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Right after posting this I realized it is probably for a second o2 sensor after the catalytic converter. But like I said there is only one o2 sensor, so why would I be getting any reading on it?
I got no codes except the old “34” (maf) code that I never cleared. I’m having some minor idle issues.
Just to clarify, my girl friends car was having some major issues. I changed: plugs,wires,distributor cap, rotor,ignition modual,maf,o2 sensor,iac,manifold temp sensor,fuel pressure regulator, plenum gaskets,air filters,oil,oil filter,engine and trans mounts,struts,brakes,wheel bearings. I also adjusted the tps. I was loosing vacuum through the climate control, but that has been fixed. And just to answer what you are probably wondering, I was not just throwing parts at it. ALL of this was needed.
The idle (when it is up to operating temp) fluctuates a bit (about 300 rpm). I still need to adjust the timing and I have a feeling the timing chain needs to be replaced.
ANYHOO, I was just wondering why this o2cc thing showed up. I’m not really good with these new fangled computer things.
[quote=”thisisbuod” post=41617]1987 iroc 5.7 multiport fuel injection about 150,000 miles. Just ran codes on it (obd1) and had a question. along with all the other sensors, there was something that said o2cc. It was fluctuating between 0 and 2. What is that? The car only has 1 o2 sensor and the specs for that were under “o2”.[/quote]
O2cc is a useless piece of data. IT stands for O2 cross counts. This would be the number of times the O2 crosses the 450mv set point. The idea with this data parameter was to give you an idea of how well the O2 is switching from rich to lean. The problem with this parameter is the amplitude of the O2 signal can be very poor (bad sensor) and still have a good cross count reading.
So again, ignore it, it is a completely useless piece of information[quote=”ScannerDanner” post=41658][quote=”thisisbuod” post=41617]1987 iroc 5.7 multiport fuel injection about 150,000 miles. Just ran codes on it (obd1) and had a question. along with all the other sensors, there was something that said o2cc. It was fluctuating between 0 and 2. What is that? The car only has 1 o2 sensor and the specs for that were under “o2”.[/quote]
O2cc is a useless piece of data. IT stands for O2 cross counts. This would be the number of times the O2 crosses the 450mv set point. The idea with this data parameter was to give you an idea of how well the O2 is switching from rich to lean. The problem with this parameter is the amplitude of the O2 signal can be very poor (bad sensor) and still have a good cross count reading.
So again, ignore it, it is a completely useless piece of information[/quote]Wow, I’ve never heard of that haha. Thanks ScannerDanner!
If my scan tool is showing me that most everything is working normal but the car has small issues could it be that the computer in the car is bad? Cause I have changed damn near everything else in it and I still have this slight idle issue and the thing runs like crap until it starts warming up.
[quote=”thisisbuod” post=42057]If my scan tool is showing me that most everything is working normal but the car has small issues could it be that the computer in the car is bad? Cause I have changed damn near everything else in it and I still have this slight idle issue and the thing runs like crap until it starts warming up.[/quote]
while these early gms had computer issues. the symptoms you describe is not one of them. another VERY common problem on this engine is shorted injectors. it is so common that anytime i have a running problem on one of these it is the first place i start.
a scope is the best way to identify this condition but on ohmmeter test on the injectors is the next best thing. these injectors should be 12.6 ohms each. check your resistance on each and let me know.[quote=”ScannerDanner” post=41658][quote=”thisisbuod” post=41617]1987 iroc 5.7 multiport fuel injection about 150,000 miles. Just ran codes on it (obd1) and had a question. along with all the other sensors, there was something that said o2cc. It was fluctuating between 0 and 2. What is that? The car only has 1 o2 sensor and the specs for that were under “o2”.[/quote]
O2cc is a useless piece of data. IT stands for O2 cross counts. This would be the number of times the O2 crosses the 450mv set point. The idea with this data parameter was to give you an idea of how well the O2 is switching from rich to lean. The problem with this parameter is the amplitude of the O2 signal can be very poor (bad sensor) and still have a good cross count reading.
So again, ignore it, it is a completely useless piece of information[/quote]It’s awesome having ScannerDanner here. If I’m not mistaken this was the precursor to fuel trim readings?
That said your fluctuating idle may be the result of your TPS adjustment, if that wasn’t adjusted correctly it can cause idle problems. I’d also recommend you check for vacuum leaks (particularly at the intake gaskets) as that can also contribute to an idle problem.
Checked for intake leaks already. I even checked the snorkle hose. I was losing vacuum through the climate control, but I have fixed that. Checked the replacement o2 sensor and it’s fine. My code reader and multimeter both say the tps is at 0.54 volts when closed and smoothly goes up to 4.2 volts at wot. So that is with in spec. I think it is probably spark timing. So when I have some free time I’ll get a timing gun. I’m pretty sure the timing is set somewhere around 12 degrees. I also intend to change the timing chain sometime in the spring.
You may have to disable the computers connection to the timing when you set it. Be sure to follow factory procedure. While you’re at it you might check for timing chain slack. You can do this by removing the distributor cap and observing the rotor while you turn the engine clockwise. When the rotor starts to move, stop and turn the engine in the opposite direction. If it takes more than 7º of crank shaft rotation before the rotor starts to move then you have excessive slack in the timing chain. Those old engines used a nylon coating on the timing gears that would wear out and cause this excess slack.
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