Need advice with high idle; P0507.

The G-Series Tuning Forum is the place to discuss G35/G37 performance modifications and mechanical repair.
donutDrift
Posts: 14
Joined: Thu Nov 24, 2016 7:47 pm
Car: 2003 Infiniti G35

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Hey what's up guys; hate that this has to be my first post but I need some help. First of all, I've owned my '03 G35 6MT for about a month now after I traded my '94 Miata for it (miss it dearly :sad:) but I'm enjoying every bit of it.

The issue I'm looking to get help on is the notorious high idle which is throwing the code P0507. I've read a bunch of forum posts and done the ECU/Idle relearn countless time and none seem to fix the problem.

Here's the procedure I'm following which was posted by a user called 04G35DPM in the G35driver forum.
4.) Idle Air Volume Learning
1. Perform EC-91, "Accelerator Pedal Released Position Learning" .
2. Perform EC-91, "Throttle Valve Closed Position Learning" .
3. Start engine and warm it up to normal operating temperature. Skip this if the engine is already warm as you might throw the code in idle.
4. Check that all items listed under the topic PREPARATION (previously mentioned) are in good order.
5. Turn ignition switch OFF and wait at least 10 seconds.
6. Confirm that accelerator pedal is fully released, turnignition switch ON and wait 3 seconds.
7. Repeat the following procedure quickly five times within 5 seconds. This interval must be 5 seconds before step 8 begins.
a. Fully depress the accelerator pedal.
b. Fully release the accelerator pedal.
8. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the MIL stops
blinking and turned ON.
9. Fully release the accelerator pedal within 3 seconds after the MIL turned ON.
9a. Perform step 10. within the above 3 seconds. The photo below shows the car in run after the 3 seconds. But, this never worked for me.
10. Start engine and let it idle.
11. Wait 20 seconds.
12. Rev up the engine two or three times and make sure that idle speed and ignition timing are within the
specifications.
13. Turn off the car and restart within/ before 10 seconds. (Better = 5 seconds) Now it should work. I think you have everything up til here, so try this last step.
After step 12 the car will idle around 700-600 but when I go to turn off the car and turn in back on; it will idle back up around 1000-900. Some things I should mention is that the car has a Injen CAI and (according to the PO) an Exedy stage 2 clutch. Also, when I go to turn off the car I step on the clutch to avoid a small rattle noise; the PO told me to do this. Could this be throwing off the idle back up? I've done the procedure turning off the car both ways; stepping on the clutch and simply switching the key off.

This is where I'm looking for some help or advice; maybe I'm doing the process wrong. If not then I'm to the point of just taking it to a Nissan dealership and having them set the idle themselves. The thing holding me back is that the car also has a bad knock sensor harness (showing code P0327); will this be an issue if I was to take it a dealership?

Any help will be appreciated.


ArmedAviator
Posts: 526
Joined: Tue Mar 22, 2016 5:28 pm
Car: 2012 M37x
Location: SW Ohio

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When you start the car back up, do you let it idle for a few minutes or drive it for a bit before determining the idle is high?

All modern vehicles now idle high after starting when below normal operating temp to warm up the emissions systems (cats). Depending on temperatures, this may last 5 minutes before returning to normal idle.

donutDrift
Posts: 14
Joined: Thu Nov 24, 2016 7:47 pm
Car: 2003 Infiniti G35

Post

ArmedAviator wrote:When you start the car back up, do you let it idle for a few minutes or drive it for a bit before determining the idle is high?

All modern vehicles now idle high after starting when below normal operating temp to warm up the emissions systems (cats). Depending on temperatures, this may last 5 minutes before returning to normal idle.
I do let it idle for a bit but the RPMs never drop back down to normal, but no I don't drive it for a bit since I went ahead and concluded it was a failure. One time when I went back to restart the car; the CEL came back on. Also, before I began any of the reset procedures I made sure the car was already warned up by taking it on a short drive.

I forgot to mention that a couple days ago I took apart the CAI to clean the MAF and also TB (made sure not to touch the butterfly valve). I did unscrew the TB but didn't disconnect anything; one thing I noticed was that the valve didn't close properly/flush. It had a small opening at the top and bottom. Could this mean that the TB needs to be replaced? Or is the point of the reset procedures to make sure the valve go back to normal.

Should I try and replace the knock sensor harness first or does that not have anything to do with a high idle.

ArmedAviator
Posts: 526
Joined: Tue Mar 22, 2016 5:28 pm
Car: 2012 M37x
Location: SW Ohio

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Don't know why people don't like to touch the butterfly valve.... It's not voodoo. I disconnected mined, cleaned them thoroughly, open then up and got all the crud out. Worked fine on reassembly. The slight opening of the butterfly valve is normal. This is usually set at the factory with a set screw on that shouldn't be changed.

MotorvateDIY
Posts: 14
Joined: Sat Nov 26, 2016 12:39 pm
Car: 2011 G37 Sport Sedan

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On the G37, if the "Idle Air Volume Learning" does not work you need to:
(1) Turn off car
(2) unplug one MAF
(3) start car, check engine light will turn on
(4) Clear code
(5) Try "Idle Air Volume Learning" again.

I wonder if this might work for you?

donutDrift
Posts: 14
Joined: Thu Nov 24, 2016 7:47 pm
Car: 2003 Infiniti G35

Post

ArmedAviator wrote:Don't know why people don't like to touch the butterfly valve.... It's not voodoo. I disconnected mined, cleaned them thoroughly, open then up and got all the crud out. Worked fine on reassembly. The slight opening of the butterfly valve is normal. This is usually set at the factory with a set screw on that shouldn't be changed.
I'm new to these cars, so I'll believe what people tell me. :bowrofl:

donutDrift
Posts: 14
Joined: Thu Nov 24, 2016 7:47 pm
Car: 2003 Infiniti G35

Post

MotorvateDIY wrote:On the G37, if the "Idle Air Volume Learning" does not work you need to:
(1) Turn off car
(2) unplug one MAF
(3) start car, check engine light will turn on
(4) Clear code
(5) Try "Idle Air Volume Learning" again.

I wonder if this might work for you?
Will I damage the car if I start the car with out the single MAF plugged in? And I'll need an OBDII to clear the code right; good thing I have one on the way. Also, what noise am I supposed to be listening for when I do the "Throttle Valve Closed Position Learning"? I can't hear anything when I do it, so maybe that could be the reason the reset is not working

Slammedg35
Posts: 1
Joined: Mon Jan 09, 2017 4:31 pm
Car: 2005 g35 coupe

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I had the same problem and none of those methods work so just take it in and get it reprogramed

donutDrift
Posts: 14
Joined: Thu Nov 24, 2016 7:47 pm
Car: 2003 Infiniti G35

Post

Fixed. One day I did the ECU reset and miraculously the idle went back to normal.


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