j-dawg

Failed emissions Monday with no fewer than three codes - I realize that the reason I've seen no CELs is because my CEL is either burnt out or disconnected.

The MAP is straightforward enough. I'll replace that.

The other two were the rear O2 and the knock sensor. Two questions:

1. Does the knock sensor cause you to fail emissions? I know it doesn't throw a CEL, but it showed up on the list of Fails the EPA dudes gave me. I'm gonna not replace it until the O2 situation is dealt with, since I hear O2s can throw erroneous knock sensor codes.

2. How big an exhaust leak do you need to booger up the rear O2 readings? I've got a miniscule leak after the cat, so that could conceivably be my problem, but it's really tiny: it makes a tiny whining noise. I don't think it's anything huge; is there any easy way to seal it up? Some sort of silicone grease, or something that wouldn't require replacing the cat/pipe? I don't want to install a $80 O2 sensor and find out that the problem was my leak and not the sensor itself. Is there any way to test the sensor?

asand1

iTrader: (1)

you can try tiger patch muffler tape. search google for muffler tape. try napa or AZ ot wtvr.

Daniel1120

iTrader: (1)

Yes, there is sealer for exhaust leaks. If it is a really small leak like you say then that should work. No, you will not fail emissions for a knock sensor code. At work 2 weeks ago a guy at my shop passed someone with the same code. Really should replace it though, its affecting you hp and gas mileage.

Id recommend you patch the exhaust, replace the map, then clear your light. Drive it and see if the o2 code comes back. And replace that knock sensor as soon as you can.

Daniel1120

iTrader: (1)

Oh and one more thing, have you removed your intake manifold lately? Notice any intake leaks near the intake manifold? If so that could be causing a code for a map sensor.

j-dawg

well i'm retarded the map just wan't plugged in all the way

so that's good

I can't get the O2 out and don't want to round it off, so I'll take it to a muffler shop tomorrow.

Regarding the KS: My multimeter only goes up to 2M ohms instead of 10M like the FSM recommends. I get resistance between the KS sub-harness and the battery negative terminal, but I can't get a good reading. It isn't open, though - there's definitely a connection. Is that good enough to assume the KS is probably not bad?

I'ma hit up the junkyard tomorrow to try and get my mitts on another KS anyway, but if I can't, I don't want to spend $100 on a new sensor to find out that I didn't need it.

Daniel1120

iTrader: (1)

Just about every 4th gen knock sensor goes bad. Its just a matter of time. A junkyard one might not be a good idea. I got one on ebay for $50 new. Even came in the original nissan packaging. Patch that pipe and reset the light, then go from there.

nelledge

iTrader: (6)

You have to be careful here. Texas is fairly lenient on inspection codes. Some states will not pass an inspection if any codes are present. Also, in Texas you can fail an inspection, drive down the road, and pay someone else for an inspection, continuing the process until you pass. While in other states you get flagged and must return to the original inspection station with the violation corrected. It kinda sucks.

Daniel1120

iTrader: (1)

True that. The state you live in does matter alot.

j-dawg

ordering this ks in the next few hours if nobody sees anything wrong with it

at $20 i can't see why not even if it's a POS it only needs to last until i'm through with emissions

http://cgi.ebay.com/ebaymotors/NISSA...ht_11372wt_907

j-dawg

or actually this one
http://cgi.ebay.com/ebaymotors/MAXIM...Q5fAccessories

faster shipping

i may have failed to mention that i need everything in working order with no codes soon because i'm leaving town next wednesday until spring break..thus if i can get the sensors replaced and some miles in by the time i leave, it should be ready to go for emissions

j-dawg

Got the O2 installed today at the muffler shop. That's two of my three codes hopefully worked out.

Since I want to avoid "NOT READY"s (I want this thing passed and registered by Tuesday), I don't want to clear the ECU. The dude at Autozone said the codes should go away after the usual 50-200mi of driving. Will the codes, in fact, go away now that the problems have been righted?

rdw72777

Autozone wouldn't clear the codes for you? Then you could drive around and if they don't come back you know you're good. And it should take less than 50 miles for the codes to re-appear in most cases I think.

Curious, what did the O2 sensor and install cost. I've got a P0130 code and the O2 is beyond my skill level (but probably within my budget).

Daniel1120

iTrader: (1)

It can take a LONG time for the light to go away by its self. Alot of codes are reset by the number of run cycles. And most autozones seem to start refusing to clear the codes, something about liabiltity.

RDW, do you live in the north or someplace with alot of rust problems? Doing an o2 sensor is retardedly easy. Just need the right o2 sensor socket and a long ratchet. You can easily pay for the cost of the socket and ratchet by doing it yourself, and you'll save some.

rdw72777

In Philly. Snow on the ground, its cold, i'm an idiot, I park on street and have no where to work on a car, etc.

And its not something I'd probably enjoy given all this. Car is a 1995 and I'm pretty sure it hasn't been changed before...so I'm guessing it won't be as easy as it seems "on paper".

Oh, and my right hand wrist is in a splint....LOL

Daniel1120

iTrader: (1)

Well if your in philly its probably pretty rusted and seized on. And considering your meat beater hand is in a splint, its probably better to just take it to a shop.

maxgtr2000

iTrader: (29)

Won't they just let you do the sniffer test? That's what they did when I cleared my codes and ran down to take the test like an idiot. 3 tests and a 1/8 tank of denatured alcohol later I was able to get my tags. If you do the sniffer make sure you go with a fresh oil change and good plugs.

j-dawg

The Autozone guy said he's not supposed to clear codes, but since he's been like my BFF these last few days he said he could do it. I'd just rather avoid the potential for NOT READYs on systems that were good to go - if the O2, KS, and MAP codes clear themselves, then I should be set.

Regarding the replacement of O2s, it cost me $50 to get the old one out, and I'd paid about $80 for the new one at AZ. I don't think it's outside of your skill level if you've got a ratchet and an O2 socket, but it was pretty far out of my equipment level without a lift because the thing was rusted in so tight.

rdw72777

The tools and convenience factor kills me (though my tool collection has expanded in recent years). I'm willing to tackle most things if I go in from the top and think it will actually save me money. O2 sensor, ehh it seems like a minimal investment to get it done by someone else.

j-dawg

Yup. I coul dhave spent $50 on a ****ty impact driver, or $50 to just get it done.

Knock sensor: I can't see to get the socket to stay on the bolt head; when I turn my ratchet, it twists the U-joint so the socket sits at an angle instead. Any advice?

Daniel1120

iTrader: (1)

My advice is goto sears and get a 3/8 dr 12 mm swivel socket. A couple of long extensions and your in. Ive tried using my 1/4 dr 12mm swivel socket but it just didnt work as good. The socket should be about $7.50. Make sure you have a long magnetic pick up tool, its easier to get the screw back in using that. Dont get too frustrated trying to get it back in, its a PIA. If you do a search on youtube you will find 2 videos by pmohr (i think). He shows two methods to get it. GL

j-dawg

The problem is that in pmohr's video he just gets the socket on there, presses the extensions up against the manifolds, and cracks it loose. When I start turning my ratchet, the U-joint tilts the socket off the bolt instead of turning it. The bolt feels quite stuck, and I feel like I'm just not transmitting the torque properly.

The bolt head is fine as of now, but I'm afraid if I keep doing it I'll round off the corners. (And, as pmohr says, hate myself.)

Daniel1120

iTrader: (1)

A u-joint works, but an actual swivel socket is better.

j-dawg

Next time, I'll remember that. I ended up breaking the bolt with a v. long screwdriver and a 12mm wrench (as in the KS pt2 video). New KS went in easy.

I did my best to estimate the 15-20ft-lb, but I really don't think there's any way to get that torque correct at this angle. If it's going to be under-sensitive, I might as well have just installed the resistor. I'll be filling it with premium anyway.

Daniel1120

iTrader: (1)

Glad you got it. Notice the power improvement?

j-dawg

Gotta drive it still. I'll make some trips tomorrow and then, if Autozone says my codes are clear, take it to good old Naperville for emissions. If codes are clear and I pass, hooray! If not...well, I'll be back in March to drive it some more.

Thanks for the advice y'all

floydthedog

having your own OBD reader is a worthwhile tool is this situation. You can check/clear the codes yourself and monitor when the systems come back online. You can even force them to back quickly by completing particular drive patterns. Good luck!

mmgio

You can clear the codes yourself by turning the screw on your ecu.There are detailed instructions in the how to's and stickies.It is simple.

neosmatrix

iTrader: (2)

WOW!! Here in MO (At least the part stores I go to) you walk in ask for the OBD scanner, leave your license and walk out and do what needs to be done.

Walk back in, say "Thanks" and get your license back
S

j-dawg

In Illinois the EPA handles emissions at dedicated test stations. They aren't making any money from it, so they can afford to be stricter.

The guys at the Naperville emissions test center are actually really nice, contrary to what you'd expect out of government work, but they aren't cutting you any slack on passing the tests. They're helpful to the extent that they can be.

EDIT: Oh, you meant to get the codes scanned or cleared. Yeah, I don't think the guys at most stores really care.

As it turned out, the codes hadn't cleared. I had them clear it before driving the 15-20mi to the test station, but no dice. Still, my RHO2 system was ready and didn't throw a code, and I can tell the knock sensor is better, so the car should be fine. Later that night I drove something like 150mi, so when I go back home in March the car should be all kinds of ready for the test.