A 43 is an indicator of engine knock being detected.
To attempt to cure the problem, the computer dials back the timing.
Yes, it can be a faulty sensor; but many times a senor that is doing its job gets blamed.
What I'm saying is perhaps you really have an engine knock.

Have you checked the timing?

 

Well drive it, it's not gonna blow your engine up as soon as the light comes on.

I'd run some carb cleaner down the throttle body with the throttle open, might be carbon build up...
empty the can, heck buy a few cans.. Check the timing and vacuum leaks...Maybe use some of the carb cleaner to check for the vacuum leaks. Inspect the injectors... I don't know what else to point at.. I know my engine in a 94 knocked 2 degrees advanced...

Sent from my SM-S908U using Tapatalk

 

I haven't yet checked the timing. There is no audible knocking that I can hear.

 

You don't have to hear it, the knock sensor does lol...

Sent from my SM-S908U using Tapatalk

 

right... LOL

 

If you hear the knock driving down the road then you have a real problem.. Knock sensors are delicate...
Do you have a gutted cat, headers, aftermarket cam?..
Have you done anything in the last year to the vehicle...Getting a feel if you can feel me lol...

Sent from my SM-S908U using Tapatalk

 

I had a knock sensor code on a 94 and changed it to no success. .. I did a complete tune up around that time and some of the TBI "mods"... I mean I did tons. Ignition, spark plugs, head gasket, comp cam, pcv, map sensor, EGR, tons more. If autozone had it I bought it. I was starting to travel for construction and did just about everything I could except all new engine. All to make sure that truck kept the money flowing.

Sent from my SM-S908U using Tapatalk

 

I have done nothing new in about 4 years when I changed out the O2 sensors and a few other things I can't remember. LOL. It isn't mt daily driver and it has 328,000 miles on it, but I still would take it cross country if I needed to.

 

Then run some carb cleaner in, check for vaccum leaks and timing. I'd definitely start there.

328k miles???

Just curious...What's your cold and warm oil pressure at idle?

Sent from my SM-S908U using Tapatalk

 

How long do you take to run a tank of gas through it? Highly unlikely, but don't used old gas while diagnosing an engine problem
..

Sent from my SM-S908U using Tapatalk

 

Not sure what the oil pressure is, I haven't driven it in a min. The gas is about 3 weeks old.

 

Have you changed your Electronic Spark Control Module, (Not to be confused with Ignition Control Module) or look at the wire from the knock sensor wire going to it? Not a cheap part so I'd look for wiring damage. I'm not certain if it's open or close that triggers the code/timing retard. Don't forget about the coolant temp sensor by the thermostat housing....I think that guy causes code 43 too... I've changed those more than Ignition Controlodules, and ICM's fail a lot...

Sent from my SM-S908U using Tapatalk

 

Well, I was going to suggest you check the belt tensioner, I know it sounds off the wall, but would potentially set a code regardless of the temperature. With those miles, which is very impressive by the way, you could also very well be getting some main bearing or rod knock that is almost imperceptible to your ears. The knock sensors are quite sensitive, so any unusual noise or tapping around or on the block could easily do it. Also, a sloppy timing chain might do it as well. Everything, even very well maintained vehicles, as yours must be, eventually wear out parts.

 

Thanks for the advice so far, I'm busy with work over the next few days then I will try additional troubleshooting steps. I haven't tried the ESC, nor checked the wire higher up after the pigtail that I changed out already. I initially had seen something posted somewhere (YOUTUBE I think) about the coolant temp sensor but on deeper research, couldn't really find any other references.

 

Collant temp sensor can make you run warm up rich after warm up.

Not sure it would cause 43, but who knows...

Sent from my SM-S908U using Tapatalk

 

OK, So I took a chance and changed out the coolant temp sensor with no luck. Didn't fix it, but it wasn't over $20. Cold oil pressure is about 50 lbs and goes to about 25 when warm. Next step is to check the timing on my next day off I think.

 

I know my 94 had a temp sensor and temp switch. one for gauge, one for computer I believe???? I agree though, check the timing before spending any more money. And if anyone knows what the two sensors do please buzz in.. Clearly one is for gauge, but what does the other do?

Sent from my SM-S908U using Tapatalk

 

So, I checked the timing today and it was dead on TDC which is what the Haynes manual said it was supposed to be. So, that avenue is closed. Reading the Haynes manual was cluing me in to the Electronic Spark Control so I decided to just change it because it was still less that taking it to the shop. Took the part home, popped the hood, removed the air cleaner and no ESC in the location it was supposed to be. WTF? LOL

 

I know this is old by now, but wanted to give an update. After changing the parts listed I took a chance on a computer from the wrecking yard, that one did the exact same thing so I took it back and swapped it for another, even though they don't take returns, Since I buy from there now and then they swapped it out. It was $50 and neither one worked. I finally relented and took it to the dealer. The dealer changed out the brand new knock sensor (said it was grounded internally) and the pigtail (said it was covered in oil and shorted out) and then they changed out the computer which they said was shorted internally also. It took 3 months to get the part in because of the supply backlog. But... That was what fixed it. Only cost me $1,000. You live you learn I guess.So, my pain can be your gain. Good luck!

 

Thanks for the update spyder