VinneousMaximus

So, all of a sudden I'm feeling like something isn't right with the ride. Now I was riding my motorcycle hours before noticing this, but I'm pretty in tune with how she runs, and things just didn't seem right. I seem to be getting a lag/hesitation most noticeably around the 1800-2000rpm range, mainly when driving city at around 25-35. Now normally I can apply gas in such a way that she picks up fluently and quickly, but now, not so much. It feels like I really have to gas it to get her to move. I may be making it sound more drastic that it really is, but it is that noticeable to me. Then when getting on it harder she feels like she's lagging ever so slightly, and I sincerely feel like she's got a very very very slight stutter. Nothing while cruising, only accelerating. And seems less noticeable right after start-up. I'm being real **** about this, but really feel like something is definitely wrong. Could it be some not so great gas killing me? I did put in 2, not even full, tanks of 89 just before this happened. Could it have taken a little bit for the PC to adjust to that, as I've only ever used premium since birth?

Anyone got anything, this is killing me. I may stop in at my dealer who is pretty good. maybe he can throw his scan tool on it and check the IAT, and TPS readings? Oh, no codes thrown obviously. Sorry so long winded.

whitem1ke88

iTrader: (2)

Try mid or premium grade gas! I can't run reg.

slvrmax7

iTrader: (4)

I'd say it's the gas, I noticed a pretty substantial difference when some moron gas-pumper in NJ put in 89 instead of 93.

MaXXXpower

iTrader: (4)

^^I agree. Sounds like my car when the wife puts in 89.

Shoey1

octane dosnt give you more HP it is just more stable and less prone to preignition or detonation when hot or in a high compression motor...im in school right now getting my mechanics license so im not just some random internet factoid guy...heres proof

http://en.wikipedia.org/wiki/Octane_rating


i would be looking more in the direction of spark plugs out of gap, clogged fuel filter, or weak coils. your tech probably wont be able to tell you much without a check engine light on. the new scanner at our shop is a top of the line snap on unit, and it wont tell you much unless the check engine light is on.

DeusExMaxima

iTrader: (1)

But the gas door does indicate that 91 is recommended for MAXIMUM performance

STARR

iTrader: (1)

I've read that the CVT puts the ECM in optimum performance mode all the time, I guess having a trans that is suppose to run the engine at peak performance will require the maximum performance needing premium

jcalabria

All true IF octane is the only variable. However, changes in ignition timing WILL effect both power and efficiency. The higher octane fuel keeps the engine from retarding the timing when knock is present (more likely with lower octane fuel), therefore preserving the power and efficiency an advanced spark curve allows.

redls1

iTrader: (2)

Ive been using lower octane gas in the wifes car and havent noticed a difference. I dont know how the nissan cvt trans work but could it be trans related ? Ive had cars before that were low on trans fluid and had a hesitation.

Apollos2

iTrader: (16)

I always use premium, but it's getting real tough when it was $4.03 last night when I filled it up.

jrpaytonAlpha06

$4.03?!!! Please UPS me some. I just paid $4.29 a gallon in Largo, MD!

To OP, as everyone said, try using 93.

Lovemycar

right it sounds like you need to run some 93 up in that ***** -jrpaytonAlpha06 4.03
in mass i'm paying 4.05 a gal

VinneousMaximus

Thanks all. I through a bottle of Techron in her, and premium. Trying to get through it to fill her up again. I'll keep you posted as time goes on. Keep your fingers crossed.

xorbitman

iTrader: (1)

The ECU needs time to adjust to the lower octane...more than two fillups IMO. In Europe you can''t buy gas lower than 100 octane. Up here in Canada PetroCanada sells 94 octane and my Max seems to really like this stuff. It was $1.53/ liter today....that works out to $5.50 a us gallon and that's not factoring the fact that the Canadian Dollar is now higher than the US @ 1.02 or 2%! Ouch!

BlackSpeed

iTrader: (1)

$4.19 in South Atlanta. It's killing my RC Helicopter money....

ramberg

iTrader: (29)

Reg gas here in NYC is $4.10 and 93 is about $4.40.

ramberg

iTrader: (29)

Try a couple of tanks of high test. I can't see it being the fuel filter which is in the tank unless you pumped in dirty gas.

Question when you filled up last time was the tanker truck unloading gas. This happened to me a long time ago all the dirt comes up from the bottom of the tank than settles back to the bottom. I hand to get my whole fuel system cleaned out. From that to to now when I see the tanker in the sation I move on.

jcalabria

Any chance you had your A/C button off during the cold months and just started using it again? Lately I can really feel my compressor cycling, especially in that same 25-35 mph city driving range you mentioned. It feels much like what you describe - sort of a stutter and a lag. Might want to turn the A/C off and see if any difference is noticed.

Mine is also surging slightly when stopped at traffic light when the compressor cycles. If your foot isn't TIGHT on the brake the car will actually start moving forward when the compressor kicks on. If you just put on the e-brake you can actually feel the rear end squat each time the compressor cycles on. Funny thing is you see absolutely no movement in the tach and no change in engine tone, but it still starts pulling.

BTW, the good stuff just cracked the $4.00 mark here in Charlotte - but still only $.15 more than regular. Don't forget that Memorial Day weekend has ALWAYS been a high-priced gas time (never $4 before, though).

modenaf1

iTrader: (3)

I'm not some random internet factoid guy either and anyone can tell you that our Nissan ECU's base ignition timing advance off the knock sensor. So if you think about it, higher octane gas does what? It is more stable. It is less volatile, it won't pre-ignite as easily. This means the ECU can advance the ignition timing. And of course, advancing the timing does yield more power....

jcalabria

Not ALL the time - only if you drive it that way. There are lots of personalities in there to play with. If I restrain my right foot, I can go for weeks at a time in my daily commute (up to 50 MPH) and never exceed 2000 rpm in my Max and still be pulling away from everyone at the traffic lights.

When you drive it that way, the tranny short-shifts you down to sub-1500 rpm even while you are accelerating (yes, it is somewhat strange to be accelerating yet see your tach sliding downward). Those low rpm/high load conditions are VERY conducive to knock - and it is here that premium fuel provides the most advantage.

I have played, tested, experimented and learned a bunch about my CVT's behavior. When driven with a somewhat heavier foot (but not necessarily WOT), or in steady state highway cruise conditions - there is nothing to be gained by using premium fuel. Those conditions do not encourage knock. If there is no knock, there is no advantage to having the higher octane fuel. However, the econo-mode conditions I described above are VERY knock conducive and there is a noticeable difference in engine response and fuel economy when the ignition timing is inevitably retarded to keep the knock in check. Premium does provide an advantage in these conditions because it directly prevents knock and thereby indirectly prevents retarded ignition timing. That retarded ignition timing is what hurts both efficiency and torque.

My '07 VQ35/CVT returns considerably higher suburban driving mileage than my '03 VQ35/4AT ever did. This is true with either regular or premium, but the difference is greater with premium. With the small difference in cost for premium here in Charlotte (< 4% right now), and I can consistently get 7-8% better mileage driving that way, the premium is a good deal. If your cost differential for premium is higher, or you're doing more low-load highway driving that cannot gain anything from the knock-inhibiting qualities of premium fuel, then premium is not a good deal.

jcalabria

Yes! Yes! Yes!... except that the timing is normally advanced regardless of fuel and is retarded only in response to knock. The ECU doesn't advance the timing in response to the fuel... it retards it in response to knock. From the '07 service manual:This is why people can legitimately report that they sense no difference between fuel types. If their driving conditions do not encourage knock: no knock... no retardation... no difference.

This is is also what makes statements about the ECU needing time to "adapt" to different fuels pure poppycock, at least in terms of ignition control. The ECU will keep timing advanced and will only retard timing if it senses knock. This occurs instantaneously and re-advances immediately unless knocking reoccurs. There is no adaptation period (although there may be some dilution issues in the tank when fuel types are changed), and there is no "fuel type sensor" of any kind other than the knock sensor.

The manual also indicates that fuel injection timing control has the the knock sensor as an input. Although the manual does not state this (nor does it contradict it), the normal assumption is that richening the air-fuel ratio will also reduce knock. Knowing that, we can surmise that this is what the injection system will do if knock is sensed, further increasing fuel consumption. It is here that "adaptation time" might come into play, as the fuel injection timing has a "fuel trim" function with both a short term (instantaneous) adjustment range and a long term adjustment range meant to keep the short term adjustment range "in the window" needed for current driving conditions. However, the manual does not state what the relative timeframes are, nor does it state that the knock sensor is a control input for this function - just that it maintains the ability of the injection system to keep the correct A/F ratio for current conditions.

VinneousMaximus

Ok, so i mentioned that I was going to maybe take her in. i did today and met with my tech who took good care of me when i had her in the shop for almsot 3 weeks for the receiver module.. Anyway, this tech is real good, so good that he was telling me that he is now the Ace and only mechanic at this place that has been trained to work on the new GT-R's coming soon. Said that they had to have someone trained before the dealership was even allowed to apply to sell the car. Again, anwayz, as I get off topic. So I stopped by, no appointment mind you, and he's there. I start telling him of my conditions. At first he's thinking that it could be just a bad tank of gas, told me to use it fast, and keep plugging premium in it. After a little more talk and a few more conditions popping into my head under all the conditions that I have been trying to remember, he starts thinking that maybe the TPS unit (all in one with the IAT with the electric throttle control), but really can't tell for sure. He said he could try relearning it, but the tranny needed to be cold for this, so no go. So he had some time and asked if I had the car with me, well duh, of course. He grabbed his consult (scan tool) and we went out to the car. Plugged in and BAM!!! Knock sensor was showing faults. He tells me that this should be it, and that the knock sensor wouldn't have set a MIL. Proceeded that with a " yeah, these are real fun to change too!!!" says that there in the valley under the intake, no problem though.

So this is hopefully the culprit. I will have it in in a few weeks as the dealership is moving into a new building soon and he recommended to wait a few weeks. I told him about the knocking in the suspension (struts) and he said no problem, just tell the service writer that I'm hearing a clunk and he'll just change out the strut. I even got real lucky, he had some stut bearings just laying on his cart. He told me to take them and leave the, on the seat when I come in. Nissan won't replace with the strut since their fine, but he'll do them anyway for me since it's apart then.

Lastly, he did mention that these cars like/need premium and that I should only use it. He was gonna tell me something further but someone walked in and needed something.

SOrry so long, but thought I'd share the good news.

monstorc28

i am a mechanic, i have seen a lot of complaints about car lagging and not taking power and come to find out it's just the low octane gas. most time we use a additive from Strauss call fuel-on power and that always remedy a bad gas problem.

lightonthehill

I guess I have been very lucky. Since the manual for my '04 said the engine was designed to run on regular gas, but premium was recommended for maximum performance, I went with premium until the price gap widened between grades. I then moved to mid-grade with no problems.

Once the price gap around here reached 40 cents a gallon, I switched to regular, and still had no problems. The price gap between regular and premium at some stations near me is now at 49 cents a gallon and growing. That is over $8 a tank. I have tried various driving situations, from trying to lug the engine at low speeds to all-out accelleration, and the car purrs like a kitten on regular (major brands only) gas under all conditions. And we all know octane has no connection to MPG, so I still get around 28 or 29 MPG on freeway trips, and 25 to 26 in suburban driving.

But I have the 5 speed tiptronic, and I have no idea what the setup might be for CVT's, or whether CVT equipped Maximas would perform well on regular.