RizVet

My all original 71 350/270 w/air has a 4bb Quadrajet with the idle stop selenoid switch - question - their only seems to be one vaccum connection on the switch. I have seen on this forum pictures and text referring to this plastic connector having 2 vacuum connections....what is correct. My car has the original switch and it only has one that I can see. If its 2 where do they route? Thx

MelWff

this is an idle solenoid, it has no vacuum connections, so what part do you mean?

http://www.ecklerscorvette.com/solen...dle-71-72.html

RizVet

71 part has a plastic housing on it with connection(s) for vacuum hoses.

MelWff

are you talking about the part on the passenger side of the carburetor known as a choke pulloff, see half way down on this link

http://www.cliffshighperformance.com/parts.html

RizVet

I appeciate the response but its not the choke pulloff. It is a part that looks similar to the one you posted. Search for other threads and youll see a picture of this part. My question is around the amount of ports on it...can their be a version of this part with one port?

MelWff

OK, I found it, you have a 1 year only setup, look at page 4 of this link, manifold vacuum goes in one port and the other port is connected to the distributor advance.

http://ncrsrmc.org/Downloads/Mar-2006-Newsletter.pdf

gq82

There are 2 vac ports that you can see on my 71. Looking at them from the passenger side (2nd picture) the one to the left goes to the vac advance can, the one to the right goes to the upper right vac port on the carb.

BTW the above link MelWff posted is to a teriffic article on how this one year only setup works.....it's saved on my pc.





Here's a pic of a spare solenoid I have.

RizVet

perfect...thx guys.

CraigH

Have a look here as well

http://forums.corvetteforum.com/c3-t...id-wiring.html

I spent some time working out how it works as well, The NCRS article is a great start but did not cover enough.

Craig

Alan 71

Hi r71,
Over the last few months I've been working on getting the CEC system working on my 71, 350/270, 4speed.
Once you understand what and where all the various components are, and what they do, the system is pretty cool considering there's no computer controlling it. The solenoid is the most visible and complicated part of the system.
Once the engine is at running temperature, I can't see that the system has any sort of negative impact on performance or drivability.
I'm just hoping it continues to work for at least a while.
Regards,
Alan

gq82

I followed your thread with great interest....my CEC system works but thanks to you I have a much better understanding of it should I ever have a problem .

RizVet

I guess this real trick is finding out if the system is working properly Alan.....how is it tested? These relays of mine are old but there and everythign is routed correctly. If car is running ok am I to assume the system is as well?

RizVet

I need to post picture of my original switch. I now see the second vaccum connection but one is straight out the rear of the switch and the other is perpendicular to that orientation...the one above has two parallel ports....strange huh? Only thought Mopar did funny things like this (ex Challenger owner).

Mike Ward

Not that this helps directly, but the equivalent solenoid on 4 speed '73s is known to have at least three different configurations. One is typical of factory production, the other two are service replacements.

gq82

In the NCRS paper there is a trouble shooting guide with symptoms that could be caused by a defect in the CEC system.

Another way to check it is when you start your car turn the ignition to on (not start), depress the gas pedal and you should be able to hear the solenoid fire (extend) to increase cold start rpm. On a warm start use the same procedure. The solenoid fires increasing idle speed for a about 15 seconds (delay relay). It then de-energizes and the idle rpms drop to normal.

Alan 71

Hi,
On the 71 CEC system, besides the functions that GQ described the solenoid fires to a second postition, (lower rpm than at start-up but higher than idle), anytime the transmission is put in 3rd or 4th gear... even when sitting still.
Regards,
Alan

Alan 71

Hi RIZ,
If the car is running well it's still possible for the system to be functioning only partly or even not at all. (It was very easy to disable in the olden days !!!).
You asked for it!!!
To check the system you perform the test as GQ described...
Turn the key to 'on', but not to 'start'... the solenoid fires. You can hear it and see the plunger move.
Start the car... the solenoid holds the idle speed above the normal cold start choke idle speed.
After a couple of minutes the temp sensor in the passenger side head sends a signal to the delay-relay which times 20 seconds, and then sends a signal to the reversing relay and the solenoid plunger retracts to let the idle drop to 'choke idle'. You can see it retract and hear the rpm drop.
At any time after the engine is at operating temperature the idle increases about 300 rpm above warm idle speed when the trans is in 3rd or 4th. You can easily hear and see the difference.
On warm start up, the solenoid fires, but the temp switch in the passenger side head immediately sends a signal to the delay-relay which times about 20 seconds, and then sends a signal to the reversing relay which sends a signal to the solenoid to retract the plunger.
The CEC really does all that!
Regards,
Alan

RizVet

Thanks Alan - a great response as usual from you. Very helpful. Everything seems to be working but havent seen the plunger retract after 10 minutes of run time...maybe relay is bad. I cant imagine finding a replacement for that right? Nontheless, I had to "screw down" the plunger a bit at cold start because it had my RPM way high (15k). If it doesnt retract then I will run the distributor vacuum hose direct to the high carb port and call it a day. Should I disconnect the power plug to the selanoid as well? I am concerned if I leave the system intact and the solenoid does not de-energize that my vacuum advance may not work properly (btw my car is a automatic). Thoughts?

Alan 71

Hi Riz,
The 'temperature sensor' in the right-side cylinder-head must send the "warm" signal to the 'delay relay' (which is mounted closest to the firewall on the same bracket as the 'reversing relay') which then allows the 'reversing relay' to unfire the 'solenoid'.
I thought working parts would be impossible to find but they are available if you search and ask.
Regards,
Alan

You can test the 'temperature sensor' (when the engine is obviously warm), (if the delay relay is working), by unplugging temp sensor wire... the solenoid should unfire in about 20 seconds.
For years I ran the engine CEC-less with the temp sensor unplugged, the solenoid unplugged and vac. hoses off, and the vac. advance connected to a nipple on the carb.

Rowdy Rat

Jerry,

Is that the original CEC solenoid to your car? Just want to compare notes on a few things if it is.

Alan,

If you are following, I seem to remember that your original solenoid ended up MIA?

Any luck with the gentleman who used to work the service area of the Chevy dealership where you purchased your car?

Regards,

Stan Falenski