Cold Start + Normal RPM = Weird?

[TRUboost]

Whew, glad I'm not the only one. Thought I was imagining things.


Just like women.

I hear you on the headlight start up sequence. I love when they dance, but I can't make them dance when I want them. Damnit, even more like a woman.

Lmao so true. The worst part about it is its completely random. I've tried it in park, park with e-brake, drive, reverse, upside down, during a j turn. Nothing.

 

[Stadpad]

my service reminder ding goes off when i start the car but if i start the car and quickly get out it wont beep until i get back in.

 

[acewayne]

I recently started parking my car outside and I was wondering the same thing. Upon searching I came across this on golfmkv and golfmk6. Makes sense I suppose.

To understand this you must first understand why the car is loud in the first place. Your ecu is programmed to start and hold a raised rpm at startup to warm up the cat quickly in order reduce startup emmissions. This is only on pzev cars.

The reason your car is not doing this anymore is because it is too cold out. The ecu won't allow raised rpms on startup below a certain temperature in order to reduce cold start piston wear.

When it is below a certain ambient temp, the ecu does not run the cat warm up cycle to minimize the cold start wear on the engine

 

[bburns36]

I noticed that if I leave mine outside overnight and it's less than 32deg F in the morning, the secondary air pump doesn't run, and i get the normal 800rpm-ish idle immediately on cold start. Or so I thought...

This morning it was 43deg in my garage, and the pump didn't run. Or actually, after 10 seconds it kicked on for maybe half a second (dimmed the headlamps even) and then back off. I can't figure it out. I heard somewhere that under 32deg it won't run the pump in case there's moisture frozen inside it, which would kill it.

Also last week with a semi warm motor the SAI pump came on for 10sec as I was backing out of the garage but wasn't on immediately at startup. :iono:

 

[SRoads]

Intermittently, I will start the car (cold outside; NJ winter), and the car will idle at the normal RPM as if it were warm. Normally (even during the summer), our cars will rev to about 1200RPM for a solid 30-40 seconds before slowly leveling out.

Anyone else experience this?

When the temperature is low enough the ecu does not use the map to heat up the cat quickly for emissions. Instead it use the low rpm (warm) idle map to reduce cold start wear on the engine.

 

[steady-_-eddy]

This also started happening to me recently when the temperature here in NY dropped to below freezing in the morning.

I go to turn the car on and it turns on just fine but doesn't make all the noises and doesn't REV up to 1200 like it normally does. I thought it was something wrong with my car, but I see its happening to a number of people.

 

[boosted27]

Happens to me! And I usually let the car run in the morning for that 40 seconds until it drops . I usually just figure its been good amount of time when this happens.

 

[grambles423]

Happens to me! And I usually let the car run in the morning for that 40 seconds until it drops . I usually just figure its been good amount of time when this happens.

The point in this thread is that the RPMs DONT rise upon cold starts. You crank the car and it stays at idle RPMs.

But yes. Always wait for the RPMs to drop before you take off.

 

[lilfleck]

Yep.

Excuse the cel...

**Sorry for the large size, not sure how to resize easily**

Tapped and talked.

 

[flyguy27]

So, is it a bug if we all seem to have this happen or an intentional design?

 

[NYCRabbit1]

So, is it a bug if we all seem to have this happen or an intentional design?

It is intentional...read posts 18 & 20 on page 1 for explanation.

 

[mkvince]

Happened to me again this morning. I'm not too worried about it.

 

[Richyroxx]

My car hasn't ran cold start rpm for about a week now and I was very worried because I just installed a unitronic intake hoping that didn't screw with the ecu but after finding other members having this problem I feel much better

 

[lilfleck]

Yep, this is a good bump too since you're probably not the only person asking.

 

[prospal]

Yeah, this happens to me too Albert. Basically whenever its really cold outside.