Well After 80K miles I decided this weekend was the right time to finally clean out the TBs. Over the past few months I've read many posts and watched several DIYs and decided I would do a 'safe' but perhaps less thorough cleaning. My method was remove the throttle bodies but do not remove any harnesses, do not move the butterfly valve and leave the battery connected.

All was straight-forward, I removed a fair about of carbon build up mostly from the backside of the TB. Put everything back together and started it up. Initially it wasnt too bad idle settled at 1100-1200rpm. I figured the ECU would auto adjust for the extra air and it would gradually settle back down to ~650rpm. Well the reverse happened, after driving for a bit the idle actually increased and then started surging. My service engine soon light also came on.

Well there you have it follks even doing what I would consider a very safe cleaning where nothing was unplugged or tampered with, it appears I have full symptoms so you never really can tell.

Will be doing a full re-learn tomorrow. Wish me luck

 

 

It's pretty common knowledge on here that you should always unplug the TB's and disconnect the battery before you work on them just to be on the safe side. I'm not sure if that could have prevented your issue though, these things are tricky *****.

 

Did this a few months ago but as Blue Dream says, I read on here that its better to unplug the battery, ground out any residual power, unplug thottle body, then clean. Hell, I even moved the butterfly a tad and when everything went back together had zero idling issues.

 

There's clearly no "right" way to do this. One method works just fine for some while it turns into a disaster for others.

Disconnect the battery, don't disconnect it. Unplug the TBs, don't unplug them. Move the butterfly, under no circumstances in h**l should ever touch the butterfly. Remove the TBs, don't remove them.

I cleaned mine (twice) with no issues and from what I've read, I consider myself lucky !

 

I'm not sure why so many folks have issues with the TB cleaning, I use about half a can of tb spray and never move the butterfly by hand, just keep spraying until every tiny bit of crap is blown off.

I suspect it's damage to a worm drive gear from trying to work the butterfly by hand but I'd need to disassemble a malfunctioning one to verify.

Probably the most important step and this might be where a lot of the problems occur is doing the proper reset once you have cleaned it. You have changed the airflow potential of the throttle body once it's cleaned and the computer needs to relearn a few things about the TB for it to function properly, it needs to know where the zero stop is (even if you left it plugged in it might zero out slightly different once cleaned), and it needs a new idle airflow calculation, the engine needs to be at operating temperature for the idle airflow. Also since you have changed the potential airflow of the motor you should also reset the fuel trim ,which was likely already done by having the battery unplugged long enough to clean the TB, but I recommend a manual reset once everything is up to temp.

The resets need to be performed in a specific order as well: ECU reset - Throttle pedal released - Throttle body closed - Idle air reset.

Just follow the steps in order listed here.
http://nicoclub.com/archives/g35-350...procedure.html

There are also some preconditions that need to be met before you do the idle air reset, vehicle MUST be in park/neutral, MUST be up to operating temp for both engine and transmission temp, all electric loads MUST BE TURNED OFF including headlights, heated seats, AC system, window defroster, etc. Your foot must NOT be on the brake pedal, the steering wheel MUST be pointed straight ahead.

Intake leaks or PCV valve failure will cause all manner of problems if you perform the idle air calibration without fixing those problems first.

If you can't manage the pedal dance method you can use some of the android apps via bluetooth OBD2 to do the idle air reset, NDS2 for android works perfectly for this.

 

I've done ECU resets, IAVL reset, throttle body/pedal resets at different times but honestly don't recall if I did it when I cleaned the TBs. I didn't have to do it as it idled fine. I know that the engine and transmission temp wouldn't have been up to temp anyway.

Along the lines of the IAVL, I ran into a hiccup with that recently. I have the NDISIII app which has a simple 'button' for performing this. I tried it multiple times after a 20+ minute drive so the engine, coolant, and transmission temp were sufficient, turned off all electrical loads, etc, etc but it failed every single time. The next day while driving, after it was warmed up good, when I would accelerate fairly gently, I'd get a 'bump' in 1st gear when still below ~5 mph. Our daughter was driving one day and me being in the passenger seat, I could feel it but I asked her if she noticed it, and she didn't.... My wife drove it that same day and didn't say anything either. Because it started after attempting the IAVL, I had my fingers crossed that it was related to that, especially since it "failed". When you do the pedal-dance and it doesn't work, I believe the car just ignores you. With NDISIII, it's doing something though. In my case, it seems like it set something wrong too.

I started trying to find out why NDISIII was failing. I already had some add'l requirements of coolant temp being above 160º F, battery voltage at 12.9v or higher, etc and confirmed all of those. There's a Canadian guy on YouTube, Motorvate DIY or something like that, that has a manual transmission and says you need to set the parking brake so that DRLs are disabled. I don't have DRLs but what's the harm in setting the parking brake. Well, I did, and interestingly, I heard what sounded like the TBs' motors operate, and then used NDISIII. The IAVL ran and indicated 'Success'. I've actually been nervous or concerned that this was a transmission issue so I didn't even test it afterwards. Driving to work the next morning, the 'bump' was gone. It seems to be resolved too. Hopefully posting this doesn't jinx me !!#s3gt_translate_tooltip_mini { display: none !important; }

 

The ECU has a value called "electrical load switch" and if ANYTHING is turned on including the radio it will show the switch being ON. In order to use the digital option like NDS3 to complete the reset the value of that switch needs to he OFF or it will not reset. It does look at the transmission temp as well and will not reset if ANY of the parameters fail.

 

I turned off everything, i think. No radio, climate control off, no headlights/parking lights, etc, etc. Steering wheel was centered, brakes (foot) wasn't on. Until I set the parking brake, it failed every time. I'm just glad it worked !

 

Me too, I wonder if some models are not technically "in park or neutral" unless the ECU received signal from both the PNP switch AND the parking brake switch?

Just to confirm you do NOT have DRL's correct, no aftermarket module either?

 

No DRLs. I do have the 'tail-as-turn-sign' module but as long as I don't have the turn signals on, it shouldn't factor in, right ?

 

Yeah that shouldn't be an issue, basically it just makes the signal control a different light. Signal is still the same and there's zero load when it's off.

 

Nothing worked for me, I ended up taking it to the dealer, but not just any dealer.

After calling around to all the Infiniti's in my area, I finally found a service manager that knew exactly what the issue was and had already successfully dealt with several customers with a high/surging idle. (Especially 2007 cars) The other dealers, didn't want to do anything except charge $120 for a diagnostic. After I made the appointment i had to wait a few days so i decided what the heck, I've got nothing to lose, I'll do a full thorough cleaning. This time I disconnected the battery and moved the butterfly valve by hand even fully extending it open so i could get inside everywhere, all this did was make the idle even higher.

Well they had it all done in 15mins. They re-flashed the ECU and then performed the re-learn. Car idles perfectly now.

I got lucky, even a well regarded nissan/infiniti performance shop near me didnt really know how to fix it. They wanted to start pulling ignition coils to try to get the engine to idle lower so they could do a relearn...