91 Jimmy code 43

[slacker2620]

Hi all,


I hope someone here can help me. I have a 91 Jimmy that has had the engine replaced. It is a TBI 350 with about 9000 miles on it. Ever since I bought it it has thrown a code 43 when under load, heavy acceleration, or when shifting gears. I have checked the fuel pressure ( 11 psi ), replaced the knock sensor, knock sensor wire, ESC module, Plugs, cap, rotor, wires, distributor, fuel filter, set the base timing at 0, 2, 4, 6, degrees advanced with the plug disconnected. Still no relief from this code 43 . I have replaced the ECM with 2 known good ones. One from a 90 suburban 2 wheel drive, and one other from a 93 1/2 ton 4x4 truck. I have checked continuity from the ESC module to the B7 pin on the ECM and it is good. The ground at the ESC module is good, and it is receiving 12 volts. Wire going to the ECM is at 9 to 10 volts. But I cannot get the voltage at the knock sensor connector to read anything at all. I am now considering that the timing gear could possibly be one tooth or so out of correct setting. Sorry for such a long post, but I wanted to give as much info as possible.


Thanks, Slacker2620

 

[primergray4x4]

The G.M. code scanner book that I have says "electronic spark timing(EST)circuit-low voltage detected. Or Electronicspark contrl(ESC)-circuit problems." Good luck with it these things can be a real pain in the a$$ to trouble shoot.

 

[slacker2620]

Thanks for the reply,

Tell me about being a pain in the a$$. I have been all over the books and troubleshooting flow charts and they all say there should be 4 to 6 volts on the wire going to the knock sensor. However, I have tested both my 2 wheel drive suburban, and my 2 wheel drive 89 truck with a 305 and neither one have voltage to the knock sensor and both have no codes. This thing is drivin me crazy. To add more to the mix I had the catalytic converter tested and it is fine, also put a rebuilt TBI unit on it. Whenever this thing gets fixed I should be good for 200,000 miles cause everything is new!