Have 1991 Z-28 and all of a sudden it has no power at all I read the codes and it came out with a 43 that says low voltage at electronic spark timing circuit. Does this mean the computer is bad or exactly were is this thing. Please help email me at timothyberlinski@yahoo.com Thanks guys.

 

code 43 has to do with the knock sensor, it very well can cause a low power problem as the timing will stay at the base setting. what normaly sets that code is the connector has came off the sensor or the sensor wire could also have gotten against the exhaust & is grounding out.
the knock sensor is down near the starter in the block between the starter & crossmemeber. it's the thing that is always in the way when you need to remove the starter. its common for either the sensor connector, the sensor or both to get damaged when replacing the starter.

i know Trickster has posted up a trouble tree for checking it out.
a search here should turn it up.

 

I know where it is but my question is how do you test it. My haynes manual says normally it sends 8-10 volts to the ecm and when a knock is detected it shuts off. But then it says the opposite in the testing. If it is good with the key in the on position how much voltage or whatever measurement should it be putting out? Thanks.

 

If you have the TPI engine in your car, there is not an Electronic Spark Control module in your car. There is only a dark blue wire running from knock sensor to pin "F9" of the ECM. I will post the troubleshooting chart for it later.

 

Yeah i got that wire but I can't find what voltage is supposed to be there. The haynes says if no knock is detected then 8-10 volts. But that does not seem right. Thanks.

 

Oh yeah the problem seems to have just went away. I'm thinking maybe loose ground somewhere, if the knock sensor is going bad could it be intermitant like that or would it just take a crap?

 

Hello Pave Tim,

Perhaps this will be of a little more use than your Haynes manual.

 

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