Non-steady RPM at idle! Video included.
10-01-2010, 11:19 AM
#1
Non-steady RPM at idle! Video included.
Ive had this issue since I bought the car about a year ago. I've been patient with it, cleaned the throttle body, changed out the spark plugs, and just now put new coils ( All 6 ) but it still does this.
Well When the AC is on, it doesnt really do it, but watch the video and you'll see what its doing.
After reading a lot of similar threads, how do I determine if its the
A) IAT
B) IAC
C) Leaky fuel injector
D) Maf ( When I disconnect the maf, the RPMS go up, but you can still hear it "surging" .
What controls the idle when the AC clicks on? ( as in, what makes the engine know to increase the revs alittle)?
Youtube Video located here: http://youtu.be/8mKZ76zgM-4
Well When the AC is on, it doesnt really do it, but watch the video and you'll see what its doing.
After reading a lot of similar threads, how do I determine if its the
A) IAT
B) IAC
C) Leaky fuel injector
D) Maf ( When I disconnect the maf, the RPMS go up, but you can still hear it "surging" .
What controls the idle when the AC clicks on? ( as in, what makes the engine know to increase the revs alittle)?
Youtube Video located here: http://youtu.be/8mKZ76zgM-4
Last edited by speed3000gt; 10-01-2010 at 11:22 AM.
10-04-2010, 06:34 PM
#5
I'm going to do the testing shown in the latter part of this video tomorrow":
http://www.youtube.com/watch?v=4GU9CRI1F_4
My question is, what tests can be done to the rear injectors besides checking their resistance?
http://www.youtube.com/watch?v=4GU9CRI1F_4
My question is, what tests can be done to the rear injectors besides checking their resistance?
10-04-2010, 08:59 PM
#6
i believe the idle when the a/c is on is controlled by one of the sensors on the iacv. I forget if its the pink plug or the purple one...but its one of those i believe.
what i would do, is go outside, and turn the little black screw thats on top of the iacv, itll basically just raise the idle a tiny bit.
what i would do, is go outside, and turn the little black screw thats on top of the iacv, itll basically just raise the idle a tiny bit.
10-05-2010, 06:41 AM
#7
Member who somehow became The President of The SE-L Club
iTrader: (19)
Join Date: Jun 2001
Posts: 16,033
While the car is off, unplug the TPS then restart. That will cause the car to run on the default throttle plate closed position with no activity from the IACV. If the loby idle stops, it's either the TPS or the IACV which is at fault. If the loby idle continues you'll have to do more troubleshooting.
10-05-2010, 07:19 AM
#9
While the car is off, unplug the TPS then restart. That will cause the car to run on the default throttle plate closed position with no activity from the IACV. If the loby idle stops, it's either the TPS or the IACV which is at fault. If the loby idle continues you'll have to do more troubleshooting.
The TPS has two connectors, right? I disconnected both of them and started the car. It dies after about 1 second.
Correct me if I did something wrong.
Thanks!
10-05-2010, 07:21 AM
#10
If getting the AC fast idle solenoid functioning from the IACV solves that rough idle then a nonfunctioning AAC is probably the culprit. To get the AAC valve to operate the TP switch needs to be set closed. To set that TP switch you'll need a feeler guage to insert between the set screw and plate and a multimeter to read the TP switch connectors:
http://www.lyberty.com/car/Maxima_A3...NTB99-053b.pdf
You'll then need to adjust the 'Default Idle Speed'. Do a search for that procedure on this forum.
http://www.lyberty.com/car/Maxima_A3...NTB99-053b.pdf
You'll then need to adjust the 'Default Idle Speed'. Do a search for that procedure on this forum.
10-07-2010, 02:59 PM
#11
Junior Member
Join Date: Jan 2010
Posts: 24
This is the third recent thread I've found that describes this. That video shows pretty much what my car does. Has your car lost like a LOT of HP lately?
Some people say it's the coilpacks. I'm thinking about getting 1 front and 1 rear coil from the junkyard and playing musical chairs with them.
Some people say it's the coilpacks. I'm thinking about getting 1 front and 1 rear coil from the junkyard and playing musical chairs with them.
10-07-2010, 05:24 PM
#13
No, sorry I already replaced all the coil packs.. I never had a loss of horse power... Just this random rpm fluctuation when i came to stoplights... Sometimes I would put it in neutral and it would lessen... It comes, then corrects itself, then comes again all within a 40 second range. It will dip as low as 200 rpms and look as if its going to die, but it never does.
I'm guessing its either the TPS or a leaky fuel injector (although I havent found what a leaky fuel injector does to a car).
In this colder weather we are getting, or in mornings I should say, it doesn't dip.. So I dont know if that has anything to do with the IAT sensor thats in the intake pipe.
I'm guessing its either the TPS or a leaky fuel injector (although I havent found what a leaky fuel injector does to a car).
In this colder weather we are getting, or in mornings I should say, it doesn't dip.. So I dont know if that has anything to do with the IAT sensor thats in the intake pipe.
02-28-2014, 11:29 AM
#14
I have the same problem..I already replaced the coils with OEMs and tested/swapped MAF, IACV and TPS. I'm suspecting injectors since there's a scarce few of other posts with this issue saying it was the injectors...although my car has no codes...not even misfire codes which is odd since the rpm fluctuation is quite significant...
Any solutions?
Any solutions?
06-10-2014, 06:41 AM
#15
Senior Member
Join Date: Jan 2011
Location: Central AR
Posts: 3,041
What year is your Max? I just resolved a 200 RPM bounce issue at 1,500 RPM and a slightly rough idle issue with a new EGR. The EGR makes it start up with only a touch of the starter now. Note the 99 uses an electric EGR. So the benefits may only apply to a 99 model.
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