help with a code 43 and a good knock sensor
Thread Starter
Racer
Joined: Jul 2001
Posts: 322
Likes: 1
From: Los Gatos, CA
help with a code 43 and a good knock sensor
I've been trying to troubleshoot a code 43 and the knock sensor is not the issue. It has been an intermittant that is becoming more and more consistent. I've replaced the connector that goes to the knock sensor and checked the knock sensor operation in datamaster and it is not giving knock counts. I also made sure that the 5V was going to the knock sensor connector with Ignition on.
What are the best things to check next? Is it possible that the 7-pin ignition module is dying?
Thanks for any help.
What are the best things to check next? Is it possible that the 7-pin ignition module is dying?
Thanks for any help.
Melting Slicks
Joined: Sep 2003
Posts: 2,270
Likes: 118
From: N. Babylon NY
In your post you say that the knock sensor is not the issue. Did you check the knock sensor itself? It should ohm out to 3300-4500 (on a 1992 anyway). I also chased a code 43 problem and after checking it 4 times it turned out to be a bad knock sensor. Sometimes (as I found out) they can check out o.k.
Steven
Steven
Thread Starter
Racer
Joined: Jul 2001
Posts: 322
Likes: 1
From: Los Gatos, CA
Code 43 - other things I checked
Thanks for the suggestions. I already checked the knock sensor with an ohm meter - should have mentioned that. The spark module isn't giving a code 42, but I guess it could still be a problem.
The problem started on the way back from a road race track event and it was fairly warm out during the day.
Thanks again.
The problem started on the way back from a road race track event and it was fairly warm out during the day.
Thanks again.
Advanced
Joined: Jun 2004
Posts: 81
Likes: 0
From: Manchester CT
I had the same problem with my 1987. After much checking and with help from this forum I managed to find out that I had two broken wires inside the harness that leads to the esc. Also someone told me to put a new ground wire to the ground wire for the esc. After fixing this I now have no codes and the engine runs like never before. Hope this helps.
Melting Slicks
Joined: Sep 2003
Posts: 2,270
Likes: 118
From: N. Babylon NY
What kind of trouble does this cause?
Or worse if there is pinging and the ecu does not retard timing it can cause serious motor damage.
Steven
Pro
Joined: Apr 2001
Posts: 744
Likes: 13
From: Lenoir City TN
Going thru the same thing myself. I get a solid 43, not intermittant. I've changed the following:
ECM
Knock Sensor
Electronic spark module in the distributor, because it started as a code 42, changed the module, then the ECM and then it went to code 43
Have now bought a Helms manual, and at this point it has not shed any light.
After I changed the above items and had no success I started looking aroung and found a ground wire broken that was connected on the ground stud at the transmission. Reconnected it and still no help.
The flow chart points to the Prom in the ECM if everything else checks out. I think that maybe that loose ground wire may have damaged it, if no one has any other ideas I may try that. I hate to throw money at it, but I don't know of anything else to do.
An 87 has a ESC, but my 91 does not.
One other thing that is weird, if I disconnect the oil temp sensor, if will not set the code.
The sensor and wiring checks out ok, but when it is connect it works fine, but sets the code 43.
ECM
Knock Sensor
Electronic spark module in the distributor, because it started as a code 42, changed the module, then the ECM and then it went to code 43
Have now bought a Helms manual, and at this point it has not shed any light.
After I changed the above items and had no success I started looking aroung and found a ground wire broken that was connected on the ground stud at the transmission. Reconnected it and still no help.
The flow chart points to the Prom in the ECM if everything else checks out. I think that maybe that loose ground wire may have damaged it, if no one has any other ideas I may try that. I hate to throw money at it, but I don't know of anything else to do.
An 87 has a ESC, but my 91 does not.
One other thing that is weird, if I disconnect the oil temp sensor, if will not set the code.
The sensor and wiring checks out ok, but when it is connect it works fine, but sets the code 43.
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Team Owner
Joined: Oct 2000
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From: Fort Knox, KY
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Did you torque the sensors in correctly? I think its 15 lbs. Check your Chevy service manual to be sure.
Pro
Joined: Apr 2001
Posts: 744
Likes: 13
From: Lenoir City TN
Originally Posted by aklim
You sure the wire leading to the sensor is good? You sure the connector is not having intermitten contact?
Team Owner
Joined: Oct 2000
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From: Fort Knox, KY
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Originally Posted by cshuman
If you are talking to me, I did. I only have one.
Team Owner
Joined: Jul 2004
Posts: 28,461
Likes: 3,288
From: Hartford WI
Originally Posted by cshuman
As per the Helms manual, you should show 2.5 volts at the ECM connection A11, which I am.
Pro
Joined: Apr 2001
Posts: 744
Likes: 13
From: Lenoir City TN
Originally Posted by aklim
I had that too. Problem was the pin wasn't good and when I touched the DVOM on it, it would register but when it was mated to the KS, it would not make good contact every now and then and trip the code. I came to this conclusion because I replaced it in desperation and guess what, the code disappeared. I was using my scantool to observe and could even see knock counts and what not while the old plug was in the car. That is what made me think initially that the plug was good.
Thanks