Motor Trend talks about 5-speed throttle issue
01-14-2001, 05:49 PM
#41
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Posts: n/a
Guys, this is not just a issue with the MAXIMAS, the 5spd Sentra SE's seem to exbit this same problem as well. Not sure what nissan is doing with the ECUs...but its showing on there newer cars.
Originally posted by davedzny
Hello all. Note that this is a LONG post. I have not had a chance to read the Motor Trend issue as of yet, but I will post again regarding this topic since I have been fighting Nissan for 9 months now regarding it. Bottom line is that Nissan refuses to acknowledge that there is a problem, so a fix does not look good. I am pursuing other methods right now to resolve this issue with Nissan as this problem really affects the operation of my car. I'll explain the problem below:
The real problem of all 2k Maxima's is what has been named "uncontrollable throttle" which manifests itself most harshly as a fuel cut sensation in 1st gear at low speeds. I will once again explain some tests to see how badly your car is affected, as some people feel no problem whereas others like myself cannot stand it. We all know how sensitive the throttle is in this car, as the slightest pressure really makes it go.
The first test is a stationary test with the car in neutral, and a fully warmed up engine with the a/c off. Try to hold the RPM's at a steady 2000 RPM. Impossible. Raise the RPM's up to 3000 and try to slowly decrease it to idle. Impossible; at around 2500 RPM the RPM's will drop on its own. On some cars, it drops to 1500 RPM, and on others like my car it will drop all the way to idle. Pressure is still applied on the gas pedal when the RPM's drop. This will happen on stick and automatics and is caused by logic in the computer which causes the throttle to do this. No driveability issues related to this test; it just shows that the computer is robbing you of full throttle control.
A second test to experience the bucking problem in 1st gear on stick cars is the following. In 1st gear with a warmed up engine, drive at a steady 1550-1600 RPM. You want to hold steady pressure on the gas pedal while keeping the car at this RPM range in 1st gear. At this point, the RPM's might start to raise by themself all the way up to 2000 RPM while you are holding steady pressure still. The fuel cut might happen now even with pressure applied, but it will definitely happen if you try to release the slightest amount of pressure on the gas pedal. The bucking can become so violent that the whole car will start shaking back and forth very badly.
The third test is related to the car not able to slow under a no load situation. While driving at about 45 MPH in 4th gear at 2000 RPM or so, release your foot completely from the gas pedal and watch the RPM's. They will not start to decrease for about 5 to 10 seconds. They should drop the instant you release the gas pedal. The computer is once again robbing you of throttle control. It is the lack of ability to control the throttle that makes the fuel cut happen so often in 1st gear since you try to slow down and nothing happens until you almost release the gas pedal and you reach the "closed throttle switch" on the TPS which cuts fuel. I have not tested an automatic to see if it also has problems slowing down when the gas pedal is released. That would need to be tested at a similar speed to make sure that the auto is in high gear, since most automatics will automatically upshift when pressure is released from the gas pedal.
The fourth test is the RPM hang/increase on upshifts in stick cars. An upshift at 2500 RPM from 1 to 2 will cause the RPM's to remain at 2500 when the clutch is depressed. The computer is forcing the throttle open under this unloaded condition. An aggressive upshift from 2 to 3 at 2500 RPM causes the RPM's to increase when the clutch is depressed; this can be tried without even shifting. Drive in second to 2500, and simutaneously release the gas and slam down the clutch as quick as possible. The RPM's will rise.
For those who don't believe a problem exists or aren't bothered by it, more power to you. The problem is there due to the engine management system on this car. I am not sure of the "range" of symptoms though as some people claim their cars do not exhibit driveability problems. I am sure that all cars will fail the first test in neutral, and will probably not be able to slow down under coasting like the third test.
Sorry for the long post, but I like to share this information with everyone. Note that none of the conditions will appear on a cold engine, when the car is in open loop and not being "controlled" by the computer. Also go to this website http://www.nissanmaximaproblems.com to read more and feel free to email me at davedzny@hotmail.com if you have questions or need personal contact information for Nissan staff to complain to. Take care.
Dave Z
Hello all. Note that this is a LONG post. I have not had a chance to read the Motor Trend issue as of yet, but I will post again regarding this topic since I have been fighting Nissan for 9 months now regarding it. Bottom line is that Nissan refuses to acknowledge that there is a problem, so a fix does not look good. I am pursuing other methods right now to resolve this issue with Nissan as this problem really affects the operation of my car. I'll explain the problem below:
The real problem of all 2k Maxima's is what has been named "uncontrollable throttle" which manifests itself most harshly as a fuel cut sensation in 1st gear at low speeds. I will once again explain some tests to see how badly your car is affected, as some people feel no problem whereas others like myself cannot stand it. We all know how sensitive the throttle is in this car, as the slightest pressure really makes it go.
The first test is a stationary test with the car in neutral, and a fully warmed up engine with the a/c off. Try to hold the RPM's at a steady 2000 RPM. Impossible. Raise the RPM's up to 3000 and try to slowly decrease it to idle. Impossible; at around 2500 RPM the RPM's will drop on its own. On some cars, it drops to 1500 RPM, and on others like my car it will drop all the way to idle. Pressure is still applied on the gas pedal when the RPM's drop. This will happen on stick and automatics and is caused by logic in the computer which causes the throttle to do this. No driveability issues related to this test; it just shows that the computer is robbing you of full throttle control.
A second test to experience the bucking problem in 1st gear on stick cars is the following. In 1st gear with a warmed up engine, drive at a steady 1550-1600 RPM. You want to hold steady pressure on the gas pedal while keeping the car at this RPM range in 1st gear. At this point, the RPM's might start to raise by themself all the way up to 2000 RPM while you are holding steady pressure still. The fuel cut might happen now even with pressure applied, but it will definitely happen if you try to release the slightest amount of pressure on the gas pedal. The bucking can become so violent that the whole car will start shaking back and forth very badly.
The third test is related to the car not able to slow under a no load situation. While driving at about 45 MPH in 4th gear at 2000 RPM or so, release your foot completely from the gas pedal and watch the RPM's. They will not start to decrease for about 5 to 10 seconds. They should drop the instant you release the gas pedal. The computer is once again robbing you of throttle control. It is the lack of ability to control the throttle that makes the fuel cut happen so often in 1st gear since you try to slow down and nothing happens until you almost release the gas pedal and you reach the "closed throttle switch" on the TPS which cuts fuel. I have not tested an automatic to see if it also has problems slowing down when the gas pedal is released. That would need to be tested at a similar speed to make sure that the auto is in high gear, since most automatics will automatically upshift when pressure is released from the gas pedal.
The fourth test is the RPM hang/increase on upshifts in stick cars. An upshift at 2500 RPM from 1 to 2 will cause the RPM's to remain at 2500 when the clutch is depressed. The computer is forcing the throttle open under this unloaded condition. An aggressive upshift from 2 to 3 at 2500 RPM causes the RPM's to increase when the clutch is depressed; this can be tried without even shifting. Drive in second to 2500, and simutaneously release the gas and slam down the clutch as quick as possible. The RPM's will rise.
For those who don't believe a problem exists or aren't bothered by it, more power to you. The problem is there due to the engine management system on this car. I am not sure of the "range" of symptoms though as some people claim their cars do not exhibit driveability problems. I am sure that all cars will fail the first test in neutral, and will probably not be able to slow down under coasting like the third test.
Sorry for the long post, but I like to share this information with everyone. Note that none of the conditions will appear on a cold engine, when the car is in open loop and not being "controlled" by the computer. Also go to this website http://www.nissanmaximaproblems.com to read more and feel free to email me at davedzny@hotmail.com if you have questions or need personal contact information for Nissan staff to complain to. Take care.
Dave Z
01-14-2001, 06:07 PM
#42
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Originally posted by Russ2kSE
Guys, this is not just a issue with the MAXIMAS, the 5spd Sentra SE's seem to exbit this same problem as well
Guys, this is not just a issue with the MAXIMAS, the 5spd Sentra SE's seem to exbit this same problem as well
http://forums.maxima.org/showthread....threadid=13553
Regardless of the reason behind the throttle condition, it's a pain in the a$$ to have to deal with.
01-15-2001, 07:31 AM
#43
Senior Member
Join Date: Aug 2000
Posts: 681
Re: Re: maybe it is the driver........
Originally posted by y2kse
Fair enough, DeaZaL. Now try this little test.
Accelerate in any gear at WOT to ~2500 rpm. Then simulaneously release the throttle and disengage the clutch as you would when shifting normally. But instead of shifting to another gear, keep the clutch disengaged and the throttle released. What does your engine do? Does it immediately begin to lose rpms, do the rpms hang for awhile, or do the rpms actually rise?
Report your results here.
[Edited by y2kse on 01-14-2001 at 07:41 PM]
Originally posted by DeaZaL
Maybe my car is special but I dunno i'm just a dumb computer guy so what do i know
Maybe my car is special but I dunno i'm just a dumb computer guy so what do i know
Accelerate in any gear at WOT to ~2500 rpm. Then simulaneously release the throttle and disengage the clutch as you would when shifting normally. But instead of shifting to another gear, keep the clutch disengaged and the throttle released. What does your engine do? Does it immediately begin to lose rpms, do the rpms hang for awhile, or do the rpms actually rise?
Report your results here.
[Edited by y2kse on 01-14-2001 at 07:41 PM]
01-15-2001, 08:20 AM
#44
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Join Date: Sep 2000
Location: City of the Fallen Angel, CA
Posts: 4,728
Re: Re: Re: maybe it is the driver........
Originally posted by SCCA Solo2
Maybe I'm losing my mind, but, it seems kinda present in every car i've driven.
Maybe I'm losing my mind, but, it seems kinda present in every car i've driven.
Long before I decided to pursue the throttle issue, I had already made up my mind to live with it if need be. The Maxima is an excellent automobile and I throroughly enjoy driving it. But knowing what I know now, I would definitely recommend against purchasing a Maxima 5-speed if the vehicle will be driven daily for long periods in rush hour traffic. And unless the condition is ameliorated between now and the time I purchase my next car, I for one will have to think very seriously about buying another 5-speed.
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