Engine has high revs after starting
#1
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Joined: Jun 2004
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From: Ashburn, VA
2004 C32, 2006 Honda CBR1000RR, 2007 Harley NightRod, 2013 Harley Road Glide Custom
Engine has high revs after starting
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?
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chuang (02-21-2020)
#3
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Joined: May 2006
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From: Southern Cal
a C32 AMG & S-Works Tarmac
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.
Mine now does it with every cold start and stays at higher revs longer than it used to.
#4
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From: Ashburn, VA
2004 C32, 2006 Honda CBR1000RR, 2007 Harley NightRod, 2013 Harley Road Glide Custom
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).
I thought it was just me but now see it's both c32 and c55 (maybe others).
#6
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#11
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From: Western Canada
2013 C63 AMG P31, 2014 GMC Sierra (6.2)
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...
#13
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
Bry
Last edited by Autotechnica; 10-30-2011 at 10:20 AM.
#20
#21
here's a video of it.
http://www.youtube.com/watch?v=ojclBJrztVM
http://www.youtube.com/watch?v=ojclBJrztVM
#22
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MBWorld Fanatic!
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From: Ashburn, VA
2004 C32, 2006 Honda CBR1000RR, 2007 Harley NightRod, 2013 Harley Road Glide Custom
#25
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From: san jose, ca
2002 C32 1987 190E 2.3 334K miles and going
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.