Vehicle: 97 Maxima SE 5 speed 172xxx
Mods: Basic bolt ons MEVI and recent 96 JWT ECU Manual Tranny and 7.5 RL

(Length was determined on a closed course, no timing monitor working at the time)

When the JWT ECU was first installed the thing worked like a dream! Awesome power gain throughout the entire rpm. Four car lengths gain/difference total!

Two weeks and a decent amount of beating later the car seems to be lacking power. Sure enough, I am three car lengths behind what I was running at first.

Facts:
-I've ran the engine up to 7500 rpm 4 times, usually shift around 7100 rpm
-I've done an OBDII scan and a new code has popped up: P1335 (Crank sensor(REF))
-Checked the sensor and it's fine. 480 ohms at 75 degrees
-Compression tested at 200 all across the board.

Things I'm going to try:
-clean out the clogged air filter
-change the worn out spark plugs
-change the 40k mile fuel filter

Any hints or advice would be helpful. Thanks guys!

 

id def go with the new fuel filter, and the rest of what u mentioned.... i hoestly think it was a coincidence that these parts that need to be replaced just happened to act up all of a sudden. def change em and let us know.. o yea how much u pay for the ecu???

 

Unless you have definitive data, you cannot really say there is a power loss.

Quantitative > Qualitative.

Get some timing maps, get a dyno, go to a track w/ timing equipment.

check your KS

 

Change that sensor. It's resistance might be within spec, but in reality that sensor produces a square wave signal that your not seeing with just an ohm meter. If that signal isn't clear your ignition system will suffer.

It threw that error code for a reason, the ECU didn't just pull it out of a hat.

 

Um your driving seems a little off too. I am not a good 5Spd driver by any means, but with I/Y/E you should NOT be running 14.89. There are some very good drivers on this forum who did that a PURE BONE STOCK Maxima.

You said you pulled your codes and got Crank (REF). You sure that was the only code? As stated above ... check for the infamous knock sensor.

 

I think the fastest time a Bone Stock 4th gen Max can run is a 15.2 tops. A 5.5 gen runs a 14.7 for comparison.

 

Then my max must be a piece of chit. Best I could do stock was high 15's.


With intake / Y pipe - hiflo cat - no resonator - 2.5' piping from headers back and a nice perf exhaust / UR Underdrive pulley / Fidanza Flywheel / High Perf clutch / The Super Lightweight Mazda Mil wheels with BFG Drag radials on them
All of my sensors are good and I have replaced my KS. I don't think I'm a bad driver? I have over 100 passes under my belt and these are the results.


Best I could pull was a 14.9 with most of my runs being 15.0's and 15.1's.
(5spd btw) Oh and with a 75 shot of the happy stuff best I did with this setup is a 14.0's flat. What gives? Nissan can't make consistant cars? Or maybe the people that pulled 14.8's stock failed to mention that they stripped their car down to the frame and shaved 400 lbs or so? I dunno?
But I will be honest, I am happy that my daily driver is able to keep up with pretty much any stock v8.
But I am totaly DONE modding my max.. waste of money modding these cars imo. <--- big emphasis on IMO -- so dont flame me for that one.

 

tru! ^^^^^^^^^^^^^^^^^^^^^^^

 

14.5 actually. http://forums.maxima.org/showthread.php?t=401613


Let's get back on topic people.


...

 

Nissan can't make good 5-speed drivers.
To the poster... check your ks (already been said) and that small list you've made.

 

Could be the gas around here this time of year.

 

Well, there are a number of factors that you forget to mention or think about before you point fingers and say i'm a bad driver:
1) Track condition and preparation (I would like to see those stock max's run that same time at Rock Falls aka Slippery Falls)
2) Temperature and humidity
3) The type of tires they are running on
4) The fact that a MEVI'd max will usually run a worst time than a USIM max but will have a higher trap speed in general. So unless you're a pro quarter-mile racer, don't go around making assumptions about driving skills.

Second off, the only code on there was the REF crank sensor, I'm sure I'd mention anything else in order to get better tech feedback.

Oh yeah guys, the knock sensor is still pretty knew, 20k miles on it so far. And when it was out it would throw a code so.... back to square one.....

Any JWT equipped guys ever had this prob?