V8 is now in but i have a code 43

[Gordon]

Ok so i finally got my 350 installed into my 95 safari van.

Engine is an 88 with tbi injection.
Van is a 95 safari sle.
wiring harness is original to the van
ECU is from a 95 1/2 ton truck.
Transmission is the original 4l60e.

The knock sensor is hooked up (only 1 knock and its original to the 350 engine) but i i am still getting a code 43 (Knock sensor signal was either above 3.5 volts or below 1.5 volts for at least 20 seconds).

Anyone got any ideas how to fix this?
Will it harm anything to drive it with this code?

Thanks, Gordon

[6spd_monte]

I think I read somewhere that the module that the knock sensor talks to is different for the V6 and V8. Did you get the correct module for your V8? I believe it's called the ESC module.

[Gordon]

Not a clue what an ESC is??

[6spd_monte]

Ok I just did a quick Google search and I learned that the separate ESC module (responsible for the knock sensor on my van) was integrated into the ECM in the early 90's. So, to answer my own question, you van probably doesn't even have one!
Look at that, we both learned something today. Unfortunately, I think it did not help you very much.

Let me try again...

Is the knock sensor original to your van or is it from the '88 engine?

[Gordon]

The knock sensor is original to the 88 5.7L engine

Maybe i need the knock sensor from a 95 engine?

[6spd_monte]

I think that's a good start. My Google search also indicated that the knock sensor that works with the ESC module (mine, and probably the '88 as well) is a different part number from the sensor that talks directly to the ECM. Can you get the sensor from the same truck that your ECM came out of?

[Gordon]

Ya thats easy.. buddy of mine has a wrecking yard with super cheap prices.

I'll change that out tomorrow.

[6spd_monte]

Sounds, good. Hopefully this will be an easy fix!

[Gordon]

Looked it up on summitracing... 91-95 is different and so is 96 and up.

Stinkin GM... leave stuff alone.. lol

[v8famvan]

The knock system circuit wire (blue wire) has 5 volts on it from the computer.
The voltage is pulled low (down) by the resistance in the knock sensor.
The computer monitors the voltage that it puts out to diagnose the integrity of the circuit.
This resistance - in the knock sensor - is critical in pulling the voltage down from the output 5 volts down to 2.5 volts.
This resistance must match the resistance inside the computer in order for the voltage to properly drop.

The simple explaination - wrong resistance sensor = Code 43.

[Gordon]

Makes sense to me.

Would this code also cause poor performance?

An engine compression test shows 170-175psi in each cylinder but it just down't have the UMPHH I was expecting over the stock 200hp V6.

Sounds damn cool though

[v8famvan]

Further explaination of code 43...

The knock sensor produces an AC voltage when it detects a knock in the engine.
The computer monitors & uses this AC signal to determine what it should do with the timing.
If the computer is detecting a knock in the engine & retards the timing, power will be adversely affected.