Idle problem after TB cleaning

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Old 07-28-2018, 06:47 AM
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Unhappy Idle problem after TB cleaning

2007 G35x idling & accelerating rough. I figured the best solution was to remove TB and clean. Surging idle afterwards, came here to discover removing everything was a bad idea. Now I have the dreaded surging idle problem. I read through the threads about doing the "pedal dance" but it seems to me that it is talking about an ECU reset, and indeed in one set of instructions, it states that a reset can be accomplished by disconnecting the battery and depressing the brake pedal. I did that, left the battery disconnected for 1 hour, but the problem persists. So my questions are:

1. Does the pedal dance accomplish the same thing as disconnecting the battery?
2. Is the air idle relearn something different than resetting the ECU?
3. I read that flashing the ECU fixes the problem. Can I flash the ECU myself?
4. Bonus question - Why are there lines running antifreeze through the body of the TB?

I also read somewhere that suggested it can take up to two weeks of driving for the vehicle to relearn on its own, is that true? Advisable?
 
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Old 07-28-2018, 10:31 AM
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Originally Posted by CraigVMN View Post
2007 G35x idling & accelerating rough. I figured the best solution was to remove TB and clean. Surging idle afterwards, came here to discover removing everything was a bad idea.
Tons of threads on this topic

Obviously you figured incorrectly. Perhaps you have a vacuum leak?
On my previous 06 G35 6 speed my throttle body was cleaned at the dealer when I had my plugs replaced at 105k miles. It ran perfect as I drove it out the door.
If you don't know what you are doing it is best to leave the troubleshooting to a pro.

Just my $.02

Telcoman
 
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Old 07-28-2018, 10:49 AM
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I went back over all the hoses & connections, and as far as I can tell everything looks fine. I did the whole pedal dance and after much trial & error, got the Service Engine Soon light to go out. I then followed the steps below, but after completing the last step, when I start the engine, it idles high then starts revving up & down again and soon after the SES light is back again. I did this several times, but to no avail.

Any ideas what I should do next?

1. Confirm that accelerator pedal is fully released, turn ignition switch “ON” and wait 3 seconds.
2. Repeat the following steps (2a and 2b) procedures quickly five times within 5 seconds.
2a. Fully depress the accelerator pedal (HARD).
2b. Fully release the accelerator pedal.
3. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 10 seconds until the CEL starts blinking.
4. Fully release the accelerator pedal (while the CEL is still blinking)
5. Wait about 10 second.
6. Fully depress the accelerator pedal and keep it for more than 10 seconds.
7. Fully release the accelerator pedal (The CEL light will continue to blink).
8. Turn ignition switch to “OFF” position and now you can start the car. The CEL light should be gone.
If the CEL light continues to remain ON, repeat the above steps. Timing is EXTREMELY critical to resetting the ECU.

Accelerator Pedal Release Position Learning
Operation Procedure1. Make sure that the accelerator pedal is fully released.
2. Turn ignition switch “ON” and wait at least 2 seconds.
3. Turn ignition switch “OFF” wait at least 10 seconds.
4. Turn ignition switch “ON” and wait at least 2 seconds.
5. Turn ignition switch “OFF” wait at least 10 seconds.

Throttle Valve Closed Position Learning
Operation Procedures
1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch to “ON”.
3. Turn ignition switch to “OFF” wait at least 10 seconds.
Make sure that the throttle valve moves during above 10 seconds by confirming the operating sound.

Idle Air Volume Learning (Throttle Position Learning)
It is better to count the time accurately with a clock.1. Perform “Accelerator Pedal Released Position Learning”.
2. Perform “Throttle Valve Closed Position Learning”.
3. Start engine and warm it up to normal operating temperature.
4. Turn ignition switch “OFF” and wait at least 10 seconds.
5. Confirm that the accelerator pedal is fully released, then turn ignition switch “ON” and wait 3 seconds.
6. Repeat the following (steps 7a, 7b) procedures quickly five times within 5 seconds.
7a. Fully depress the accelerator pedal (HARD)
7b. Fully release the accelerator pedal.
8. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the Check Engine Light (CEL) stops blinking and turned ON.
9. Fully release the accelerator pedal within 3 seconds after the CEL is ON.
10. Start engine and let it idle.
11. Wait 20 seconds.
12. Rev up the engine two or three times and make sure the idle speed and ignition timing are within the specifications.
 

Last edited by CraigVMN; 07-28-2018 at 10:56 AM.
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Old 07-28-2018, 11:50 AM
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You MUST use a watch or something to accurately measure time, the seconds counts are pretty exact.

http://nicoclub.com/archives/g35-350...procedure.html

Do all the resets.

Optionally the software NDS2 can do some of these things as well if you have a laptop that can interface with OBD2.
 
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Old 07-28-2018, 12:51 PM
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First off, I appreciate the help. Secondly, what kind of crack addict comes up with this method of this pressing & timing BS (Nissan, Infiniti...hello?)

I have followed the list to the letter enough times (using the stopwatch on my phone) to know when I've done it right & when I've done it wrong. When I do get to the last step, I turn over the engine, it idels at 2k, I wait 20 seconds, rev the engine, the SES light comes back on and the idle hunt begins anew. The first time I went through the list was first thing this morning. With all electrical items tuned off, I get the SES light off. Went through the next two procedures, then started up to drive it around to get everything warmed up. It wasn't long before the SES light was on again. When I got back home I completed the last procedure but to no avail. So I started from the beginning, and after several times of going through everything, same end result.

I bout the car used several weeks ago with 114,00 miles on it. From what I've seen working on the car, I believe it must have sat for a while in Wisconsin weather conditions. I called the local Nissan dealer, but on Saturday, they don't know if they can flash the ROM on an Infiniti (I'd be willing to bet they can) to the tune of $120, which would be worth it if it fixes the issue. In the meantime, if I hook it up to an OBD2 reader, will it tell me if there are other problems?
 
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Old 07-28-2018, 01:10 PM
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Yes they can flash it, if they say otherwise they're either dumb or they are trying to deceive you. It's literally the EXACT SAME engine controls system as the 350Z with the HR motor.

If you are getting the idle air reset to work then you probably just have a vacuum leak, take off the intake tubes, inspect for cracks, pull out the PCV valve and make sure it rattles, check the bypass connection pcv tube between the two banks, check the opposite side going up to the intake tube. Somewhere you likely have a leak, it's probably big and obvious once you get everything taken apart again.

Make sure nothing got pinched between the TB and intake manifold. Are you sure the big rubber o-ring didn't fall off of the TB ?
 
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Old 07-28-2018, 03:04 PM
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Both O rings are in place. I will inspect the tubes and hoses. Where will I find the PCV valve?

For the heck of it, drove it to Autozone for the free OBD hookup, came back with the following error codes

P1148 Closed loop function
P0031 Air fuel ratio sensor 1 heater control circuit low

Both codes came up twice, I'm guessing for the dual air intakes. It recommended replacing the Mass Air Flow sensor.

Then something very odd happened. Picked up my daughter from work, stopped at a place so she could get something to eat, turned off the engine. When I restarted it, we hear a loud pop, followed by a loud hissing sound (almost like a tire had blown) and there was a puff of white smoke/fog. Turned off the engine, looked under the hood expecting to see a burst pipe/tube/hose & fluid all around, but found nothing. Got back in, turned it on, and only the high idle persisted. Drove it home keeping an eye on the temp gauge, but the only thing we noticed was the A/C wasn't as cool, and the cabin became very humid. Did a more thorough inspection upon arriving at home, but nothing seemed out of place. I'm really starting to regret having bought this car.
 
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Old 07-28-2018, 03:28 PM
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You might have ruptured the AC line somewhere, a pressure test of the low side should be like 50psi, if you don't have an AC manifold you can buy a recharge can of AC PRO or some other brand that has the gauge on the bottle.

P0031 is likely the MAF, you don't need to buy the entire housing because the MAF itself can be replaced separately, the heater and intake air temp sensor are built into the MAF on these cars. This is likely also causing the car to spit out the P1148 since it cannot enter closed loop with a bad MAF.

Double check the harness on the MAF though since you did recently have the intake tube removed. I think on the HR you can physically swap the MAF between banks to test the harness and wire because I think the plug is the same on both sides. It should give you the code P0051 when you swap it to the other side.

The PCV valve screws into the valve cover on the passenger side, look for the big vacuum hose.
 
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Old 07-28-2018, 03:57 PM
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Thanks again man. In the meantime, upon removing the air intake hose to get to the PCV valve, I discovered this. Must have happened while I was putting it together in the dark last night.
 
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Old 07-28-2018, 05:24 PM
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Dohh! Well hopefully that fixes ALL the issues including the MAF ones.
 
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Old 07-28-2018, 07:04 PM
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In the meantime my A/C definitely went pop-hiss. Any idea what to look for as a potential trouble spot?
 
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Old 07-28-2018, 08:03 PM
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No it could be any.number of fittings, best thing is to pressure test it to see if it actually did rupture but if your AC no longer pumps out cold air that's a pretty good indicator.
 
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Old 07-29-2018, 08:11 AM
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I'm deployed in Afg right now and my son is struggling with a similar issue with his 08 G35X. First it pulled a code and P0506 at the Nissan dealership and they recommended he replace both TB's. Having owned a 05 myself years ago I know how cruddy the TB's can get and explained to him the cleaning process for the TB's and the MAF plus the relearn procedure. I was also very clear to not move the butterfly if at all possible. Upon reassembly and relearn procedure completion he started getting a high idle and took it to AutoZone to have the CEL code pulled and they reported a P2101 which is Bank 1 (passenger side) TB operation. To me the P2101 sounds like an electrical issue but none was present prior to the TB and MAF service.

It has been a while since i have worked on or around a G and hoping you all may have some tips you can share. Thank you in advance.
 
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Old 07-29-2018, 05:59 PM
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Originally Posted by CraigVMN View Post
Thanks again man. In the meantime, upon removing the air intake hose to get to the PCV valve, I discovered this. Must have happened while I was putting it together in the dark last night.
You would have realized you did that, wouldn't you ? I suspect it was broken before. It's likely the cause of P0031 code. After quickly looking up P1148, that's likely related too. Order a replacement intake tube and in the meantime, wrap some rubber sheet over the end and clamp it. Get the codes cleared after doing that and see if they return. This is a temporary fix, IMO !
 
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Old 07-29-2018, 06:13 PM
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Originally Posted by CraigVMN View Post
1. Does the pedal dance accomplish the same thing as disconnecting the battery?
2. Is the air idle relearn something different than resetting the ECU?
3. I read that flashing the ECU fixes the problem. Can I flash the ECU myself?
4. Bonus question - Why are there lines running antifreeze through the body of the TB?
1 & 2) The pedal dance is probably more "reliable". Doing it right is a different matter. As cleric said, use a stopwatch (the clock app on a smartphone works just fine). If the SES light doesn't behave exactly like the instructions indicate, you didn't do the process correctly. There are multiple 'resets' that you can do yourself:

Accelerator Pedal Release Position Learning
Throttle Valve Closed Position Learning
Idle Air Volume Learning (Throttle position learning) << the instructions I have say to do the first two before doing this

I've seen this referred to as an ECU reset too.

3) No, only dealers can do that. I think engines prior to the HR were pickier with their TBs and could be difficult to reset properly. One solution involved disconnecting the MAF(s) so that another code would be triggered. You'll have to Google the process after this as I don't remember it well enough. You obviously re-connect the MAF(s), reset the codes, and perform the ECU reset but I'm not sure of the order to follow.

4) Cooler air is more efficient
 

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