CODE 42 and 24
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Joined: Jan 2000
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From: Fresno, CA, USA
CODE 42 and 24
My car idles like CRAP I've checked everything and replaced everything. What else could be wrong you think?
Any suggestions on checking this code 42? I'm not even sure where the EST is located.
Any suggestions on checking this code 42? I'm not even sure where the EST is located.
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Joined: Dec 2000
Posts: 1,536
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From: Springfield, MO, USA
Car: 1986 Trans Am, 1991 Firebird
Engine: 355 TPI, 3.1L V6
Transmission: 700R4 in both
code 42 and 24.....I think one of them is the speed sensor and the other is the egr valve!! The EGR might be 43 but I'm pretty sure 24 is the VSS!! The VSS is what's used to tell the computer how fast you're going so it can limit your speed!! However, the VSS going bad can affect how the engine runs!! Want an easy way to test if your VSS is bad.....find a long empty stretch of road and run your car up to ohh about 120MPH and keep going....if you break 125-130MPH then your VSS is bad!! With the VSS working properly, the ECM will cut off the fuel supply at about 120MPH on most cars...mine made it to about 124-125!! You'll know what I'm talkin' about if the VSS kicks in....it's almost like the tranny kicked into neutral....that's how I would describe it!!
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1986 Trans AM
305 TPI
200,000+ miles (speedo/odometer non-funtional! Odometer reads 142,000)
4 Wheel Discs
9 bolt Borg Warner Rear (2.77's....oh joy) :P
Completely Stock
Soon to upgrade to a 383 converted from TPI to Carb, Edelbrock 600CFM Carb, Edelbrock Performer RPM Intake, Hedman Shorty Headers, AFR 195's (if I can afford them), XE268 Cam, Moroso HEI ignition kit with external MSD Blaster II Coil and an MSD 6-AL Box!!
Current project: Keeping my 305 running until I get my income tax returns!
------------------
1986 Trans AM
305 TPI
200,000+ miles (speedo/odometer non-funtional! Odometer reads 142,000)
4 Wheel Discs
9 bolt Borg Warner Rear (2.77's....oh joy) :P
Completely Stock
Soon to upgrade to a 383 converted from TPI to Carb, Edelbrock 600CFM Carb, Edelbrock Performer RPM Intake, Hedman Shorty Headers, AFR 195's (if I can afford them), XE268 Cam, Moroso HEI ignition kit with external MSD Blaster II Coil and an MSD 6-AL Box!!
Current project: Keeping my 305 running until I get my income tax returns!
Thread Starter
Member
Joined: Jan 2000
Posts: 339
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From: Fresno, CA, USA
I have a custom prom though and a brand new engine, I'm not sure I should take it 2 120 til it's broke in and I dont think I have a speed limiter anymore, right? I dunno. I thought 42 was EST circuit http://www.fastlane.net/~thartman/gmcodes.htm All I know is my car runs really rich and idles real bad. I did a search and nobody had a 1991 with a code 42. I'm thinking 91-92 might be different.
Code 42 for the TPI engines is EST.
A code 42 sets everytime you run the engine with the tan timing wire disconnected. This is normal.
The 24 (VSS) will illuminate the SES when you drive. You have a busted wire, bad ECM or the VSS is bad. (does your speedo work?)
[This message has been edited by Brent (edited March 22, 2001).]
A code 42 sets everytime you run the engine with the tan timing wire disconnected. This is normal.
The 24 (VSS) will illuminate the SES when you drive. You have a busted wire, bad ECM or the VSS is bad. (does your speedo work?)
[This message has been edited by Brent (edited March 22, 2001).]
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