Craq

Getting a Code 43. I haven't gone through the diagnosis yet but I've got a couple of simple questions first:

Does the coolant need to be drained to remove sensor? One (non-factory) book says it does; my factory manual says nothing about it.

Second: Can/should I buy LT4 sensors? The non-factory book indicates they're an improvment.

aboatguy

If you're quick you can remove and replace the knock sensors without losing much coolant.

As for the LT4 sensors I'd stick with the LT1 sensors unless swapping to the LT4 knock module, but that's just my opinion.

VenkmanP

The OBD2 sensors (there is no such thing as an LT4 KS) will not work correctly with an OBD1 PCM whether you have an LT4 KM or not.

And he has a 92, so talking of the LT4KM is just silly.

aboatguy

Vic, I didn't say he could swap to a LT4KM and if it seemed that I did I guess I need to write more clearly. I knew that the LT4 KM only fits 94+ but your info about the LT4 KS not working with the LT4 KM on a OBDI car that is info I did not know; but then again, I've never considered a LT4KM swap.

But I have replaced a KS without draining the coolant
MIke

Craq

As it turns out, I didn't have to do either. I got under the car to check volts and ohms, and everything checked. So I cleaned up the connections and that fixed the problem.

Here's an "undocumented feature" that isn't in the factory manual ('92 anyway). If there's a problem with that circiut, both cooling fans run, a failsafe mode I guess. The manual indicates that this will occur with a coolant or oil temp sensing circuit code, but it's with this issue too.

Time to get cleaned up and go for a drive. :cheers

JAKE

Yep, that's the way I'd deal with it too.

Jake

Craq

Certainly running great now. The fault must have dialed back the timing, another failsafe feature, I hadn't realized the performance loss until I just drove it with it fixed.

...it's back in "most favored" status again.

SkyKohl

I have the same problem (Code 43), which is as a result of trying to remove the knock sensor while draining the coolant. I probably ruined the sensor because I could not budge it with a 23MM socket.

Can anyone reccomend a tool/socket/wrench for removing this sensor? I understand it also needs the specific torque setting or else code 43 will come up.

Considering the pain to remove/replace and torque, you are probably better off leaving the sensors alone, and draining coolant from the radiator and hose connections.