Strange hesitation issue in the morning
10-09-2013, 08:24 AM
#1
Senior Member
Thread Starter
Join Date: May 2013
Location: Snakeden Branch, VA
Posts: 1,441
Strange hesitation issue in the morning
So this just started happening the past two days, ever since the weather cooled down here and it's around 50*F in the morning. This only seems to happen when it's cool outside and the car has sat overnight, never after it's been driven that day or even after it happens one time.
What happens is once I start up in the morning, I always let the car warm up, never push it hard until it does so. But the past few days when I turn onto the main road from my road in the morning, and I have to accelerate a bit (2500-3000rpm nothing major) the car hesitates and sounds like it's choking for air. The car still accelerates and the RPM's go up no problem, so it's not like it has no power, it's just weak for a moment and seems to choke or something.
As soon as this happens that very first time, I let off the throttle, and get back on it the problem is gone never to be seen again. So this ONLY happens ONCE in the morning, only when it's cool and the car has sat overnight, never does it otherwise. And besides that, it runs great, chirps tires and slams me back in my seat every time I get on it hard.
This has only happened the past two mornings since it's gotten cooler outside. Before that it never happened. The temps did drop by about 20F the past few days compared to before. It almost seems like something isn't warming up in time, I thought about coolant temp sensor maybe?
Any and all help greatly appreciated, thanks guys
What happens is once I start up in the morning, I always let the car warm up, never push it hard until it does so. But the past few days when I turn onto the main road from my road in the morning, and I have to accelerate a bit (2500-3000rpm nothing major) the car hesitates and sounds like it's choking for air. The car still accelerates and the RPM's go up no problem, so it's not like it has no power, it's just weak for a moment and seems to choke or something.
As soon as this happens that very first time, I let off the throttle, and get back on it the problem is gone never to be seen again. So this ONLY happens ONCE in the morning, only when it's cool and the car has sat overnight, never does it otherwise. And besides that, it runs great, chirps tires and slams me back in my seat every time I get on it hard.
This has only happened the past two mornings since it's gotten cooler outside. Before that it never happened. The temps did drop by about 20F the past few days compared to before. It almost seems like something isn't warming up in time, I thought about coolant temp sensor maybe?
Any and all help greatly appreciated, thanks guys
10-09-2013, 02:18 PM
#2
Senior Member
Join Date: Feb 2012
Location: Rollinsford NH
Posts: 413
I also have this problem. I think it has something to do with the MAF sensor, at least that's what another member told me. I havent' gotten around to replacing it yet, so I'm not really sure. Good luck man!
10-09-2013, 05:59 PM
#3
Senior Member
Thread Starter
Join Date: May 2013
Location: Snakeden Branch, VA
Posts: 1,441
Thanks for the reply dude, that would usually be a likely culprit but not in this case.
Unfortunately I have a brand new MAF, as of a few months ago. So that's not the problem. Also, a bad MAF would make the car run like crap all the time. Mine has done it twice now, ONE TIME each of the last two mornings, and at that it only did it the very first time I gave it a decent amount of throttle from being cold, then just like that the next time I hit the throttle....Hudini magic time and it runs perfect.
I've been thinking perhaps one of my o2 sensors is going out on me, because 99% of the time the car runs great AFR. But then the other 1% comes up and all of a sudden I get a rich smell when going WOT. It happens very rarely, there have never been any codes.
Anybody seen an o2 malfunction (VERY) intermittently and never throw a code?
I have no idea and need some help. Will report back tomorrow morning after my drive to work, once I see if this happens again.
Unfortunately I have a brand new MAF, as of a few months ago. So that's not the problem. Also, a bad MAF would make the car run like crap all the time. Mine has done it twice now, ONE TIME each of the last two mornings, and at that it only did it the very first time I gave it a decent amount of throttle from being cold, then just like that the next time I hit the throttle....Hudini magic time and it runs perfect.
I've been thinking perhaps one of my o2 sensors is going out on me, because 99% of the time the car runs great AFR. But then the other 1% comes up and all of a sudden I get a rich smell when going WOT. It happens very rarely, there have never been any codes.
Anybody seen an o2 malfunction (VERY) intermittently and never throw a code?
I have no idea and need some help. Will report back tomorrow morning after my drive to work, once I see if this happens again.
10-09-2013, 09:15 PM
#4
Something that shows up at this time of the year is a bad engine coolant temperature sensor (ECTS). If it is off target and reporting a temperature warmer than what is accurate, the fuel mixture will be too lean. Colder engines need a richer fuel mixture.
Many OBD code readers can display various readings, the coolant temperature among them. If you have one or know someone who does, plug it in before you start the car in the morning and see what is being reported.
You can also do a resistance test on the sensor, there is a chart in the FSM for resistance vs temperature. You can do this without removing the sensor.
Many OBD code readers can display various readings, the coolant temperature among them. If you have one or know someone who does, plug it in before you start the car in the morning and see what is being reported.
You can also do a resistance test on the sensor, there is a chart in the FSM for resistance vs temperature. You can do this without removing the sensor.
10-10-2013, 10:44 AM
#5
Senior Member
Thread Starter
Join Date: May 2013
Location: Snakeden Branch, VA
Posts: 1,441
ECTS was my first suspicion too, and sure enough it IS the culprit.
For anyone interested -- hooked up the laptop on lunch break and did some data logging, the stupid thing was reading way cold at idle (131F), and then would flip back to normal readings (182F) almost immediately once I started driving. So I figure what happened those two mornings is the cold readings caused ECU to send more fuel, providing a horribly rich condition and that momentary hesitation/power loss. Then the sensor would just fix itself right back to normal.
Also tested it with multimeter, according to FSM, and the readings were a bit off.
Going to stop by the parts store on way home and replace the ECTS tonight, hopefully this problem doesn't come back in the morning or ever.
Thanks to both of you who chimed in, I really do appreciate it
For anyone interested -- hooked up the laptop on lunch break and did some data logging, the stupid thing was reading way cold at idle (131F), and then would flip back to normal readings (182F) almost immediately once I started driving. So I figure what happened those two mornings is the cold readings caused ECU to send more fuel, providing a horribly rich condition and that momentary hesitation/power loss. Then the sensor would just fix itself right back to normal.
Also tested it with multimeter, according to FSM, and the readings were a bit off.
Going to stop by the parts store on way home and replace the ECTS tonight, hopefully this problem doesn't come back in the morning or ever.
Thanks to both of you who chimed in, I really do appreciate it
Thread
Thread Starter
Forum
Replies
Last Post
hez8813
5th Generation Maxima (2000-2003)
11
03-12-2020 12:06 AM
JoshG
4th Generation Maxima (1995-1999)
51
09-21-2015 10:41 PM
trungg86
4th Generation Maxima (1995-1999)
7
09-04-2015 04:58 AM