How to tell if my O2 sensor wire is working??

[Prelude Guy]

Hey all,

I think my O2 wire is bad. I am having VERY bad hesitation.

I changed the O2 sensor but I did not notice a difference. However, if I unplug the O2 sensor while the car is running, I don't notice a diffence in in performance. I don't get a CEL either when I unplug it.

I took a volt meter and grounded the wire on the battery and touched the positive terminal on the connection pointed on the O2 sensor. No voltage was present.

Am I doing something wrong?? How can I tell if the O2 wire is working properly??

Here is what I posted about my bogging issue before;

"My idle is rough. If I hit the gas pedal 15% of the way down, the car will rev fine. However, if I push it down further-full throttle, the car bogs. I can hear the intake sucking in air. Also, sometimes lightly pushing the gas pedal doesn't work. It will bog then too. I stalled out in an intersection when I went to test drive the car again.

Another thing to note, when the car stalls out, I have to crank it over for a good 20-25 seconds before it will start to sound like it is about to start. I have to continue cranking and then it will start.

I have stood over the engine bay while the car is running. I unplugged the MAF and the car immediately stalled out. I guess that means it works.

I have changed the O2 sensor (The tip that inserts into the header was small and all black), fuel filter (300ZX TT), spark plugs(gap was0.050), wires, distribution cap (In pretty bad shape. Corrodid), and rotor(corrodid). I even have a fresh tank of 93 octane."

Thanks,

Andy

[s13sr20chris]

o2 sensor will not typically cause major probs. it is just for minor fuel trim. if you stand on the gas will it rev all the way up? try wiggleing your coolant temp sensor and see if it changes anything. is the car running rich?

[Prelude Guy]

Wow, I wish I posted here in the tech section sooner. VERY quick response.

Ok, at idle (700rpms) if I push the pedal down less than 15% of the way down, the rpms will rise, yet still kind of hesitate. However, if I go beyone this the car will not rev higher. The revs will stay between 500and 1000rpms, jumping up and down. I have to lift off of the gas pedal and then the rpms will rise.

Now, if I slowly rev up the car to about 1400 rpms...if I push the gas pedal to the floor, the car will bog, but the rpms will rise to redline. You can tell that the car is not running well as the rpms rise.

If I drive the car, taking off, I have to keep the rpms above 1000 rpms to take off. However, if I push down on the accelerator more, the car bogs even worse.

When I push on the gas pedal while idling, I can hear the intake sucking in air pretty hard.

I do not see any smoke or smell anything odd as I am revving up the car.

Is the coolant temp harness the one directly in front of the valve cover??

I am completely out of ideas.

[Prelude Guy]

Additional info;

My car is an 89 240SX SE Hatch with 143K miles. Also, I checked the ECU for codes and I am not throwing any CELs. I get a code 55 meaning every thing is ok.

I have also unplugged as many connectors in the engine bay and reconnected them. I have also checked the hoses. I unplugged the hoses to the EGR valve and BPT valve. No difference in performance.

[s13sr20chris]

that sounds similar to a jumped timing chain. it also sorta reminds me of a clogged fuel pump screen. try spraying carb cleaner in the intake when its bogging. also check your timing.

[Prelude Guy]

Hey Chris,

Thanks for the help. Well, today I sprayed intake cleaner into the intake. It was dirty. I also replaced the ground terminal.

Starting the car took forever. I had to literally crank the car over for 2 minutes to get the car started. It will just crank....then it will eventually crank and slightly sound like it is going to start. Continue crank, the car will start to shake and then eventually start. VERY weird issue.

Maybe the timing is bad. I tried turning the distributor slightly and then test to see if the car would start. It still didn't help. After cranking the car one more time for literally 2 minutes, it started. I took it out for a test drive and the car still bogs. The battery light still comes on at idle too.

Chris, how can I fix the car if the timing belt did jump a tooth??

Could a bad catalytic converter be a possibility??

[s13sr20chris]

bad cat could do it. you can disconnect the exhaust at the down pipe to find out. you have a timing chain and its a pretty involved and time consuming job. its not difficult though. what you need to do is get a long vacuum hose and run it from the intake manifold into the car. drive the car and spray carb cleaner into the hose. let me know if that makes it run better. easier would be to get the car to run bad without driving and do it. like have someone put in drive and stand on the brake and the gas for a short time. if it runs bad like that then hit it with the carb cleaner and see what happens.

[Prelude Guy]

bad cat could do it. you can disconnect the exhaust at the down pipe to find out. you have a timing chain and its a pretty involved and time consuming job. its not difficult though. what you need to do is get a long vacuum hose and run it from the intake manifold into the car. drive the car and spray carb cleaner into the hose. let me know if that makes it run better. easier would be to get the car to run bad without driving and do it. like have someone put in drive and stand on the brake and the gas for a short time. if it runs bad like that then hit it with the carb cleaner and see what happens.

I already looked at the exhaust. It's all welded together. Taking it apart is more involved than a simple unbolt and check.

Ok, I will try the carb cleaning trick.

I just wanted to get this car running ok for the time being until I save up enough for the SR20DET (maybe a CA18DET) swap.

I REALLy appreciate the help. I really hope it is just a bad cat. It feels VERY similar to when my borther's cat went bad on his 97 Jeep Wrangler, except I don't remember it hesitating at the lower RPM level

[95hondakillr]

have you checked your oil for water sounds like a blown head gaskets, my s13 was doing the same thing im in the process of fixing it now.

[s13sr20chris]

yeah, the ka motor hates some head gaskets.

[Prelude Guy]

have you checked your oil for water sounds like a blown head gaskets, my s13 was doing the same thing im in the process of fixing it now.

Yup, I changed the oil a week ago. Beside it being VERY black, there was not any signs of coolant/water in the oil.

I pulled the pipe that originates from the intake tube right before the throttle body and goes to the tube on the valve cover. There was a metal pipe cleaner type piece in there It looked like the brush you use to clean cups/glasses. Is that supposed to be in there??

I tried to put intake cleaner while the car was running. Didn't help.

I think I am giving up on it. I think I am going to take it to a shop to see if they can fix it. The last things that I can think of that are wrong with it are the catalytic converter, injector, or timing. There is also that connector near the oil filter that I have yet to figure out where it goes.

I wanted to check out my friend's 89 240 coupe to borrow his MAF and to find out where my missing connector goes. However, he is out of the country. :help

Oh well, this car is still in better shape than what I expected when i bought it. I would be SOOO happy if the issue with it is a simple fix.

[574-240sx]

If you are talking about a hesitation try checking plugs, cap and rotor. Also you may need to buy new plug wires they do go bad. Nick

[s13sr20chris]

I pulled the pipe that originates from the intake tube right before the throttle body and goes to the tube on the valve cover. There was a metal pipe cleaner type piece in there It looked like the brush you use to clean cups/glasses. Is that supposed to be in there??

yeah, thats supposed to be there.

[Prelude Guy]

yeah, thats supposed to be there.

Oh, ok.

I tried taking out the part called the AIC (I believe this is what it is called- the part that connects to the intake where the air filter is. That didn't help either.

I am guessing it is the timing.