I have a 2000 maxima 3.0 that refuses to run right. At WOT it bogs like it's not getting the right amount of fuel and air.

Things I replaced and did.

Whole new exhaust pre cats and cat. Heads back.
New o2 sensors all three.
New fuel rail including injectors and regulators.
New fuel pump. (Whole unit) makes 47lbs up front.
New tps including reset.
New Plenum. Plus gaskets.
New throttle body.
New Maf. Including reset.
New coils. All six
New plugs.
And fresh updated calibration.
New pcv valve.
Also checked for water in the ecm plug. Nothing. Cleaned anyway.(contact cleaner)
Pined everything for the engine to the ecm. (Everything is good)

Same results at WOT.

Checked for intake leaks and nothing.

Everything done with consult 2.

I need a brain on this one.. help me please.

 

I'm going to assume that you used OEM parts (plugs, maf, coils...etc) and will move on:

Do you have a Consult? Have you pulled any logs from when the bogging is happening? How many miles on your ride? Have you considered the CKS?

When does it bog (TPS based, RPM based, both?, cold/hot...etc)? This would be pretty helpful in helping to diagnose. I realize you said WOT, but usually that means a certain throttle % threshold or above (IE, 70% +). Does it bog at 1500 RPM @ WOT? Does it only bog above 5000 RPM @ WOT?

When did it start? Were there any CEL's? If so, what were they? Did ANYthing you do make any impact at all?

 

Yes everything is from Nissan. It has no power when driving above 1500rpm. And when it does get some it lunges. It makes no power at the mid/ higher rpm range no my friends got a consult 2 but he is out of town. Everything I do seems to help just a little more but it's still crap. The weird thing is you can turn the maf about 35degrees clockwise in the housing and it builds rpm way faster but still drives like crap.

 

your MAF is bad and installed wrong take pics and post

 

lol.

Maybe you should have mentioned that (OP). I second the maf.

 

What's this? You're like the 3rd 5th gen I've seen with mysterious WOT issues.

DW

 

Lmfao.. I am a mechanic. I didn't install it wrong. Not that dumb guys. Mechanic. 15 hours a day 6 days a week.

 

I didn't say you installed it wrong, but it sounds like a bad maf to me.
You noted some telltale signs of a bad MAF.

Now if you replaced it, perhaps you should test the two in other vehicles and test your wiring to the MAF.

Do you really have no CEL codes (stored) right now?
As I mentioned in my first post check the crank sensor!

 

No cel. I confirmed it was good a long time ago on another 2k we have here on the lot. Replaced ckp and cmp a minute ago. Not any better. As i stated in my first post ive poked an prodded on the whole front of the car back to the ecm. everything checked out fine. Im pulling my hair out on this one guys.. AHHHHHHH!!!!!!

 

 

I guess that means u have nothing else to think of?lol

 

i'd say maf too but you've already replaced that lol... maybe wiring from maf to ecu is chewed up? or the maf sensor plug?

 

Well it sounds like he has "poked an prodded on the whole front of the car back to the ecm. everything checked out fine"

So our work is done here boys, pack it up...























Have you tried another ECU (temp) to see if yours is kaput?

 

Checked both and I also did the relearn. The snapon Verus I have on hand here says everything working fine. But one weird thing I keep seeing is when u have it at WOT the short term and long term fuel go to 0. The g/s for The air flow go to 25.6 that's the highest I have seen it so far.. at idle the short term is at 6 and the long term at 8. Untill u give it gas.

 

Curious: Is the fuel pressure on the 3.0 VQ vacuum or electronically regulated/controlled?
How is the CPS (crank pos sensor)? Those things catch hell.

 

I'm willing to bet you have an air or vacuum leak somewhere. Usual suspect is a crack in the accordion hose from the helmholtz manifold to the throttle body.

 

I have sprayed about $50 worth of brake parts cleaner and starter around the whole upper engine.

 

Vacuume.

 

You've got a whole list of abbreviations that made me cross eyed. I'm simple that way sometimes.
So CPS good? Hooked a fuel pressure gauge to the line and measured across throttle position/rpm range?
May be off, but my gut and experience with your symptoms and current diagnosis says fuel issue. Those fpr's can go bad time to time. Of course, it would also be easy to verify vacuum at the fpr as well, just to be thorough!

 

Fuelp pump or injectors?...

 

Said replaced in op. Said fuel regulator replaced too. Still sounds like the place to focus. I want to know fuel pressure readings.

 

Did you reprogram the ecu to recognize the newer MAF? They have upgraded them from the ****ty originals

 

I see this thread is a little old, but maybe I can inject some thought here too (since I see no post of a resolve found).
I am working on a 2000 Max with the same issues... We just picked this one up from a salvage yard as a builder car. Brought it home, removed the oil pan to replace the gaskets and o-rings, removed the intake plenum to replace all gaskets/seals/o-rings/bad vac lines/plugs/pcv/etc, replaced the accordian hose cuz it was shredded, motor flush and fresh oil change...
I began with a lean mixture code (assumed to be from the accordian... after replace and code reset, it has not triggered again)... I had noticed a lack of power and delayed shift once I got up to about 40mph, but nothing sizeable... Checked the code and cleared it, then immediately went to town on inspection and repair of anything noticeably faulty.
Upon reassembly, motor started right up fine. Idle is nice and smooth, right where it needs to be. Now, herein lies the problem... When revving up the motor, after about 40-46% throttle the fuel trim drops to 0, as if the rev limiter was kicking in to protect the motor. I have traced the datastream of IAT, MAF, o2, FT (short and long), RPMs, and engine load while diagnosing this... The IAT remains steady, and the MAF readings are a steady variable throughout the increase in RPMs... Now here is where it gets a little trickier... I can sit on a low steady throttle incline and bring the motor up over 5000 RPMS until the power valve opens up. The RPMs immediately drop down to about 4500, power valve closes, and back to normal slow climb up to over 5000 again. If I compensate with ANY little bit more throttle, it bogs down, fuel trim cuts to 0...
Now, on the other hand, from idle, all the way up the rpms band... ANY time I hit above approx 40% TPS trim, it bogs and cuts fuel trim to 0 again. If this helps anyone out there pull a miracle cure from somewhere the sun doesn't shine... I can hit redline ONLY if I do it in short WOT bursts of throttle. (i.e: WOT for 1 second, let off, immediately repeat, over and over...) No bog if I let off the throttle right away and get right back on it... My generic Actron 9185 isn't fast enough to graph the results accurately tho, and for now I have no access to any better tools to try and read this erratic throttle approach...
I will say this much though... I know for a fact the fuel pressure is not an issue, there are no remaining vac leaks, and I am fairly convinced the MAF is good too since the quick bursts works just fine... Now I turn it over to anyone with any ideas...

 

maybe its power related? Maybe your alternator has a bad voltage reg, but its not enough to trip a fuse, that would explain at wot

thats my best guess, keep us updated

 

You do know the maf is directional right!

 

The only way to diagnose the mafs its with consults data log.

It could be wiring to the mafs, mafs, etc. until you get a data log you can't say the mafs circuit and components are ok

 

That would be funny as hell if it's installed facing the wrong direction.

 

Well he said he was rotating it correct?

 

You can't install them backwards, can you? I thought it wasn't possible

 

Well if he is turing it the screws aint in it

 

He is talking about turning the whole housing I think, not just spinning the mafs lol

Anyways, id try an injector sub harness, $60 from z1 autosports. The knock sensor and tps and injector plugs all get replaced.

I had some crazy issues that went away after replacing it. I found the knock sensor write corroded, not sure that was the cause, but its possible.

Very cheap part that can cause a lot of issues

 

Not a bad guess for once, but no It wouldn't be that drastic and it would throw codes for miss fires, the sensors and ect.

 

An update and resolve for my sluggish Max...
After a thorough scan through NDS (Nissan DataScan cuz I'm too poor for a ConsultII), I found that as soon as I applied enough throttle, the MAF stopped reading properly, and even though it read high alpha readings, it wasn't reading the CORRECT airflow... Pulled out the MAF and cleaned the bloody hell out of it, and all is well now.
If you would like to test for this scenario, and you are too timid to actually pull the MAF Sensor apart, there is an easy way. This assumes you are pulling a lean running code (usually P0171 or P0174)... Start the ending and let it idle. Remove the air filter from the housing and you will see the front end of the MAF Sensor. If you race the engine and it bogs out, put your hand in front of the sensor down inside the airbox. You want to be really CAREFUL here not to damage the MAF Sensor, and also be aware that all of the engine vacuum is coming from that spot, so your hand will be sucked up to it rather forcefully.... If you can block half of the air, and now the engine runs normal, you most likely have a dirty MAF.
On a sidebar note though... My knock sensor is in perfect working order, and so is the subharness to it, but I was still getting a P0325 code in relation to the ECU trying to compensate for the MAF readings, causing detonation. After the clean running MAF was re-installed, and the motor was ran, NO new codes popped up.
All in all... Now everything runs great, and all it took was half a can of MAF Sensor cleaner. No new KS, MAF, O2 Sensors... Not too shabby.

***EDIT***
In my woes on this motor, I found the ACTUAL source of my WOT bog issue.
The MAF was dirty, yes; but cleaning it fixed the readings on that. I STILL had a bog at wide-open throttle, though not as bad now. In doing a little more searching, I found that my VIAS valve control was bad. Apparently, this is a known and common issue with Gen 5's. From the outside, the control lever engaged properly... BUT, from the INSIDE the, control valve wasn't actuating due to a faulty component in the control mechanism. After disassembly, some JB KWIK Weld, and a few hours of set time, NOW all is well... Such a profound diagnosis process for such a simple fix...
I found the info for my VIAS problem at
VIAS Fix