Car revving an additional 1k rpms at start up

[NavyVet88]

Hey guys quick question....

My 2013 Honda Civic lx 1.8L has in the last couple weeks, started revving an additional 1k rpms at start up for approximately 2-5 seconds before it drops down to its normal cold start rpms which is around 2k rpms, so with the additional rpms it goes up to about 3k rpms for that 2-5 second period before it drops. I know my vehicle and it isn't normal for this to be happening. The car has 94k on it because it was used for commuting when originally bought.

Idk if it's the cooling sensor or the thermostat. I don't think it's the thermostat since I don't have any overheat issues. What do you guys think?

 

[gregk24]

Not sure what would cause this, but we had a 2006 Suzuki Forenza and it would go to 3K on a cold start as part of normal behavior.

 

[NavyVet88]

Well I'm not getting a check engine light at any time and the vehicle warms up normally without fail. At first I though it was the 35-45 degree temperatures just making the engine a little cold natured, but then I remembered when we lived in Virginia when we first bought the car it went through several several days of sub zero temperature start ups and this never once happened then. Luckily the car is paid for now, I'm just a huge fan of preventative maintenance.

 

[NavyVet88]

I will also add that the spark plugs, oil, coolant and transmission fluid are freshly changed with the exception of the coolant which I changed about 10k miles ago. All are oem fluids and parts except for the oil it's M1 EP.

 

[chrisri]

Did you experience colder than usual ambient temperatures on those mornings?

 

[SumpChump]

Have you cleaned the throttle body? If yes, it may be relearning, if not it may bd sticking as it pops open initially searching for cold idle "balance".

 

[NavyVet88]

Originally Posted By: chrisri
Did you experience colder than usual ambient temperatures on those mornings?


For alabama weather, yes. It was around 19-23 degrees.

 

[NavyVet88]

Originally Posted By: SumpChump
Have you cleaned the throttle body? If yes, it may be relearning, if not it may bd sticking as it pops open initially searching for cold idle "balance".


That's a negative. I haven't cleaned the throttle body.

 

[ET16]

I have a van that does the same thing when it's colder out.

 

[gathermewool]

Did Honda change the maintenance minder to have the spark plugs and coolant changed so soon???

Might the high RPM issue be a result of an air pocket from the last coolant change out, only now manifesting due to cold weather?

 

[NavyVet88]

Originally Posted By: gathermewool
Did Honda change the maintenance minder to have the spark plugs and coolant changed so soon???

Might the high RPM issue be a result of an air pocket from the last coolant change out, only now manifesting due to cold weather?


I do my own fluid and plug changes and have for awhile. I made very thoroughly sure there was no air pocket in the system. It only does this a few times a week as of now but as with any good problem that's starts small...it's only gonna get bigger. I also reset the maintenance minder myself because it's easy to do

 

[HerrStig]

It may be a vacuum leak, or a result of the ECU mapping to get the converter to light off quickly in colder weather. Perhaps the dealer has a TSB on it.

 

[NavyVet88]

I just checked under the hood for a closer inspection of the coolant sensor and I do notice there is some cruddy build up around it. I may have just found the problem to be exact but I'll update the thread when I get another sensor. Thanks guys!

 

[JHZR2]

Higher is normal, 3k seems high, but obviously it's dropping fast. I'd keep monitoring, then I'd video the phenomena for when you go to the dthe aler, so you don't get a "can not reproduce" turn back...

 

[NavyVet88]

Originally Posted By: JHZR2
Higher is normal, 3k seems high, but obviously it's dropping fast. I'd keep monitoring, then I'd video the phenomena for when you go to the dthe aler, so you don't get a "can not reproduce" turn back...


+1 will do sir

 

[TFB1]

Originally Posted By: gathermewool
Did Honda change the maintenance minder to have the spark plugs and coolant changed so soon???

Might the high RPM issue be a result of an air pocket from the last coolant change out, only now manifesting due to cold weather?

That's about a trip to the moon stretch...

I dunno what/if there is a actual issue, a air pocket is going to make zero difference at startup.. I'd even go so far to say you could drain the coolant and the initial start idle stabilization would not be effected...

 

[Doog]

My Toyotas do that in Winter....I think it is the downstream O2 sensor warming up the catalyst.

 

[demarpaint]

You might have a pending code stored in memory even though the CEL didn't trip, yet. I'd check for codes.

 

[zzyzzx]

I would blame the IAC.

 

[Doc8404]

If it is only 2 to 5 seconds upon start up, I don't see how an air pocket would do that.