85 corvette knock problem
Thread Starter
Instructor
Joined: Apr 2012
Posts: 115
Likes: 0
85 corvette knock problem
Hey guys, I have a 1985 corvette with a bit of a pardiciment. The engine was rebuilt about 5 months ago(I didn't have the time or space to do it my self) so I had a shop do it 
and the said they put a high lift rv cam in it. It sounded cool until I broke in the engine and started wot runs I got a check engine light a code 43. So I replaced the knock sensor myself to my surprise when I pulled out the sensor no coolent came out and the hole was painted over. So new knock sensor and all I still get a code 43 so I start thinking it's timing so I adjusted it by ear(I don't have a timing light) after 3 try's still a code 43. So I go to the shop that did it(suspecting it was the cam swap) and they say and I qoute "we don't know the specs on the cam in there we can't help you" as you can imagine I was pissed but I don't know what could cause the code.
P.s the light only goes on over 185 degrees after an acceleration run and I don't hear a ping/knock
Thanks for the help in advance
and the said they put a high lift rv cam in it. It sounded cool until I broke in the engine and started wot runs I got a check engine light a code 43. So I replaced the knock sensor myself to my surprise when I pulled out the sensor no coolent came out and the hole was painted over. So new knock sensor and all I still get a code 43 so I start thinking it's timing so I adjusted it by ear(I don't have a timing light) after 3 try's still a code 43. So I go to the shop that did it(suspecting it was the cam swap) and they say and I qoute "we don't know the specs on the cam in there we can't help you" as you can imagine I was pissed but I don't know what could cause the code. P.s the light only goes on over 185 degrees after an acceleration run and I don't hear a ping/knock
Thanks for the help in advance
Race Director
Joined: Aug 2007
Posts: 11,889
Likes: 8
From: Whitefish Falls Ontario
St. Jude Donor '08-'09
Thread Starter
Instructor
Joined: Apr 2012
Posts: 115
Likes: 0
Melting Slicks
Joined: Feb 2005
Posts: 2,057
Likes: 5
From: Bay Shore, NY
I would just have the builder give me the part number and manufacturer of the cam and then I'd look it up myself. If you can get that information, I am sure someone here can compare that cam with what was in your engine originally.
Definitely get yourself a timing light and make sure the timing is set properly (if its an automatic, set the timing in Drive, parking brake on, DST connector disconnected). Because you don't know what cam is in there, I would start with the stock baseline timing (6 degrees BTDC I think) and go from there.
The explanation I have for code 43 is as follows:
The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194° F or the knock signal was present for 5 seconds or more during normal engine operation.
or
The ECM did not detect a knock signal during near wide open throttle operation, or the knock sensor voltage was above 3.62 volts or below 1.44 volts for 0.5 seconds.
This maybe a voltage problem to the sensor instead of anything having to do with the cam.
Definitely get yourself a timing light and make sure the timing is set properly (if its an automatic, set the timing in Drive, parking brake on, DST connector disconnected). Because you don't know what cam is in there, I would start with the stock baseline timing (6 degrees BTDC I think) and go from there.
The explanation I have for code 43 is as follows:
The ECM did not detect a knock signal during near wide open throttle operation with coolant temperature above 194° F or the knock signal was present for 5 seconds or more during normal engine operation.
or
The ECM did not detect a knock signal during near wide open throttle operation, or the knock sensor voltage was above 3.62 volts or below 1.44 volts for 0.5 seconds.
This maybe a voltage problem to the sensor instead of anything having to do with the cam.
