Engine shudder at start up

[Kenny]

Just as the title states, I encountered a strange issue with my 2011 Z. This problem arose earlier today around 3pm.

Upon starting up my Z, I noticed my engine shudders a little bit before the idle stabilizes. Also, I noticed the instrument needles of the tach and speedometer didn't do its normal wind-up. The oil temp and battery gauges didn't do their wind-up either.

Any idea? Could it be a vacuum hose or something? My Z has 37,000 miles. I did an oil and air filter change a couple hundred miles ago.

Here's a little video I made of the issue:

[JARblue]

Is it just me or is there no audio for the video? **edit** got it working

You can check the 'effect' setting or "wind-up" as you call it, in the menu on the left cluster. I would ask if you had disconnected the battery or something recently, but my experience is that it defaults to 'on'.

[DEpointfive0]

Check to see if you have a nut sitting on an intake valve.


Dealershit will tell you to try a new battery

[Trips]

Seems like the "effects" option which controls the sweep option has been turned off from the left cluster buttons options menu

Pg 2-23

http://www.nissanusa.com/content/dam...issan-370Z.pdf

On the starting issue? I would look at the battery's condition if it the original one.

Seems to sound fine once it's on.

[roy'sz]

that's a normal startup in my opinion.

[IDZRVIT]

Originally Posted by roy'sz

that's a normal startup in my opinion.

[Super Werty]

Have you checked your oil level? Almost sounds like slight engine knock.

[Mandingo]

The lack of sweeping needles at start up was due to a blown fuse in my case

[SouthArk370Z]

Originally Posted by Mandingo

The lack of sweeping needles at start up was due to a blown fuse in my case

Do you remember which fuse it was?

[Mandingo]

It was the one for the instrument cluster. Now that I am able to see the vid, I don't think his fuse is blown because the cluster lights up. Maybe the sweep setting was somehow reset in the menu.

[Kenny]

I checked my battery with my awesome free voltmeter from Harbor Freight and I got a reading of 12.71. From what I understand, that's a normal reading.




I checked the sweep effect in the options screen in the left gauge and it's turned on.




I checked my oil level and it looks normal as well.




So I fired up my Z for the first time today a few mins ago and everything was normal again. I didn't feel the engine shudder at start up and the gauge effects was operating correctly.




Yesterday, I got home from work and did some stuff around the house. Then I went out an hour later to run an errand. After my errand, I hopped back into my car, fired it up and noticed the engine shudder and gauge effects not working. I thought nothing of it and went straight home. When I got home, I decided to see if I could replicate and record the engine shudder and non-functioning gauge effects. Sure enough, the engine did shudder and the gauge effects wasn't operating.

So this leads me to believe that this problem happens when the car is warmed up/hot. After I got home from work, my Z was still warm when I went out on my errand. Then when I finished my errand, my Z was still warm when I noticed the problem. I get home and tried to replicate the issue and sure enough, it occurred again.

Cold car = no engine shudder, working gauge effects
Hot car = engine shudder, non-working gauge effects

So do you guys have any other ideas what this could be?

I'm going to try cleaning my throttle bodies per this thread here: DIY Clean your Throttle Bodies - MyG37 It looks simple enough to do. Do I have to remove my stock factory strut tower bar in order to access the throttle bodies? I want to remove as few parts as necessary.

[Kenny]

So I finally found some time this last weekend to pay some attention to my sorely neglected Z. I spent Sunday morning removing the strut tower bar, engine cover, and throttle bodies. From the outside it didn't look that dirty. But once I got behind it, there was black gunk all built up behind it. I hit some clean cloths with carb cleaner and went to work. It took a bit of elbow grease and I cleaned about 95% of it. After I reinstalled everything, the Z fired up perfectly. I also installed some new factory air cleaners too. The Z can now inhale a lot easier.



My hypothesis as to why my engine was shuddering during hot start up could be due to the gunk build up in the throttle bodies was causing the plenum to stick. When the engine was hot, the gunk melted and became sticky. That caused the throttle bodies to not operate smoothly. When it's not opening smoothly, that caused the engine to shudder and that caused the gauge sweep effect to not initiate properly.

That's my best guess. Anyhow, for those of you who have this problem can consult this nicely written DIY on the G37 board: DIY Clean your Throttle Bodies - MyG37

So that's that..

[Mandingo]

This is a tough one. I'm not sure why the needle sweep and engine shudder are connected.

On cleaning the throttle bodies: For ease and safety don't move the butterfly valve while you are cleaning them. Yes you can get them cleaner by pivoting the valve out of the way, but sometimes this causes idling issues that can't be fixed with the reset procedures. I'm not sure if this is in the thread you linked but some people ended up having to buy whole new throttle bodies.

[fuct]

my engine will studder upon start up if its hot. it happens when i shut the car off after its warmed and try to start it within 5-10 min.

[Mitco39]

My guess would be a slight overfueling while cranking. Is the car tuned?