So my Camaro recently started running like crap and I found an O2 Code and replaced it. After that the fuel pump went out.

So new fuel pump, new O2, and just replaced the coolant sensor still hesitates a bit but not half as bad.

Im looking at Data through a Snap On Modis and the O2 stays at 447mv and wont move at all, the Coolant seems right and the car wont go into Closed loop. I think my problem lays within the fact it wont go into closed loop.

as far as I know the Coolant Sensor really determines when it hits closed loop but im not totally sure. and the O2 not moving is weird to.

Any input?

Ive seen some cars stay at a certain mv and when the ECM goes into closed loop, the O2 will start switching. May be the case here but I cant figure why it wont go into closed loop.

 

With the O2 sensor sitting at 447 mV, either the sensor is bad, the wire between the sensor and ECM is open, or the ECM is bad.

The O2 value in the ECM at 447 mV is causing it to stay in open loop.

Noticing the TH350 swap, if there are headers on the engine that too can cause O2 sensor issues. The O2 can be staying too cold, and it is also possible that there isn't a ground between the O2 sensor body and the engine block.

RBob.

 

was about to suggest the 4 wire o2 swap. Either that, or the thermostat is stuck open/sticking open not allowing the engine to come up to temp.

 

The temp does come up to 200-220 even then it wont go into closed loop.

The O2 is new so I wouldnt think its bad and I swapped the ECM from my 91 Jimmy into the Camaro and the O2 still reads 447mv

Tomorrow I will run a jumper ground to the O2 its self, and get a pinout for the ecm to see if I have a open wire..

So all in all you think the O2 is the reason it wont go into C/L?

 

well its back to running normal, turned out when I re routed my plug wires I had 2 hooked up wrong.

So now it back to normal but still wont hit closed loop. I checked for good ground at the O2, and the purple wire from the EMC to the O2 is also good.
Any ideas?

ECM says its lean but I can smell its rich

 

RBob, Your the man i need to ask. I have been noticing my car running rougher, down on power, eating up lots more gas,) I decided to datalog it with TTS Datamaster. Looks like i am almost never going into closed loop! For the past six months or so, i have been getting a code 13 , but it goes away within a few minutes too. My blms are low as usual 108- 115 or so. I am suspecting a bad o2 ground maybe? What do you think? I mean if it is not the sensor , then it is either the ground or the ecm right? Coolant temp seems normal, but took the car over 6 minutes to go into closed loop and then it stayed there for less than a minute.What do you think is going on?

 

Tough to say, although it sounds like stock Multec injectors are starting to short the coils or the EGR valve is blocked open with a bit of carbon.

RBob.

 

Figured mine out: bad o2 sensor,replaced it.