81 stalls code 23 from ECM

[kmckenzi]

1981 stock corvette, 87K. Last month or so, idles up fine, runs ok on the road until it’s warmed up. Check engine lite comes on and it dies. Cranks back up and does it again within 5-10 minutes.

I replaced the fuel filter (pretty nasty) and I still get it. Today I took it out. After stopping, idling, then attempt to take off, the car would stutter, and then go. Check engine lite started flashing every minute or so. At one point, I had to cross 2 lanes of traffic, and it stuttered. Though I was gonna die.

Anyway, I pulled the codes and I get 23 Mixture Control Solenoid Circuit. I checked the connectors, cleaned them. I also noticed that turning on ignition before start, I hear a single click, then another when I shut off.

Is the switch flakey? BTW a few weeks back I pulled the dash to replace the speedometer. They dash lights aren’t working now after I put it back, could this be related? Tach works fine.

 

[Antz81]

Hi,
are the guages working correctly?
When checking the codes could you hear the mix control solenoid clicking continuously?

I would check your grounds first.

 

[kmckenzi]

Yes gauges are food. Yes I hear it clicking when reading the xodes

Sent from my SM-G920V using Tapatalk

 

[kmckenzi]

That's codes


Sent from my SM-G920V using Tapatalk

 

[kmckenzi]

Sorry. Gauges are good

Sent from my SM-G920V using Tapatalk

 

[Antz81]

Ok. Sounds like it may be heat related. Check the resistance of the solenoid make sure it's not getting low (should be over 10ohm, mines sitting at 23ohm),
after that it seems like it could be an intermittent wiring fault somewhere. Either a ground fault somewhere, or a broken wire/ poor connection.
id check for a ground on the blue wire first.

 

[Peer81]

If my memory serves me correctly the code 23 is a to much fuel code (or not enough air). If the solenoid stops working it turns to full fuel so that could be related!
It is very simple open the service manual on code 23 and follow the trouble shooting that gets you were you need to go

Greetings Peter

 

[Antz81]

If my memory serves me correctly the code 23 is a to much fuel code (or not enough air). If the solenoid stops working it turns it will turn to full fuel so that could be related!
It is very simple open the service manual on code 23 and follow the trouble shooting that gets you were you need to go

Greetings Peter

Code 23 is mix solenoid circuit open or low (less than 10 ohm). this could easy cause a code for too much fuel as well; since as you have said it will turn to full fuel.

 

[kmckenzi]

Thanks all. Seems my batteries in my ohm/voltmeter are toast. I'll check resistance and my manual.

Sent from my SM-G920V using Tapatalk

 

[kmckenzi]

Been away. Solenoid checks at 21.8 ohm

Sent from my SM-G920V using Tapatalk

 

[kmckenzi]

OK pulle ecm and cleaned connectors. Pretty nasty. Went ahead and changed o2 sensor. Pretty nasty. Same. Hooked up dwell sits at around 33. I know the MC is working I can see it. When I giose the throttle check engine flashes and engine stalls. Bad MC Solenoid?

 

[Antz81]

I assume it's still code 23. Even so that shouldn't be enough to make it stall.

I suspect you have a bad connection somewhere causing the stall. Bad ground maybe? Or on the one of the main supplies that feeds that supplies the ecm, distributor and m/c solenoid.

 

[dougelam]

How did you check for codes?
If you jump pins A&B on the DLC that puts it into field service mode so when you (goose it) it won't stall out from a bad input, and if it still does you are at a bad connection like ants81 says.

Sent from my SM-T530NU using Tapatalk

 

[dougelam]

For some reason I remember having a similar problem that ended up being the ignition module

Sent from my SM-T530NU using Tapatalk

 

[kmckenzi]

I'll check grounds and try the jumper and see what happens. Thanks!

Sent from my SM-G920V using Tapatalk

 

[John Ulrich]

For some reason I remember having a similar problem that ended up being the ignition module

Twice replaced, the third one's been good for a numbers of years now!

 

[Antz81]

Twice replaced, the third one's been good for a numbers of years now!

Strangely enough I've been warned never to replace one before if fails, as there's no guarantee that the old one won't outlast the new one (regardless of how old the old one is)

 

[dougelam]

I believe that might be more related to "no need to replace it if it is still working"
As for warned, I would add NOT to use an aftermarket module on GM HEI ignitions. They do not have the same internal timing control as OEM ones do and will cause power level changes and/or spark knock.

At your cars Era GM offered 7 different modules across their product line, Napa only had 5 part numbers to cover GM's 7!
I swapped out a few of them as the root cause of a driveability problem.

QUIZ- anyone know what the yellow or white dot found on GM HEI coil covers is for?
HINT- it is very important!

Sent from my SM-T530NU using Tapatalk

 

[John Ulrich]

QUIZ- anyone know what the yellow or white dot found on GM HEI coil covers is for?
HINT- it is very important!

I'm all ears!

 

[dougelam]

It depicts the direction the distributior turns.
Most old timers probably remember seeing them on the coil cover and on the OEM ignition module.
It also matches the color of the wires on the pole piece and the ignition coil itself as well!
Mix them up and if the engine runs it won't be very well, but it will have spark when tested with a spark tester.

If memory serves me yellow is for clockwise and white is counter-clockwise

Just a fun fact from the nighteen hundreds ☺

Sent from my SM-T530NU using Tapatalk