codes and recommendations

[Z31toZ32]

Alright guys, I have a 98 Maxima that has recently clicked on the old check engine light. I have not noticed anything wrong with it. I went to AutoZone for a diagnostic, and 2 things spit out at me.

1.) First is a EGR low/no flow detected. I looked up the EGR valve and a new one is around 100 bones, more than I'd want to pay. I did some searching and it looks like they get clogged with carbon pretty often. Would you guys recommend just buying a gasket and taking it off, cleaning it with some carb cleaner or something, and then putting it back on? It is down there in the engine bay, but doesn't look too too bad to get to. Maybe just take off the intake. Or, should I just bite the bullet and buy a new OEM one because they fail all the time?

2.) Knock sensor condition... with probable causes low fuel pressure. I don't have the tools to check fuel pressure. Is there a common fail point in the fuel system?

Thanks.

[maxhopper]

A lot of times with the EGR it's the small tube that runs from the exhaust manifold to the EGR valve that clogs up. You can try taking that off a cleaning it with parts cleaner.

As for the knock sensor, just replace it.

[Z31toZ32]

thanks for the reply scott. i have a few more questions.

i will try to get the small hose that goes from the manifold to the egr off and clean it. will the hose go back on, or do you think it will be too brittle to go back on? also, will i be able to easily identify this hose?

on the knock sensor problem/printout... the autozone code says "knock sensor condition" with the probable causes of
1.) knock sensor defective
2.) check connector and wiring to sensor
3.) engine mechanical condition-knock or rattle in engine
4.) low fuel pressure

im not sure why the autozone guy told me it was the low fuel pressure and to disregard the knock sensor probabilities. i guess i will start with the connector and wiring to the sensor, seems like the cheapest option. im not sure on number 3, there is no knock or rattle in the engine. and number 1 and 4 seem like the most expensive things. i dont want to buy a new knock sensor for $100 when it is a fuel pressure issue. is there a way to hone in on the problem without paying some quack mechanic? i know a knowledgeable and trusted mechanic about an hour drive away, but dont want to head out there before i check everything off the list i can take care of myself.

thanks

[loystock]

Check KS resistance is 500-620Kohms. If not replace the KS. You can get KS for less than $100 but beware of cheap imitations. I got mine from DeutscheParts for $45. KS replacement in a 98 I30 is not as difficult compared to a 99 I30 with CA-configuration where it's impossible to get your hands into the KS. With the right tools, KS mounting bolt removal is not that hard. Below are YouTube postings courtesy of "boredmder" to give you an idea about KS replacement.

http://www.youtube.com/watch?v=R2ntaxi7bXk
http://www.youtube.com/watch?v=fPIMOIwLISc

Getting access to the EGR tube may also be challenging. There are several postings in this forum about it...do a SEARCH.

[maxhopper]

The tube from the rear exhaust manifold to the EGR valve is a small diameter metal tube. There is no problem cleaning it and reinstalling it...other than being a pain to get at.

Bad knock sensors are very common on the 4th gens. If your code is a P0325, then by all means examine the wiring connection, but most likely it's the sensor itself.