Engine feels breathless at high rpm, NVIS?
08-06-2002, 08:53 PM
#1
Engine feels breathless at high rpm, NVIS?
I tried a couple runs tonight, first I did a 35mph drop into 1st gear, the car didn't pull as hard as usual. Then I shifted into second bringing to revs back down to 5,250 and it accelerated harder/quicker until it reached 5,500rpms.
Second run was from a dead stop. I stomped on the gas on one of those crosswalk markers on the road and my tires squealed like crazy along with wheel hop, first time that happened
I run it up to redline and get the same feeling, it just didn't pull as hard all the way to redline. Shifted into second and BAM, instant tug, but this time it actually pull all the way to 6,000rpms, then started to feel like lag.
Third run, 67mph roll, downshifted into 2nd and all I hear is the engine singing, but get no sensation of speed until I shifted into 3rd.
Usually when I rev my engine, it just pulls harder as it approaches redline, but then when you shift, its a smooth transaction and the car gains speed faster as you approach redline again. It feels like any "other" engine where you ride out the TQ curve and the engine doesn't pull as hard near redline.
First time this ever happened. What do other NVIS problem owners experience? Is this even a NVIS malfunction? Does this have anything to do with that crank/squeal noise when I shut off my engine, turn the steering wheel, or operate an accessory? Could this all be in my imagination?
Second run was from a dead stop. I stomped on the gas on one of those crosswalk markers on the road and my tires squealed like crazy along with wheel hop, first time that happened
I run it up to redline and get the same feeling, it just didn't pull as hard all the way to redline. Shifted into second and BAM, instant tug, but this time it actually pull all the way to 6,000rpms, then started to feel like lag.Third run, 67mph roll, downshifted into 2nd and all I hear is the engine singing, but get no sensation of speed until I shifted into 3rd.
Usually when I rev my engine, it just pulls harder as it approaches redline, but then when you shift, its a smooth transaction and the car gains speed faster as you approach redline again. It feels like any "other" engine where you ride out the TQ curve and the engine doesn't pull as hard near redline.
First time this ever happened. What do other NVIS problem owners experience? Is this even a NVIS malfunction? Does this have anything to do with that crank/squeal noise when I shut off my engine, turn the steering wheel, or operate an accessory? Could this all be in my imagination?
08-06-2002, 08:56 PM
#2
Member
Join Date: Feb 2002
Location: Northern California
Posts: 158
Re: Engine feels breathless at high rpm, NVIS?
Originally posted by ScreamingVQ
I tried a couple runs tonight, first I did a 35mph drop into 1st gear, the car didn't pull as hard as usual. Then I shifted into second bringing to revs back down to 5,250 and it accelerated harder/quicker until it reached 5,500rpms.
Second run was from a dead stop. I stomped on the gas on one of those crosswalk markers on the road and my tires squealed like crazy along with wheel hop, first time that happened I run it up to redline and get the same feeling, it just didn't pull as hard all the way to redline. Shifted into second and BAM, instant tug, but this time it actually pull all the way to 6,000rpms, then started to feel like lag.
Third run, 67mph roll, downshifted into 2nd and all I hear is the engine singing, but get no sensation of speed until I shifted into 3rd.
Usually when I rev my engine, it just pulls harder as it approaches redline, but then when you shift, its a smooth transaction and the car gains speed faster as you approach redline again. It feels like any "other" engine where you ride out the TQ curve and the engine doesn't pull as hard near redline.
First time this ever happened. What do other NVIS problem owners experience? Is this even a NVIS malfunction? Does this have anything to do with that crank/squeal noise when I shut off my engine, turn the steering wheel, or operate an accessory? Could this all be in my imagination?
I tried a couple runs tonight, first I did a 35mph drop into 1st gear, the car didn't pull as hard as usual. Then I shifted into second bringing to revs back down to 5,250 and it accelerated harder/quicker until it reached 5,500rpms.
Second run was from a dead stop. I stomped on the gas on one of those crosswalk markers on the road and my tires squealed like crazy along with wheel hop, first time that happened
I run it up to redline and get the same feeling, it just didn't pull as hard all the way to redline. Shifted into second and BAM, instant tug, but this time it actually pull all the way to 6,000rpms, then started to feel like lag.Third run, 67mph roll, downshifted into 2nd and all I hear is the engine singing, but get no sensation of speed until I shifted into 3rd.
Usually when I rev my engine, it just pulls harder as it approaches redline, but then when you shift, its a smooth transaction and the car gains speed faster as you approach redline again. It feels like any "other" engine where you ride out the TQ curve and the engine doesn't pull as hard near redline.
First time this ever happened. What do other NVIS problem owners experience? Is this even a NVIS malfunction? Does this have anything to do with that crank/squeal noise when I shut off my engine, turn the steering wheel, or operate an accessory? Could this all be in my imagination?
08-06-2002, 08:59 PM
#3
Nissan Variable Induction System of course
Could be a clogged air filter.... I haven't changed the dam thing for like 38k miles
I filled up with 91 octane today, I usually run 93 octane because thats basically the one thing that we have around here besides 87/89. I was suprised to find 91, could be a bad tank of gas
Could be a clogged air filter.... I haven't changed the dam thing for like 38k miles
I filled up with 91 octane today, I usually run 93 octane because thats basically the one thing that we have around here besides 87/89. I was suprised to find 91, could be a bad tank of gas
08-06-2002, 09:24 PM
#4
Member
Join Date: Feb 2002
Location: Northern California
Posts: 158
Originally posted by ScreamingVQ
Nissan Variable Induction System of course
Could be a clogged air filter.... I haven't changed the dam thing for like 38k miles
I filled up with 91 octane today, I usually run 93 octane because thats basically the one thing that we have around here besides 87/89. I was suprised to find 91, could be a bad tank of gas
Nissan Variable Induction System of course
Could be a clogged air filter.... I haven't changed the dam thing for like 38k miles
I filled up with 91 octane today, I usually run 93 octane because thats basically the one thing that we have around here besides 87/89. I was suprised to find 91, could be a bad tank of gas
08-06-2002, 10:15 PM
#5
Senior Member
Join Date: Mar 2001
Posts: 654
If you are still on a stock air filter, I bet it's gummed up by now. Another thing you may try is to clean the throttle body. I cleaned mine this weekend and it's not hard, just a bit of work to take the intake off. My car has 20kmi and it definitely needed it. Along with a new air filter, the car now feels smoother and more responsive. Are you running a good brand gas (Chevron, Texaco)? You may want to try a bottle of Techron fuel injector cleaner, I put it once a year.
08-07-2002, 05:51 AM
#6
Dyno plot says I have the most area under the Administrator curve
Join Date: Jul 2001
Posts: 7,060
NVIS? I thought it was VIAS? Oh well
The 'NVIS' crossover on the DE-K engine is 5000rpm. I guess it's tough to hear on the stock airbox (do you have an intake?), but pay attention right around there and see if you can hear anything.
You should be pulling hard all the way up to redline, but not if the NVIS ain't working. This is VERY easy to see on a dyno.
The 'NVIS' crossover on the DE-K engine is 5000rpm. I guess it's tough to hear on the stock airbox (do you have an intake?), but pay attention right around there and see if you can hear anything.
You should be pulling hard all the way up to redline, but not if the NVIS ain't working. This is VERY easy to see on a dyno.
08-07-2002, 11:39 AM
#7
Maxima Pilot
Join Date: Oct 2001
Location: Beaverton, Oregon
Posts: 1,467
Careful here..yes the engine should not 'flatten',
at 5k rpms but...the 3.5 liter wont pull hard all the way to redline as will the 3-liter...the HP and torque curves on these two engines are very different but good 'ol Nissan did'nt change the redline on the tach misleading everyone who has a 3.5 liter that the shift points are the same.
The 3 liter engine makes its max HP right at redline (6600-6700 rpms) whereas the 3.5 liter engine drops the HP peak to circa 5800 rpms...much, MUCH different.
As a result, the ideal shift points on the 3 liter is redline in each gear, on the 3.5 it should be right around 6000rpms -fully 700 rpms less.
The 3 liter engine makes its max HP right at redline (6600-6700 rpms) whereas the 3.5 liter engine drops the HP peak to circa 5800 rpms...much, MUCH different.
As a result, the ideal shift points on the 3 liter is redline in each gear, on the 3.5 it should be right around 6000rpms -fully 700 rpms less.
08-07-2002, 11:43 AM
#8
Senior Member
Join Date: Aug 2000
Posts: 2,151
The 2 easiest ways to tell are a dyno or go to the track. My VIAS was broken and on the dyno it showed. My engines peak hp was at around 4800 rpms and then after that it would stay flat for a while then fall. The engine should be making its peak hp at redline. Max_Gator and myself can provide you with some more info once you figure out if it is truely a bad VIAS.
08-07-2002, 11:44 AM
#9
If the NVIS in the newer 3.5VQs are still just rpm dependant, you should just be able to rev the engine while the hood is up and see if the vacuum actuated lever on the side of the manifold is moving or not. If it doesn't move, it's probably not opening up.
08-07-2002, 12:12 PM
#10
Senior Member
Join Date: Aug 2000
Posts: 2,151
Originally posted by Jeff92se
If the NVIS in the newer 3.5VQs are still just rpm dependant, you should just be able to rev the engine while the hood is up and see if the vacuum actuated lever on the side of the manifold is moving or not. If it doesn't move, it's probably not opening up.
If the NVIS in the newer 3.5VQs are still just rpm dependant, you should just be able to rev the engine while the hood is up and see if the vacuum actuated lever on the side of the manifold is moving or not. If it doesn't move, it's probably not opening up.
08-08-2002, 10:01 AM
#13
Supporting Maxima.org Member
Join Date: Sep 2000
Posts: 2,038
Re: Engine feels breathless at high rpm, NVIS?
Originally posted by ScreamingVQ
I tried a couple runs tonight, first I did a 35mph drop into 1st gear, the car didn't pull as hard as usual. Then I shifted into second bringing to revs back down to 5,250 and it accelerated harder/quicker until it reached 5,500rpms.
Second run was from a dead stop. I stomped on the gas on one of those crosswalk markers on the road and my tires squealed like crazy along with wheel hop, first time that happened I run it up to redline and get the same feeling, it just didn't pull as hard all the way to redline. Shifted into second and BAM, instant tug, but this time it actually pull all the way to 6,000rpms, then started to feel like lag.
Third run, 67mph roll, downshifted into 2nd and all I hear is the engine singing, but get no sensation of speed until I shifted into 3rd.
Usually when I rev my engine, it just pulls harder as it approaches redline, but then when you shift, its a smooth transaction and the car gains speed faster as you approach redline again. It feels like any "other" engine where you ride out the TQ curve and the engine doesn't pull as hard near redline.
First time this ever happened. What do other NVIS problem owners experience? Is this even a NVIS malfunction? Does this have anything to do with that crank/squeal noise when I shut off my engine, turn the steering wheel, or operate an accessory? Could this all be in my imagination?
I tried a couple runs tonight, first I did a 35mph drop into 1st gear, the car didn't pull as hard as usual. Then I shifted into second bringing to revs back down to 5,250 and it accelerated harder/quicker until it reached 5,500rpms.
Second run was from a dead stop. I stomped on the gas on one of those crosswalk markers on the road and my tires squealed like crazy along with wheel hop, first time that happened
I run it up to redline and get the same feeling, it just didn't pull as hard all the way to redline. Shifted into second and BAM, instant tug, but this time it actually pull all the way to 6,000rpms, then started to feel like lag.Third run, 67mph roll, downshifted into 2nd and all I hear is the engine singing, but get no sensation of speed until I shifted into 3rd.
Usually when I rev my engine, it just pulls harder as it approaches redline, but then when you shift, its a smooth transaction and the car gains speed faster as you approach redline again. It feels like any "other" engine where you ride out the TQ curve and the engine doesn't pull as hard near redline.
First time this ever happened. What do other NVIS problem owners experience? Is this even a NVIS malfunction? Does this have anything to do with that crank/squeal noise when I shut off my engine, turn the steering wheel, or operate an accessory? Could this all be in my imagination?
At the bottom of that box is a wiring harness that can simply be unplugged.
If you do that, your vias (not nvis) will be inoperable. Drive it around and see if there is a difference.
Before you do that, though, locate the actuator lever. It will move when the engine hits 5k. While under the hood work the throttle lever until you get high enough rpms (you'll have to guess) and watch the lever. If it works, you'll know that the only problem with the vias could be the internal butterflys. If you do that test with the vias unplugged, the acutator lever won't work.
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