Automanual question

[smockers83]

Has anyone with ATs ever noticed that the engine runs about 200 RPM higher in the manual mode than it does in just D? Can anyone offer insight as to why?

[Beancooker]

In "D" it will shift before redline. In manumatic, you can shift at redline.

Now if you mean that it sits at a higher RPM while at idle in gear, I haven't had that problem.

It could be something with the ECU as well. Might be something similar to turning off the VDC. The car just might set itself differently.

I have to go to Nissan for a transmission and diff service tomorrow afternoon. I'll ask Adrian and see what he says.

[smockers83]

Once I get to a cruising speed in the automanual, most times when I switch over to D, the RPM will drop about 200 while maintaining my speed. I'm sure its something with the ECU but the thing that's got me is where's all this extra power being produced going and not being used? Thanks for checking for me.

[Beancooker]

I'll check it out when I drive today. I don't know if mine does that or not. Usually when I'm in manumatic, I'm not crusing...

As I said earlier, I'll ask Adrian tomorrow, and see if he has an explanation. Will be easier, if my car does it too.

[Beancooker]

My car doesn't do that. I tried again and again. Adrian said that he isn't sure of the cause of the problem. Could be ranging from needing a transmission flush, a bad (or going bad) valve in the valve body, the TCM... the list went on. He did say that it's something you might want to have looked at, especially if it's still under warranty.

[smockers83]

Hmm, that's interesting. It only has 16,000 miles on it so its not in need of a flush. I will have it looked at then. Thanks bean.

[Beancooker]

No problem.

[rmezz13]

what speed and what gear are you cruising at? could it be something as simple as overdrive kicking in...... is that dumb of me to ask? you did say a cruising speed then it drops 200 revs when you put it into drive right? I figure if your going 45 in 5th gear and you shift to 6th it drops about 200 revs......

[cheapazz]

On my way home I shifted from D to automanual at about 50mph and the revs jumped 200, then back down 200 when I switched back to D. Maybe the same thing??

[smockers83]

Yeah, lets say I'm in manual mode and I reach a cruising speed of 60 and I'm maintaining that. In manual mode it'll hold at 6600 and when I switch to D it'll drop to 6400. If I were to keep my engine speed up at 6600, I could go 65 in D if I wanted to. Happens at most speeds.

cheapazz, that's interesting. If I'm in D and cruising in what would be 5th and I shift over to manual, mine automatically goes into 4th. Does anyone else's do this too or is this also just me?

[rmezz13]

i am confused.... are you truly running at 6400-6600 rpm's in 4th and 5th gear @ 60mph????? or is it just reference to what your saying? (we could have a whole other problem)

[Beancooker]

If I'm in D and cruising in what would be 5th and I shift over to manual, mine automatically goes into 4th. Does anyone else's do this too or is this also just me?

Mine shifts into 4th, unless I'm above 80 MPH.

When I checked if mine did the same as yours, it was from M5 to D, at 60ish, and from D to M5 and back to D at well above posted speed limits.

[cheapazz]

Sorry I didn't specify, yes it does shift to 4th and increases by 200 rpm then drops again when put into D.

[Sentientbydesign]

That's probably just the difference between 4th and 5th gear.

D will use the highest gear possible for a given speed (within a certain parameter to allow for adequate power).

[smockers83]

i am confused.... are you truly running at 6400-6600 rpm's in 4th and 5th gear @ 60mph????? or is it just reference to what your saying? (we could have a whole other problem)

Sorry, sorry!!! Typos, only typos. How about we make that 2400 and 2600.

[tollboothwilley]

Tested this several times in the last few days...

I have no drop in RPM's when i switch between manual and auto unless i'm going from D (5th gear) to Manual (in 4th gear).

Other than that, you shouldn't be seeing a change in RPM's

[smockers83]

The past couple of days I haven't been able to repeat this "problem" even though it's happened to me for a long time (over a year).

[BrandAidDesignG35]

Me too,

Tested this several times in the last few days...

I have no drop in RPM's when i switch between manual and auto unless i'm going from D (5th gear) to Manual (in 4th gear).

Other than that, you shouldn't be seeing a change in RPM's

I tried a few time last night, no dice...

That does seem wierd though.... I also tried cruising just above 80mph and slapping it to manual mode.... It still dropped to 4th though, Does anyone else do this? or would it automatically stay in 5th for you guys?

[smockers83]

Well its happening again, I'll take my camera with me and post up a video to show you guys. When I get back in the area of an Infiniti dealership, I'll have it checked out as I'm due for an oil change soon.

[morrison82]

Ok I dont understand what the problem is. The reason your rpms jump up 200 rpms is because when you switch between auto to manual, the trans drops you into 4th gear instead of 5th. The reason is so you have more power in manual mode. All you do in this case is shift up to 5th gear and you should see the rpms drop back down. Personaly I would not use manual mode on the highway, not to fuel efficient if you dont shift up.

[BrandAidDesignG35]

I beg to differ, just for fun - I tried driving in 4th Manual mode on the highway, keeping speeds at or above 60mph for a full tank, the difference was suprising!!! The gear ratios are very close between 4 and 5, so which ever gear you choose would be OK on the highway... above 75mph, you'd be better off in 5th for sure.

I noted a while back, a few people had said they get better MPG while cruising at 80mph instead of 60mph...

So, I tried to keep the engine running at its most efficient rpm... the results? better than usual

Anyone else tried this??? I know in the manual it says the engine redline RPM for each gear,1st 45mph2nd 63mph3rd 85mph4rth ---5th---

Notice 4th & 5th gears share a common interest I know the manual suggests shifting into a lower gear up hill, and I do a lot of that type of driving.

[tollboothwilley]

I noted best gas mileage at 70 MPH in 5th gear, still good at 75 MPH. 80 -85 didnt seem a great cruising speed for gas mileage where as 90-95 seemed to be really good actually.

[smockers83]

Ok I dont understand what the problem is. The reason your rpms jump up 200 rpms is because when you switch between auto to manual, the trans drops you into 4th gear instead of 5th. The reason is so you have more power in manual mode. All you do in this case is shift up to 5th gear and you should see the rpms drop back down. Personaly I would not use manual mode on the highway, not to fuel efficient if you dont shift up.

Thanks, I know how it works. If I did that, it would jump in the neighborhood of 1000 RPMs.

I'll explain again. If I'm driving in manual and reach my cruising speed of say 60 MPH in 5th, I'm running at 2600 RPM. When I shift over to auto, it drops to 2400 RPM while maintaining speed at 60 MPH. If I wanted to maintain my RPMs at 2600, I could go 65 MPH when I move into auto.

[smockers83]

Alright, here's a video of what's going on. Took this on my way to work this morning. It was on level ground. I realize I slow down towards the end by maybe 1 MPH, but you'll notice that the tach drops before I start slowing down. Plus, 1 MPH slower isn't 200 RPMs.

[Sentientbydesign]

I'm not doubting your problem, but just for the sake of true information, I can actually see a 200 rpm drop being quite plausible if you were on the throttle to maintain 60mph and you let off slightly down to 59.

Remember that you have "slush boxes" slippage is part of the the design.

I'd be really bothered if this situation could somehow apply to a 6mt (not really applicable in any sense). Then we'd have some serious problems.

This is a shot in the dark, but I'm wondering if the TCM and ECU have different setting depending upon if you're in D or DS?

[smockers83]

But even if I do slow down and I get back up to speed, it stays down there. If I did the same in manual, it would stay at the higher RPM. I don't know, its beyond me. All I know is what it does. Maybe I'll try setting the cruise control to make sure I'm maintaining speed and switch.

[audtatious]

That's simply the transmission dropping into 4th gear out of 5th.

Have you tried it at 80mph to see if it is the same RPM drop? I would assume the faster you are going then the more the RPM's would drop when going into 5th gear from manual modes 4th.

[smockers83]

Huh? I was in 5th, the car didn't shift gears at all.

I've tried it at 80, haven't done that in awhile though. IIRC it still drops but not as much at 80. I'll test it out tomorrow when I'm on the freeway headin back home (no freeways around here).

[cheapazz]

OK, so I was playing aroung with my G today and decided to see if I could do the same thing. When in drive and you push the throttle just enough, does your transmission go into the "passing gear"?(used for lack of better terminology)....ya know, the one BETWEEN 5th and 4th..........It is a very subtle difference but it does happen. I would go from cruising 5th, make it go into "passing gear" and then shift into 4thautomanual and there was a differance. Try this.......when cruisin' bout 45 or so and at a steady speed, barely push down the acc. and it will change gears and speed up......right after it does this, flip it into manual - it should go into 4th - and you'll feel what I'm talking about. You may have to play with it to find its sweet spot in the shifting, but it is there. I'm thinkin maybe your transmission just goes straight back to the top 5th gear after you shift back to D from 5th in manual. Just a thought. Lemme know how it goes.

[Sentientbydesign]

Based on all of your descriptions, I would think that the ECU is just modifying the fuel output depending on your need for power.

Having autos means the torque converter will always slip so some degree.