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Discussion Starter · #1 ·
I've searched through number of 2005+ idle-related threads, but here's a theoretical question about the Nissan throttle body system I'm wondering if someone knows a definitive answer to (not just speculation). Using a Consult III or possibly aftermarket tuner (SuperChips, UpRev, etc.), which of the following is a true statement (or are both)?

All things being equal, truck at normal operating temperature, no performance issues or other truck differences between the two statements.

Statement 1: You can adjust/raise the RPM at idle in gear with no effect on the throttle throughout the driving range. So if the throttle is normally at say 1% open at idle, you raise it to 1.5% open, but it defaults back to whatever % is normal no matter where else the engine is in the RPM range.

Statement 2: You can only adjust/raise the throttle across ALL conditions. So if the throttle is normally at say 1% open at idle, you can bump it to 1.5% open, but it will ALWAYS default to 1.5% open no matter where the engine is in the RPM range. That means that at say 40mph, foot off the gas in 5th gear (automatic) the truck will be "accelerating" at 0.5% higher than it normally would.


Thanks very much,
 

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I actually tune cars and trucks for a living. Mainly american muscle cars. I haven't tuned my truck yet as i just got it and been trying to reach uprev for about a week and a half. Idle tuning is just that, it just commands a certain rpm and adjust throttle (and timing) to achieve desired idle. It has no relevance to any other part throttle situations. Your tuners are only going command an rpm at idle and not affect other things in the tune like dashpot decay rate (how slow the rpms come down) or decel fuel cut off which all affect how i comes down. EFIs usually have different conditions for throttles depending on conditions. Once i get the software from uprev and dial in my truck i'll let you know of what is adjustable, if its like the the stuff i've worked on before. If so, i should be able to adjust throttle response as well and of course torque modulation our trucks come with factory. I'll talk with uprev and see if transmission controls are adjustable as that would be nice too.
 

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Discussion Starter · #3 ·
Ok, that's great information. Thank you. That really helps clarify a few questions. Thanks for responding!
 

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Discussion Starter · #4 · (Edited)
So to close out this question and topic (mods, feel free to lock):

Two weeks ago, I took my Frontier to the dealer I bought the truck from for the third visit involving a concern about a noisy idle. The problem I am experiencing is a very loud cabin, in drive, normal operating temperatures, across all seasons. Truck currently has ~14K. I know this is a persistent problem with the VQ40 across platforms and has been for a while. Some are worse than others, a lot having to do with the driver (assuming). At any rate, I feel mine is excessive.

First visit: (a few months ago) was told there was a heat shield contacting part of the exhaust. Noise did go away slightly, so maybe that was a legitimate cause of it. But it didn't go away 100%.

Second visit (two weeks ago): requested dealer diagnose again. As an aside to this, I met a 30 year Nissan technician a few months ago (not from my area, unfortunately) who has also had three or four Frontiers (05+) and he said all VQ40s do it. It's just a matter of bumping the idle around 50-100rpms (+/-) until the objectionable portion goes away. Some owners it bothers, other's not so much. So at this visit, they raised the idle significantly, so in drive, it was idling around 950 (+/-). Noise was indeed gone.

But here's the kicker: it seemed to have "opened" "cracked" or whatever word you want to use to the throttle across ALL RPMs. So when you were slowing down, the downshifts were significantly more pronounced as the throttle was blipped and while cruising with foot off the gas, the "costing" speed was significantly higher and I had to actually downshift to second or first gear (automatic trans) in order to go the speed I usually like to travel in my usual routes (neighborhood, normal roads I drive).

Cost: $65.

Third visit (today): asked service advisor specifically if they can adjust ONLY the idle. Answer: "to his knowledge, they could only raise the entire thing across the board." So I just had them remove the tune and set it back to stock.

Cost: $31.

Wasted dollars on this foolishness: ~$100 +5 hours of my time in early morning and some sleep. Thanks to the truck being out of the 12/12 warranty, this is not something Nissan was going to pay for.

So this got me to searching in older posts and I found a few people with tuners have raised their idle slightly, so my next purchase will probably be a Bully Dog after confirming they ACTUALLY work with the '14s (idle being really my only concern). I can let a lot of things with this truck go, but this is one of those things that I really want to fix/correct. I'm willing on spending the $400 on a tuner to raise the idle ONLY very slightly so the noise goes away and I have the ability to shift it around as needed.

I'm really left with two options: 1) go to another dealer, start all over again, pay more money for potentially the same result (that Nissan scan tools can only adjust the entire throttle body open across all RPMs) or 2) buy some sort of tuner that will work with the '14. I'd rather own the device than pay for an upRev or custom tune. If I ever get rid of the truck it's just easier to return to stock that way.
 

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So to close out this question and topic (mods, feel free to lock):

Two weeks ago, I took my Frontier to the dealer I bought the truck from for the third visit involving a concern about a noisy idle. The problem I am experiencing is a very loud cabin, in drive, normal operating temperatures, across all seasons. Truck currently has ~14K. I know this is a persistent problem with the VQ40 across platforms and has been for a while. Some are worse than others, a lot having to do with the driver (assuming). At any rate, I feel mine is excessive.

First visit: (a few months ago) was told there was a heat shield contacting part of the exhaust. Noise did go away slightly, so maybe that was a legitimate cause of it. But it didn't go away 100%.

Second visit (two weeks ago): requested dealer diagnose again. As an aside to this, I met a 30 year Nissan technician a few months ago (not from my area, unfortunately) who has also had three or four Frontiers (05+) and he said all VQ40s do it. It's just a matter of bumping the idle around 50-100rpms (+/-) until the objectionable portion goes away. Some owners it bothers, other's not so much. So at this visit, they raised the idle significantly, so in drive, it was idling around 950 (+/-). Noise was indeed gone.

But here's the kicker: it seemed to have "opened" "cracked" or whatever word you want to use to the throttle across ALL RPMs. So when you were slowing down, the downshifts were significantly more pronounced as the throttle was blipped and while cruising with foot off the gas, the "costing" speed was significantly higher and I had to actually downshift to second or first gear (automatic trans) in order to go the speed I usually like to travel in my usual routes (neighborhood, normal roads I drive).

Cost: $65.

Third visit (today): asked service advisor specifically if they can adjust ONLY the idle. Answer: "to his knowledge, they could only raise the entire thing across the board." So I just had them remove the tune and set it back to stock.

Cost: $31.

Wasted dollars on this foolishness: ~$100 +5 hours of my time in early morning and some sleep. Thanks to the truck being out of the 12/12 warranty, this is not something Nissan was going to pay for.

So this got me to searching in older posts and I found a few people with tuners have raised their idle slightly, so my next purchase will probably be a Bully Dog after confirming they ACTUALLY work with the '14s (idle being really my only concern). I can let a lot of things with this truck go, but this is one of those things that I really want to fix/correct. I'm willing on spending the $400 on a tuner to raise the idle ONLY very slightly so the noise goes away and I have the ability to shift it around as needed.

I'm really left with two options: 1) go to another dealer, start all over again, pay more money for potentially the same result (that Nissan scan tools can only adjust the entire throttle body open across all RPMs) or 2) buy some sort of tuner that will work with the '14. I'd rather own the device than pay for an upRev or custom tune. If I ever get rid of the truck it's just easier to return to stock that way.

I'd imagine these techs are unaware of how to properly adjust these vehicles. I wasn't even aware they could makes changes like that at the dealership, but i'm not as familiar with the Nissans as i am domestics. First of all 950 in gear idle is extremely dangerous as the vehicle will want to accelerate away at idle. Second whatever they "adjusted" was extremely dangerous as well. Throttle body tuning is a very sensitive system with a lot of failsafes built in these days. Making an adjustment like that not know what it could do could result in a runaway vehicle. You might remember the first days of the drive by wire systems where the toyota prius cars were running away and many people died. Throttle body was staying open no matter what pedal position was requested. Modification to these tables is extremely sensitive and they need to know what they are doing or something like this could result in something a lot worse than just an unhappy customer. Setting of target idle will no have any affect on throttle conditions in any other area. Like transmission functions, decel, coasting etc. It will have an affect of course of idle pull or speed with foot off the brake.

My truck too has a little vibration at idle and agree idles too low. I imagine Nissan like all manufactures set idle speeds based on emission and MPG requirements. Slightly higher idle generally means things function better, like water pump moving more fluid, alternator charges a bit better, and a/c compressure turning faster too.

I'd suggest getting a good tuner and adjusting it yourself till you find a happy spot for you and your truck.
 

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I have a '14 & a Bullydog. You can adjust idle rpm & timing +/- 2 degrees. the timing adjustment may fix your issue as well. Just remember you may need to adjust, turn off, restart, drive around block before you can assess the timing adjustment. (i did 1/2 the time) the idle rpm is right then & there.
The guage features are nice, especially if you offroad or tow, you can monitor trans temp & set an alarm limit (mine's set to 195)
 
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