rajpatel

Hi all,

I have a 2008 G37S 6MT. I've been having the problem where the engine stalls right after starting unless you give it some gas. This happened a few months ago and I got the TB's cleaned and did the idle relearn. Soon after that, the same issue happened, so did the relearn again.

For a few months now, problem seems to have gone away. However, I'm experiencing this new issue where the idle is high (around 800-1000RPMs), car sometime surges forward on downshifts, and RPM spikes happen when trying to pull out of 1st/2nd gear. However, this doesn't happen normally at normal operating temperatures.... it only seems to happen after driving around for a bit. After trying to figure out what triggers this condition in the car, I realized it happens fairly easily on really hot days, or when I really push the engine hard. It seems as though it may be caused when the engine reached a certain operating temperature.

I've done the idle relearn many times including the valve and accelerator position reset... but problem still occurs. When the car is first turned on.. it always idles correctly and drive fine... just not when engine gets hot.

I thought about doing the ECU reset... but also don't want to mess things up further.

Any suggestions?

Джон

kinda sounds like a problem with the rev matching side of the house

infinitiman96

Who cleaned the throttle body's? Were the careful when opening and closing the butterfly's? My understanding is that the throttle body's on G's is very sensitive and they could have been damaged.

An ECU reset isn't likely to do much much. You may want to try an idle air relearn again.

M3ng

I had idle issues for the longest time after I cleaned my TB(opend the valve w/out disconnecting battery). I've done the relearns/reset countless times. My issue was only resolved when a friend of a friend reset my ECU with a scanner(solus). Apparently, all conditions have to be correct, even with the scanner. Infiniti dealership could not even reset my ECU; they advised to get a new TB which was over $2k. He also did all the relearns with the scanner. Idle issue went away.

rajpatel

Dealership cleaned the TB's.

Also car usually runs fine except when engine gets to hotter operating temps (seems to be what triggers it).

I guess resetting the ECU by battery disconnect is not the same as with a scanner?

If I take it to the dealership.. they think I'm crazy since their stupid computer doesn't pull any codes... despite me telling them there's a problem and I drive it everyday

M3ng

I'd take it back and let them know that it's not running right. Have them do the reset for free. I've read that other members have paid around 200 to get it reset at the dealer.
My friend manages a Meineke so he had his tech do it for free after hrs : ) good luck.

ggggg37

I have the same issue but my rpm doen't spike, it only happens in hot weather or driving in traffic, my rppm reading normally shows 600, but when this problem occurs, it reads at 800, car becomes sluggish and there is a smell of burned rubber or something like that, happens rarely at night because temperature is a lot cooler, I never figured out what was the problem or even if it is a problem

thanks

Gamer

having the exact same issue with my g37 . Did you resolve the issue?

audiRS4ever

I'd also be interested if there's any progress on this - I've had this issue intermittently since purchasing the car in 2015 and would love to finally solve it. Always worse in the summer.

Satchel

I've had the exact same issue intermittently on my 2008 G37S since I bought it 3 years ago. It is driving me absolutely nuts I'm sick of not being able to figure it, car has been at my mechanic and Infiniti dealer multiple times trying to diagnose. They cleaned throttle bodies and did the reset/relearn stuff, the car runs better now lol but this did not fix the issue.

It really seems like a certain "mode" the car gets stuck in - suddenly after driving for a while (especially hard driving) the idle is too high and engine is revving by itself, yet turning the car off then back on makes it go away. If I don't turn the car off/on it is just messed up this way for the entire rest of the drive.

I bought an OBDII scanner and phone app - I noticed that voltage drops by 1+ volts at the same moment the car gets this way and revs go bad. None of the other sensors seem to change, I clicked all of them, other than RPM being jacked up of course:



Please help if you have any ideas.

Satchel

I was just reading the 6MT hesitation when accelerating under 3k rpms thread too. Do you think fusible link could be a possible culprit?

Satchel

New fusible link installed last week and added the battery bracket which was completely missing from my car (the battery could move around). These things didn't help the issue.

I would love some more ideas, right now I'm between thinking it's some intermittent electrical issue (alternator?) or that I should just try a different ecu in the car and see if anything changes.

SonicVQ

First of all, excellent troubleshooting!

The ~1 volt battery voltage drop is normal on the G37. The battery voltage level is controlled by the ECU and is part of the variable alternator control.
Also, the "OBD volts" are not generally very accurate, as they use the OBD tool's built in analog to digital converter. (part of the ELM327 chip)
"Control Module voltage" is accurate.

The ECU has a built in 5 volt power supply that is used for all important engine sensors, so a changing battery voltage doesn't matter. The 5 volt line is always 5v.

Have you checked with the dealer if there is an ECU update? -OR-
If you give me your ECUID (often reported as "Calibration ID" in NDS III Lite, Torque Pro and OBDFusion/OBDLInk) I can tell you if there is an update.

ILM-NC G37S

iTrader: (3)

For anyone who has erratic idle issues- especially on the older ('08/'09) models, keep in mind Infiniti issued a technical bulletin to address this issue. ITB07-048b, for reference.

For my car, the engine would be fine one minute, then all of a sudden the idle would jump from 650 to 900-1100RPM. It would NOT return to normal unless I shut the engine off and restarted. Only for the cycle to eventually repeat again..

Dealer wanted to replace this and that and the other part. I refused and I showed them the ITB. They reflashed the ECU. This was roughly 8 years ago and since then the engine has idled at 650RPM ever since (slightly higher with AC on).

While this bulletin may not be a blanket "cure all" for idle issues- especially for those with newer models, it is something to consider. At the least the ITB offers you folks some ammunition/ guidance for when you take your car to the repair shop. I didn't exhibit all of the symptoms the bulletin "mandates," but it solved my issue.

Just my 10¢.

Satchel

Thank you both. I had the car at an Infiniti dealer a few weeks ago, they didn't think it was ECU and said "the car isn't getting enough power". Wanted me to redo the battery posts/clips and replace the fusible link. My mechanic disagreed with this but we did it anyway (and added the missing battery bracket like I mentioned last post).

Sounds like I need to go back and argue with Infiniti, ask for an update or at minimum re-flash the ECU. Car is manual transmission btw, looks like ITB07-048b is talking about auto. But the idle issue you described does sound basically identical to mine...

My calibration id from the app is 1JK75BVJK00A.