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The way I understood the multiport, when the vehicle is shifted from park/neutral to drive it compensates with more fuel. I'm also assuming that any time the vehicle is in drive the idle is increased due to this.
I haven't spent enough time confirming the issue is resolved as the transmission heats up, and my trips are typically short, but I've always assumed it takes a while to thoroughly warm the transmission.
Let us know if you learn anything from your appointment today!
I won't be able to thoroughly test my heat theory for a while as I'm in Iowa and it's getting colder.
Below is a video from yesterday where the vehicle is idling correctly after sitting.
8:10am vehicle overnight cold but in garage, around 50 degrees in garage. Drove kids to bus stop and thoroughly warmed the engine until 8:22 - when I parked in garage idling at 500 in drive.
9:20am drove to work after car sitting in garage, ambient temp 40 degrees according to vehicle, after a few minutes engine warmed up and idled correctly with no A/C in drive. Total drive to work about 8 minutes - this scenario, which I can duplicate almost daily, is leading me to believe that something heats up enough to function properly.
I just read all 8 pages and have a suggestion:
• Using your OBD scanner, why not log / graph / display the absolute throttle position (bank 1) and Absolute throttle position B (bank 2)
Then you can see what the throttle position is when in gear with the idle is proper and when it is low. This may give a clue is the ECM is controlling the idle speed, or if the transmission is slightly increasing the load in drive.
What is the idle speed in gear with a cold engine?
I just got a Bluetooth scanner and OBD Fusion and will attempt tomorrow. Apparently there's no way to get transmission temp without official Consult so I can't get that.
I have noticed my car idles around 675 in park/neutral/reverse and 535 in drive when low.
Does turning your steering wheel cause the rpm to drop around 500? While I have the same issue mentioned above, when at a full stop in drive and turning my room drops in the same manner when coming to a stop n the rmp goes to 540.
UPDATE:
Well… here is the moment of truth. I had my appointment at Nissan on Saturday (10-26-19) and they adjusted the idle. Here’s how I worked it around. When I called and set the appointment, I told them I wanted the tech to check the idle with the scan tool and report it to me. When I arrived for my appointment, I explained everything again to the adviser. I also added that the idle may need adjusted as it seems low in Drive, causing excessive vibration. I stayed at the dealership while they worked on it (in-case there were any questions). They came back out and said the car was ready and that the idle was at 663. The adviser didn't specific whether that was peak or base. I'm assuming peak since you see constant fluctuations on a scan tool. Cost was $95 for the diagnostic fee.
I then told the adviser that due to the excessive vibration in D, I requested that the idle be adjusted to 700. The adviser said I would need to speak with the tech--and I did!
I explained the issue in detail, as well as everything we have been taking about here. I also asked any TCM/ECM fuel concerns as Eric had outlined in his posts. He said everything on the car was working as normal and there were no communication errors. I asked if there were any inconsistencies with the TB’s, he said no. I then asked him to adjust the idle to 700 in an effort to eliminate this vibration. He said he was not sure about where to do that. I confirmed with him that they use CONSULT 3, and explained it was under the Work Support section of the scan tool. He knew where that was and said he will need to speak with the master tech, so he said he will check it out and get back to me. About 20 minutes later, the adviser came out and said they can adjust the idle to 700, but it will cost another $100. At first, I was thinking of arguing that this should have been done while the car was connected the first time. But, I was on a mission here, so I told them to go ahead. However, I made it clear to raise the idle until the vibration was gone. After about another 45 minutes or so, the adviser came back out with my keys and paperwork and said the idle was adjusted to 700 and the vibration is no longer there.
So far, everything is working perfectly and the vibration is gone. The question is whether everything will be the same 3 months from now. I’ll be watching this like a hawk, so I’ll be able to detect any fluctuations or potential drops. As always, I’ll post any changes here. Was it expensive? Yes!
$220 out the door for diagnostic work is pricey. However, given the circumstances here, I find it worth it (thus far).
Pic below was taken on my way to work this morning). Also, idle stays constant when I shift from P to R, N, D… then back up through to P.
Last edited by Jsbach1685; 10-28-2019 at 12:49 PM.
UPDATE:
I explained the issue in detail, as well as everything we have been taking about here. I also asked any TCM/ECM fuel concerns as Eric had outlined in his posts. He said everything on the car was working as normal and there were no communication errors. I asked if there were any inconsistencies with the TB’s, he said no. I then asked him to adjust the idle to 700 in an effort to eliminate this vibration. He said he was not sure about where to do that. I confirmed with him that they use CONSULT 3, and explained it was under the Work Support section of the scan tool. He knew where that was and said he will need to speak with the master tech, so he said he will check it out and get back to me. About 20 minutes later, the adviser came out and said they can adjust the idle to 700, but it will cost another $100. At first, I was thinking of arguing that this should have been done while the car was connected the first time. But, I was on a mission here, so I told them to go ahead. However, I made it clear to raise the idle until the vibration was gone. After about another 45 minutes or so, the adviser came back out with my keys and paperwork and said the idle was adjusted to 700 and the vibration is no longer there.
So far, everything is working perfectly and the vibration is gone. The question is whether everything will be the same 3 months from now. I’ll be watching this like a hawk, so I’ll be able to detect any fluctuations or potential drops. As always, I’ll post any changes here. Was it expensive? Yes!
$220 out the door for diagnostic work is pricey. However, given the circumstances here, I find it worth it (thus far).
Pic below was taken on my way to work this morning). Also, idle stays constant when I shift from P to R, N, D… then back up through to P.
Very interesting!
Expensive? Maybe. Fixed? Sounds like it!
Curious to see how it works for you but in theory it should be fine. Even when the car is "acting normal" you'll only be 30-50 RPM above spec and will have your foot on the brake so negligible impact.
For the communication error, I'd be curious what the TCM is reporting when the idle is low. My assumption is the TCM is incorrectly reporting the gear but does maintain communication with the ECM.
I just read all 8 pages and have a suggestion:
• Using your OBD scanner, why not log / graph / display the absolute throttle position (bank 1) and Absolute throttle position B (bank 2)
Then you can see what the throttle position is when in gear with the idle is proper and when it is low. This may give a clue is the ECM is controlling the idle speed, or if the transmission is slightly increasing the load in drive.
What is the idle speed in gear with a cold engine?
1st attempt at logging is attached, however I need to tweak what I'm capturing. When I initially started this, my vision was:
RPM
Coolant temp
Gear
Vehicle speed
Throttle position
With that information, I could zero in on when the vehicle is stopped (0 MPH), in drive, see the RPM and the throttle position.
What I got? Not so much and could welcome input on what to select.
Attached are two logs from this morning with my (apparently reproducible) scenario:
8am - cold start, drive for 20 minutes, low idle in drive (last of the CSV was me sitting in the garage shifting between park/reverse/neutral/drive several times).
9:30 - 9:38 - after 60 minute heat soak. Once engine temp again rose to normal, vehicle idled correctly in drive. As before - end of the CSV is me shifting between gears several times.
Only data I removed from both is the GPS coordinates - after all, this is the internet
For the communication error, I'd be curious what the TCM is reporting when the idle is low. My assumption is the TCM is incorrectly reporting the gear but does maintain communication with the ECM.
-Eric
If the TCM was reporting the wrong gear, you would have errors in the ABS and TCM modules, as they are used to verify the gear, RPM, vehicle speed correlations.
Absolute throttle position when stopped: 1.9% (The 2.7% may be from when you took your foot off the brake and the car is preparing to move)
Absolute throttle position when stopped: 1.9%
Absolute throttle position when stopped: 2.7%
This is when you were going through the gears. Absolute throttle position was mostly 1.9%
What does this tell us?
• Not as much as I hoped.
We are looking at the absolute throttle position when stopped in drive, BUT we don't know if there is a change in engine load from the transmission, power steering pump, alternator or something else.
All looks fine to me.
Eric, I know the vibration in drive bothers you...
I guess the question to be answered is.... Does it bother you enough to spend $220 to get your idle changed?
(assume you can find a shop that will do it)
Absolute throttle position when stopped: 1.9% (The 2.7% may be from when you took your foot off the brake and the car is preparing to move)
Absolute throttle position when stopped: 1.9%
Absolute throttle position when stopped: 2.7%
This is when you were going through the gears. Absolute throttle position was mostly 1.9%
What does this tell us?
• Not as much as I hoped.
We are looking at the absolute throttle position when stopped in drive, BUT we don't know if there is a change in engine load from the transmission, power steering pump, alternator or something else.
All looks fine to me.
Eric, I know the vibration in drive bothers you...
I guess the question to be answered is.... Does it bother you enough to spend $220 to get your idle changed?
(assume you can find a shop that will do it)
Great stuff - curious how you're creating the graphs - but that's for another time. And - is there anything else I should be logging?
The middle graph (which I kept above) shows greater absolute throttle (2.745) when stopped in drive and the RPM is higher. The other graph, in the 1.9 range, shows lower throttle and lower RPM in drive, also when the power train is cold. I'll need to read up on what this means, specifically absolute throttle and if this has anything to do with the position of the throttle body. The ECM is supposed to increase fuel when the vehicle is put into Drive - I don't think I would see this here.
Question is why? And why some cars and not others? It seems when someone takes a moment to look their automatic has the same issue that they never noticed. If you don't have an auto (or for some reason don't experience this) it isn't that noticeable. However, once you see it it's hard to ignore as it doesn't make sense - typically things, like idle speed, are fairly constant and don't fluctuate without reason (engine temp, engine load, accessory load (A/C, cooling fans, alternator)).
Is this enough of an issue for me to spend $220 to increase the idle speed? Probably not. I've been reporting/documenting this issue since shortly after I purchased the car in October 2017 (my original thread here) and have let it go several times. However this thread seems to have more traction than any other time this has been discussed and I would like to see it resolved or at least explained.
At 6:18 I headed home after the car sat outside all day - never went above 500 in drive even though engine warm,
Left again @ 6:57 after car sat in garage for about 30 minutes. Low idle for the first few stops then at an extended light the idle increased and stayed for the rest of the trip. Maintained this through several more trips.
Why? Engine temp was over 180 so certainly able to idle correctly.
Here's a snip from where the idle decided to increase while sitting at a stop light around row 260.
10-23-2019 | 10:52 AM
