trbo2nr

This doesn't happen all the time but at least once a month when starting the engine, it races high rpms for a few seconds. Anyone else seen this?

cannonball55

my c55 does this occasionally too....

ScottW911

It's my understanding that this happens more as the catalytic converter ages. It take a bit more to warm it quickly for emissions purposes.

Mine now does it with every cold start and stays at higher revs longer than it used to.

trbo2nr

oh ok. The next time it happens, I'm going to pay attention to the actual RPMs.
I thought it was just me but now see it's both c32 and c55 (maybe others).

hooleyboy

This is going to sound stupid, but check your gas peddle slip cover my was sliding up causing the engine to rev high after the start.

cannonball55

was it every time or just occasionally..


mine happens occasionally and not just on cold starts...

jturkel

i get this once every two or three weeks

mikev7

Anyone got any more info on this situation?

Wilsophia

I m guessing the weather is getting cold now and the engine doing like this?

mikev7

It does it when fully warmed up in the summer also.

wawy

When I start mine for the first time in the morning it revs (although not excessively) for about 15-20 secs and then the engine and rpms drop off to a gentle idle. It has done this for as long as I can remember. I've always assumed it's purposeful. It does not, however, do this when the car is at operating temperature...

mikev7

Mine does it every once in a while. It seems like its been idling high more than normal. The car is just about to turn 70k mikes.

Autotechnica

Mine does this every single time. It's perfectly normal. If you guys look in your manual it even mentions that it does this to reduce cold start emissions (running too rich when the motor is cold). It will inject more air into the motor during cold start, also referred to as the Secondary Air Injection system. I don't think it has anything to do with heating the cat for cat efficiency. I could be wrong.

Bry

Viper98912

We're probably confusing different thoughts here. We should probably state what RPM's you're talking about.

Autotechnica

everytime I cold start the car, my engine automatically holds around 1500RPM for a good 5-8 seconds then returns to the normal 700RPM idle.

Budget Baller

Yup my car does it every so often also

mikev7

It's closer to 20-30 seconds.

karlo 17

how high do the rpms go?

mikev7

Sorry it's like 15-1600 rpm.

03MBC32

Normal. Mine will stay there for up to 20 seconds from a cold start. I do have an occassional cold start rev to 2500-3000 rpm for about 2 seconds before the revs drop to 1500.

mikev7

here's a video of it.
http://www.youtube.com/watch?v=ojclBJrztVM

trbo2nr

I forgot to mention my RPMs showed 2500 when it happens.

Bob

AMG3.2

Same, mine revs high sometimes.

terrymary512

Anyone else seen this

60n5pt1

Mine revs up to close to 2200 to 2500 for about 6 to 8 seconds and then drops to normal idle rpm. Almost everytime in the morning and but shorter time when engine has been driven over a longer period.