Gas Pedal Delay

IcedZ · 09-07-2010, 01:10 PM

Does anyone know a lot about O2 sensors? I read this article: OXYGEN SENSORS and it makes sense. Is this accurate? Does it apply to our car? If so, I am going to record just O2 sensor data this evening, and try to post it tomorrow. Even if the problem doesn't show itself today, maybe it'll be a good baseline. Can anyone confirm how many O2 sensors I should expect to see?

6spd · 09-07-2010, 04:35 PM

o2 sensors have nothing to do with this problem, or much of anything in all reality, except pollution control.

WarmAndSCSI · 09-07-2010, 04:48 PM

Quote:

Originally Posted by 6spd

o2 sensors have nothing to do with this problem, or much of anything in all reality, except pollution control.

Well, a primary O2 sensor being out of whack could cause your fuel trims to be pretty extreme. That would lead to kind of a "dead" feeling every time you crossed over from closed to open loop fuel operation.

But if it were that bad, your ECU would let you know about it (service engine light).

Secondary O2 sensors have no bearing on fueling or how the car runs. They are the "rear" two sensors downstream from the catalytic converters - one per bank.

6spd · 09-07-2010, 06:30 PM

Quote:

Originally Posted by WarmAndSCSI

Well, a primary O2 sensor being out of whack could cause your fuel trims to be pretty extreme. That would lead to kind of a "dead" feeling every time you crossed over from closed to open loop fuel operation.

But if it were that bad, your ECU would let you know about it (service engine light).

Secondary O2 sensors have no bearing on fueling or how the car runs. They are the "rear" two sensors downstream from the catalytic converters - one per bank.

while yes, in theory, you are correct, but ive never seen a sensor cause such havoc. for all intents and purposes, the o2 sensors are mere monitors and even bad ones wont cause fuel trims to change performance, noticeable anyway. but who knows, this car has proven to be a very weird car already in other ways.

IcedZ · 09-07-2010, 06:45 PM

Quote:

Originally Posted by 6spd

while yes, in theory, you are correct, but ive never seen a sensor cause such havoc. for all intents and purposes, the o2 sensors are mere monitors and even bad ones wont cause fuel trims to change performance, noticeable anyway. but who knows, this car has proven to be a very weird car already in other ways.

Agreed, however, if the ECU algorithm is jacked, I think it could cause exactly that. I just realized my OBD software won't let me save data, so I can't post my drive =( Will keep looking for other software.

Has anyone had this problem in the evenings? Or mostly in the day time?

TROOPER · 09-07-2010, 04:54 PM

So anyone talked to a dealer about this yet?

KillerBee370 also mentioned his tuner fixed this (see page 13)....
What was the fix...??

IcedZ · 09-07-2010, 06:56 PM

Quote:

Originally Posted by TROOPER

So anyone talked to a dealer about this yet?

... Yes. I got blown off. But then again, this dealer is notorious for crappy service. This time I am trying to bring them hard evidence of something, and also going to address it as a safety concern. If that doesn't go anywhere (which I kind of suspect it won't), I will move up the chain.

6spd · 09-07-2010, 07:16 PM

from what has been documented ever since electronic throttles became instituted in just about everything, the real culprit is the time it takes for voltage to be sent from pedal to the ecu to the throttle body to the TPS to the ecu to the injectors, so on and so forth. ET's add extra time to the mix unlike cables that are as close to instant as you can get.

this same idea can be seen clear as day if you hook a volt meter or gauge to your battery and start the car. the meter will read 13.5-7 or so. now have someone rev the motor, and watch the meter or gauge go up to 14.2-7. the jump isn't instant, it climbs, not slowly, but slower than instantly. the increased rpms spin the electromagnets in side the alternator faster, but voltage still has to be transferred.

it seems like this sprint thingy speeds up the process by increasing voltage, making the lag less noticeable.

IcedZ · 09-08-2010, 09:30 PM

Quote:

Originally Posted by 6spd

from what has been documented ever since electronic throttles became instituted in just about everything, the real culprit is the time it takes for voltage to be sent from pedal to the ecu to the throttle body to the TPS to the ecu to the injectors, so on and so forth. ET's add extra time to the mix unlike cables that are as close to instant as you can get.

this same idea can be seen clear as day if you hook a volt meter or gauge to your battery and start the car. the meter will read 13.5-7 or so. now have someone rev the motor, and watch the meter or gauge go up to 14.2-7. the jump isn't instant, it climbs, not slowly, but slower than instantly. the increased rpms spin the electromagnets in side the alternator faster, but voltage still has to be transferred.

it seems like this sprint thingy speeds up the process by increasing voltage, making the lag less noticeable.

You do know electricity travels at roughly C (the speed of light - 3 MILLION meters per SECOND)... and most processors these days process data in fractions of milliseconds.

6spd · 09-08-2010, 10:52 PM

Quote:

Originally Posted by IcedZ

You do know electricity travels at roughly C (the speed of light - 3 MILLION meters per SECOND)... and most processors these days process data in fractions of milliseconds.

yep you're right, but step motors, ecu's, sensors, and relays dont work that fast. the step motors in the throttle dont snap closed to fully open at the speed of light - 3 million meters per second, it is gradual, as is the depression of the gas pedal.

WarmAndSCSI · 09-09-2010, 12:34 AM

Quote:

Originally Posted by 6spd

yep you're right, but step motors, ecu's, sensors, and relays dont work that fast. the step motors in the throttle dont snap closed to fully open at the speed of light - 3 million meters per second, it is gradual, as is the depression of the gas pedal.

The throttle plates on the VHR are fully open during normal operation - the VVEL actually throttles the engine by adjusting lift.

6spd · 09-09-2010, 04:38 PM

Quote:

Originally Posted by WarmAndSCSI

The throttle plates on the VHR are fully open during normal operation - the VVEL actually throttles the engine by adjusting lift.

no ****! i didnt know that, im not familiar with new VQ's much at all, hardly ever have to work on them. the way i was describing the actions were just generalized concepts used in "most" electronic throttle cars. im glad you enlightened me!

m4a1mustang · 09-07-2010, 07:20 PM

That's not really what the issue many of us are describing, though. Of course there's going to be a signal delay, but with this, the engine responds, bogs for 2-3 seconds, then surges forward.

What would happen to me is I'd give the car throttle and initially get put back in my seat, only for the car to STOP accelerating, bog for 2-3 seconds, all while lunging me forward because I was bracing for acceleration... then all of a sudden it'd violently take off again. It felt more like fuel starvation or TC/VDC cutting power more than anything else, although there's no evidence to suggest that's the case. That's what it feels like, though.

Bottom line is I solved the problem... I bought a new car. :/

L8N8 · 09-07-2010, 09:27 PM

^^sucks you had to give up the car to fix the issue.

For whatever it's worth, I haven't done any performance mods yet. The car is bone stock with this acceleration issue. I'm going to be giving it to Nissan for a couple days this week so they can troubleshoot it. If they can't do anything with it and no one has found a fix on this site by then, I'll press on with new intakes and possibly a tune. If nothing by then, I'll seriously consider going the route the previous poster has just taken.

6spd · 09-07-2010, 09:33 PM

Quote:

Originally Posted by m4a1mustang

That's not really what the issue many of us are describing, though. Of course there's going to be a signal delay, but with this, the engine responds, bogs for 2-3 seconds, then surges forward.

What would happen to me is I'd give the car throttle and initially get put back in my seat, only for the car to STOP accelerating, bog for 2-3 seconds, all while lunging me forward because I was bracing for acceleration... then all of a sudden it'd violently take off again. It felt more like fuel starvation or TC/VDC cutting power more than anything else, although there's no evidence to suggest that's the case. That's what it feels like, though.

Bottom line is I solved the problem... I bought a new car. :/

gotcha, how do you like the 'stang? things beast and a half i hear.

I get what you describe real bad in first gear, even before the vdc would, i assume, kick in, as well as low rpm 2nd and 3rd.

09-07-2010, 04:35 PM	#2 (permalink)
6spd A True Z Fanatic Join Date: Aug 2009 Location: South Florida Posts: 3,001 Drives: Q50RS Rep Power: 25	o2 sensors have nothing to do with this problem, or much of anything in all reality, except pollution control. __________________ -Jay- jonathanjamesphotographer.com

09-07-2010, 04:54 PM	#6 (permalink)
TROOPER A True Z Fanatic Join Date: Jun 2010 Location: Baltimore, MD Posts: 1,297 Drives: Your Tax Dollars Rep Power: 17	So anyone talked to a dealer about this yet? KillerBee370 also mentioned his tuner fixed this (see page 13).... What was the fix...?? __________________ Darren "Guv Motors Passion Wagon"

09-07-2010, 07:16 PM	#8 (permalink)
6spd A True Z Fanatic Join Date: Aug 2009 Location: South Florida Posts: 3,001 Drives: Q50RS Rep Power: 25	from what has been documented ever since electronic throttles became instituted in just about everything, the real culprit is the time it takes for voltage to be sent from pedal to the ecu to the throttle body to the TPS to the ecu to the injectors, so on and so forth. ET's add extra time to the mix unlike cables that are as close to instant as you can get. this same idea can be seen clear as day if you hook a volt meter or gauge to your battery and start the car. the meter will read 13.5-7 or so. now have someone rev the motor, and watch the meter or gauge go up to 14.2-7. the jump isn't instant, it climbs, not slowly, but slower than instantly. the increased rpms spin the electromagnets in side the alternator faster, but voltage still has to be transferred. it seems like this sprint thingy speeds up the process by increasing voltage, making the lag less noticeable. __________________ -Jay- jonathanjamesphotographer.com

09-07-2010, 07:20 PM	#13 (permalink)
m4a1mustang A True Z Fanatic Join Date: Feb 2009 Location: Northern VA Posts: 55,385 Drives: on two wheels Rep Power: 6963	That's not really what the issue many of us are describing, though. Of course there's going to be a signal delay, but with this, the engine responds, bogs for 2-3 seconds, then surges forward. What would happen to me is I'd give the car throttle and initially get put back in my seat, only for the car to STOP accelerating, bog for 2-3 seconds, all while lunging me forward because I was bracing for acceleration... then all of a sudden it'd violently take off again. It felt more like fuel starvation or TC/VDC cutting power more than anything else, although there's no evidence to suggest that's the case. That's what it feels like, though. Bottom line is I solved the problem... I bought a new car. :/ __________________ - Steve Zs & Coffee - Saturdays at 10AM in Fairfax, VA and Columbia, MD (Click the banner!) LIKE us on Facebook!

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09-07-2010, 01:10 PM	#1 (permalink)
IcedZ Base Member Join Date: Feb 2009 Location: Gainesville, FL Posts: 194 Drives: 09 370 Yellow, 6MT Rep Power: 17	Does anyone know a lot about O2 sensors? I read this article: OXYGEN SENSORS and it makes sense. Is this accurate? Does it apply to our car? If so, I am going to record just O2 sensor data this evening, and try to post it tomorrow. Even if the problem doesn't show itself today, maybe it'll be a good baseline. Can anyone confirm how many O2 sensors I should expect to see?

09-07-2010, 09:27 PM	#14 (permalink)
L8N8 Base Member Join Date: Feb 2010 Location: VA Posts: 36 Drives: fast, takes chances Rep Power: 16	^^sucks you had to give up the car to fix the issue. For whatever it's worth, I haven't done any performance mods yet. The car is bone stock with this acceleration issue. I'm going to be giving it to Nissan for a couple days this week so they can troubleshoot it. If they can't do anything with it and no one has found a fix on this site by then, I'll press on with new intakes and possibly a tune. If nothing by then, I'll seriously consider going the route the previous poster has just taken.