boris

I think would make sense to check your coolant temperature sensor

capframe

iTrader: (1)

Yeah, that's a very good idea but unfortunately I listed some of the parts I already replaced in the opening thread and the Coolant Temp Sensor is one of them.
Its amazing how a car like this with such an advanced ECU lost sooo much power yet not a hint of SES/Check Engine Light, YIKES!

Child_uv_KoRn

iTrader: (7)

I'm starting to think no one has even scanned for codes, seriously. Have you taken it to like Advance or wherever and watched them do it?

Tards you've been talking to apparently think no CEL = no codes.

Scottwax

iTrader: (8)

You need someone with an advanced scanner who can not only find any pending codes, but also examine how your engine is running-coolant temperature, ignition timing, lean or rich, etc.

capframe

iTrader: (1)

I've tried many places but apparently there aren't any smart technicians that know how to use the scanner like that or they don't care as they'd rather crank guaranteed business instead of dealing with anything complex...

Here's a sample of my trouble with idiots and what they said:
Nissan Dealer 1: Can't find any problem with your car...

Nissan Dealer 2: Yeah, we feel the highly reduced performance but no SES light, can't help, so we'll file this under " no problem found "

Shop 1: I'm sorry but without a SES light it's too hard, we don't have time.

Shop 2: Sorry, can't see a problem with your car, if you lost performance you need to go to a high-performance tuner shop.

" High Perf shop 1 ": Oh yeah, we can find the problem, I definitely feel what you're talking about,... [ next day come in to drop off the car ] I'm sorry but your car has so many CAT converters I'm afraid we would need too many labor hours to find the problem and your best bet would be the dealer...

Now, if u know any smart techicians in Orange County, CA I would love to know so I can take my car there.
But a consumer shouldn't have to be in a forum and go to 20 different shops to get their car fixed so it seems to me like the brains of car technicians have not caught up to car technology.

Thanks to the EPA, new cars are now forced to have more failure prone components like CATs.

I think as cars from around year ~2000-2003 start to get older and pick up miles more and more people will be taking their cars to be fixed and be turned away OR be robbed of thousands upon thousands to throw parts at the problem.

One of the technicians that wanted to help but then turned me away pretty much wanted to charge me $300 to start off by replacing " knock sensor " for ABSOLUTELY NO REASON ", he didn't want to TEST it, take it out and INSPECT IT, he just wanted to replace it. I never mentioned any " forum " EVER because I think it's a bad idea and but the idiot mentioned that " Maximas are prone to Knock sensor break downs " I reminded him that it didn't apply to the 2003 Maxima but the older ones, he realized his mistake and that really got him embarrassed and soon after came up with excuses and turned me away.

boris

+1. There might be some stored codes that don't trigger the light. I would check it first to make sure.

capframe

iTrader: (1)

Both Nissan stealerships have made this exact point, that the CEL light doesn't always come on and there may be ghost codes and we'll scan bla bla, both have told me that there are no codes whatsoever after the scan.

I wish it were that easy.

BUT, the stealerships are kind of retarded so thanks for the tip...I will have the car scanned for codes again for the heck of it...

KRRZ350

iTrader: (29)

Primary o2's like to fail but not give any codes, or only the occasional p0300 (random/multiple cyl misfire) once warm. This problem wouldn't apply to WOT though, are you sure it's sluggish WOT when warm?

You can also unplug your primaries and secondaries and see how it runs even after it's warmed up, or have a good tech take a look at your fuel trims.

Stormzusmc

iTrader: (17)

^ For me yeah it's during WOT...I had a code a while ago for exhaust leak if I remember correctly, but it went away kind of odd.

capframe

iTrader: (1)

How many primary O2 sensors are there? I see one near the fans, is that 1 of X or is that THE only primary one? ...and is that the one you are talking about when you say it likes to fail but no SES?

OOmaxSE

iTrader: (19)

There are two primary sensors and two secondaries.

capframe

iTrader: (1)

Where exactly are the two primary sensors located?

Derrick2k2SE

iTrader: (3)

The primary o2 sensors are on the exhaust manifolds right before the precats. The one up front is easy to see. There's one on the other side of the motor in a similar location. The computer reads their output and adjusts fuel trim accordingly. A mechanic can easily plug in and read their output during any driving condition.

The secondary o2 sensors are after the precats. All they do is tell if the precats are working properly and throw a code if they aren't. The computer doesn't use them for any tuning at all.

capframe

iTrader: (1)

Thank you for that...so is it true that the primary O2 sensors can be screwed up in such a way that the ECU will not throw a code but make the car run like crap? that's actually possible? not that I don't believe the other people that vaguely mentioned such possibility but I want to understand how that could be possible in a slightly detailed fashion.

Stormzusmc

iTrader: (17)

OP does your 1/2 throttle feel the same as full throttle at higher speeds once the car warms up?

capframe

iTrader: (1)

If I'm understanding you correctly...I think so...when I floor it at higher speeds it is so weak that it feels like I'm only doing half throttle.

Before I had this problem I used to floor it on the freeway and the car would down-shift and everyone on the freeway would hear the cold air intake and crap their pants thinking a fighter jet was about to drop a bomb but it was just me...but now when I floor it it sounds like Mary Kate blowing air to make bubbles, so weeeak...and not just weak but actually GASPING for air, seriously, I floor it and the car seems like it is breathing, it's crazy.

Stormzusmc

iTrader: (17)

If you were to downshift manually (in your auto) to 2nd at 60 and go full throttle, it feels the same as half correct?

capframe

iTrader: (1)

yes

Stormzusmc

iTrader: (17)

Yeah I get the same thing...

Child_uv_KoRn

iTrader: (7)

But does the engine sound like it's working harder (it's noisier)? If you have an intake it should scream, but sound abnormal compared to a properly running engine, like it's desperate.

Just tryin to get a feel for what it's doing.

Stormzusmc

iTrader: (17)

I can't hear the intake during normal operation or WOT. Only when I initially hammer down I hear the "whoosh" "sucking" noise then my exhaust overpowers the intake sound.

With that, it sounds like the car is working harder during full and not as hard during 1/2, but as stated feels the same and the time from 60-80 is very similar.

KRRZ350

iTrader: (29)

Couldn't have said it better myself, but just want to add that on the 5.5 gen ecu- if a fault is detected with a primary o2 (and code present) it will actually still go into closed loop and read off of the secondary/s.


Yes it is possible, if you read the 0300 thread right near hear you will see that on maximusmorpheus car I actually found one of his o2's to be straight up 100% broken off (the internal ceramic tip was rattling around loose) and yet it didn't come up with any codes except 0300. I think I looked at the fuel trims though and saw that it was out of whack first before I decided to pull it, can't remember though.

But again, if it is definitly 100% a problem during WOT it's not the o2's.

Maybe try verifying that the throttle is fully opening, no carpet stuck under the pedal etc? Once the car is warmed up shut it down, pop the intake tube off and have an assistant mash the gas w/keyon and watch the throttle plate move? Do it cold first so you can see if there is a noticeable difference? I'm just tossing ideas out there, it's easy enough to check. Just dont ever touch that plate with the tb plugged in, in fact I never ever touch or clean them unless it stalls upon start-up or idle issue/code that a relearn won't fix, so basically just watch it and don't touch or clean it, it's not giving you a problem.

pmohr

iTrader: (26)

Just remember it's got to be in gear with the key on (with the engine not running) in order for the throttle plate to move.

Never noticed this thread before...time for a bit of reading.

Stormzusmc

iTrader: (17)

thanks for chiming in, im beginning to think its in my head lolz

pmohr

iTrader: (26)

At this point, personally I'd be taking the car in for a dyno. Not only will it give you absolute numbers (making sure your butt dyno isn't broken), but it also gives relatively consistent conditions under which to test. At least one run cold and one at operating temp.

I'd also try to find a shop that has a copy of Cipher, and can do a complete datalog during the runs. A Z/G performance shop is best for this.

Dynos typically vary from ~$35 (dyno day type event) to $80 for 2 or 3 pulls.

Between a DRF and a Cipher (or similar, but preferably Cipher/CONSULT-II) datalog, it should be relatively easy to identify the problem.

Stormzusmc

iTrader: (17)

I was going to be doing a dyno anyway so I'll have to talk with a couple shops around here and see if they have a Cipher or Consult II...I know dynos are 75 for 3 pulls here. It won't be for at least a week or 2 thought (I will be out of town) =(.

capframe

iTrader: (1)

Thank you for this easy check-up tip but it looks like the throttle is in fact fully opening.

capframe

iTrader: (1)

Please help me figure out what in the world this TUBE is!

While I was taking apart the Cold Air Intake to inspect the throttle, I discovered this weird lonely tube.

The tube was tangled and stuffed in between a bunch of crap and the end of the tube was NOT connected to anything.

I untagled the tube, brought it to surface, pulled it to an open area and took photos for your analysis:

http://www.pascalonline.net/nissan/tube/

Thank you.

Reizy

iTrader: (48)

Its a breather tube for the transmission. Its supposed to be open on the end.

KRRZ350

iTrader: (29)

Yeah I was thinking of mentioning dyno also, but first, something stupid and easy to check: Get the car warm, jack up the rear wheels and make sure the rear brakes aren't dragging.

Stormzusmc

iTrader: (17)

^ I understand the concept, but explain to me how that would work when the car is warm?

pmohr

iTrader: (26)

It wouldn't really if you sit there, let it idle until it's warmed up, then notice the loss of power. However, if you start it up, and drive it around until it's warm, the brakes dragging could indeed be a trouble area.

Stormzusmc

iTrader: (17)

How would the car being warm create dragging of the brakes....metal expanding...?

pmohr

iTrader: (26)

Essentially, yes.

When you're driving around and getting it warmed up, more than likely you would be using the brakes, and you know how the rear calipers pistons are prone to sticking.

But the problems apparently are directly related to coolant temperature, regardless of the car having been driven or not; I wouldn't suspect the brakes right off, but it never hurts to hit them with an IR thermometer.

Stormzusmc

iTrader: (17)

I can give it a quick check, not hard at all. After driving today and listening to how the engine sounds cold and warm is different. When cold it sounds...more hollow and metal sounding (if thats a way to describe thats understandable) working harder and running faster... ..when warm it sounds smoother but working just as hard and I can hear what sounds more like air rushing, all that coupled with less power...

Child_uv_KoRn

iTrader: (7)

Since it's not cold anymore, I say rig the thermostat haha. If the ECU thinks it's always cold, then you'll be in business if you can keep the valve open.

But I guess you couldn't idle or do heavy city driving haha.

pmohr

iTrader: (26)

That's just a ridiculous bandaid, really.

Besides, warm engine == efficient engine.

Child_uv_KoRn

iTrader: (7)

Maybe so, but I wish mine was packed in ice all the time. I can feel major power loss when it gets warm outside. I do need IM spacers, but I'm waiting on money (getting decent amount). I'm thinkin about blowing it on a S/C....

capframe

iTrader: (1)

haha please see this video, haha

http://www.youtube.com/watch?v=y0Hr_2bRsY4

Stormzusmc

iTrader: (17)

Hmm probably not..doesnt sound good for the engine lol

i got the spacers...the uim isnt cool to the touch after hard driving for 20 min but i can touch it...lol