This just started today and it's got me stumped for the moment. 96 GXE manual, no engine mods but a drop in K&N.

Under part throttle everything is fine, but when you push it past about halfway it hesitates for a split second, then accelerates, then hesitates again. This does not stop until you lift off the gas. And I noticed when this happens the tachometer seems to lose its signal since it drops at the same instant that the engine stops pulling, then shoots right back to the right RPM the instant it comes back to life. And this i with the clutch out flying down the road, the engine isn't actually coming to a stop.

It's next to undriveable. I mean you can drive it and never give it much gas and it's fine, but when you floor it it's violent enough to whip your head back and forth.

First, I hope I've described this well enough that everyone can understand it; it's kinda hard to explain. Second, I think the tach thing is the key to all this since it is clearly failing at the same instant that the engine is. Gotta be related somehow.

Any suggestions?

THANKS!!!!

 

MAF?

 

OK...It sound likes the engine is stumbling upon acceleration. Do you have yur haynes manual...there is definitely a troubleshoot item about this. I dont have mine on me but maybe one of out fellow members will hook u up.

When did u install the K&N? A faulty MAF could cause a lean mix...but stumbling that violently is weird. Maybe spark plugs need to be changed. Maybe the fuel pump. Maybe the fuel injectors. MAybe the KS. I mentioned all this stuff first cuz as a DIY these are the easiest to change. I would start with the cheapest and work yur way up.

Unless u want to bite the bullet and go see the mechanic man hehe

 

Hey guys sorry been out of town for work. Still having the same symptoms. Ran by autozone earlier and here are my 3 codes:

P0105: MAP sensor. I've had this code pretty consistently in the past, have replaced MAP sensor and solenoid with boneyard parts a time or two in the last couple of years, but never had any driveability problems that I associated with the MAP. Could also be caused by a vacuum leak, which would not surprise me.

P0325: Knock sensor, the whipping boy of all 4th gen DTC's. I replaced this with new several years ago and also checked out the wiring at the connector. Code keeps coming back anyway and has for ages. Nothing new just yet...

P0605 (also 0301, please correct me if I'm wrong): THIS IS THE SCARY ONE! AAAAAAHHHHHH! The DTC Sticky says and I quote "ECU". This one I have never seen on my car. Some initial reading indicates that it might be worthwhile to check the power and grounding to the ECU, which looks like a fun chore (that's a lot of wires!) . Has anybody had this code, and how did you fix it? I'm totally open to suggestions! This may be the excuse I need to get a reflashed computer, so maybe its a good thing

HELP!

 

PS I'm about to start searching, will post what I find on the org.

 

If you're losing the tach as well, the first things I'd check are both CKPS' and the CPS. Wiring, sensors, and reference voltages.

There is no real diagnosis for P0605 other than clearing the code, idling for 30 seconds, and seeing whether or not it comes back. FWIW I've never seen a P0605 on a Maxima, it indicates a problem with internal calculations (likely a startup self-diagnostic check).

Also be sure to check the engine control harness where it curves around the right side strut tower, they're known to fail there. Give that harness a good shake, see if the symptoms return.

Power/ground is easy:

 

I have a similar concern. It's most noticeable at moderate throttle in 2nd gear, a steady, even pulsation that you can feel and hear. I have no clue what it is but I do have a bad downstream O2 sensor.

 

That's interesting about the harness by the pass side strut tower, because I hit a deer a couple of months ago and smashed the right side up pretty bad. I've been driving without the fender for most of that time so the harness is probably exposed to the elements a lot more than normal.

 

I have the same issue. Infact last year. My car used to die in idle sometimes. Checked my MAF and it had a bad connection, I then resoldered it and it was good, then this past spring the car started to buck/hesitate when I gave it a few pumps of gas and sometimes before a stop light or a stop sign I will just throw it in Neutral after the clutch and hit the breaks and my RPM will slam down to 300 and back up to 600 after. I am starting to think it is a MAP or a bad misfire.

 

That would have been about 2004.

 

To me, it sounds like a fuel problem. Either a fuel line or the fuel filter.

Also, as stated above, it could be the MAF, or a dirty throttle body.

How many miles are the car? Has routine maintenence been done on the engine? Anything recently?

 

You're right, on its face it acts like a fuel issue. But what makes me lean toward the computer is the fact that the tachometer fails simultaneously with the engine. And the dreaded ECM DTC.

I cleaned the TB about a year ago. If there's something going on with the MAF it's not a total failure because when the MAF goes it won't rev over 2500 rpm (just a limp home mode).

It's up to date on all routine maint. Has A ton of miles (well over 300K). Only recent change has really been the removal of the fender so I can turn left with a full size tire .

BTW I don't intend to drive it like this (that is looking like the terminator with half its face ripped off, LOL) long, I have all the parts I need to restore it except for a hood, and really just use it as an extra car since I have another.

 

But if the engine hesitates and is not revving then the tach will not be working either.

 

I'm not sure what you're saying. The actual speed of the engine isn't changing, this is going down the road with the clutch out. Or rather it is dropping, but not by 500-600 rpms as indicated by the tach.

I'm pretty sure what I'm seeing is the tach input is being lost, as opposed to the engine just stopping.

 

over 300k...thats awesome. I love these cars...they are indestructible

 

I was just saying that it sounds more like a fuel issue than an issue with the ECU ... But I'm no expert.

 

Tough as nails. And it was quite the pretty car until that little altrication with Bambi. Did I mention fast too? (for a 13 year old japanese 4-door)

I didn't mean to flame, sorry dude. I'm sure you've picked up a few things after 7 years on the org.

I'm chasing down the ECU issue ATM, that doesn't mean I've totally ruled out a fuel issue. But there would probably be multiple mis-fire codes as well as an O2 sensor/AFR code of some kind if it was starving for fuel. Not ruling anything out, but the ECM lines up with the symptoms.

 

These are also symptoms of bad coilpack(s). Surprised no one mentioned this.

 

Thanks Wiz!

I've been all over the coilpacks for a year or two now due to starting and other problems. Last time I had them out (a couple of months ago) they all looked good and passed the impedance checks. I also wrapped the tubes with fiberglass heat tape to control any arcing through the tubes. Not to say that they are still OK, though.

Would I expect to see a single-cylinder mis-fire code if a coilpack was going out? And if a coilpack was failing, could it cause the tachometer to fail too? Not criticizing, just trying to get my head around the theory.

 

You may or may not throw a code for a misfire, it's really just luck of the draw.

As far as the tach losing signal, a failing coil won't do that.

 

No worries ... Just trying to help

 

I'm thinking that since they occur together that they're both caused by the same problem. I printed off the pin table you posted, what should I be looking for on the CKPS pins? I'd assume a constant 5V signal on the ref? Or is ref just ground? I have a pretty nice automotive multimeter with the tach/dwell inductive pickup, if that's any help.

I won't have time to do much until the weekend, so I'm trying to get myself educated now...

 

****!!!!!!!

being an old school member I was afraid of this. =( and I believe wizard because he is like in the top10 of the most knowing maxima owners here. lol

This sucks bad coils are legit like 75$ a pop and there is no way to tell the bad one unless your good with a DMM and even that is not perfect because I bet heat would be a factor.

 

Like pmohr said, it's luck of the draw.

Keep in mind, I had this same exact problem as you a while ago. I tested the coilpacks per the FSM, Haynes etc and they checked out good believe it or not.

I still had my doubts. So, I swapped my coilpacks with a friend and sure enough, my problem went away! I then bought six new coilpacks (didn't bother to troubleshoot the bad coilpack(s)) and never looked back.

I'm not saying that you're guaranteed to fix your problem by getting new coils, but don't dismiss them just yet.

 

96gxe5spd Search for this thread : Defective Coil Pack Symptoms

a fellow member listed the symptoms for a defectic coil pack...

Im online tryin to find a pick of what the look like

 

This the one?

http://forums.maxima.org/4th-generat...-symptoms.html

I'm slowly warming up to this since I have had many of the symptoms listed here over the last few years. Any opinions on buying coilpacks off the for sale section? I've seen a few sets for sale there for pretty cheap, mayby buy a used set and see if it helps. Or a single new one and move it around until it clears up. A new set is a BUNCH of money!

 

No org members in your area you could swap/experiment with for 10 minutes and test things out? Free and easy!

 

Not any orgers in my town (columbia) that I know of. But do have a friend or two with maximas. Only one is a 4th gen, I'll need find out if the 5th gen uses the same coils. Got a buddy with an 01 model that I see pretty regularly.

 

Checked out a few websites and the 5th gen coils look different. bummer.

 

Front coils are the same, rears are different.

 

Well that may be a good start!

 

Hey PMOHR:

I just hooked up a 97 auto ECU just to make sure that wasn't the problem and it still has the symptoms. I'd like a little more detail on your post below. Like what steps to take to check the CPS and CKPS ref and pos signals, and how to backprobe that huge connector.

 

The best way is to use an OBD-II or CONSULT compliant scanner to monitor the crank/cam signals when the problem happens, but I suppose you could do it with a multimeter if you're quick enough.

As far as backprobing the ECU harness connector, basically just stick your multimeter's probe into the pin you want to check; most probes should fit in and make good contact.