I have a 97 gle with 104k on the clock. Can o2 sensor(s) be bad and not throw a code? I am not getting an o2 code.

Car seems to run good but the mileage sucks 21mpg hiway 70mph average.

I know I get worse mileage in the winter, but it's worse this winter, used to be 23-24 in the winter.


Thanks

 

to answer your main question yes. They can begin to go out and not trip the CEL sense its either part way functioning or it hasent been enough miles that the ecu has completed its O2 sensor cycles. If theres any doubts on any sensors currently in the car you midaswell replace them. Even if there not bad its a good thing to do if you plan on keeping your car a while just so you dont really have to worry about them.

 

my o2 sensor came up and its messin around with the knock sensor does that make sense to happen?

 

I think I'm going through a similar problem. I noticed a loss of power & mileage and after reading the forums, all signs pointed towards the knock sensor.

So I replaced that, and the car immediately drove better. The mileage didn't improve *that* much, but the power was definitely better. It was back to 'normal'. However, just yesterday (about three weeks after I replaced the knock sensor), the CEL came back on and the car went into limp mode! It sounded completely different when the revs went up, well they didn't go that high since it seemed to be limited to 3k rpm. Unfortunately, my commute is about 50 miles each way so I had to drive home like that. Not wanting to screw anything up, I set cruise control at 110km/h (~2200rpm) and drove home. When I got off the highway, I noticed the engine seemed to be a better, but still not as powerful. The engine tone sounded better and it would rev past 3k rpm. The CEL is still on.

I'm going to go now and try to see what code it is throwing. I have a feeling it is the O2 sensor.

 

It’s not an O2 sensor, the O2 sensor will not do that, it’s the MAF, guaranteed.

 

it is very common to have a 02 sensor throw a knock code as well. dont worry about that. but how about your air filter? or throttle body or spark plugs are thos bad maybe you just need a tune up. did ya think of that?

 

Not sure if that was directed at me, but the air filter has been replaced recently (about a month ago). The throttle body was cleaned about two - three months ago.

The spark plugs were changed about 5 months ago (or so).

 

It wasn’t, and if it was, it still doesn’t address your problem, and is inaccurate in that sense. Read my reply, it’s accurate and 100% directed to you.

 

All up in my forum

But in any case, on the MAF diagnosis.

 

Well I just checked the codes and according to the flashing lights I'm getting 0201 & 0512.

More to follow shortly

 

It's definitly the maf,It does not allow you to rev past 3000 RPMS or It will not allow you to have full power and some what choke your cars performance and some times If it's bad enough the car can cut off on It's own and die down. It will also cause the engine to eat up more gas so It can runs as It's supposed to.

 

2500 RPMs, and just a tiny bit more than 'somewhat choke' performance. But otherwise, sure.

 

So how does one diagnose the MAF?

 

FSM.

 

Thanks. But if the MAF is the problem, shouldn't it throw a trouble code?

 

Be nice to believe, wouldn't it? It should, but it won't always.

 

That's pretty silly

Wouldn't the 0201 indicate something else was wrong?

 

Here is the video of the CEL light flashing. I taped enough to capture two full cycles.

It should show 0201 & 0512 twice.
http://www.youtube.com/watch?v=D6KSiokg4-o

 

some times it does flash if your tappin the throttle a little but if you are stuck at 2500 rpms then for sure you got a bad MAF.

 

hmm. It's not like that anymore (not reving past 2500rpm), but it still does feel 'different'. It feels slower and more hesitant. But it does rev past 3k now.

 

It took mine 2 weeks (700 miles) to throw a MAF code when mine died.

They're sinfully cheap on www.car-part.com Look for Air Flow Meter.

 

I thought a flashing CEL indicates misfire.

And oxygen sensors, etc, do not cause the knock sensor code. The knock sensor was already bad but itself does not trigger the CEL. Thus when something else triggers your CEL and you read the codes you find the KS code as well.

 

Flashing CEL is a potential catalyst damaging misfire, yes.

KS is rather often thrown by other codes as well, even when it's fully functioning. Oxygen sensors and other emissions equipment can can throw a P0325/DTC0304.

But you are right that the KS does not light up the CEL.

2 out of 3 isn't too bad.

 

A couple of stupid questions:
1) To remove the fuel injector plug, do you have to remove the metal shroud that covers each injector? Or do I just press the green tabs and yank the plug out? I tried doing that but the plug didn't come out, and I didn't want to pull harder at the risk of screwing something up.

2) What are the best brands of coil packs? I read on the forums that I should go for Mitsubishi brand, but I can't find them. I checked Rock Auto and they have Hanshin brand, which, as I understand, is a bad brand.

3) Do you guys recommend any online stores to buy these automotive parts from? I'm also interested in buying a ODB2 scanner tool. I wanted the one at Amazon.com, but they do not ship to Canada (and Amazon.ca does not carry these parts).

 

1. Grab and yank, basically. No need to do anything 'special' to remove the connectors themselves.

2. eBay is your friend.

 

So just hold the plug and yank it out? I don't have to press any tab or anything? Interesting. I just assumed I had to press something to remove the plug.

When you buy a component from ebay, how do you know you are getting a brand new working component? That is my only issue.

 

Well no, obviously you need to release the catch tab on the connector, but you don't have to do anything special other than that.

You don't, really. Then again, you don't know that when you buy it from a reputable online store or new in a physical store, either. Just look for high ratings, power sellers, etc.

 

NO IT'S NOT. It's thought that by many people because the KS code is a ghost code and they never knew they had it for ages until the other cel illuminating code came up.

Also, a KS code should be diagnosed by checking the ohms, 87 octane on warm days, as well as many other issues that can cause knock, will trip the KS code. When knock exists the KS goes out of it's ohm range and the ecu retards timing, The ecu doesn't know the difference between actual knock and a faulty ks.

 

Also, FTR in regards to o2's and lack of codes, within the past few months I've seen this twice on 4th gens:

Horrible gas mileage accomponied by Bank X lean code/s because of faulty primary o2's.

 

Holy crap Ebay is cheap. Check this out! $240 for all 6 ignition coils? All the other stores have them for $70-90/each! How can this be so cheap without something being fishy?

http://cgi.ebay.com/ebaymotors/New-N...spagenameZWDVW

 

I've had a KS code thrown by O2s before

 

1 out of 1000 times I could see it happening if the o2's were failing and sending a rich signal during lean conditions, but it's been my experience that they usually do the exact opposite.

Also, who's to say that you did or didn't have knock for one reason or another? even dropping a wrench just right could have done it, or it could have been the o2's, we will never know, I'm just trying to dispel the common misconception that the ecu magically throws a KS code because of other codes.

 

My car pinged like a tin can with marbles and it never set off a KS code.

 

That's probably because you tourqe them to spec you loser

No seriously though, my moms I35 is bone stock and pings like a bat out of hell as well, allthough I have my suspicions it might just be the pre-cats wiped out, I'll find out at 70k when I own joo on the exhaust debate (cast retains heat ). But anyways, back on OT, I've got nothing for you there Sometimes the way things SHOULD work isn't always the way they are. I'm just going by my own expereince/stupidity of listening to the .org and FSM in regards to the knock sensor. Two seperate cars, once resistors were installed I found out the hard way why the KS code was coming up even with sensors that spec'd out. My geuss on yours is that either A: You're bs, or B: your knock sensor isn't pzioelectiricing like it should be (does that make any sense?) or C: The sound was indeed something else that didn't transmit its frequency's to the block.

 

edited Nmex

 

It always happened in hot (as in your av) weather, and a lot more after I got a JWT.

 

Ummm, actually your av is pretty sexy as well, I've been trying to get my hands on a spare one of those and I'm gonna cram mangle and cut whatever I have to to make it fit on a 4th gen. Even on my GXE I'm retaining the stock airbox. Thanks to your valiant research I think the 5g would be sweet.

 

Hi Folks,
Reading this thread, and some information seems relevant...but I still can't pinpoint my issue here.

I have a 97' Maxima 5speed. Recently, during regular maintenenace, I had my Block1 Sensor 1 Oxygen Sensor replaced. About 200km after the service, the service engine light went back on. Sure enough....the same sensor failing. It was replaced under warranty.

Given that this oxygen sensor has now been replaced twice, any idea what this could be?

 

There is a whole bunch of knowledgeable guys on this forum, and I could use some advice on this same question.

I have a '96 GLE. I moved to The Netherlands that year, and wanted to bring along the best car available at that time. It's run 131K without any trouble. Had it serviced regularly at a small local shop (Nissan dealer tried to rip me off in '97) I LOVE this car!

To keep a long story short: After a code for a O2 sensor a long time ago and a code for the KS later, I decided to have all three O2 sensors replaced. I had recently been getting very poor gas milage and the engine would often stall at low RPM, and have lack of power when accellerating. (feels like you have the hand brake on)

Before this, the spark plugs have been replaced, throttle body and connections cleaned.


Now I've driven it for 300 miles and the CEL is back on, it hasn't stalled yet, but sometimes it doesn't accellerate well. Could the O2 sensors get ruined by some other underlying problem? Should I get the KS and/or MAF sensors replaced? Any thoughts on this?

I have to wait until Monday to have the codes read at the shop. I have the 1996 Service Manual, and theoretically I know how to read the codes from the ECM with the flashing lights, but I'm afraid to mess something up.

I'll check back with you guys when I have the codes.

 

Sounds like a MAF to me, but I already responded to your other post.

At least you searched first, you'll get your answers, I think I'm right though