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2005 G35 4dr Sedan - Idle miss whilst in D or R

posted Jun 02, 2016 19:32:59 by thefauvels@verizon.net
We've been plagued with an intermittent miss at idle whilst in gear at stop lights.

There are no codes being thrown, and is not present at any other speeds.

when it first happened, the "hiccup" was just a couple of times at each stop light.
Then it progressed to several hiccups per stop light.

we tried Chevron's fuel injector cleaner and for about a tank, maybe two.
The problem went down to one hiccup per day rather than per stop light.

the problem came back and we tried B-12 injector cleaner, and that only got marginally better.

The problem is way more prevalent whilst in D or R, and barely noticeable and less frequent
in N or P.

I vacillate between the replacement of all the injectors to an issue with the torque converter.
I have nixed the torque converter as it can happen in N and P.

thoughts? Please help, too embarrassing driving like this.The G is not a beater car,
so shouldn't run like one. :-(
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14 replies
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Tyler said Jun 03, 2016 00:52:38
Agreed, the G35 is NOT a beater, even though I see some owners treat them that way :-(

Do you have any access to scan data? Even though there's no codes setting, I'd still like to have a look the fuel trims during the miss. The upstream A/F ratio sensor signals during the hickup would be best.

Honestly, my first thought is towards the ignition system. I know, it doesn't necessarily fit with your symptoms, but I've seen plenty of 3.5's like this that would miss under just the right conditions, but not at any other time.

If it is truly a miss you're chasing, then the tough part will be to find the offending cylinder. Any mode $06 misfire data available?
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thefauvels@verizon.net said Jun 03, 2016 12:54:52
Tyler
I do have an Iphone App called DashCommand that, with an ODB11 wifi interface, I can trap fuel trims and O2 readings. I will get the data this weekend.

not sure what $06 misfire data is. I am not a professional mechanic with professional grade scanners or scopes.

The injectors are very hard to get to on a G35 or 350z, you have to remove the air plenum and Throttle Body to get to the fuel rail, which leaves the motor inoperable.

would like to get the tools to do the injector balance flow test that ScannerDanner has shown on youtube (1.8l part 1/part 2). Not sure what tools to get though.


NOTE: this DID start to occur AFTER my mechanic replaced all of the spark plugs to fix a miss when accelerating from idle or from cruise....however, that DID throw a code so we were able to pinpoint which cylinder, and went ahead and replaced all plugs. That fixed the miss on accelerating, but shortly afterwards the hiccup at idle started happening. We had him re-check all the coils and plugs, but I think you're right that is too coincidental to be ignored.


Thanks

Chris
[Last edited Jun 03, 2016 12:57:20]
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Tyler said Jun 04, 2016 13:32:53
I do have an Iphone App called DashCommand that, with an ODB11 wifi interface, I can trap fuel trims and O2 readings. I will get the data this weekend.


Nice! That'll work perfectly. Hopefully, we'll be able to use the upstream A/F sensors and the fuel trims to ID which bank the miss is happening on. It still won't tell us which cylinder, but it's a start.

not sure what $06 misfire data is. I am not a professional mechanic with professional grade scanners or scopes.


I understand, no worries. Mode $06 is part of Global OBD that provides test results pertaining to various emissions systems (EVAP, EGR, O2 sensors, others). There's actually a James Danner video out there that goes into using Mode $06 to find a misfiring cylinder. I'm not positive if your vehicle has the same data available, but worth checking.

The injectors are very hard to get to on a G35 or 350z, you have to remove the air plenum and Throttle Body to get to the fuel rail, which leaves the motor inoperable.

would like to get the tools to do the injector balance flow test that ScannerDanner has shown on youtube (1.8l part 1/part 2). Not sure what tools to get though.


Love that case study series! Lots of good info in there. Doing the injector balance test will take some work/tooling. You'd need a fuel pressure gauge, and the fittings to T into the fuel line (no Schrader valve available). I have a Lisle test kit for stuff like this. Then you'd need the injector pulse tester. And the tools to get the intake off. Not an easy test to do on this engine, unfortunately :-(

NOTE: this DID start to occur AFTER my mechanic replaced all of the spark plugs to fix a miss when accelerating from idle or from cruise....however, that DID throw a code so we were able to pinpoint which cylinder, and went ahead and replaced all plugs. That fixed the miss on accelerating, but shortly afterwards the hiccup at idle started happening. We had him re-check all the coils and plugs, but I think you're right that is too coincidental to be ignored.


Ahhhhh OK, that makes sense. I'm sure your mechanic did good work, but we'll leave ignition on the table for now. Just curious, would you happen to know what kind of plugs got installed?
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thefauvels@verizon.net said Jun 04, 2016 15:12:42
Ahhhhh OK, that makes sense. I'm sure your mechanic did good work, but we'll leave ignition on the table for now. Just curious, would you happen to know what kind of plugs got installed?
I know he installed the factory iridium plugs.



Sorry can't do the tests today, forgot ( :-) ) that my daughter's graduation party is today...maybe tomorrow.
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Tyler said Jun 04, 2016 16:30:17
I know he installed the factory iridium plugs.


Awesome, good to hear.

Sorry can't do the tests today, forgot ( :-) ) that my daughter's graduation party is today...maybe tomorrow.


No worries, let us know what you find!
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thefauvels@verizon.net said Jun 06, 2016 01:18:42
Ok I have the log captured...the data is saved in Excel, with two tabpages, the first sheet is ALL the data that was captured, the second sheet is just data that have to do with O2 sensors , SHRT FT and LONGT FT

https://dl.dropboxusercontent.com/u/73794091/2005%20G35%20ECM%20Data%20Logs/2005_G35_Missing_at_idle_Jun%2005%202016%2007_27%20PM.xlsx

Link to XLS of data...


let me know if you have any issues with the XLS, if so I can copy up the CSV file instead.
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Tyler said Jun 06, 2016 02:38:49
Nice, thanks sir! LOTS of data in that first sheet, lol.

Looking at scan data on a spreadsheet is new to me, so bear with me. The first thing I noticed is how the B1S1 and B2S1 O2 sensor voltages never really change during the capture, but the short term fuel trims seem to be changing. Not sure if the vehicle is actually in closed loop at this point or not, especially since the .3V on the B1S1 O2 is the standard Nissan/Infiniti bias voltage (indicating a cold O2 sensor).

Ignoring that, the second thing I noticed is how the long term trims are higher for bank one from the start, and end up around 14% total trim at about 40 seconds in. Compare that to bank two, which never goes over 6% total. Again, not sure that we can rely on the trims since I'm not positive about the loop status, but that would tend to suggest a problem on bank one.

I'm crossing my fingers that you'll say you felt a miss at around the 40 second mark, lol.
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thefauvels@verizon.net said Jun 06, 2016 04:51:05
I'm crossing my fingers that you'll say you felt a miss at around the 40 second mark, lol.


The capture was done after the car was warmed up...there are no misses when it is cold and in gear.

within that capture the car was warmed up and in gear and was bucking from the get go. I stopped the logging after a couple of seconds of running normally. :-(

so in actuality at the 40 second mark it might be where it is running nicely.


I can re run the capture and run a stopwatch to see at what timestamp did the event occur, but in this case the EVENTS were occurring from the get go.

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thefauvels@verizon.net said Jun 08, 2016 01:59:03
I have a 350z the same year and same engine and took a two minute capture at idle to compare to see where the differences were.

I also updated the original g35 capture with charts of the data.

on the third tabpage of the 350z capture I included the charts for both cars side by side.

the only thing I see wonky is the LongtermFT and advance timing..the g35 went down to 13 degrees at one time...also the z is running at about 800 rpm, which seems higher than the G35

New 350z capture at idle - running fine

Updated g35 capture with charts
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thefauvels@verizon.net said Jun 22, 2016 14:30:00
Update - Still not fixed
My wife called me last week with glee, the car finally threw a code and turned on the SEL for a bit. The codes were P0300 and P0303....At least now I had something to go on.

being that it reported cylinder #3 misfire, I tackled into looking at it.

Took the coil off and the took out the spark plug. checked the ohms between the coil's terminals and compared the readings to the manual's expected numbers and it was within spec. I pulled out coil #2 and Coil#4 to do the ohm check there too to see if #3 coil was different. the test between pins 1 -2 were all infinity for all three coils

changing the range of the meter to Kohm I got very close numbers
#2 kOhm between pin 1 and 2 = 1.733
#3 Kohm between pin 1 and 2 = 1.619 (the reported misfired cylinder)
#4 Kohm between pin 1 and 2 = 1.644

the remaining tests between 1 -3, and 2-3 were all as per specs = inifinity

I re-gapped the three plugs to .043 inches, they were all a little narrower like .041 -.042

I moved #3 plug to #2 cylinder and moved #3 coil to #4 cylinder....#3 cylinder has #4 coil with #2 plug

warmed up the car to about 180 degrees and thought the problem was fixed until I took it for a longer drive, the issue is the same(water coollant at 190 degrees)...and not throwing a code yet. I hope the code appears and tells me it is on the driver's side rather than the passenger side.

I have taken another log when the car is missing and will compare the results to the previous log and post the results to dropbox.

Thoughts? still think it is ignition?
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Tyler said Jun 22, 2016 17:22:01
Awesome! It finally coded, lol. Misfire monitors, man. Some are waaaayyyy too sensitive, some are just oblivious.

I love what you did with the coils and plugs, it's exactly what I would have done in the same situation. I'd say give it another few drives to see if it codes again, then maybe go in another direction.
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thefauvels@verizon.net said Jul 12, 2016 18:09:12
Tyler!!

wow it has been a while, drove the car for weeks with it missing after moving the components to the other side, with NO CODES THROWN. One time it threw a code, but it was just Multi Cylinder MisFire, not helpful.

Yesterday it threw a code P0304 !! which means that #4 cylinder mis-fired and based on what I did above, points to a coil. Going to put in a coil this afternoon to see if it fixes it. Unfortunately I can't return the unused injectors, but I guess once this is fixed I'll go ahead and replace the injectors...can't hurt.


Chris
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Tyler said Jul 13, 2016 00:06:14
Hey man, great to hear back from you! I'd say you're clear to put a coil in it, no problem.

I'm totally happy that we finally got this one tracked down, but I'm still trying to think of how i could have helped you narrow this down faster. I'll check the next newer Nissan for Mode $06 misfire data, see if it's available. I really do believe that would have pointed us in the right direction sooner than waiting for the code.

Sure, there's current ramping and such, but that all requires more equipment. Anyway, I'll have to think on that some more.

Let us know how the coil replacement goes!
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thefauvels@verizon.net said Jul 14, 2016 20:31:43
Tyler,
Installed the coil into #4 spot this lunch time before wife went to Sam's Club....response from her -? Fixed!!


the funny thing is the addition of injector cleaner seemingly making the car run right for a few bottles. Purely coincidental, I'm sure...but led me down the wrong path....now I have $350 work of injectors I can't return (pass the 30 day return policy)

I wish the car threw codes a little faster.
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