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code 43?

jpdrake

jpdrake

1/2 ton status
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Oct 31, 2005
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mass/ cape cod
im very limited in my tbi know how. ive just rebuild my 88 350tbi. <new egr valve, new knock sensor, new o2.> got it registed today threw the plates on took the top off and went for a ride in it for the first time in over a year. it just dosnt have that crisp throtle responce, runs real rough from idle to 1200rpm. can i get some help? i need to pass MA emisions by next fri.
 
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From chevythunder.com

Code 43- This code is related to problems with the esc system. The code is usually set when there is a voltage detection of the wire going to the esc module to the ecm pin B7. The code will set whenever the engine is first started, and the ecm checks the function of the esc. Also once engine operating temperature is reached and the throttle is nearly open, the ecm will advance the timing until pinging is heard and then back off the timing. If the ecm does not detect the knock sensor operating, it will also set a code.
 
now i did unplug the brown wire with the black strip under my brake booster.
will that effect code 43?
 
Unplugging that wire (timing bypass) will always throw a code 42. Not 43. The code will stay stored in the ecm untill it is cleared. If the wire is still disconnected you need to connect it. You will get no timing advance with it disconnected.
Are you using a scanner to read the codes or counting the CEL flashes?
If counting the flashes maby you counted wrong.
Un plug the -Batt cable for a few minutes to clear all trouble codes.
Then take it for a drive, check codes, see what comes up and let us know
 
im counting flashes. i know its code 43 i didint know if the timing bypass would affect it. im basically looking for a direction to head towards, should i be looking for something or replacing more parts. ive been looking up previous threeds to find the same ?s with now answers.
 
The thing i dont understand is if you unplugged the bypas wire you should be getting a code 42 along with the 43 Unless you cleared the 42 after you unplugged the bypass wire.
As for the code 43 here are the main things that can go wrong with a code 43: Poor electrical connection, open or short in circuit; defective ESC module; defective knock sensor; defective ECM". The ESC module is the square thin box on the right side front of the TB with no vacuum line going to it. Check your connection there.

If your truck sat for a year. Did you put fresh gas in it? old gas will make it run very bad.
 
yup ran it down to empty and put fresh gas in. 42 is clear, all i get is 12 and 43 esc(electronic spark control) "check the wires from the ESC moduale to the ECM. check the wires from the knock sensor <that was replaced> to the ESC module. Check for loose connection. replace knock sensoe or ESC module"
now is a knock sensor the same as ESC senor? 2 names same part? should my next step be a new ESC module?
 
You've actually verified the other wires are good, right?

no not yet ive been busy watching the red sox

from what i gather is there are 3 parts the knock sensor <cheapest> the ESC module <$75> and the ECM <im betting very expensive>

what do i need to check for wires? the wire to the knock sensor, i dont know what wires in the harness at the ESC or ECM should read?
 
Did you use thread sealant when you installed the new knock sensor?
If you did that may be your problem. you should not use thread sealant or teflon tape on any sensor because it will not let the right voltage go to ground. Unless it is a special Dielectric sealant.
 
Knock sensors I believe are not part of the thread sealer problem group.

They generate voltage on their own based on knock, and don't use the block as anything other than a mounting point. You might serve to deaden the sensor a bit, but GM did that themselves.

The new Delco knock sensors I've got for the gen 1 SBC's have thread sealant already applied to them.

For wiring, you need to check that none of them are shorted to ground, don't have continuity, or have power when they shouldn't. Also looking to see that the terminals in the connectors are seated correctly, not broken, and providing good contact. The GM manual pages in the link I posted previous show the wire color/number/connector pinout at the various components.
 
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