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Problem starting; did battery, valve replacement & Throttle body cleaning

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Old Dec 29, 2010 | 08:35 PM
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Long time to crank car up, added sound clip; Valve and batter replaced already

Guys, I've had a problem starting my car up for the past few weeks. First I went in and they did a TSB for the battery and the vent control valve replacement. Then a few days later I cleaned the throttle body. I'm still having problems and it seems to be getting worse. I'm posting up a youtube clip of the start up. Listen to it and tell me what you guys think I need to do.
Btw, I made an appt for Tuesday to go to the dealership but wanted to take some ideas to them.

YouTube - Start up.mpg

Thanks in advance people!

Last edited by ohsogood; Jan 3, 2011 at 10:33 AM. Reason: Re-wording title
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Old Dec 30, 2010 | 09:06 AM
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^Bump to get some help!
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Old Dec 30, 2010 | 10:22 AM
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can't be the battery, its cranking but not starting. Just call Infiniti Roadside and have the dealer look at it. You don't' want to start messing with it and void the warranty. I wouldn't mention that you cleaned and moved anything.

The "do it yourself" should be done when there is no warranty left on the vehicle.

Just take it in!
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Old Dec 30, 2010 | 10:30 AM
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Originally Posted by RaulGCustom
can't be the battery, its cranking but not starting. Just call Infiniti Roadside and have the dealer look at it. You don't' want to start messing with it and void the warranty. I wouldn't mention that you cleaned and moved anything.

The "do it yourself" should be done when there is no warranty left on the vehicle.

Just take it in!
I agree with not telling them I cleaned or moved anything.
Fortunately, my dealership is great about working/fixing stuff on my car with no complaints. One of the few times I can say a dealership will do everything they can to help me out.
Just wanted to see if others had the same problem or might know what caused the problem before I take it in next week.
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Old Dec 30, 2010 | 11:12 AM
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Just as a quick FYI, throttle body cleaning won't do much on the VQ37VHR engine since it uses the VVEL system to regulate the air input. There are two throttle bodies but they are always fully open and they are just there as backup incase the VVEL system fails.
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Old Dec 30, 2010 | 11:16 AM
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Originally Posted by JohnEnglish
Just as a quick FYI, throttle body cleaning won't do much on the VQ37VHR engine since it uses the valve to regulate the air input. There are two throttle bodies but they are always fully open and they are just there as backup incase the VVEL system fails.
Hmm interesting.. I felt like my car was so much smoother after the cleaning of the throttle body. After a full stop, it would be so sluggish going into the different gears, but after the cleaning, it felt so smooth.
Maybe it was in the head?
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Old Dec 31, 2010 | 12:42 AM
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I agree that it seems to be taking longer than "normal" to start. It sounds like it isn't getting fuel initially. Have they checked the fuel pump pressure or the injectors? If they are ok have they checked the plugs. While it doesn't sound like it is missing a bad plug can slow ignition.

How does it run under WOT? Is the car sluggish under acceleration? What about when the car is hot/cold? Does it sputter when accelerating from a cold start?

You don't say how many miles the car has on it, when was the last time you replaced the air filters? I know the manual says at about 30k. I replaced my filters at 20k and it did make a difference, and I wasn't having any problems. Pull both filters (one at a time) and look at them, are they dirty? Replace the filters, about $25 each at the dealer and see if that helps.

Good luck.
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Old Dec 31, 2010 | 12:52 AM
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Originally Posted by chairman25
I agree that it seems to be taking longer than "normal" to start. It sounds like it isn't getting fuel initially. Have they checked the fuel pump pressure or the injectors? If they are ok have they checked the plugs. While it doesn't sound like it is missing a bad plug can slow ignition.

How does it run under WOT? Is the car sluggish under acceleration? What about when the car is hot/cold? Does it sputter when accelerating from a cold start?

You don't say how many miles the car has on it, when was the last time you replaced the air filters? I know the manual says at about 30k. I replaced my filters at 20k and it did make a difference, and I wasn't having any problems. Pull both filters (one at a time) and look at them, are they dirty? Replace the filters, about $25 each at the dealer and see if that helps.

Good luck.
Just reached 40k and I did go get my car serviced for 30k and I think I remember them saying the filters didn't need to be replaced.
Feels fine under WOT. It did feel sluggish but cleaning the throttle body made a huge difference. I'm only have problems with the start up. Fortunately, it hasn't died on me once yet. It's just struggled to start like you heard.

So I'm thinking I should tell my dealer to look at:
Fuel pump pressure and injectors? And then the spark plugs?

I wish my dealership wasn't so busy. They couldn't see me until Tuesday.
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Old Dec 31, 2010 | 07:56 AM
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Originally Posted by ohsogood
Hmm interesting.. I felt like my car was so much smoother after the cleaning of the throttle body. After a full stop, it would be so sluggish going into the different gears, but after the cleaning, it felt so smooth.
Maybe it was in the head?
Yeah, probably.
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Old Dec 31, 2010 | 12:23 PM
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Originally Posted by JohnEnglish
Just as a quick FYI, throttle body cleaning won't do much on the VQ37VHR engine since it uses the VVEL system to regulate the air input. There are two throttle bodies but they are always fully open and they are just there as backup incase the VVEL system fails.
I thought it was for emissions.
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Old Dec 31, 2010 | 03:34 PM
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Originally Posted by joeposter
I thought it was for emissions.
What was for emissions?
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Old Jan 1, 2011 | 12:23 PM
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Originally Posted by sharif@forged
Their wording is a complete marketing ploy. This is a conventional engine, who's engine speed is controlled by the two throttle bodies. They are trying to meld VVEL and spin it to make it sound like it can control the throttle/engine speed...but it cannot do this. This engine requires TB's, and its not something just for emissions purposes.

Hope that helps.
I'll trust this since he actually takes these things apart and tunes them...
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Old Jan 1, 2011 | 03:29 PM
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Originally Posted by BradManUWF
I'll trust this since he actually takes these things apart and tunes them...

Sorry but was a bit confused with your statement from the previous quote. Are you saying the throttle body cleaning does make a difference on the 2008? Felt a huge difference after my cleaning.
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Old Jan 1, 2011 | 04:19 PM
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Originally Posted by BradManUWF
I'll trust this since he actually takes these things apart and tunes them...
Originally Posted by ohsogood
Sorry but was a bit confused with your statement from the previous quote. Are you saying the throttle body cleaning does make a difference on the 2008? Felt a huge difference after my cleaning.
Take a look at the technical presentation for VVEL. You can see that the throttle bodies are left open all the time and air intake is controlled by the VVEL system. The throttle bodies are just there in case VVEL fails. Specifically page 5 onwards explains how the throttle bodies are left open all the time.

A Nissan press release explaining VVEL which says
While conventional engines control air intake using a throttle valve, VVEL-equipped engines do this directly at the intake valves, continuously controlling their valve events and lifts. C-VTC and VVEL together control the valve phases and its valve events and lifts, allowing free-control of the valve timing and lift. This results in more efficient airflow through the cylinder and significantly improves responsiveness, optimizing the balance between power and environmental performance.
You also can watch this video which shows the VVEL system in action. Towards the end of the video you can see that as the accelerator is pressed all that changes is the valve lift. The throttle body stays open all the time and air intake, and therefore engine speed, is controlled by the VVEL system.

It even says in the video:
Air intake is controlled by finely variable regulation of the degree of valve lift and valve timing resulting in a highly efficient engine.
So, the throttle bodies are there for backup and are not needed in the regular operation of the engine.

Last edited by JohnEnglish; Jan 1, 2011 at 04:33 PM.
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Old Jan 3, 2011 | 10:30 AM
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This is just for the people who might face or have the same problem with their car..
I just sent the clip to the dealer and he stated it seems like it's a fuel injector problem. I'm taking my car in tomorrow to get it fixed. I just wanted to relay this information out to other G users so they could hear my sound clip and if they have the same problem, at least they know what the issue is.

Hope this helps for other future readers
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