Code 42?
Thread Starter
Senior Member
Joined: Sep 2012
Posts: 500
Likes: 9
From: Whitter, CA/La Puente, CA
Car: 1992 Z28 Targa Top. Full air ride
Engine: 305 5.0 tpi v8
Transmission: A4
Axle/Gears: 3.73 gears posi
Code 42?
Ok, i need my tpi gurus to help diagnois this. First and formost....
1992 5.0 tpi w/ auto tranny
About 120k on the clock.
It started this morning going to work. About 5 blocks from home as i'm driving doing about 35-40 the car dies. About 5 seconds later it comes right back on. Check engine soon light is now on but all gauges read normal (oil pressure, water temp, volts, etc.) I pull it to the curb and shut it down. Key to on possition, I check the fuel presure and it reads about 40psi. Normal. Check the oil and its a little low but nothing alarming and its not milky or bubbling. I try to start it a couple times and it starts up everytime.... I decide to turn around and bring it home. Feels very sluggish and underpowered and the check engine light is still on. Once at home i check the obd codes. Only reads code 42.
So what happened and how do i fix it? I dont want to start throwing money at parts aimlessly. Where should i start looking?
1992 5.0 tpi w/ auto tranny
About 120k on the clock.
It started this morning going to work. About 5 blocks from home as i'm driving doing about 35-40 the car dies. About 5 seconds later it comes right back on. Check engine soon light is now on but all gauges read normal (oil pressure, water temp, volts, etc.) I pull it to the curb and shut it down. Key to on possition, I check the fuel presure and it reads about 40psi. Normal. Check the oil and its a little low but nothing alarming and its not milky or bubbling. I try to start it a couple times and it starts up everytime.... I decide to turn around and bring it home. Feels very sluggish and underpowered and the check engine light is still on. Once at home i check the obd codes. Only reads code 42.
So what happened and how do i fix it? I dont want to start throwing money at parts aimlessly. Where should i start looking?
Joined: Nov 2008
Posts: 2,093
Likes: 175
From: Milwaukee
Car: 92 Firebird, 77 Trans Am SE, 86 Z28
Engine: 5.7 HSR, T/A 6.6, empty
Transmission: T-5, TH350, T-5
Axle/Gears: 3.08 posi, 3.23 posi, 3.23
Thread Starter
Senior Member
Joined: Sep 2012
Posts: 500
Likes: 9
From: Whitter, CA/La Puente, CA
Car: 1992 Z28 Targa Top. Full air ride
Engine: 305 5.0 tpi v8
Transmission: A4
Axle/Gears: 3.73 gears posi
Re: Code 42?
Ignition.... Well that sucks. Most of the ignition system has been replaced already within the last year or so (distributor, cap, rotor, coil, wires, plugs). Could an ignition module really go bad in less than a year?
Joined: Nov 2008
Posts: 2,093
Likes: 175
From: Milwaukee
Car: 92 Firebird, 77 Trans Am SE, 86 Z28
Engine: 5.7 HSR, T/A 6.6, empty
Transmission: T-5, TH350, T-5
Axle/Gears: 3.08 posi, 3.23 posi, 3.23
Yep. But you could have a wire or connection gone bad.
Thread Starter
Senior Member
Joined: Sep 2012
Posts: 500
Likes: 9
From: Whitter, CA/La Puente, CA
Car: 1992 Z28 Targa Top. Full air ride
Engine: 305 5.0 tpi v8
Transmission: A4
Axle/Gears: 3.73 gears posi
Re: Code 42?
That flow chart doesn't make sence. It says to probe terminal D4 and then D5 but on the diagram for a 90-92 F-body there is no terminal D4 or D5 on the ECM.... Looks like the flow chart is based on the 85-89 ignition system. How do I test for a 92?
Thread Starter
Senior Member
Joined: Sep 2012
Posts: 500
Likes: 9
From: Whitter, CA/La Puente, CA
Car: 1992 Z28 Targa Top. Full air ride
Engine: 305 5.0 tpi v8
Transmission: A4
Axle/Gears: 3.73 gears posi
Re: Code 42?
Well maybe it does make since. Perhaps Spark Timing and EST are interchangable, they are the same color wiring. Maybe the Designation of D4 and D5 isn't important as much as checking the correct color wire. Wish I was at home to start checking and not at stupid work.
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