbys.

Have a good day!

George

Craig wrote:

Where did I criticize you?

I think I did a very polite correction of your (many) misconceptions. I also gave suggestions to other things that could fail or be misadjusted that would cause the problems that you're having. Sorry that it all went way over your head. Suggest you try alt.trucks.chevy.kindergarten next time you have the need to ask for help.

I never said that I worked at a GM dealership for 20 years. Perhaps you have a comprehension problem? (uh-huh, uh-huh, uh-huh, uh-huh, uh-huh, uh-huh, uh-huh) In fact, the only time reference given by me in my post was "3-5 minutes" in reference to how long the choke stat takes to heat up and fully open the choke plate. You're looking like heap big moron now...

You're doing -something- as you go, but I now seriously doubt there's any learning.

I should have suspected that you were a mistake to begin with. Your frustrations are no reason to lash out at me.

Learn to read.

Knock yourself out.

As I said, those "trade secrets" are in just about any repair manual. They're listed under the carburetor settings, and it's customary to look them up and follow them.

The only jerk here is you because you can't handle the answers to your questions.

Go have a good cry, I'm sure it will make you feel better.

Thanks George.

You weren't at the Milwaukee GM training center by chance were you?

No, I spent my time in the GM Training Center just north of Oklahoma City, just after high school. Many many years ago.

I remember the "thrill/honor" (???) of being in the first batch of technicians trained to overhaul the Q-jet. If I remember right, the thrill lasted about 15 minutes :))

If your skin is really that thin, you don't belong in the newsgroups anyway.

No loss.