[New] Ex35 Stalls on low speed

[anasalali]

Dear All,

this issue is driving me crazy!

my car is Infiniti Ex35 2008;

this issue happened 2 weeks ago after changing the engine Oil and filter; it started to stall on low speed; I took the car to the dealer and since it is out of warranty - they gave me a crazy quote to replace basically every sensor in the car!!

I took to couple of repair shops and still nothing happened!

there was an error P0024 - P0014 - I replaced the crankshaft sensor - now it is stalling without ERROR!
I cleaned the throtle, changed the oil, flushed the engine,...

I don't know what to do anymore? can you please help me?

[NJGuy]

I wouldn't know off hand what would have caused the problem; but here is what member XIS found on Google a while back on the engine trouble codes:
please-help-with-potential-purchase-t56 ... l#p6405328

Google found this for me as well:
http://my350z.com/forum/maintenance-and ... to-do.html

My guess is that the previous owner never changed the oil on time, and decided to trade in the car when the problems started showing up.

I'm afraid that you'll have to throw a good amount of more money into your EX to get it working right. Good luck and please let us know what happens.

[anasalali]

Thanks NJGuy,
my Idle RPM is 650! is that normal???

the issue is when I cleaned the Throtle, the idle RPM was 850 and the car worked fine till night and started stalling again;

the issue is no one know exactly the problem since there is no error!

I noticed something, some time the RPM is coming down quickly from 1000 to 100 then back to 600 - you feel the car is choking!

I paid already a lot! where to start?

[NJGuy]

An idle speed of 650 RPM is normal when the engine is warm.

So are you saying that the stalling didn't happen again after the crankshaft sensor replacement until you cleaned the throttle bodies?

I wish I could help you out more, but I'm not overly familiar with the details of Nissan's VQ35HR engine. It could be caused by a vacuum leak somewhere, due to an issue with the idle control valve, or something else; I don't really know. If I were in your situation I'd reluctantly bring it in to either the dealership again or find a good shop nearby that's familiar with Nissans/Infinitis. If you want to do some reading yourself, check out file "EC" of the factory service manual here: http://www.nicoclub.com/FSM/EX/2008/ .

[anasalali]

thanks for the file,

I cleaned the throttle and the problem stopped for half day - after that it began stalling again; then I did the replacement of the sensor - worked fine for 1 day and it again it is stalling!
when you are driving - it might not stall at all or it might stall couple of times! there is no indicator on when and where it will happen.

I will start invistigating from the exhaust timing control unit since there was P0024 P0014 error; I know the problem is minor but the issue is how to get it!!

[jsk11ex]

is it stalling while driving at low rpm's or just idling?

[anasalali]

It is stalling on low speed - RPM arpund 1200 to 1000 like you are in the parking or entering a roundabout or reversing! It will stall forsure; but never on idle stop!

[CDNicecube]

Isn't there a procedure to follow after cleaning the throttle bodies? I thought there was and when I got it done at the dealership, it really smoothed out the engine. But I didn't have any stalling issues...

And could it be bad gas?

[anasalali]

something related to the idle air learning? I think he did it!

our Gas in UAE is premium; I don't think that it is a bad gas issue otherwise it will shake a little bit before! right?

[anasalali]

New Update:

the car is heavy when driving and the steering is really tough!!!! it stalled many times in the morning, in the way back it didn't!

[CDNicecube]

New Update:

the car is heavy when driving and the steering is really tough!!!! it stalled many times in the morning, in the way back it didn't!

Are you sure someone did the relearning procedure after the clearing?

After a stall, does it start right up?

If the symptoms went away even for half a day, you might want to recheck (re read) the codes and the sensor. Perhaps you got a bad one. But you were on to smoothing.

Nonetheless, .... These are odd (new?) symptoms. Checks your battery. I had similar weird electrical problems with an Honda odyssey that we're finally traced back to the weak battery. In your kind of weather, heat kills batteries.

But what was going on in the way back? Was temperature different? Engine warm?

If there are no codes anymore, stalling like this could be gas pump, throttle, injectors, spark plugs. I would start with the obvious.

[anasalali]

New Update:

the car is heavy when driving and the steering is really tough!!!! it stalled many times in the morning, in the way back it didn't!

Are you sure someone did the relearning procedure after the clearing?


If the symptoms went away even for half a day, you might want to recheck (re read) the codes and the sensor. Perhaps you got a bad one. But you were on to smoothing.

.

Actually for the relearning: it was spouse to hold the car rpm on 2000 and do it, they tried it several time without success; the car never hold on 2000: either 2700 or 1500RPM.. so they told me that the car will do the relearn by itself
is that right for the car????

another thing, there is no code or engine light.. my guess is the throttle because I remember reading somewhere that I shouldn't touch the pads inside the throttle while cleaning because of some kind of a sensor and if you did you have to replace the whole throttle! I did that !!

another thing to mention, when we cleaned the throttle: the car seemed to be more active!

Nonetheless, .... These are odd (new?) symptoms. Checks your battery. I had similar weird electrical problems with an Honda odyssey that we're finally traced back to the weak battery. In your kind of weather, heat kills batteries.

the battery is OK;

After a stall, does it start right up?

yes, while driving and stalling - I put into N and hit the button and restart again smoothly! but imagine doing that in a roundabout!!

If there are no codes anymore, stalling like this could be gas pump, throttle, injectors, spark plugs. I would start with the obvious

for the gas pump, throttle, injectors, spark plugs: is there any symptoms like shaking? or any indicator?

[anasalali]

[New Update]: I got to the repair shop (the same one who cleaned the throttles) - he adjusted the idle RPM; the car seems to be more smooth and had more energy; and it didn't stall till now since the morning!
he told me, if the stalling happened again; then we need to change the 2 throttles! because the throttle are closing and the engine is dying with the air that is why it is stalling without any Error or engine light!

what do you think?

[AWGD8]

How did you clean the two throttle bodies?
Did you flip open the throttle plates manually?

[anasalali]

Yes, since 1 week; and I opened them manually 2 days ago!!!

Just now when I was trying to enter the roundabout, the RPM went down to 300 Like it was going to stall and 2 lights switched on (i remember the oil and one else) and the car shacked and then it went normal without stalling..

My repair guy told me that I need to change the throttles since no code/no engine light on;

[anasalali]

The repair guy take them out and clean them by special spray,,, there was a lot of carbon around it,,,

[AWGD8]

Ok . You are not supposed to open the throttle plate manually by hand when cleaning it. You'll mess up the throttle bodies calibration on the sensor. This issue had been discussed at G37 and Nissan forum. The worst case is those 2 throttle bodies need to be replaced if issue cannot be fixed.

If you want to clean the throttle bodies, you just leave the plates close and use a spray and qtips to slowly dissolve the gunk in between. This really takes some time to do. Make sure disconnect the battery terminal also.

I have seen some guys who just removed the intake tubing that connects to throttle bodies and one guy pushes the gas pedal to open the throttle plates and another guy is spraying and cleaning the throttle bodies. I never done this except the qtips method..

You can also remove the whole throttle bodies (not connected to the wire harness) and clean it on the floor like your mechanic did. But I think the harm is done when you tried to clean it initially. Did you also disconnect the harness when you cleaned the throttle bodies?

[CDNicecube]

Ok . You are not supposed to open the throttle plate manually by hand when cleaning it. You'll mess up the throttle bodies calibration on the sensor. This issue had been discussed at G37 and Nissan forum. The worst case is those 2 throttle bodies need to be replaced if issue cannot be fixed.

If you want to clean the throttle bodies, you just leave the plates close and use a spray and qtips to slowly dissolve the gunk in between. This really takes some time to do. Make sure disconnect the battery terminal also.

I have seen some guys who just removed the intake tubing that connects to throttle bodies and one guy pushes the gas pedal to open the throttle plates and another guy is spraying and cleaning the throttle bodies. I never done this except the qtips method..

You can also remove the whole throttle bodies (not connected to the wire harness) and clean it on the floor like your mechanic did. But I think the harm is done when you tried to clean it initially. Did you also disconnect the harness when you cleaned the throttle bodies?

Awgd8 is right. We are not supposed to open the throttle body manually. It is very picky calibration. This is a few thing I get/paid the dealer to do. I believe you need to call Infiniti and ask if they can recalibrate those you have. If not, you will need to get new ones. Or from a junk yard? Keep us us posted because we need to know the solution, if it can be recalibrate do. We never know...

[anasalali]

[New Update]: after 3 days of testing and driving the car, it seems that raising the RPM by 100PRM solved the problem;

it was in the throttle - that is why there was no error / engine light;

[AWGD8]

[New Update]: after 3 days of testing and driving the car, it seems that raising the RPM by 100PRM solved the problem;

it was in the throttle - that is why there was no error / engine light;

That is great news! So the dealer raised the idle RPM from 650 to 750RPM?

The only way to raise the RPM is to go deep into the ECU programming.
Like what i do for my Uprev tuned EX35.

[anasalali]

It was 600rpm and now it is 700rpm;

He reprogram it!

[AWGD8]

600RPM seems to be a bit low for the stock EX35.
Before I increased my idle RPM to 775RPM using an Uprev ECU tuner, my stock EX35 idle setting was 650RPM.

[anasalali]

[New Update]: the car stalled again today at the roundabout!!!!

after full week of not stalling, it stalled again!

what is your suggestion? shall I change the Throttle bodies? since it didn't stalled since we working around them?

[anasalali]

any help?

[AWGD8]

any help?

Can you try these 3 instructions?

Accelerator Pedal Released Position Learning
DESCRIPTION
Accelerator Pedal Released Position Learning is an operation to learn the fully released position of the accelerator pedal by monitoring the accelerator pedal position sensor output signal. It must be performed each time harness connector of accelerator pedal position sensor or ECM is disconnected.

OPERATION PROCEDURE
1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch ON and wait at least 2 seconds.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Turn ignition switch ON and wait at least 2 seconds.
5. Turn ignition switch OFF and wait at least 10 seconds.

Throttle Valve Closed Position Learning
DESCRIPTION
Throttle Valve Closed Position Learning is an operation to learn the fully closed position of the throttle valve by monitoring the throttle position sensor output signal. It must be performed each time harness connector of electric throttle control actuator or ECM is disconnected.

OPERATION PROCEDURE
1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
Make sure that throttle valve moves during above 10 seconds by confirming the operating sound.

Then follow this video. It is easier to follow his timming while watching it than doing it on your own.

http://youtu.be/95WszTnphPI

[AWGD8]

Isn't there a procedure to follow after cleaning the throttle bodies? I thought there was and when I got it done at the dealership, it really smoothed out the engine. But I didn't have any stalling issues...

And could it be bad gas?

These are the procedures above after cleaning the throttle bodies.

I reread your post and you never had a stalling issue on idle stop. Only on slow speed or turn? How does the tachometer movement on idle stop? Is it steady ? No weird vibration etc..?

If it is the throttle bodies, you might have issue on idle or starting up the car or rolling from the stoplight ( surging , hesitation etc.), but this is not the case.

Yours stall while on the go on low speed. Does it stall after you drive it at medium speed of 35+ MPH?

[AWGD8]

New Update:

the car is heavy when driving and the steering is really tough!!!! it stalled many times in the morning, in the way back it didn't!

Is the tough steering resolved on it's own?

[AWGD8]

1) I know this is weird, but can you observe like if your gas is close to empty and see how many miles per gallon left in the tank? Just check the tiny dash screen (red) if the Miles Left correlates to the fuel analog dial in your dash.

Then when you fill up fuel, try the shell V-power 93 Octane and also try the Royal Purple Injector cleaner at Walmart. A bit expensive $13 but this can be use for full tank of gas, instead of waiting for an almost empty tank.

I am trying to see if this is fuel pump, fuel line, fuel filter , injector issues...

2) For the Ignition test, can you drive without accessories on ( radio, fan etc.) and see if stalling will happen...

3) Does this stalling happen on D mode ? Can you try DS mode or Manual mode and see if stalling happens?

[jamesstock]

Connect the scanner and read the throttle voltage and the APP angles. Eventhough there's correct voltage going via the TPS sensors asking the motors to 'flip' / adjust the throttle plates, the motor might NOT react correctly.

Adjusting the idle rpm w/ the ECU seems 'odd' to me as it's drive by wire and adjustments should be made 'automatically based on conditions of the vehicle.

[anasalali]

an update:

I haven't changed the throttles yet because of the price!! can you imagine that 2 throttles will cost me 3,270$ from the dealer!?!!!!

the car is heavy when driving and will stall on a situation where you are on a heavy traffic jam (stopping and moving frequently!); I tried D - DS no difference! still you can't predict the stalling.

what I am planning to do is find a good scrap throttles with good price and try them to check if this is the problem!
and for the fuel, our fuel here is 95 and 97 - so I suppose no issue!

thanks guys, I will keep posting.