code 42 after setting timing
Thread Starter
Pro
Joined: Feb 2009
Posts: 711
Likes: 3
From: charlottesville Virginia
code 42 after setting timing
I set the timing a after receiving code 42 and having terrible idle all of a sudden, along with setting tps and replacing the iac. The car ran great at first, but after about a half hour the code came back and the car began running rough again. Right now the car will run hot after only driving for 20 minutes or so in town, oil and coolant 220 and trans temp over 250. I am only getting 8 mpg opposed to 16 I previously had. The car seems to rev up a lot and not have the power it did, along with hesitating from a stop and bogging while constant throttle is applied. I am also getting code 33, MAF and both relays have been replaced, not sure what the issue is there or if it is related. Any ideas before I replace the ecm, I would rather it be that than the distributer since thats easier on the wallet? I replaced the ICM last year, so I know that is fine.
Burning Brakes
Joined: Jun 2003
Posts: 1,079
Likes: 1
From: Niagara Falls ON
Did you disconnect the wire for setting the timing? There is a wire that needs to be disconnected. That is probably giving you a code.
Don't replace the ECM. Trace the problem. Look for bad grounds, bad connections.
If it is running terrible and you are getting code 33 then you may need to check the condition of the MAF.
Don't replace the ECM. Trace the problem. Look for bad grounds, bad connections.
If it is running terrible and you are getting code 33 then you may need to check the condition of the MAF.
Team Owner
Joined: Jan 2003
Posts: 20,292
Likes: 239
From: Summerland B.C. Canada
Your symptoms and mileage are pointing to your 33, fix that, then move onto the 42.
http://members.shaw.ca/corvette86/Code%2033.pdf
http://members.shaw.ca/corvette86/Code%2042.pdf
http://members.shaw.ca/corvette86/Code%2033.pdf
http://members.shaw.ca/corvette86/Code%2042.pdf
Thread Starter
Pro
Joined: Feb 2009
Posts: 711
Likes: 3
From: charlottesville Virginia
I've been chasing the code 33, as well as 34 sometimes for over a year, it has been intermittent up to this point. I have changed both relays as well as the MAF, sometimes a change fixes things for a little while, sometimes not at all. I know the ECM can be a cause of the code 33 as well, which is what had me thinking it was the ECM. Both codes are finally consistant and appear immediately after reconnecting the battery.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
You will get an error code 42 when you disconnect the EST connector to set the timing. You could also have a bad connection somewhere between the distributor and the ECM. The four wire cable coming out of the back of the distributor goes to a 4 pin connector that may have a problem.
The error code 33 means that there is a higher than normal voltage between the MAF and the ECM. This could be a bad MAF, but is much more likely to be a bad connection, either a broken wire or some problem with the connector pins, such as dirty pins or loose connections. Sometimes the pins get pushed out of the connector shell and cause a bad connection. If you pull on the wire the pin should not come out of the connector.
You can reset the ECM error codes by opening this connector (no tools required):
The error code 33 means that there is a higher than normal voltage between the MAF and the ECM. This could be a bad MAF, but is much more likely to be a bad connection, either a broken wire or some problem with the connector pins, such as dirty pins or loose connections. Sometimes the pins get pushed out of the connector shell and cause a bad connection. If you pull on the wire the pin should not come out of the connector.
You can reset the ECM error codes by opening this connector (no tools required):
Melting Slicks
Joined: Jan 2001
Posts: 2,940
Likes: 5
From: Chesapeake VA
If I read your original post right, you siad you set the timing and then the idle got worse and the car ran rough and lost power, yes?
If this is correct, do you know the age of your harmonic balancer? I ask beacuse mine was original and it had begun to slip, and what I though was 6 degrees was really 14 degrees and I had similar idle and roughness symptoms (without the engine codes).
Just a thought.
If this is correct, do you know the age of your harmonic balancer? I ask beacuse mine was original and it had begun to slip, and what I though was 6 degrees was really 14 degrees and I had similar idle and roughness symptoms (without the engine codes).
Just a thought.
Thread Starter
Pro
Joined: Feb 2009
Posts: 711
Likes: 3
From: charlottesville Virginia
If I read your original post right, you siad you set the timing and then the idle got worse and the car ran rough and lost power, yes?
If this is correct, do you know the age of your harmonic balancer? I ask beacuse mine was original and it had begun to slip, and what I though was 6 degrees was really 14 degrees and I had similar idle and roughness symptoms (without the engine codes).
Just a thought.
If this is correct, do you know the age of your harmonic balancer? I ask beacuse mine was original and it had begun to slip, and what I though was 6 degrees was really 14 degrees and I had similar idle and roughness symptoms (without the engine codes).
Just a thought.
I unplugged the EST connector when I set the timing, the code came right back the next time I drove the car. I'm not worried about just resetting the code and not having it on the dash, I just want it to run correctly.
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Thread Starter
Pro
Joined: Feb 2009
Posts: 711
Likes: 3
From: charlottesville Virginia
unplugged then reconnected the EST connector, everything was perfect this afternoon, no lights, no stuttering, no hesitation, temps were normal, mpgs were normal. After a while the light came back on stuttering and hesitation came back, mpg dropped temp went up. Disconnected and reconnected the EST connector again, no change. While driving down the interstate the throttle became unresponsive and the car started backfiring, pulled off to the side and the car would turn over but not stay running. Towed home and it started right up, but the light came back on. Was checking out the EST connector and it looks like it somehow wiggled its way next to the exhaust manifold and melted part of the wire, I'm thinking this is the root cause of all of these problems. I will post again after changing that section of wire out.
