MaxSpeedSE

iTrader: (3)

The best way i can explane it is below 5K the car is very slugish, it even sounds diffrent.
If i were to race off a roll, and have my rpms in power band at 4K and gun it, the car will grunt and barly take off, then the second i hit about 5K it kicks in hard and takes off kinda like if i were to have Vtec. I know there is a power issues cuz i raced my friend Clark who is stock and below 5K he pulls on me ( witch shouldent be happening ) then when i hit 5000 i start coming back a little but the second i shift and im below 5 agian he starts leaving me agian.

Any help would be awsome
-Chris

SkoorbMax

That's especially weird, since I've noticed that in my 97 the torque goes through the floor somewhere after 5k. My 00 pulls quite steadily up to redline, bu my 97 basically takes a coffee break as you approach redline, and looking at the torque curves that were posted on the article about wheel weight and torque, that's typically how the 4th gen's VQ is supposed to work. Not sure why yours is no good until 5k

SteVTEC

It could be your knock sensor pulling timing before 5k. But that's really weird if it's RPM dependent. Might be something else then.

If I've said it once, I've said it 1000 times, OBD-II scanners are "the" essential tool for diagnosing problems on modern cars. Can check and reset codes, see what the timing is doing, monitor O2's, etc. Otherwise you're just guessing half-blindly. If you don't have a scanner, get one, see if you can borrow one from somebody local, or go to autozone and have them scan it for you (free).

MaxSpeedSE

iTrader: (3)

Ok guys i put on a OBD 2 sensor ( snap on ) on my car today at work

my timing was all over the place, from what i read the maxima should be 0-25 mine shot everywhere from -7 to 45! im changing out the Knock sensor asap.


-Chris

I30tMikeD

iTrader: (8)

I am no expert on this, but I believe that different scanners will read timing differently. A reading of 45 on one does really correlate to 45 degrees....make any sense? It's just a function of how the timing changes....someone correct me if I am wrong.

SteVTEC

Your VTEC isn't kicking in

I'm pretty sure timing is an absolute measurement. The throttle position seems to be relative, which is measured in a percentage. And I posted this in your 4g thread, but I did a nice looooooong write-up in the 4G FAQ on what your timing should and should not look like under various states of knock sensor operation. So before you go throwing money and labor at the problem, try to understand it a little better first.

I saw 0-45 degrees of timing on mine. never saw -7, but I do have a 99/Cali spec which could be a bit different than 95-98's. From what you stated, that doesn't mean that your KS is shot. Timing will in fact jump all over the place. The dead giveaway is what your WOT timing is near redline. 10-12 degrees = shot KS. 23-25 degrees is what you should be getting.

MaxSpeedSE

iTrader: (3)

Stevtec to test timing near redline could this be done by reving the car while its in neutral or must the car be driven?

njmaxseltd

iTrader: (19)

If your ignition timing is moving around I'd be looking closely at both Crank Position Sensors. Those sensors control engine timing. I think POS controls ignition specifically. That sensor is located under the car on the tranny bell housing. It tends to collect fine matalic dust on the magnetic head which distorts it's ability to detect the exact position of the crank. You might want to take that sensor out and clean it up nicely then see what your timing does or just go for a ride. While your down there, clean up Crank Position REF as well. That sensor is located right by the lower pully and is easily seen behind the right front wheel splash shield.

Another sensor to look at is the Camshaft position sensor. Make sure it's also in good shape.

MaxSpeedSE

iTrader: (3)

Good idea, thanks for the heads up I’ll check out those sensors.

Im not sure witch sensor your talking about on the tranny, could u tell me where it is with more detail?
That one makes a lot of sense to me cuz i took off my plastic panels at the bottom of my car that shields the tranny so its really dirty, maybe that sensor need to just be clean.


-Chris

spirilis

iTrader: (2)

Was this during a dyno run?

Keep in mind that the Maxima's ECU will advance timing pretty far... I've found on my 2000 it takes it up to 40-60 deg BTDC sometimes right when I get on the gas. This is usually only for short moments. Plus, the timing should be advanced more at higher RPMs than lower RPMs, unless the ECU's doing some funky stuff with timing curves or something...

It will read -7 when you have your foot off the accelerator with the engine above idle (FUEL CUT; hence why it's reading -7... I think -7 is a limit)

Typical timing at cruising speed is ~20-30 BTDC I think. At idle mine sits around 14.

MaxSpeedSE

iTrader: (3)

nah, it wasent a dyno run that we got these numbers at. We hooked up a OBD II to it ( snap on ) and we keeped reving it up in Neutral

-Chris

flashover

Dont forget noobs, OBD-II is a free thing...
If you go to Autozone or Advanced and make the guy pull any codes.
... As usual, the true color of the .org shows its face when SteVTEC, njmaxseltd, and spirilis hit the keys.
You guys make this place worth it.