Hey guys, I'm new to Thirdgen.org and I have a question for you guys.

I own a 1988 Camaro with a 305 TBI. I recently completed a head gasket job and while I had the motor apart installed a set of Edelbrock emission legal headers and a flowmaster 80 series exhaust. The car is running very well except for a few things, one of which the electric fan will not start on its own, even with a new sensor so I have to activate it with the air conditioning switch from in the car. The other problem I have is I keep getting a code 43 from the computer every once and a while. I read up on this and it seemed that the problem was the knock sensor. Well I replaced that and driving the car home today got the good ol service engine soon light on again. If I shut down the car and restart it the light goes off and the car seems to run well again becuase when the light comes on the car runs a little rough. This light only comes on when the car is warm, not durring start up.

I'll appreciate any help you guys can offer since I need this vehicle to pass emissions so I can regsiter it. It failed today before I fixed the knock sensor but I think it was because I had a 160 Tstat in the car, which I switched to a 170 later in the day. Lemme know what you guys think could be the problem. Also the timing is turned back almost as far as you would want to go, that is what we thought the trouble was at first.

Thanks guys

 

This code 43 DTC on the TBI's is a common problem. Most of the time it is caused by a failure of the forced knock test. If you backed off the timing this can cause the forced knock to fail. Here are a couple of threads with good code 43 info in them:

https://www.thirdgen.org/techbb2/sho...code+AND+knock
https://www.thirdgen.org/techbb2/sho...code+AND+knock
https://www.thirdgen.org/techbb2/sho...code+AND+knock

RBob.

 

Thank you very much for the info, it is a huge help.

The other problem I have is the timing, my marker has 4 notches where as my hanes manual has 6 on it. I am not sure where zero is. Can anyone give me some insight?

 

We aim to please:

https://www.thirdgen.org/techbb2/sho...ng+AND+picture

See pic of timing tab, this one is from a '85 LG4.

RBob.

 

I love this website lol. I do have another question though. My father is a mechanic by trade, owns his own business and I talked to him about advancing the timing on the car to get rid of the code 43. He said to him it makes no sense if you advance the timing that the knock sensor test will not fail. Maybe if you have the time could you explain to me how advancing the timing will clear this code. We backed the timing off for two reasons, one was my HC was really high on my first emissions test and two to try to clear the knock sensor code. Now that the car passed emissions ( 170 Tstat did the trick ) I plan on advancing the timing anyway, but I just want some clerification why this will clear the code.

( I did replace the knock sensor by the way )

 

The engine has to knock in order for the code 43 test to pass. When lowering the timing, running a colder thermostat and possibly running a higher octane fuel, the test can not get the engine to knock, then code 43 pops up.

The whole test scheme is based on the engine being able to actually detonate. There is a code patch to bypass this portion of the ESC system diagnostics.

RBob.

 

RBOB- After reading some of your old replies, you have left me with more questions regarding code 43. You said there is a patch code to bypass the ESC sys Diagnostics. Now that would be nice. so how do you get the "patch code"? How do you find pin B7 and CKT 439.. I have some tables in Baechtel's TPI book, but they don't make sense- because the number of lines in the tables does not correllate to the number of pins on the socket. This is driving me crazy, because I'm only left to replacing parts. 90 iroc SD swapped to 5.7 "J" motor. I am still trying to solve 12v with key on at the knock sensor socket.