Code 43

[Bmartin]

I have a 93 k1500 Silverado with a code 43 and I can't figure it out I need help it lopes at idle and when u come to a stop and my temp gauge does not get past the 1/4 mark never close to 210 I put new sensors in a knock sensor and connector new distributor can someone PLEASE HELP ME

[ChevyTech]

Welcome to the board!

One thing that could be causing all the problems is a thermostat that is bad so the engine never gets up to operating temp. If this is the problem the truck will run rich a lope at idle, the code 43 will set because during the knock sensor test, the truck can't produce a ping, when the engine is so cold it will not ping no matter how far the computer advances the timing.

I would test the actual engine temp using a infrared thermometer on the intake right at the thermostat.

I would also test the ohm reading of the coolant sensor by the thermostat and test it against the spec.

Coolant specs can be found here:
http://67-72chevytrucks.com/vboard/s...d.php?t=322811

[Bmartin]

Thank you so much for your reply I will try that tomorrow and let you know didn't think about the Thermastat being stuck open feel like a dumb a**

[ChevyTech]

You're welcome.

If it is running at the correct temp consider the possibility they sold you the wrong knock sensor. This has been a big problem lately.

You could also try clearing the code 43 and pay attention to when it gets set.

If the knock sensor is not connected they set a code within a minute of start up. To much Teflon tape on the knock sensor threads can also cause this.

If it sets the code when you are trying to pass someone on the highway, it is from high knock counts. This is from pinging or something the system detects as pinging (rattling or knocking parts).

If it sets the code as the engine warms up the system is failing a self test it runs in which it advances the timing expecting to see knock counts from the knock sensor

[Bmartin]

Now that temp is right it set code right after I start it and it hooked up and I'm getting my voltage at computer and knock sensor I can hit the block and I get ac volts from the sensor and it lopes real bad when it's doing it at start up worse if it's cool outside

[ChevyTech]

When you replaced the knock sensor connector, how did you splice the wires?
Solder, crimp connectors, twisted wire & black tape?

When you replaced the distributor how did you set the timing?
Did you use a timing light?
Did you unplug the set timing wire when you were setting the timing?
Where did you set the timing?

[Bmartin]

Yes sir I did set it with timing light with the wire unplugged and the knock sensor connector I crimped it

[Bmartin]

I set timing at zero

[ChevyTech]

Test the resistance between the engine block and the terminal of the knock sensor.

Knock sensor resistance
1993 fuel & emission – 4l60e with 4.3, 5.0, 5.7 – 3900 ohms


Also let me know which engine & transmission your truck has.

[Bmartin]

350 with a 4l60e and I ohms it to battery and block it was good

[ChevyTech]

Test the voltage on the wire to the knock sensor with everything connected and the engine idling.

Let me know what you find.

[Bmartin]

Sorry it's taken me so long my chickens went out and I didn't have time to mess with it but my volts at sensor is 4.823

[ChevyTech]

There is the problem.

That is the full voltage being sent out by the computer.

The wire is not getting a good connection to the knock sensor, or the splice is bad.

If the connections were good the voltage should read about 2.5 volts.

This voltage test should have been done with the wire CONNECTED to the knock sensor, testing the voltage on the wire.

[Bmartin]

Ok so I need to replace the whole wire to the computer is that very hard

[ChevyTech]

My first guess is the problem is at the splice where you put the new knock sensor connector on.

It really should be soldered.

[Bmartin]

Ok but I had 5 volts on it before I replaced the connector I thought that was what it was suppost to have on it 5 volts

[ChevyTech]

Near 5 volts on the wire with it UNPLUGGED from the knock sensor

About 2.5 volts ON the wire with the wire PLUGGED ONTO the knock sensor.

[Bmartin]

I'm back probing the connector with it idling and that what I got was 4.8 volts and with the old connector on there it read the same so does that mean I got a bad wire to the computer

[ChevyTech]

What connector are you back probing?
Are you leaving EVERYTHING connect while you do this including the knock sensor?

Try to be way more specific.

If you are probing the knock sensor wire, near the knock sensor, with everything connected and getting 4.8 volts then
-The knock sensor connector in not making connection with the knock sensor,
-The knock sensor base is not making connection with the block,
-Or the knock sensor is much higher resistance then it should be.

[Bmartin]

Thank you so much for your time and help it was the knock sensor never would have thought it when it was new

[ChevyTech]

You're welcome.

I am not surprised the new sensor was bad.

The quality of replacement parts is terrible.

Big names in the parts business that were though of a high quality USA made parts years ago are now sourcing parts from outside the US boarders.

I jokingly tell people it is because the kid making the part in China was distracted because he needed a restroom break and was not allowed to take one for another ½ hour.

So many new parts are bad out of the box that you may add more problems by replacing parts then you fix. Scrutinize every part you buy. Don't try to fix something by replacing parts to see if it fixes it. Test, test, test, and then replace bad parts only.

Testing skills have become much more important then the ability to change parts.

[Bmartin]

Thank you very much you made me alot more wiser on that side of things means alot