ROCKART

iTrader: (23)

so i bought this 97 GLE with 41k about 8 days ago from the original owner. the car was poorly maintained overall, but especially cosmetically. the CEL was on when i bought it but i took it to autozone that day, before i bought it, and saw that it was two emissions (0705 and 0903) and the KS (0304) being thrown.

last saturday i took it to my local Nissan dealership to have a tech give it a good once-over. on top of telling me my valve cover gasket was seeping oil (not a big deal....yet ) and my "fan belt" is starting to crack, he also said i have an emissions leak. he ran the codes and got 0304, 0705 and 0903. i knew the KS was beat becuase i can feel the flatness in pickup that i felt on my 96, but the others i have never encountered before.

so i looked up 0705 (Evap Emissions Control System Leak) in the stickies and from what i see its a general code indicating one of many possibilities - it lists about 25 options..... im assuming that the 0705 code is actually in reference to the 0903 code, which is Evap Emissions Canister Vent Control Valve.
am i right in that assumption? if i take care of the 0903 code, it will clear the 0705, right ??

next question: i think i know where the emissions canister vent valve is located - drivers side, under the fuel door, behind the tire - but is this something that i could inspect/do myself? i see theres a plastic shielding with a couple of screws.
how would you even begin to know what is causing this leak? should i just be checking for loose wires or connections? is there a part that is known to be faulty with this unit? keep in mind this was was driven MINIMALLY (under 4k a year) and filled with nothing but low grade 87.
if i were to get this fixed at a shop, how much would i be lookin to spend?
i know this is a hard question to answer without knowing what is causing the problem, but any info/experiences is appreciated.

would these codes contribute to bad gas mileage? im gettin like 250 to a tank (i know the KS is also a factor). i live in a city environment and i drive hard, but 250 seems pretty low.

also the day that i had the Nissan tech run the codes, he cleared them and got the CEL to turn off. he said it would return in a day or two, but today, 5 days later, it is still not showing. should i be worried?

thanks

Double E

No serious worries but yes, it will come back. The only worry I would have is that 250 a tank is eating me for fuel expenses ...and depending on your state inspection regulations, it will not pass.

More than likely, they are causing the mileage to be close to half of what it should be. (There could be other stuff contributing.)

Fix the KS. Not sure about the evap. thing. I have not had that happen yet.

Do the KS yourself if you can... valve cover gasket too...or prep to pay hundreds in labor.

ROCKART

iTrader: (23)

yea the valve cover leak isnt bad at all. its a mild seeping at best. i was thinking about just tightening the valve cover bolts a little (a little) to extend the life.
doesnt replacing that gasket involve removing the entire manifold?

and yea the KS is second on my priority list behind brakes/rotors.

i was just hoping someone has had these codes on their car before and could point me in the right direction as far as checking individal connections, seals, etc. so i could at least begin to rule parts out.

yea and there are no emissions/inspections in florida. im not worried about that

KRRZ350

iTrader: (29)

Has it been awhile since 87 has been through it?

IIRC there is info in one of the stickies about how to tell if you have the earlier style evap control valve that was tsb'd. Test it per the instructions in the fsm, and pay close attention to the rubber hoses.

Tightening down the valve-cover bolts isn't a bad idea, I've done that on more than one occasion, yes it requires removing the IM to replace, if you go this route make sure you get new plug seals as well.

scooby68

On the KS sensor. As a reborn again mechanic, I can tell you the KS replacement is fairly easy to accomplish without the IM being removed, I've seen a write up here about it, but it didn't mention the tools or complete technique. I used a 12mm Universal socket on a 15"-3/8" extension bar that turned the ticket. By applying some upward pressure against the underside of the manifold with the extension bar helped steady the socket on the KS bolt. Also removing the small solenoid valve and two vacuum hoses closet to the opening of the "V" gave much better access for my moderately large left hand to access the sensor. I replaced the harness for the KS also, for 15 bucks why not, also cleaned the engine ground connections thoroughly and spray protected them. I had the same spec of 550 kOhm reading on both the old bad sensor and new sensor, so ohming them doesn't tell the whole story. Hope this helps. GL

KRRZ350

iTrader: (29)

^^What's the chance you put 87 in your car?

ROCKART

iTrader: (23)

ive actually been running 87 since i bought it. i wasnt going to start going highend until i replaced the KS. u think thats a bad idea?

KRRZ350

iTrader: (29)

Yes, don't replace the KS until you disconnect the subharness and check the ohms on it first, or run premium through it for a little bit, reset the code, and see if it comes back. You might still have a bad KS as well, it is very common for them to crack, melt, etc. but running 87 will cause the KS code as well, the FSM & all the stickies and threads on the .org make no mention of this (that's why I put it in my sig!), but the way the knock sensor works is pretty simple. If it detects knock, the ohm's change and the ecu then throws a knock sensor code & retards ignition timing.

FunLovinMaxima

I have the same EVAP problem and I posted about it a few weeks ago. How to test where the leak is for sure? A tech can hook up a "smoke" machine through a service port in the EVAP system and look for where "smoke" leaks out. Since you've got the canister vent valve code, its extremely likely that the EVAP "leak" is just a result of the valve being stuck, so I wouldn't bother with paying for any diagnostics at this point.
I'm told that this is a fairly common problem on our cars. It is definitely something you can fix yourself. There are a handful of bolts to remove which is very easy (unless they have rusted to oblivion like mine) but even then its not a huge deal (and in sunny Florida you don't have to worry). The harder part in my case is removing all of the rubber hoses which are really hard to wiggle off because they are only about an inch or two long and have thick walls due to the pressure the system is under so there is literally no flex. if you try to squeeze them with a pair of pliers you're likely to cut them and cause a real leak. But that's not a huge problem either. if you are comfortable crawling under your car, it is something you can do yourself pretty easily as far as working on a car goes.
note that i haven't actually fixed the problem myself because i haven't had a weekend to spare in a while. i believe i heard that the valve costs about $200, but please don't quote me on that.

ROCKART

iTrader: (23)

the response i was looking for. thank you.

MaximaSpd85

iTrader: (14)

you can take the valve off of the charcoal cannister and clean it....but a common problem that people encounter is that the bolts holding it on just keep spinning and spinning and it will not come off. So i went to a junk yard, found another charcoal cannister with the valve on it, and replaced the whole thing. Yes, you're taking a chance on it being good, but its definitely a lot cheaper and worth a shot. it was less than $20 at the junk yard.

ROCKART

iTrader: (23)

by chance does anyone have a pic of the cannister or the valve?

MaximaSpd85

iTrader: (14)

dont have a pic but it is under your car near your left rear tire as you suspected. its the only black box under there. you cant miss it. the valve is bolted onto the side of it.