My maxima has lost it's off the line acceleration it had before and it bothers me since I get my azz handed to me more often now than when I had it initially. The throtle response(tr), especially off the line, is weak at best. I have changed the fuel filter, the front three injectors, all the spark plugs, but the difference I feel is at the top end. As for the initial tr, it is still weak.

I'm thinking the ignition timing may be off or maybe it's just oldage catching up to the 160,000+ engine. Can anyone please throw me a bone because I have become desperate since I took it to the track for the first time ever and ran a 17.9
Help me! help me pleeeaase!

 

Why did you change the injectors?

Did you check/change your Knock Sensor?

Air filter?

 

You need a knock sensor. Thse are the same symptoms I had, even though my check engine light wasn't on. And I have 181K+ and she still pulls hard as hell, with a new knock sensor of course. With the old one, life sucked, you get beat off the line all the time, no low end power, so get it fixed and guaranteed you'll be a happy camper.It's like the best and most noticeable "mod" I've done since the VI, and it's actually maintenance, not a mod.

 

This may be the best advice I have recieved to date. Did you change it yourself? If so, how hard was it and how much $ are talking about.

"Why did you change the injectors?

Did you check/change your Knock Sensor?

Air filter?"

I changed the injectors because my engine had sterted vibrating and it ran like I lost a cylinder. I did some good old dignostic work and came up short. I took it to nissan and $90 dollars later, they said the sixth injector was dead. I figured I might as well change all three front ones.

No I have not checked the knock sensor( I will asap).

And I have a home made midpipe for the intake and the filter is new

 

Changing the knock sensor is actually really easy. It took me about 10 minutes. I lodged a 1/4 inch drive in their with I think it was a 12mm socket, and used leverage from a jack handle, you know the one that you use to jack up the car and let the pressure go when you lower the car, well, it has a hole on the end of the tube and ususally a 1/4 inch drive fits nicely in there. Just turn the rathet until it pops loose. It is located under the lower intake manifold plenum, do a search, and I am 100% sure you'll find a lot more info on this. The part cost about $126 from Pinnacle Nissan. It was cheaper at www.thepartsbin.com, but the do not have any in stcock at the moment.

 

i have the same problem...i was clueless until now.....great advice

 

what's the knock sensor?

 

Thingamagic that senses knock.

 

Not to flame but everyone seems so quick to assume the knock sensor. I would pull my codes before I just started swapping out expen$ive sensors. Also, I would check the adjustment on your throttle cable. They do stretch out over time. Maybe at wot you're not actually wot. Aside from that, good luck and let us know if you find out anything. My car is at 141,000 and is starting to act old and cripple like me.

 

haha.. you are funnie....

 

do a search for knock sensor. Skippy has excellent directions.

 

Because the diagnosis fits the symptoms described, and it is a common problem with older 4th gen Maximas.

 

I agree more and more people are having problems w/ the knock sensors, I too have replaced mine. All I'm saying is that the knock sensor seems to show up in every thread. Given the mileage of 160,000 there could be a whole magnitude of other possible causes. I'm of the opinion some people would just read knock sensor and replace it only to find it wasn't their problem. Oh well

 

Thanks for the advise but I was just wondering what state you are in because over here in AZ, the cheapest I found was at a nissan dealership for $177. I will be getting it friday after next but hopefully I can find it cheaper by then.

 

Try out expressautoparts.com. They have good prices sometimes. But right now they are out of stock

 

not try to sound like a salesman.
i have a knock sensor in my garage,never been use.
i just need money right now. i'll sell it for $95 shipped.
let me know. email or pm me for any question.
icq # 86135545

Ryan.

 

- I'm really interested in this thread because the dealer let me know that my knock sensor was dead while they were checking something else a month or two ago. My low-end power has also felt sluggish for the past few months. After reading this thread, I'm wondering if my problems are KS related.

- But here's the problem: Knock sensors screw around with timing to prevent knock. If they sense it, they retard ignition timing. You lose top-end as a result, but gain more low-end.

- If it breaks and the car is sluggish at low revs, that would indicate that the timing is stuck in an advanced mode. But, if that were the case, the car should/could be knocking under heavy load and/or at high revs. (Maybe we aren't hearing it?)

- If the Knock Sensor is set to return to a default retarded mode when it breaks, that would mean you would have tons of low-end and no top-end. But this doesn't seem to be the case - its the exact opposite.

- Maybe, and this is purely hypothetical, when the knock sensor breaks, the ignition curve goes to a setting that is safely advanced for running 91+ octane fuel. You lose low-end power, but keep enough mid and top-end power for running around without knocking. At the same time, you don't get any audible knock.
- This is the only thing that I can think of that would fit the theory of losing low-end power when the KS breaks. But frankly, why would Nissan do that? If the ignition curve gets any more advanced, or you run a heavy load, or its really, really hot outside, you could be a candidate for knock. If it was me, I'd set the default for a retarded ignition curve.


What do you guys think?

 

Your last hypothesis makes a lot of sense because the job of the ks, in essense, is to prevent knock. And the reason, I would think, for setting the default to the safest level when the sensor breaks is to maintain that primary objective, preventing knock(as much as possible)and if doing so results in a loss of low end power then so be it at least you don't have to loose any sleep because your engine keeps making funny noises. But I totally agree with your point for it makes sence to have a timing that shoots for more torque when the sensor breaks which is at the low end.

 

If the engine is runing rough and the code throws out an 03 04 saying it's the knock sensor what else could be causing the problem. An error code for the Evap Canister purge control vale (08 06) is also being shown.

If it was an O2 sensor, wouldn't that be dispayed as well?

 

an o2 sensor would trigger a CEL

 

it may be carbon deposits in the intake manifold

 

Well I finally got the Sensor and Installed and now I'm back to tesring them civics new a$$holes. Thanks to everyone for their imput.

 

Good to hear that you got it fixed and that it indeed was the knock sensor. Go back to the track when you get a chance and let us know what kind of times you pull now. 150000 miles shouldn't be crippling for a VQ... at least that is not what I will be expecting at 150K! I better not be in for a surprise.

 

15.823 @ 88 mph did this with only an intake and a mufler and I took out the spare, the front passenger seat and the rear seat. not bad for 170,000 miles.

 

hope you aren't a 5-speed w/ that time.

 

nope! autocrap hoping to get a valvebody mod soon

 

Good Job...Time for a YPIPE!!!!!! Shell out the 160 for a budget, it's way worth it =)

 

...I am SO surprised that some folks are hearing about a KS for the
first time...Also, doesn't anyone search for codes these days???

In any case, check out my website for pics of the knock sensor,
and where it's located...My Website

ONE LAST THING -- I also had to replace injector #6...

take care,
FLO_BOY

 

Heh heh, I have 160,000 miles...

This should upset you :
http://forums.maxima.org/showthread.php?threadid=180629

 

Actually, timing that is retarded can impact engine output across the entire rpm band. Some engines can use full advance at RPMs as low as 2000 to 2500 -- hardly in the range of top-end operation. If the advance curve fails to provide enough timing advance at lower RPMs (befoe reaching full advance), the engine will not produce good low-end torque. Conversely, if too much advance is dialed in too fast, the engine will run badly and be prone to detonation. This is especially true when operation the engine at part throttle. During part throttle operation most engines require more advance not less (to a certain maximum of course.)

Bottom line, if the ECU believes the Knock Sensor is faulty or if the KS is falsely detecting engine knock, the advance curve will be retarded which will cause the engine to be less responsive (sluggish) and be down on power.

However, sluggish operation and a loss of power do not automatically point to a bad Knock Sensor.

 

l

Give me a break, Ive only owned my max for about 3 months and still relatively new to the forum so I'm still finding out things about the car. And if you had read for enough in the thread you would know that I already replaced the KS.

 

actually, I wasn't directing the comment at you...
FLO_BOY

 

Yes that upset me very much but now, Yota, I must learn the way of the jedi or at least how the f**k you did that. My tire pressure after my second run was 45psi and how do turn that trans resistor switch off. Please do tell how you setup the everything I want to know.

PS. "OSCAI ducting" what is that.

 

well excuse me then I thought the contrary.

 

All of your questions can be answered here or here.