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Discussion Starter · #1 ·
Hi all,

I have a 2012 fortwo with less than 50K on the engine, and I was wondering, when ever I start the engine, I always heard this higher engine sound and after about 30 seconds, it would sound down to a regular engine sound. I have noticed the last 3 times I have started it after sitting all night, that it doesn't do it anymore. Is there something going on that I should be aware of, concerned about, etc.??? I just hate when things change that I am not aware of and then I get afraid to drive it for fear I'll blow my engine.

Thanks for your help, Diane.
 

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Discussion Starter · #3 ·
It always had the higher engine sound until 3 start ups ago, now it is just a regular sounding engine. I don't know what you mean by saying "it always starts up every time the car does".

What does the secondary air pump do? Should I be alarmed? Thanks
 

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If it’s cold outside then the pump won’t run and if it goes out you’ll get a check engine light and the car will run just fine withou a working secondary injection pump. The temps for it to run are 45-97 so winter mornings when your car is below 45 it doesn’t run perfectly normal
 

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Discussion Starter · #5 ·
Oh, ok. Where do I find this secondary injection pump on my car? It has been awful cold here where I am at almost 32 degrees at night. I have no engine light on, so I guess I'm safe. If I find that the pump doesn't do it's thing anymore, do I replace it or just not worry about it? Will it hamper smog checks? Thanks.
 

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It would hamper smog test I would assume we don’t have that here in Louisiana. But at 32 degrees after sitting for a few hours your not gonna hear the pump run. If you have no engine light don’t worry about it there’s a 99% chance the next warmer day when you crank it up you’ll hear your little dirt devil vacuum cleaner running for 30ish seconds again. And it’s also located behind the fender well on the rear passenger side
 

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Here it is

:)
1 Cylinder head
2 Combination valve
3 Air hose
4 Vacuum hose
M33 Secondary air injection pump
Y32 Secondary air injection pump switchover
valve
 

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It always had the higher engine sound until 3 start ups ago, now it is just a regular sounding engine. I don't know what you mean by saying "it always starts up every time the car does".

What does the secondary air pump do? Should I be alarmed? Thanks

It assists with heating up the cat converter rapidly while also cutting emissions while the engine is still cold. If you don't hear it anymore, it is possible that it has failed. Are you getting a check engine light?
 

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Discussion Starter · #10 ·
It assists with heating up the cat converter rapidly while also cutting emissions while the engine is still cold. If you don't hear it anymore, it is possible that it has failed. Are you getting a check engine light?
No engine check light. But it's beginning to all make sense. SoCal is experiencing unusual cold weather and where I am at, it's near/below the freezing level. So I'm sure it will come back once it warms up a bit. Otherwise, car runs fine.

Thank you for replying to me and the help. Diane
 

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Discussion Starter · #11 ·
Awesome pictures! I wished they still had the (Edmund's?) Motor Manuals we had back years ago! Thank you very much for assisting me! Diane
 

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Discussion Starter · #12 ·
Where did you get these pictures? I'd love to have pictures and diagrams of my engine so I could understand it more. Thanks! Diane
 

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No engine check light. But it's beginning to all make sense. SoCal is experiencing unusual cold weather and where I am at, it's near/below the freezing level. So I'm sure it will come back once it warms up a bit. Otherwise, car runs fine.

Thank you for replying to me and the help. Diane

If it's starting to act weird, look for it to continue to do that for some time until it finally quits...
 

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Quits acting weird or quits running...…..:shrug:

I had one of them go out on one of my smarts and heard others die in customers' cars, they exhibited symptoms of irregular noises prior to eventual failure and refusal to operate. I've also heard the same issue on other MB vehicles with the same part. Usually it starts with the strange noises before it eventually quits. The eventual might be years later or tens of thousands of miles later so it's nothing to panic over.
 

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Discussion Starter · #19 ·
You can subscribe to Evilution.co.uk or ALLDATAdiy.com and get lots of tech info, and there's always the 2008 Intro to Service Manual for overall reference to the operation of the 451 smart. :)
Wow! Thanks for the link. I downloaded and printed the Intro Service Manual. I never got anything like that. I do have an owner's book but that's for just basics. I really appreciate everyone's tolerance of my questions. Diane
 
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