Code 24 Z34 Lumina.

[FastZ34Lumina5]

I have a 1991 Z34 Lumina five-speed. I keep getting a code 24.when you first start the car up it runs fine. When you rev it up it throws the check engine light. code 24. then the car will barely run. I put in a new speed sensor. I also checked all my connections and wiring for brakes are bad spots. can anyone help me here?

[robertisaar]

i've had 24 get set from doing the same.... i'm fairly certain that what happens is the vehicle speed sensor starts picking up on the high voltage pulses of the secondary side of the ignition.

i would try isolating the two as much as possible. perhaps make sure the VSS wiring is twisted at least the 9 or so turns per foot the factory recommends. then if that isn't sufficient, perhaps shielding the wires might ne necessary.

[FastZ34Lumina5]

That's interesting. I will try that. it sits and idles fine. as soon as you rev it up. That's it. It's like someone pulls three plug wires off. And then the check engine light comes on code 24.

[1988GTU]

check timing?

[FastZ34Lumina5]

Already checked the timing lol that was the first thing I did lol

[1988GTU]

Visually check the ICM over for anything unusual?

[robertisaar]

i don't know if i've ever had the engine act oddly when 24 gets set..... depending on the transmission, i either lost TCC(4T60) or 4th gear and TCC were disabled(4T60E).

[FastZ34Lumina5]

Yes took a look at that and all the wiering. I have the HM284 5 speed.

[1988GTU]

check the coils?