We did the race style hooker lt's. Bloked the egr. Programed out the egr.

Now my abs light is on, abs works, 3rd brake light wokrs.

SES is on. Code 16, 23, 43. Once car goes into closed loop the o2's stay .900mv + It acts like a short somewhere because sometimes the light goes off and the air/fuel acts like its in closed loop again.

Code 16: Opti - I know its not this, car runs too well.
Code 23: MAT - I had a second IAT, swapped and no help.
Code 43: Knock sensor circuit. The wire looks good on the sensor but other than that I suppose they can go bad... Logging reads about the normal level of knock retard though.

Car runs and pulls fine. No misses except at idle it will bog down sometimes because its so rich. Does not happen in open loop, seems to be worse when fans are on. It does this off and on going down the highway. 30secs good, 30 secs bad. It is not really a specific amount of time just bounces back and forth.

Anyone seen anything similar? I am just trying to figure out where to start.

 

I had similar problems... the wires on my car going to the O2 sensors and crank sensor were melted because they go down near the headers... I just had them replaced and covered in thermal wrap and everything is fine. Look from under the car and see if the wiring going to any of those are melted. My #10 fuse would pop 96 but i have OBDI computer... My MAF sensor would throw a code and my air flow on freescan was stuck at a high # and it would run on speed density.

 

Ill do a pretty thorough check again later. I checked wires yesterday. I did make my own extensions but they were all ok. The harness that goes down the pass side fender was touching a primary but I could not feel any holes.. .guess I need to look there some more.

 

I went and messed with it again. Double checked the harness. It has a burn spot on the outer plastic but all the wires seem ok.

It only does it when the fans are on. They kick on, ses comes on, they go off the light goes off. I could program the fans to a higher speed... but thats counterproductive too.

 

The ks showed 4k ohm and had 4.8V feeding it. So I dont think thats it. But it showed the same symptoms when running with the ks unplugged.

Could it be the module? Guess its time for a lt4 one... This sucks.

 

the fans are coming on because of the SES, not the other way around.

sounds to me like you burned the wires in the harness on the passenger side that goes by the header. btw i have found that if you have a knock sensor circuit problem, the PCM will make the car run very rich

 

Ill go start testing all the wires individually, but I am getting the correct voltage so I don't think its grounding out or anything...

 

if the wires are ok then i would definitly change the knock sensor. i have had a couple of them go bad and cause the knock sensor circuit code to come up. at the same time the cars this happened on were running very rich, especially at WOT despite me trying to lean them out through programming (programming had no effect on the WOT a/f readings). found out after replacing the knock sensors, that the PCM must add a lot of fuel when it sees the knock sensor circuit code, because after installing the new sensors and eliminating that code, they were no longer running rich and programming affected the A/F ratio like it should once again

 

Thanks... I just unwrapped the wires all the way back to the compter. Visually they all look good and they all showed good continuity (sp). I am going to reroute them just to be safe though.

Im checking locally to see if anyone will let me borrow theres for a sec to see if that fixes it, but I was wanting an lt4 anyway and its cheep. Guess Ill order one.

Heres to hoping...

Oh ya, after clearing the codes only the knock circuit comes back.

 

i was talking about replacing the knock sensor in the block, not the knock module in the pcm that many people replace with an LT4 knock module

 

Well thats cheap too,,, I guess I am walking to the parts store

 

yes they are cheap, just a bit of a PITA since you need to drain the cooling system, and you will still have a lot of coolant come out when you pull the old knock sensor out

make sure you get the correct year knock sensor, since the 96-7 OBD2 knock sensors are not the same as the 93-5 OBD1 sensors

 

They had to order it for me. Will be in tonight. I ordered an lt4 km also, it will be here next week.

Wires were perfect. I wrapped them back up with new loom and some heat reflective tape and moved them about an inch farther from the headers. Should be safe.

Ill post up when everything is done, and thanks again.

 

I would be interested to hear what happens too. My car is throwing the same code. Knock Sensor Circuit Low Voltage and also Intermitent Voltage. Don't really want to change it, but if I have to and it fixes the problem I am all for it. Let us know.

Thanks,
Anthony

 

Do all the tests that shoebox gives. I just got the sensor and will put it in tomorrow morning. My sensor did test good on the ohms though @ 3800. Mine is intermittent also though.