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97 Prelude O2 Sensors (question) *newbie*


Sixpackjeanie
10-04-2009, 10:34 AM
Hi all,

Female here...just joined today :)

Been doing some research on this specific problem I am having. Haven't really found anything that would make the light come on and say, "ah ha!"

Browsed for two hours on here looking as well. Sorry if this is a repeat thread.

Got this 97 Vtech last summer. All stock except my muffler. Ran great till my hubby mis-shifted and downshifted into 2nd instead of 4th and somehow broke the knock sensor. Anyways, my car is right at 90,000. Recently dumped about a grand replacing the alternator belt, tensioner, timing belt, some oil leaks and a new knock sensor. Again.

With all this stuff I've replaced, still has some idling issues (which I know can be adjusted) and the engine light comes on from time to time. Then it wants to knock off when I come to a stop or if I slow down really quickly and lags when I start moving from a stopped position. I really like my mechanic. He's knowledgable and very fair on prices. Each time the CEL comes on, I take it up to him, he plugs it into his computer thing and it reads out that my O2 sensor is slow to respond. It's not malfunctioning, he says, just slow to respond. He said before that it was from me not "gettin' on it" or "drivin like I own the road" and said that the sensor (that's located in the exhaust) was getting clogged up, that a good hard run for a couple hundred yards should do the trick. I did, and it worked the first couple times, lol. Most driving I do is all in-town, so it would make sense.

This last time right after getting it fixed, I started it up after driving to the store and it knocked off on me. I was pissed. Then it just drove funny...lagging and not enough power it seemed. Next morning I took it up to my mechanic...he plugged it in. He checked my catalytic converter and the exhaust. He called me outside and low and behold it's the stupid O2 sensor again. Since I got it out of the shop I've been driving it like it should be driven. Not slow, but not insane either. I finally have all this stuff fixed and I can really *drive* it.

So this time he says that it's because of my muffler that it's causing the air to move either faster or slower, never really got a firm grasp on what he was saying, but seemed he was saying that since the exhaust is moving quicker because of the muffler, that the sensor isn't given enough time to get a reading. So then it causes the engine light to come on. Then it goes into a sort-of backup system and changes the idle, the performance, gas mileage, etc. :eek7:

Now I'm not exactly stupid and certainly wouldn't call myself an expert at all, but I'm not sure how to take what he said as truth. Figured I'd ask some guru's. My hubby is an american-made car guy and doesn't know anything on foreign cars.

I want to continue working on this car...I have always wanted a prelude. My mechanic also mentioned when I put a cold air intake on, that there will be an air sensor in there that will appear to malfunction. Air mass sensor or air pressure sensor...don't remember what he called it.

What is you all's take on this issue.

Thanks so much :)

Airjer_
10-04-2009, 01:02 PM
Posting the exact code would help a lot.

If the upstream O2 is slow to respond than its probably bad. It doesn't have anything to do with your muffler or whether the exhaust is flowing to fast. IF your exhaust was flowing to slow (plugged catalytic converter) there would be some other symptoms like lack of power/acceleration.

Your cold air intake should have places to mount all the various sensors that need to be in place in order for your vehicle to operate correctly. If it does not than you have the wrong application for your vehicle.

Sixpackjeanie
10-05-2009, 04:05 PM
Well I don't remember the code...I'll try to get that.

So I should just replace the O2 sensor then? I was thinking of doing that anyways, since it seems to act up every few weeks. Why wouldn't he just say, "replace the 02 sensor" since this seems to be a reocurring issue? Now this makes me want to second guess my judgement of him.

Thanks alot for your input :)

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