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Maxima 5-speed Problems

bigk200bigk200 Posts: 170
edited March 21 in Nissan
Just when things were getting interesting, "L8
Apex" pulls the rug out from under us!

I hope everyone finds this new space.
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Comments

  • bigk200bigk200 Posts: 170
    For quick and easy reference for everyone, I will repost the info that I recently posted in previous board.
  • bigk200bigk200 Posts: 170
    OK, I’ve been holding out on all of you for a
    while, and now I am going to finally explain the
    “fuel-cut” problem in detail. I have tried for
    several weeks to persuade a Nissan zone representative to provide an extended warranty to
    me in exchange for what I have learned, but I have
    not been successful. In fact, Dave’s contact
    (Carol) called me personally to tell me that Nissan didn’t even want my information if it was provided for FREE! I think Nissan and Firestone are cut from the same fabric!

    I had considered just fading away from this board…
    taking my knowledge with me. After all, if Nissan
    doesn’t care about their customers, then why
    should I? After a few days of thought, I have
    decided that the customers deserve to know why
    their cars are screwed up.

    In a day or two, I will receive the “go jump in
    the lake” letter from Nissan. I might scan it and
    post it for all to see. Anyway, here goes….

    In a sentence, the smoking gun is the idle control
    valve, and the way that it is controlled by the
    ECM.

    The 2K Maxima is designed to accelerate
    aggressively with only a slight movement of the gas pedal. The way that Nissan achieves this is by simultaneously dumping a huge amount of auxiliary air into the engine via the idle control valve. Nissan Engineers probably did this to “wind up” the automatic transmission torque converter as quickly as possible in order to make the car very quick off the line.

    The aggressiveness of this air dump is VERY new to
    the 2000 Maxima design. In fact, the entire
    intake system (including the idle control valve) is different from the 1999 model. In addition, the ECM was redesigned for year 2000.

    The large amount of air that is dumped into the
    engine via the idle control valve is not a huge
    problem at first, except that it’s possible to run
    over a pedestrian. However, the extra air ends up
    being a problem when slowing down because the idle
    control valve is not subsequently closed as the gas pedal is released.

    The “fuel-cut” scenario goes like this:

    The driver steps on the gas to accelerate, and the
    idle control valve opens to assist with the
    acceleration. The increased voltage on the TPS
    (throttle position sensor) provides an “advance
    notice” to the computer to expect additional air.
    This expected additional air is then matched with
    additional fuel from the injectors. The computer
    then watches the mass air flow sensor signal to
    verify that the additional air really did arrive,
    and if a major discrepancy is detected between the
    TPS signal and the mass air flow sensor, the check
    engine light will be illuminated. Ultimately, the
    mass air flow sensor (and exhaust sensors to some
    extent) have final control over the amount of fuel
    that is injected into the engine. The TPS only
    provides “advance warning” to the computer and does not ultimately control this process.

    And so, after the engine has accelerated and the
    car is traveling at some higher speed, the driver
    will eventually want to slow down. The most
    obvious way to do this is to just ease off the gas
    pedal. However, as the driver attempts to deprive
    the engine of air by releasing the gas pedal, the
    engine continues to acquire large quantities of air from the idle control valve. (Remember… I said earlier that the idle control valve remains open even as the gas pedal is released). Because the mass air flow sensor has the final say in how much fuel is injected into the engine, and because the engine continues to receive air through the idle control valve, the engine continues to produce more power than is desired. Finally, when the gas pedal reaches the end of its travel, the TPS outputs a “throttle closed” voltage and the computer subsequently cuts fuel. This is the “fuel-cut” phenomenon that so many have complained about.

    Thus, the engine cycles from producing a fairly
    significant amount of power to producing NEGATIVE
    power in the fuel-cut mode. The word “negative” is used because the engine is compression braking
    during the “fuel-cut” mode. There is no in-between it either produces too much power or negative power.

    And now back to the sequence off events:

    While the “fuel-cut” condition is in effect, the
    engine provides maximum compression braking. It is also operating at maximum vacuum… which means that it is sucking as much air as possible through the idle control valve. However, as long as the TPS is outputing a “throttle closed” position, the “fuel-cut” mode remains in effect.

    If at some point during the “fuel-cut” mode the
    driver decides to speed up, the TPS will
    subsequently stop outputting the “throttle closed”
    voltage and the computer will begin providing fuel
    to the engine. Because the idle control valve has
    remained open during the entire “fuel-cut” period,
    and because the mass air flow sensor has continued
    to see air flowing into the engine, the computer
    calls for a large amount of fuel to match the air
    that is flowing into the engine. Thus, the car
    will accelerate more than expected. Sometimes this surprising acceleration will cause the driver to quickly let off the gas, only to be subjected to an immediate “fuel-cut” again. Thus, a vicious cycle can occur during low speed driving… lurch (accelerate) forward… hard compression braking… lurch forward… hard compression braking… etc.

    Excessive air from the idle control valve is also
    the cause of rising engine rpm’s between shift
    changes. A small delay is designed into the ECM
    prior to issuing a “fuel-cut”, and as the engine
    continues to acquire air through the idle control
    valve during shifts, the computer matches this air
    with fuel. Thus, the unloaded engine rpm’s will
    float up about 400-500 rpm during each shift
    change.

    And so, the engine cycles continually between too
    much power and too little power with no ability to
    feather the throttle up and down at minimal outputs of power. This cycle repeats itself over and over and over and over again…. until the driver is stark raving crazy. To further enhance the drivers emotional torture, Nissan Engineers and zone reps routinely tell owners (with a straight face) that the car is perfect and “it is all in the drivers head”.

    The “fuel-cut” problem manifests itself in several
    ways:

    1.) Excessive fuel consumption because the engine
    gets a big dump of air and fuel each time it comes
    off of idle, and because the engine is often
    producing more power than is desired.

    2.) An engine that lurches between no power and
    too much power while operating with cruise control.

    3.) An uncontrollable throttle on 5-speed models,
    making the car lurch badly at low speeds and
    annoyingly at higher speeds.

    4.) Hard downshifts on the automatic transmission
    models, which is probably caused by a sudden
    “fuel-cut” on “closed throttle” from the TPS.

    5.) Rising engine rpm’s between shifts on the
    5-speed models.

    6.) Unsafe/uncontrollable accelerations when
    starting out, which can cause a collision with
    another vehicle, or possibly with a pedestrian.

    For those of you who want to argue that this is
    normal, and was done because of emissions, let me
    remind you that emissions laws are the same for
    year 1999 and 2000. This driveability problem has
    only surfaced with the 2000 model. Furthermore,
    other manufacturers have not resorted to such high
    flows of air and fuel to achieve compliance with
    emissions laws, so why should the Maxima be unique
    in that regard?

    Also, for those of you who want to argue that only
    a few Maximas have the “fuel-cut” problem, and it
    must be due to a faulty component, I would have to
    disagree. I have yet to find a 2000 Maxima that
    passes the stationary test (trying to ease rpm’s
    from 3,000 rpm to 2,000 rpm). They all fail this
    test (both 5-speeds and automatics) because of the
    idle control valve. The only real difference from
    one car to the next is the driver. Some slight
    differences probably exist from car to car, but the biggest variable has to be the driver.

    For those of you who think there must be a faulty
    component, then here is a list of the candidates: Idle Control Valve, Throttle Position Sensor, Absolute Pressure Sensor, Front and Rear Oxygen sensor, VIAS system, Mass Air Flow Sensor, Intake Air Temperature Sensor, Coolant Temperature Sensor, EGR system, and EVAP system. Go ahead and check them all out. I think you will find all of them to be in good working order. It is the ECM's control of the idle control valve that is the problem.

    In summary, the 2K Maxima engine has been
    optimized for the automatic transmission with
    little or no thought given to its compatibility
    with a manual transmission. The 2K Maxima 5-speed
    needs to have its own engine control software
    rather than shared software with the automatic
    models. THE IDLE CONTROL VALVE NEEDS TO BE CLOSED
    AS THE GAS PEDAL IS RELEASED. FURTHERMORE, THE
    IDLE CONTROL VALVE
    OK, I’ve been holding out on all of you for a
    while, and now I am going to finally explain the
    “fuel-cut” problem in detail. I have tried for
    several weeks to persuade a Nissan zone representative to provide an extended warranty to
    me in exchange for what I have learned, but I have
    not been successful. In fact, Dave’s contact
    (Carol) called me personally to tell me that Nissan didn’t even want my information if it was provided for FREE! I think Nissan and Firestone are cut from the same fabric!

    I had considered just fading away from this board…
    taking my knowledge with me. After all, if Nissan
    doesn’t care about their customers, then why
    should I? After a few days of thought, I have
    decided that the customers deserve to know why
    their cars are screwed up.

    In a day or two, I will receive the “go jump in
    the lake” letter from Nissan. I might scan it and
    post it for all to see. Anyway, here goes….

    In a sentence, the smoking gun is the idle control
    valve, and the way that it is controlled by the
    ECM.

    The 2K Maxima is designed to accelerate
    aggressively with only a slight movement of the gas pedal. The way that Nissan achieves this is by simultaneously dumping a huge amount of auxiliary air into the engine via the idle control valve. Nissan Engineers probably did this to “wind up” the automatic transmission torque converter as quickly as possible in order to make the car very quick off the line.

    The agg DOES NOT NEED TO BE OPENED SO
    SEVERELY WHEN ACCELERATING FROM IDLE SPEED.

    I hope this helps everyone understand why the car
    drives so poorly.
  • y2ksey2kse Posts: 104
    Let's keep those cards and letters coming!

    Bruce...
  • bigk200bigk200 Posts: 170
    Glad you found the new space. What a crummy time for "L8 Apex" to freeze our topic!
  • y2ksey2kse Posts: 104
    Right you are. I just sent an e-mail to our good buddy L8_Apex, to wit:

    If it wouldn't be too inconvenient, perhaps in future you'd announce that you're closing a topic with something more than the time it takes you to slam the door. That way, topic participants could re-create the topic elsewhere and advise others where to find it.

    As you're the only entity capable of posting into the old Nissan 5-Speed Issues forum, I'd appreciate it if you'd be so kind as to publish an announcement that the topic has moved to the following location:

    http://townhall-talk.edmunds.com/engaged/edmund.cgi?c=Maintenance&t=1698&a=1&H=2&f=0

    You'll note that the new location is consistent with your suggestion.

    Thanks.

    Bruce... (y2kse)
  • y2ksey2kse Posts: 104
    Thanks, and good night.

    Bruce...
  • I'd be interested in this Max meeting again if it didn't already take place. Please let me know where and when.
  • If over 650 posts is not reason enough for having
    a forum, I don't know what is! Maybe we'll get
    better treatment in here!

    That said, hats off to Edmunds for sponsoring our
    little swarree. NOW, back to business.

    BigK, I think we should add number 7: Difficulty
    in starting out without stalling because the bottom sometimes drops out! (Add your own improved techie explanation.)
  • L8_ApexL8_Apex Posts: 187
    At 652 posts, the old topic was due for the usual reincarnation. For those of your unaware with the normal procedures, topics are usually frozen, and recreated if necessary, after they reach 500 posts. As recreating another exclusive "5-Speed Problem" topic was more suitable for this conference, I recommended that it be placed here and kindly offered to link when the topic was created.

    Thanks for your understanding,

    L8_Apex
    Sedans Host
  • To tie into the rpm drop out related to the "fuel cut" problem. I was sitting at a red light the other day and of course getting ready to feather the gas to bring the rpms up to a startable level. The light turned green and I didn't quite give the car enough gas and the rpms drop to almost nothing I quickly depressed the clutch back in to prevent a stall and the rpms jumped to about 1500. maybe just more proof that bigk is right in his assesment of the fuel cut problem.
  • bigk200bigk200 Posts: 170
    Keep driving and observing. Over time you will know for sure that my assessment is correct. It all makes sense once you understand what is going on.

    maxdave:

    In regard to your observation that he rpm's jumped to 1500, check this out: If a person could bump the TPS voltage up a tiny bit from the "closed throttle" position without actually opening the throttle (ie. the gas pedal), the rpm's will actually go immediately to 1500 rpm. Pretty remarkable huh? The reason for the quick jump to 1500 rpm is that the idle control valve quickly opens up when coming off of the "closed throttle" position. So even though you think you are "driving" the car with the gas pedal, the idle control valve and ECM are actually doing it for you.
  • y2ksey2kse Posts: 104
    "Scary" is more like it! And perhaps that's why, when I run the fuel-cut test on my unloaded engine, the engine "bumps" at 1500 rpm on its uncontrollable and precipitous descent to idle from around 2800 rpm.

    Bruce...
  • My car also misses @ 1500 RPM during the 3000-2000 RPM idle test. I showed this to the Nissan DTR, but he came up with a weak excuse of the car being in neutral and unloaded. I wasn't in the mood to argue. Warrenul's and Maximizd's cars didn't do this, and both of their cars actually stopped at 1500 RPM for this test and then varied between 1500 - 1700 RPM.

    The three of us will probably meet again next week to compare cars, so anyone with suggestions for tests and such let us know! BTW, I also posted some links to our boards here in the USENET group alt.autos.nissan.maxima

    Dave Z
  • I don't have a Maxima right now so I can't pop the hood, but would it be possible to swap in the IAC from a previous model year, which seemed to have less of a problem with the fuel cut? On my Mustang the IAC is bolted on to the throttle body. Is it on the Maxima, or is it integrated into the throttle body/intake? If so, maybe a solution would be to swap the entire intake/throttle body from a previous year. Then again, since the IAC is just a computer controlled valve, maybe they didn't actually change the IAC at all, but reprogrammed the ECU to hold it open wider/longer/sooner? So maybe a solution would be to intercept the signal from ECU to the IAC with a resistor? to decrease the voltage sent to IAC (which I assume would be a linear signal-inc. in voltage=inc. in idle air). That might affect the base idle though...but maybe a simple circuit could be designed that would reduce the voltage for everything but base idle?
  • bigk200bigk200 Posts: 170
    The IAC is a unique part number from last years car. The entire intake system is also different. I guess it might be possible to swap it all out, but it would be expensive with no guarantee of success.

    Really though, the problem is with the ECM rather than the valve. The valve is only doing what it is told to do.

    In regard to your idea of adding a resistor or some kind of circuit to modify signals going to the IAC, that would not work because of the way that the valve works. The IAC is not controlled by a linear voltage, but rather, it is stepped in and out with alternating voltages on each of (4) wires. It would be very difficult to alter its movement with an external circuit because you would have to simultaneously keep track of the ECM's signals so that the valve could be returned to where the ECM thinks it should be prior to idleing.

    Thanks for your ideas though because they certainly are appreciated.
  • y2ksey2kse Posts: 104
    I've already spoken to JWT about ECU upgrades for the 2K+ Maxima. They informed me that Nissan changes their ECUs on practically an annual basis. As a result, a great deal of reprogramming has to go into each and every model year. Reprogramming simply isn't economic, particularly for a small firm like JWT, until sufficient vehicles and demand exist to warrant the investment.

    There is an aftermarket alternative that's expensive (~$1200) but appears to offer substantial horsepower and torque increases. My understanding is that it works on a 2K+ Maxima. Whether that alternative would address the fuel-cut issue is unknown, however.

    Check out the following URL:

    http://www.racersgroup.com/program/theprogram.htm

    Bruce...
  • Hey guys,

    First of all, thanks for all this info on the cut-off problem. I bought my 2K 5-spd SE in July and have loved everything about it since then. It seems to drive great to me, but my last car was an '87 Caprice wagon with a worn out timing chain, so just about anything would be a dream to drive after that monster.

    Anyway, I tried the 3000 to 2000 RPM test and my car fails it too, however I can't really understand what the significance of it. I haven't noticed the engine cutting out when I actually drive the car, just when I do the test at a standstill, and it doesn't even cut out. It just goes to idle speed. I drive the car 120 miles a day -- I have a nightmarish commute -- and have not noticed anything, except that occasionally I can't get it into 4th gear for the life of me.

    So, here are my questions:

    1) What difference does it make if the engine drops from 2500 RPM to nothing when you rev the engine up at a standstill but experience no problems changing gears when driving? I have about 3900 miles on my car now; should I expect the cut-off problem to get worse with more miles?

    2) Has anyone experienced the 4th gear lockout problem? It hasn't happened to me very often, maybe 2 or 3 times, but is annoying, especially in a new car. What could this mean?

    3) What's new for the 2001 year? I think I read somewhere on this list that there would be radio controls on the steering wheel.

    Thanks
  • y2ksey2kse Posts: 104
    Try this.

    Let your engine warm up thoroughly, then find a nice, flat, empty road. Put your car in 1st gear and bring the engine up to 1500 rpm. Now try to hold your speed without either accelerating or decelerating. My bet is you won't be able to do it no matter how finely you try to control the gas pedal. That's the fuel-cut condition in action.

    I haven't experienced 4th gear lockout, but I was getting some pretty sticky shifts into 2nd gear. I drained my transmission and filled it with Red Line MT-90 Manual Transmission Lubricant. The MT-90 provided a significant improvement. Try it. You'll like it.

    Check out Redline products at:

    http://www.redlineoil.com/

    Bruce...
  • I was also wondering the necessity of buying 93 octane gas. What will happen if I use 89 or 87? The manual says it will dameg the emissions system I believe.
  • Hello All
    Very Interesting Forum
    Has anyone tested the 2001 Maxima 5 Speeds?
  • y2ksey2kse Posts: 104
    I doubt that using lower octane gasoline will damage your emissions system. But you will pay a price in power.

    My wife uses 89 octane in her 2K Max GXE A/T. Her car runs just fine.

    Bruce...
  • y2ksey2kse Posts: 104
    I haven't driven a 2K+1 yet, but I'd be interested in finding out if it continues to exhibit the fuel-cut condition.

    For my money, I'd like warrenul or davedzny or bigk200 to test one and report back. They've been banging their heads against this issue for a lot longer than I have.

    Bruce...
  • Yes, would any current owners test the 2k+1 for those who are considering purchasing one? I was so close to purchasing a 2k Se 5-speed last week. It didn't exhibit any of the fuel-cut problems during my brief drive. However, I did find it hard getting into some gears. First gear was kinda weird. Anyway, I'm interesting in knowing if the 2k+1's have corrected ECM's.
  • 29632963 Posts: 37
    Well, while my '98 SE 5 speed was getting an oil change this morning at my local Nissan dealer, I walked over to the sales floor and shortly thereafter took a '01 20th Anniversary SE 5 speed out for a pretty aggressive 25 minute test spin.

    In a nutshell, here are my thoughts: great car overall, although I personally can do without the 20th Anniversary's "boy racer" tack-on front/side/rear spoilers. The clutch was lighter on the foot than my '98, and the transmission did not seem to have any noticeable improvements when compared to my current Maxima's (although tolerable, I wish the tranny's on the Maxima's did not feel as rubbery as they do). Also, I really enjoyed the new interior and dashboard designs, and could tell this car has a roomier trunk and interior than in my '98.

    The steering wheel audio controls were very handy, and I was surprised at the sound quality of the new Bose seven speaker system (did not notice any rear deck rattling induced from the subwoofer's new location). I was also able to notice a difference in the ride quality when comparing the 17" wheels to the 16" wheels on my '98 (a firmer and sportier feel, especially when driving over dips and potholes).

    And now, the "fuel cut" issue: while performing the stationary test at idle (with a warm engine), the RPM's dropped to idle @ approx. 2300 when I tried to back the RPM's down from 3000 to 2000. I performed this test about five times (to the amusement of the salesman sitting next to me), and it did it each time. However, in the short time I had the car, I really didn't notice the problem manifesting itself in any other ways. My range of driving on this test drive went from near redline shifts to mellow "parade-like" cruising, and it really wasn't an issue for me.

    After the test drive, I went over to pick up my '98 from the service drive and briefly spoke with my service advisor about the "fuel cut" problem with the 2000+ Maxima's. He told me he had heard nothing about it until a few weeks ago, when a customer brought in his '00 SE 5 speed for a check (the customer was having the "bucking" problems while on the freeway during stop-and-go traffic).

    My service advisor said he was able to re-create the customer's problem during his own test drive, but was unable to correct it since the car performed to factory specifications when diagnosed and checked out by a mechanic. His exact words to me were: "I saw the problem, but we just don't know how to fix it!" He also added that I was (reportedly) only the second customer to bring this issue to his attention.

    So, where do I go from here? When the '01 5 speed SE's start hitting the showrooms in mass (hopefully in about a month), I will be trading in the old for the new. The new Maxima was just too nice...
  • y2ksey2kse Posts: 104
    Go here:

    http://www.nhtsa.dot.gov/cars/problems/ivoq/default.htm

    By the way, if you do register a complaint, you won't be alone. Check out the Customer Complaints section. Look for the following:

    ODI ID: 720641
    Make: NISSAN
    Model: MAXIMA
    Year: 2000
    Date of Failure:
    Incident: No
    Fire: No
    Number of Injuries:
    Component: FUEL:THROTTLE LINKAGES AND CONTROL:PEDAL
    Summary: THIS VEHICLE IS EXHIBITING A PROBLEM OF NOT BEING ABLE TO CONTROL THE ENGINE SPEED WITH THE THROTTLE PEDAL. THERE HAVE BEEN NUMEROUS COMPLAINTS REGARDING THIS


    Bruce...
  • Benito,

    So after test driving the Anniversary Edition Maxima, which Maxima are you going to trade your 98 Maxima for?

    Did the dealer give you any indication how much they wanted for the Anniversary Edition Maxima? I e-mailed some dealers inquiring about pricing on the Anniversary Edition Maxima, they said close to MSRP? Would you pay MSRP for the Anniversary Edition Maxima? How did you like the perforated leather seats compared to the regular leather seats?

    George
  • Bruce, I hate to tell you, but that NHTSA Complaint that you posted is mine! I was bored one day and saw that you could post a complaint either online or via fax to NHTSA. I heard nothing back from them, but hoped that someone might read it..... Another way for those who want to complain about our problem. I guess our next step is an "Unofficial Maxima Fuel Cut Web Page"!.. LOL

    Dave Z
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