Desi.LT1

I am troubleshooting an electrical problem with my 1971 LT1 Coupeville. Is it normal for the CEC switch/solenoid to activate when the ignition switch is moved from Off position to Accessory? I'm trying to figure out why the starter won't crank, I have no lights, courtesy or others. Battery has 13.3 volts, + terminal at the starter makes 12.5, horn relay is getting 11.9.
I noticed that when I move the ignition to Accessory mode, I hear an electric click that I traced to the carburetor CEC solenoid.

dan1495

The solenoid on my my 72 LT1 is energized as soon as the key is turned on. As far as I know that is the way it is supposed to work.

Alan 71

Hi D,
First Post! WELCOME!!
A 71 LT-!, VERY nice!
I believe the CEC solenoid is normally only energized (the plunger 'fires') when the ignition switch is turned to the 'on' position as Dan posted, but not when it's turned to the 'accessory' position.
You should have courtesy lights as soon as you open the car door…even with the ignition switch off…. do you?
Regards,
Alan

Easy Mike

I give up. What's a Coupeville?

7T1vette

Sounds like a problem with the neutral start switch or the starter solenoid.

Alan 71

Hi,
If it were a problem with the neutral safety switch wouldn't the courtesy lights and all other electrical accessories still work.
Regards,
Alan

Desi.LT1

Thanks for your responses. My interior lights used to come on when the door opened, but not any more. Every thing is dead, except that when I turn the key to Accessory mode, the CEC plunger fires.

Alan 71

Hi D,
What have you been working on lately that might be the instigator of this problem.
In the recent past did the lighting and engine starting/running procedure seem normal?
Regards,
Alan

Desi.LT1

The car was running fine after being resurrected from its slumber. I had the engine rebuilt, new everything except when it comes to wiring. The transistor amp harness has been replaced, new coil, starter, alternator, headlights. I did take the dash apart to work on the center gauges and radio though. Had been driving it just fine for a few days, with the gauges out while waiting for the radio to be done. Now I am dead and can't find a reason why. The dash is still waiting for me to put it back together. So I bought new battery cables and engine harness, waiting for them to arrive from Corvette Central.

Desi.LT1

I got it started tonight! Turned out to be a bad engine ground cable. I didn't realize that there is a cable from the frame to the engine block until I pulled the starter and saw it bolted there.

But now the CEC switch engages on start and stays there which is causing a very high idle speed, so I unplugged it.
Does anyone know what effect this will have on how it will run?

Alan 71

Hi Desi,
The solenoid is controlled by engine temperature (cold start-up), a length of time (hot start-up), and gear selection (normal operating temperature).
There are 4 parts that control all this; Reversing Relay and Delay Timer,(mounted on firewall), Temperature Sensor Mounted in right side head, and Transmission Switch (Mounted on the transmission case).
Diagnosing the cause of the of your problem could be involved because of the parts and wiring involved.
Do you know if all the parts are there?
Regards,
Alan

Reversing Relay and Timing Relay (Circled).


Temperature Sensor.


Transmission Switch.

Desi.LT1

Thank you for your help. Yes I do have all the parts installed that you mentioned. Great pictures!