Sentra Shuts Off While Driving in neutral

[Dave Sherman]

I'm going with "don't do that" for reasons others have mentioned. Lifting off the gas while in gear, it's very likely that it will cut fuel while engine braking is happening. Now if you're coasting in neutral, one would think that some software engineer put enough smarts in it to detect that it could be coasting in neutral even though it's a manual. My Saturn was a stick shift, but from the service manual I know it sensed what gear it was in based on engine RPM and wheel speed and whether you were clutching or not.

Perhaps there's a bug in the ECU that when the wheel speed coincides with the engine RPM for a gear, maybe it thinks you're actually in gear and it tries to cut fuel thinking it's time for engine braking. Kind of a long shot, but since coasting in neutral is generally illegal anyway, and you're not saving gas, I'll stick with "don't do that".

 

[mk378]

Simple ECU software cuts fuel when the TPS is at 0% (i.e. gas pedal not pressed) and the engine rpm is above idle.

 

[nobb]

I noticed my Ford Ranger with the 3.0 engine and automatic transmission does this too. No idea if this is normal or just some sort of fluke where the ECU is confused and is cutting fuel. Do all automatics exhibit this behavior?

No, it's not good practice to ever be shifting your engine to neutral while on the highway, but wish more people would comment on the technical reasons behind what is happening rather than bad driving practices.

 

[sirgerman]

I'm going with "don't do that" for reasons others have mentioned. Lifting off the gas while in gear, it's very likely that it will cut fuel while engine braking is happening. Now if you're coasting in neutral, one would think that some software engineer put enough smarts in it to detect that it could be coasting in neutral even though it's a manual. My Saturn was a stick shift, but from the service manual I know it sensed what gear it was in based on engine RPM and wheel speed and whether you were clutching or not.

Perhaps there's a bug in the ECU that when the wheel speed coincides with the engine RPM for a gear, maybe it thinks you're actually in gear and it tries to cut fuel thinking it's time for engine braking. Kind of a long shot, but since coasting in neutral is generally illegal anyway, and you're not saving gas, I'll stick with "don't do that".

I did not know it was not legal to cruise in neutral gear, are you guys sure about that ?
I was under the impression that cruising in neutral will save you fuel, I wont do that anymore
I will check RPM in neutral and in 6th gear

 

[gathermewool]

I’d love to have some one here quote an actual statute stating no neutral coasting to a stop is allowed in an MT. Sounds like BS to me.

When I drove stick, deciding on whether to coast or engine-brake depended on the grade and distance to stop. Sometimes engine-braking made sense, sometimes coasting did. Usually, it was a combination of the two. Well, unless you’re one of those youngsters who thinks down-shifting every gear or two at once makes you sound cool, engine-braking at 5k RPM and all. It’s even better when you fail to rev-match…

I just love how everyone is jumping on the OPs case but a total of ONE actual helpful post has been made about the actual problem. Maybe some of you should get off your high horse and focus on the actual problem, huh?

 

[supton]

I did not know it was not legal to cruise in neutral gear, are you guys sure about that ?
I was under the impression that cruising in neutral will save you fuel, I wont do that anymore
I will check RPM in neutral and in 6th gear

It would have back in the days of carbs, where gas would flow through the engine under decel anyhow. A lot changed with EFI.

I don't know the statue but I do recall it "always" being illegal.

 

[dishdude]

I’d love to have some one here quote an actual statute stating no neutral coasting to a stop is allowed in an MT. Sounds like BS to me.

See 28-895.

https://www.azleg.gov/arsDetail/?title=28

 

[mightymousetech]

a few months ago, never had that problem before
I like to cruise in neutral in order to save gas

Uh, you are using significantly more gas with it in neutral than leaving it in gear and coasting.

 

[JTK]

I’d love to have some one here quote an actual statute stating no neutral coasting to a stop is allowed in an MT. Sounds like BS to me.

When I drove stick, deciding on whether to coast or engine-brake depended on the grade and distance to stop. Sometimes engine-braking made sense, sometimes coasting did. Usually, it was a combination of the two. Well, unless you’re one of those youngsters who thinks down-shifting every gear or two at once makes you sound cool, engine-braking at 5k RPM and all. It’s even better when you fail to rev-match…

I just love how everyone is jumping on the OPs case but a total of ONE actual helpful post has been made about the actual problem. Maybe some of you should get off your high horse and focus on the actual problem, huh?

Totally agree.

I'm not sure some of the posters caught the fact this is an MT as opposed to an AT.

I know some Nissans can need a throttle re-learn (if E-throttle equipped) after a battery swap or no power to the PCM for some time. It's a DIY job. I wonder if that's the case here. I would imagine a 2012 would be E-throttle, so no IAC, etc.

 

[Pew]

I’d love to have some one here quote an actual statute stating no neutral coasting to a stop is allowed in an MT. Sounds like BS to me.

Illinois Section 625 ILCS 5/11-1410
Utah 41-6a-1709 - although this looks like it was repealed in 2015 and I can't find an amended one.

 

[Kuato]

See 28-895.

https://www.azleg.gov/arsDetail/?title=28

The statute says "traveling on a downgrade", not "coasting to a stop sign", which is what OP is doing. So cannot agree this statute would apply. ComPLETEly reasonable to have a manual trans in neutral when coming to a stop.

100% agree with gathermewool; seriously only 1 post that was helpful up to that point and a bunch of whiners over analyzing fuel consumption rather than answering the question.

Agree that there is something in the computer or sensors that's shutting down the engine; clean as suggested, check plugs and ignition, and remap ecu if necessary.

Is it throwing any codes?

 

[grjr]

You state that you are coasting in neutral to save gas but as others have stated you are doing the exact opposite of that. In other words stop doing that, you are not achieving your goal.

Does the engine idle rough at any other time? Not familiar with your car, does it have a MAF sensor? Someone mentioned cleaning the throttle body and the idle air control valve (IAC), this may be a good place to start. If it is drive by wire there won't be an IAC. Get the car scanned for any codes as well. Have you done any modifications under the hood?

 

[samven]

I have been through many many towns with a sign that says NO ENGINE BRAKING , never seen one that said No Coasting.

 

[grjr]

I have been through many many towns with a sign that says NO ENGINE BRAKING , never seen one that said No Coasting.

they are referring to jake brakes on big rigs which are loud and disturb the residents.

 

[sirgerman]

I did not know it was not legal to cruise in neutral gear, are you guys sure about that ?
I was under the impression that cruising in neutral will save you fuel, I wont do that anymore

they are referring to jake brakes on big rigs which are loud and disturb the residents.

Well RPM during costing below 1000, 700 to 800. RPM at 65 M/H around 3000, more likely to save gas in Neutral
Also no codes or engine light

 

[supton]

Well RPM during costing below 1000, 700 to 800. RPM at 65 M/H around 3000, more likely to save gas in Neutral
Also no codes or engine light

During engine over-run, EFI cuts fueling, at least it usually does (every manufacturer can do something different). Do you have a Scanguage or even the Torq adapter, so that you could monitor instantaneous mpg? You might be surprised at what the engine is doing, and will give you the feedback about your actions that you are after.

 

[Nesterenko]

Sentra Shuts Off While Driving in neutral.
I have a 2012 Nissan Sentra and I have a weird problem, every time I take the freeway exit, I put the car in neural and drive for a less than a minutes to save gass , between 50 to 60 miles/hour, when a reach the stop sign the car shuts off ( I dont touch the brakes or anything ), I can see the RPM from 3000 to 0 and the car shuts off. It happen at the same place. No engine light, the car seems to be working fine
Any idea what cut it be ? Which part should replace ?

Sorry the car is a manual

Welcome to Roswell

 

[GMBoy]

Start with cleaning the throttle body and checking the IAC.

THIS ^^^

Many problems solved by cleaning the throttle body. There is probably dirt/oil residue stopping bypass air. Newer cars don't have an IAC as idle is controlled thru the throttle body - even just wiping it down inside around the butterfly with a good cleaner will help if you don't have any carb/intake cleaner on hand. Minimize moving the throttle body blade - just spray all around it good and wipe it.

 

[dumkid]

cruising in neutral is less safe than cruising in gear, but when you're coasting in gear you're engine braking. this will slow you down faster, and then you have to put your foot back on the gas pedal to make it to the actual stop sign.

 

[justalubetech]

I'd start with a good 'ol Italian tune up (driving it hard for a bit). Op sounds like they are driving it very gently, cat might be getting clogged or buildup in the throttle body.