I would agree that taking it to the stealership, but on my last trip up there I stopped and talked to 3 of the techs and 1 of the service advisers, and I asked them whether they thought it might be worth it to bring the car into them so they can hook it up to Consult and diagnose it for me, and all of them said No. They said that I have covered everything they would have tested and/or replaced, and there isn't really anywhere else for them to look. They were kind enough to take a look at my scan data and freeze data while I was up there too, and they said they weren't sure what to tell me.

They even complimented how knowledgeable I was about the whole thing, and said "There's quite a few techs up here that are ASE certified and don't know what to do with even simpler problems than the one you've got."

In any case, I'm not sure I completely understand the way that the ECU reads, detects, and reacts to information sent by the APP, I was theorizing based on what I read and researched about it. And I'm not sure that it would be a guaranteed fix either. I'm pretty convinced that my problem lies elsewhere if I'm honest, which is why I haven't spent the $200 to replace it yet. I'm heading out of town today so I can be with my woman and child on Mother's Day, so we'll see how the Max does on a 4 hour (220 mile) drive.

I changed the fuel pump this morning as well, with no change whatsoever. The next thing I'm doing is unbolting the exhaust at the end of the Y-pipe. I've got a rattle that has just developed from the resonator, and it sounds like the resonator is either falling apart or possibly stopped up. If it is clogged, then unbolting the exhaust at the Y should free it up and my problem would be solved. If that makes no difference, then the pre-cats are next.

-Nathan

Amave - Yes, it's an 02 6-Speed. It's not drive-by-wire, but it is fly-by-wire; meaning there is no cable linkage to the throttle assembly, it's all electric.

 

Keep us up to date man, you might also consider testing them injectors (unless you already have).

 

The electronic unit on the gas pedal is not sold by Nissan, but you can get it online. Part number 18919-5Y700... Also used on the Nissan x-trail, but I'm not sure if they use the same pedal.

 

I've quickly run through this thread, so forgive me if its been mentioned before, but how about a clogged or crimped exhaust? You should have someone feel the exhaust flow out of the tailpipe as you rev to 3000 rpms or so.

Or maybe your cat converter is dying but wont throw a code

DW

 

The main catalyst was removed by the previous owner. That was actually the very first thing I wanted to check. I have some suspicions about the exhaust, the resonator specifically, but with the way my fuel trim looks, I'm really leaning more towards pre cats, due to the fact that only bank 2 seems to be afflicted.

I haven't been able to do much in the past few days, as my grandmother passed away, so the car faded to the back for a while. But I'm getting ready to get back on it again, and I'm actually going to start at the intake manifold again. My brother pointed out a hissing sound that I was unaware of up to that point. It can only be heard if you put your ear all the way towards the firewall. It's definitely coming from the manifold, but I can't for the life of me figure out where on the manifold it's coming from while it's still attached, so I'm going to have to pull it off... Again... Lol.

Anyways, I'll keep up to date and let you know what happens.

Knight - Did you ever get that APPS installed? If so, did it cure the problem?

-Nathan

 

No, I've been working a ton of overtime. Hoping to do it thursday after my e-test

 

Cool. Very interested to see the outcome.

-Nathan

 

I have that hissing noise coming from the back of the i.m. , i had a vaccuum leak test performed on it and no leaks found. i wouldnt focus too much on it, i think its a "narmal hiss"

 

Hmmm.. that's pretty odd. Never heard of a motor that had a "normal hiss" from the manifold area. Haha. Thanks for letting me know that though. Saves me from tearing it apart to possibly find nothing. Much appreciated.

-Nathan

 

OK, so my problem is solved. Almost. I replaced that sensor on the gas pedal. I then hooked up my laptop with autoenginuity so I could do my idle air relearn. As i was scrolling through my list of sensors, i noticed that i can look at the voltage for accelerator sensor 1 & 2, and accelerator closed position. I checked them all out after the install and the voltages are all within spec. I could not get the idle air to reset though, so I am a little lean at idle. I'll try the old fashion gas pedal method on the weekend. I wish I had known autoenginuity could look at those signals, because I would have recorded before and after.
Any way I took it for a spin and I can get over 60kph with my foot to the floor in second, and over 80 kph in 3rd with it matted. I would "redline" at those numbers previosuly. That's as far as i got with it. On the way to work tomorrow i will test 4th and 5th.

 

Alright, I would like to see if anyone could answer something for me. I noticed that the VQ30 has butterfly valves for each of the cylinders that open under heavier acceleration. I found someone who had an issue where the valves weren't opening properly on one bank and it caused pretty sever bogging. Can anyone verify that this would not apply to VQ35 as well? If it does apply, I may look into that and see if that might be an issue.

An update on my car; I haven't done anything else to it recently and my car randomly, on 3 different occasions snapped out of it, and took off like a stabbed rat! Hauled *** all the way up to 5,500 before I shifted it, and then as soon as I shifted it went back to bogging. It did the same thing twice more, and the two later occurrences lasted through two gears rather than just one. I have no earthly clue where this came from, because the only thing I did right before that happened was install new headlight bulbs. Lol. I ran seafoam through it last week, and put the remainder of the bottle in the tank. Injectors coming unclogged maybe? I think I'll run another whole bottle through my next tank and see if that helps it at all.

-Nathan

 

You're describing the exact problem I had. 90% of the time the car would bounce off the ghost rev limit, but every once in a while it would fly right by and be good for a few shifts. Then it would be right back 10 minutes later.

As for your VIAS, not working, it doesn't break like the 3.0 ones do. They have problems with the little cup and it has to be repaired. Ours uses a solenoid, which will throw a code if it isn't working properly, but it wouldn't hurt to see if it is sucking air due to an unplugged vac line.

 

Well, I installed the NWP VIAS block off plate, which is for the valve attached to the side of the upper manifold. Do the 3.5's have individual butterfly valve's like the 3.0's? I'm kind of thinking you're already answering no, just want to make sure I understand correctly.

Anyways, you're saying APPS then? I'm actually thinking I'm going to test my injectors and make sure they are all spraying properly. It's kind of a pain, but this is still going a step beyond confusing at this point. Lol.

I've got my daughter with me while I'm in Texas, and I'm heading back home to Louisiana tomorrow, so I doubt I'll have any time to mess with it until I get back home. It does ok on the highway cruise between my shop here in north east Texas to south west Louisiana (220 miles). Hell, I even averaged 37.8 mpg on the trip here on Tuesday. Lol.

-Nathan

 

We have one big butterfly valve which you removed in favor of the block plate

 

OK. Gotcha. I figured that's why I wasn't finding anything about it. Lol.

-Nathan

 

Small update... The car moves like a stabbed rat when cold. Every time I start it up it feels as though it has the power it should, but as soon as it warms up to over ~140*F coolant temperature, it bogs down and continues it's mischievous ways. I haven't had much time to get after the front pre-cat yet. Being back home means that the Mrs. has me doing house work in lieu of automotive work.

But I digress, this sounds like a catalyst to me, but I want to make sure no one else has any other ideas that I might look into. If not, no worries, and I'll update after I've changed out the pre-cat.

-Nathan

 

well now we can say it may be heat related , and what happens to metal when it gets hot?

it expands



Sensors tend to do this when getting hot , try getting the specs for the coolant temp sensor and maybe hook up a DVOM when its cold and check the readings vs when it gets hot

 

Well the coolant temp sensor is brand new, as I replaced that immediately upon realizing it was acting up like it was only when warmed up. I still am yet to replace the secondary o2 sensor on bank 2 (which is still the only bank acting up according to my scan data), but other than that, everything else seems to be good to go. Any other sensors that might cause that kind of behavior?

-Nathan

 

I have a question mainly to make sure that I'm looking at this right. I tested my bank 2 IVT control solenoid because I have suspected it possibly causing my horrible bogging and terrible timing. The FSM calls for 7.0 - 7.5 ohms of resistance between terminals 1 and 2 at 68*F. It is currently about 90 degrees outside and it tested at 7.8.

My question is, with the temperature being 22 degrees higher than the specified testing temperature, wouldn't that cause the result to be lower than the specified range and not higher? If so, then it would be safe to assume that my bank 2 IVT is probably no good yea? Let me know any thoughts you all may have.

-Nathan

 

I have unhooked my bank 2 IVT solenoid completely and the car ran normally with it unplugged.
Reading through your post it appears that your P0300 is gone? So you are not getting any codes now?

 

Incorrect. I am still getting the P0300 code, and experiencing the same hesitation, bogging, and lack of power/acceleration.

Thanks for the info on the IVT solenoid mate. Definitely helpful. I have been waiting for something besides P0300 to pop up, but I have never once received any other codes. I'm in the process of pulling my bank 2 pre-cat, but that has been stalled by a bolt that is misbehaving. I'm waiting on some tools to come in, so I can proceed with that. My current thought is that the pre-cat is clogged, though I can't be sure. I am, for the most part, out of other options though, unless you can point me in a different direction.

Thanks again about the IVT solenoid. Cheers.

-Nathan

 

It may be possible that the ECU itself may be the issue. After it heats up from being in use it could somehow be causing the issue? I read once that bad solder joints on the board itself can cause hot/cold running issues. You might try early in the am or whenever it is the most cool in your area to startup the car and run it with the AC directed to the floor. Trying to keep the ECU as cool as possible and see what happens. Just a thought.

 

The symptom of your car acting OK when cold but unpredictable when warmed up suggests that your ECU is not readings all of its sensors OK. I would try adding a grounding kit and perhaps unplug and re-plug in the ecu harness.

DW

 

A sound thought. I had the same idea, and, unfortunately, it didn't work. It will only behave normally for about the first 15 seconds after cold start-up. I'm kind of leaning towards it being this pre-cat, since catalysts have been known to act weirdly when warm/hot vs. cold. I could be wrong though. This whole fiasco has kind of screwed my ability to logically problem solve it seems.

In any case, I have actually wondered about the grounds myself. The engine ground appears to be just sitting on a tab hanging off of the coolant runner just above the flywheel. Kind of an odd place for a ground in my mind. I've though that it would be a good idea to relocate that to a more solid ground, but didn't think that could be causing such a major issue, since it is, in fact, still grounded. I'll give it a look again though for sure.

-Nathan

 

If you go the improved ground route, check out these links

>
http://forums.maxima.org/audio-elect...other-how.html

http://forums.maxima.org/6th-generat...e-i-bored.html
<

 

I'm interested in knowing a bit more about this as well. When I checked mine yesterday, at about 90+ degrees, my reading was 8.0 on both front and back IVT solenoids. You're right with the spec, FSM says 7.0-7.5 ohms.

Could be, possibly, maybe, needing replaced?

My pre-cat in the back is definitely leaking.. so I wonder if it's clogged. Seems we have basically the sames issues

 

Yea I actually had to attach my ground when I bought my car a few months ago. The P O had left a great deal of things very suspect. In fact my ground was not even attached!
I ended up grounding it down by the starter. And now come to think of it, I was experiencing very "Random" issues prior to that. And the P0300. In addition to the ground issue I also tracked down a leak in my upper intake manifold due to a crack on the inside of the manifold itself. The PO over tightened it when installing the Intake spacers. It was the stud closest to the timing cover. So did you ever try removing the O2 sensor and seeing if it ran? I noticed someone mention that earlier in the thread and I honestly wondered if that would work? You seem to have replaced or tested everything except that header and the ECU itself.
Do you have a camera scope with a light on it? If so you could try removing the Bank 1 cam sensor and inserting your scope with the light on high to try and focus in on the signal plate. See if its chipped etc?

 

Bump!! Updates!!??

 

For first 15 second, the ECM is running in open loop. After that it adjust the mixture according the the O2 sensors. IF you want to play further, disconnected the PRIMARY O2 sensors and see if you get the performance all the time.

I will think of something while you do that experiment :-)

 

Yea, I did that a while back with no luck. I was hoping it would work so I could R&R and be done with this. Maybe next time. Lol.

As for updates, my wife hasn't been feeling well, and since I'm back home in Louisiana, I've been working as a full time dad taking care of my 9 month old. She's started feeling better this past weekend, so I relaxed a bit, and I'm going to dig back in to the Maxima tomorrow. We have a house out in the country where there's nothing to do anywhere close, so I haven't had any need to drive anywhere, and even then, I just take the Rav4.

In any case, I don't have and have never had a P0011/P0021 code for the IVT solenoid, but I've been reading about them and I think I'm going to pull them and clean them (similar to how one would clean an IACV) and see if that might help a little. I pulled them both this evening and noticed that there's oil on the gasket between the ports, so I'm wondering if the seal is bad and thus causing unequal pressure or pressure being dispersed to another port that it shouldn't. In more basic terms, think of it like a blown head gasket between the cylinders; there's no oil mixing with coolant (or vice-verse) or overheating, or even smoking, but it can, and most likely will, cause a power loss due to low and uneven compression.

I'm also pretty convinced, based on my experience and knowledge gained from reading up on other people's IVT issues, that it's entirely possible that this condition would not trigger an IVT code, but IVT solenoid malfunctions HAVE been known to cause P0300 codes. Anyways, just throwing out what's in my head to see what you all might think about it.

Any thoughts? Have I lost my mind yet?

I'm still yet to change out my pre-cat too btw, I started on it a week or so ago and was halted by a bolt that is almost completely rounded. It's the bottom most bolt of the three that connect the pre-cat to the Y-pipe. I hammered a 12 onto it and it still started rounding; that's how soft the metal is. If anyone has any nifty tricks that might help me get it off without ordering a damaged bolt extractor kit and a new bold, I'm all ears.

-Nathan

 

Perhaps you could try welding another head to the rounded nut to get it off?

 

Well, to be honest, I'm a pretty competent mechanic, but I'm about as useful as a poopy flavored lollipop when it comes to welding (kudos to anyone who gets that reference. Lol.). If I can't get it off the easy way, then I will probably torch the flanges off and weld new ones onto the Y-Pipe. I have a replacement pre-cat, so I don't particularly care about the flange on it, but I will need a flange on the Y-Pipe one way or another to bolt the new one to.

-Nathan

 

Pretty sure that oil on the IVT gasket is normal. I just went over the gasket with some copper spray gasket because I had some crusty oil build up in that area.

 

Alright good to know. Wasn't sure if that could possibly be the source of bogging or not. Thanks.

-Nathan

 

This might sound stupid simple, but I'll throw it out there - you never know...

I recently met this guy in my neighborhood with a 5.5gen. He was telling me of this severe bogging problem he was having, which turned out to be that there was too much oil in the engine. He drained the excess oil and problem solved!

 

Interesting. I've heard of an issue similar to that before. However, I only have one bank (Bank 2/Front) that is causing the issue. I, personally, doubt oil pressure would cause that kind of reaction only on one bank. I could be wrong though. It wouldn't be the first time. Lol.

-Nathan

 

I've read through this entire thread. By the first page alone I was thinking clogged exhaust system. The low MAF numbers even point to it, so does the uneven fuel trims as well as the cold -vs- hot performance.
Spot on, clogged catalyst.
Your engine is an air pump. Low MAF numbers means it's not pumping enough air.
The uneven fuel trims indicates one cylinder bank is getting enough air, the other is not.

Everybody is looking at spark and fuel, nobody picked up on the lack of air being pumped through it?
MAF READING or Fuel Trims?

You have a blockage in your exhaust system. I'll bet anything on it.

I had a Lincoln that did the cold-vs-hot performance loss. No check engine light ever appeared. It had a split exhaust system, we looked at everything even replaced the MAF sensor because of the "low readings". Turned it over to the dealer after we couldn't figure it out. Only took them 20 minutes to discover the clogged cat. The tech told me, MAF + Uneven Fuel trims was a dead giveaway.

 

Umm, back in the day, May 13th, this guy suggested it too

 

Seems nobody is listening to us then. I'm 99.9% sure that's his issue.

 

Yea, I assumed it was a clog from the the first drive home with it before I even read any scan data. I had the exhaust system inspected and I was told the exhaust system was most likely not the problem, so I focused elsewhere first. I am in the midst of changing out the front pre-cat, but I've been hung up by a badly damaged bolt and the fact that I'm at home, 220 miles away from my shop. I may have to drive it like this all the way back to the shop so I can get to my good tools to get it done.

In any case, I probably should have gone with my gut and changed the pre-cats out straight away, but, as they say, hindsight is 20/20.

-Nathan