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Discussion Starter #1
Got an 81 Elky, runs fine, but check engine light comes on intermittently. Oil pressure, temp, etc. looks fine. How do you pull the codes from the computer on this . There appears to be a connector located under the dash, but unlike newer s, this one only has one row of connectors instead of two like the newer ones.
 

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glassman said:
How do you pull the codes from the computer on this.
You have the distinct honor of having one of the first Computer Command Control (CCC) systems put into an El Camino. I think it was first introduced in California in 80 and the rest of the U.S. got it in 81. The 80/81 CCC system is different from all other 5th Generation El Camino CCC systems.


This is the 1981 Assembly Line Diagnostic Link (ALDL)

In order to pull the stored codes do this:

1. With the ignition off, jumper the two far right terminals as shown in the picture. "D" is the diagnostic terminal and "E" is ground.
2. Turn on the ignition but do not start the engine.
3. The SES light will begin to flash a Trouble code 12. One flash, a short pause, and two flashes. There will be a longer pause and the Code 12 will repeat two more times.
4. The stored Trouble Codes will now flash. Each Code will be repeated three times. Write them down.
5. When Code 12 flashes again that indicates that there are no more stored Trouble Codes.

Let me know what codes you pull.

:mrgreen:
 

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Discussion Starter #3
Engine Codes

OK, I've got two codes "12" and "44". Also, there is a loud clicking coming from the caruretor, when I have the ignition on, but the car isn't running. When I disconnect the wiring harness at the front of the carb. on the passenger side, it stops. I think this is the electronic mixture control solenoid. It shouldn't be making this noise when it isn't running should it? I've noticed lately that from time to time, the alternator guage gets pulled way low by something periodically. I took it in and had teh alternator checked and it was fine. Now that I've disconnected this solenoid, that problem seems to have stopped, but now the car doesn't run very well. I figure these two problems are related in some way.

So what's the diagnosis?
 

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Discussion Starter #4
I spoke a bit too soon. The car actually runs pretty normal with the mixture solenoid disconnected. But now the check engine light stays on continuously instead of being intermittent.
 

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Don't worry about the code 12.

The code 44 is a "Lean oxygen sensor signal". This means after the ECM has gone into closed loop, the feedback from the oxygen sensor indicates that your exhaust is running lean. You either have a vacuum leak, the carb needs to be rebuilt, or you may have a bad oxygen sensor, (in that order).

The clicking sound was the mixture control solenoid. That's normal when you turn on the ignition. Pulg it back in. If you leave it unplugged you'll get a code 23 "Open or grounded M/C solenoid circut" That's probably why your check engine light is always on now.

:mrgreen:
 

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Thanks for the help. I'll plug the solenoid back in. I'll readily admit I'm not familiar with this caruretion system. I had a Chrysler with a similar Holley carb with electronic mixture control, and it didn't make this sound when the engine was not running but the key was on. I figured they were similar, but I guess not.

Any idea why it's pulling the alternator guage down when the car is running? With it disconnected, it sits right at 13 volts, just like it's supposed to, but with the solenoid connected, it will drop down to 10-11 volts and lower at idle. I had the alternator checked at Auto Zone and they said it was putting out around 14 volts at idle so they didn't see anythiing wrong with the charging system. Maybe my guage is just getting flaky, but it seems strange that this mixture solenoid has this effect on it.

I'll check for vacuum leaks as this is the most probable cause of the problem. The oxygen sensor is almost new, I replaced it about 2 months ago, just routine maintenance.
 
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