I have a 92 Camaro RS 305 tbi. I have done many mods with the car running fine after each one. A while back I installed some Hedman Shorties on it and just unplugged the O2 and sat it to the side until I could get a bung welded on later. Of course it runs rich for this period of time because the ecm is getting a lean signal. So the time comes to weld a bung on and I go buy a new O2 and install it. So its running fine for a while and then I notice something when im at idle. It feels almost like a miss or a slight hesitation. Now, a month later, it is so bad that my car is dieing at lights and im running rich, really rich. Im going through tanks like crazy. BTW, I already rebuilt the TBI unit with new gasket and o ring kit, cleaned the IAC like everyone said to and checked my MAP, TPS and a number of other things. What is going on??!! Any help would be appreciated.

 

Did you reinstall the o2 sensor properly ?

Jut go buy an other one ..

 

More to the point, is the rich condition continuous or only when you go into closed loop?

 

Its more in closed loop that it goes rich and the problem occurs

 

Well first thing is, do you still have that little miss? Have you checked the plugs (also try at night when you'd see and arcing boot better). If you do have the miss/hesitation/tick I'd take a WAG at you misfiring on a cylinder. Double check the firing order, cap/rotor etc.?

 

I have chacked the cap and rotor and even though they are less than a couple years old. They look really clean. and the wire seemed ok too. I just put new plugs in it last week. I had it idling the other night and didnt see any sparks.

 

It idles at 600 like its supposed to, then it drops to around 300 or 400 and comes back suddenly. It used to just die occasionally but now its getting worse. It dies at almost every light.

 

When I replaced my plugs with Bosch platinum 2's , I didn't tighten one enough all the way and it was missing a spark occassionally. Enough to make my car cough , Might want to just do a quick run around with a 5/8's and make sure all of them are tight and make sure all the plug caps are 'clicked' on securly.

Another possibility is since it was running so rich and dumping so much fuel down the cylinders , you may have fuel in your oil and it's causing a weird firing or something to that effect. Change your oil , do the plugs and then check her out. The 305's are crap. Get a 350 and drop it in there =D

 

What type/kind O2 sensor did you get? To test O2 sensors, you can heat them up with a propane torch and measure the voltage with a multi-meter. Apply heat and see how rapidly the voltage changes, it should change pretty quickly. Then take the heat off and see how fast the voltage drops. Again it should change pretty quickly.

 

It was a bosch O2 sensor. I read in another post that these werent worth a dime. Is that right? Should I get another one?
And if I do does anyone think it will honestly fix my problem?

BTW, I've been reading up on some stuff and I've datalogged my car and it gives me quite a bit of knock counts. If my timing chain is causing enough knock counts, would that retard the timing enough to cause my problem? It does and always has rattled quite a bit.

 

your knocks might be caused by the fuel contaminating your oil... doubtful, but if it's severe enough.... yes, your knock sensor could be retarding your timing enough to the point that it kills the car.

 

You also said you installed shorty headers, so the O2 sensor is probably farther down the exhaust than the factory location. This will frequently cause a one wire O2 sensor to run too cool and you could be going into open loop while idling (back to the very rich condition and the engine could be flooding out).Have you data logged it to see if it's going back into open loop at idle?

If so, you might want to consider doing what most of us with ehaders have done - convert over to a 3 wire heated O2 sensor (Delco AFS-74). Simple to do - hook the one differently colored wire to the current harnes O2 wire, run the other two wires to ground for one and a key on power for the other. Works like a champ.

FWIW - I too prefer the Delco O2 sensors, the Bosch seem pretty unreliable to me. Unfortunately, they cost more.

 

Ok, Thanks vernw. I will think I will give this a shot. Someone also said that maybe a universal heated sensor would work better. What does everyone think?

 

OK, so I put a heated sensor on and reset the computer and its not dieing anymore but still kinda drops the rpm's. Is this gonna settle out since I just reset the comp. or is something still wrong?

 

Drive it a day or two for the ecu to "relearn" and see how it does then.....

 

Alright, it started stumbling again and I got to thinkin how this never happened before I plugged the O2 in so I just unplugged it to see what happened. Again, it runs a lot better at idle but, it is stuck in open loop and still has a very very slight stumble every so often. Again its not near as often or bad as when the O2 is plugged in. SO what does this mean? Whether the O2 is in or not WinALDL says its running rich. I dont get it.

 

Check all sensors that come into effect after the car warms up. Might wanna try your Coolant Temperature Sensor, I know that mine was brittle and basically fell apart in my hand when I was replacing it.