Post your VIN - I think you can tell by the VIN number....

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Not sure how accurate it is but someone did send me this site awhile ago and ive just had it bookmarked for awhile GM VIN Decoder - Your #1 GM & General Motors Information Resource

 

This is for your vin. I'll check mine to let you know.
Positions four through eight describe the car with such information as the model, body type, restraint system, transmission type and engine code.


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I'm sure the vin would state its a 3900. I guess i just wanna be sure the engine hasn't been swapped or anything. Is there a vin located on the engine itself anywhere? or any kind of code stating if its a 3.5 or 3.9? Thanks.

Oh also, is there a way to tell if it has AFM or displacement on demand, etc? Would the computer be able to provide any info on what engine is currently installed?

 

Well first off is it an LS, LT or LTZ?

I'm sure if you take it to a dealership or somewhere and have it hooked up to a tech 2 it will test you most if not all the information you are looking for.
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Do a Google search for both engine types and compare pics of each to your engine - shouldn't be that hard to figure out....

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It's a police package. I might try a dealership. im just trying to be sure it is what it is. I've tried looking up pics of the engine by itself and installed in a car, but i've noticed that some 3900's look different than others, the top's of them will look different, and even the plastic engine covers look different, but still state 3900. Problem is, one of the 3900's looks exactly like the 3500 from the top. So i'm still not sure exactly what i have. i can't seem to find any numbers on the engine anywhere. There's gotta be a way, or else someone could just pop a 3900 plastic engine cover on top of a 3500 engine and call it legit.

 

The 2006-2011 Police & LTZ Impalas will be a 3900, optional 3900 on LT. The police always got the larger engine
A 3900 would have dual exhaust as well
There might be a sticker as is on my 07LTZ under hood front right side just to right of the support says 3.9 LITER

 

I forgot about that sticker! I have one as well that states 3.5 Liter.


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But he is saying he is sure the VIN indicates 3.9 and a 3.9 was the original engine. He is worried the engine has been swapped. No idea why that's such a big concern.....nonetheless. ...if it was, VIN check and sticker check don't help him. Agree, he should go to the dealer and get it hooked up.

 

Yea ill try and get it checked out. The dealership i bought it from is wayyyy out of town so maybe someone in town can help. I'd just like to know, you know. Like i dont care if its been swapped, it drives great, but i'd still like to know. Oh and Lol, when i got the car home, i felt like the gas pedal was a bit sloppy and not as responsive as my 2000 impala. I figured it was just cause that's how the electronic gas pedals felt. The gas pedal was actually hanging off the firewall by one loose bolt. I had to get down there and tighten it up, and the other bolt was on the floor.
Makes me wonder what other bolts might be loose or gone. It's a cop car so i've already ripped out the interior and double checked all the wiring. It was pretty sloppy, i had to fix alot of wires that were just cut off and hanging were they could short out on the body. Had to replace some missing interior screws and plastic clips. Went ahead and deep cleaned everything and the interior is looking brand new
Anyway, thanks for the info guys. I've been reading the forums for many years, first time registering lol.

 

for the record, when i put my VIN into GM VIN Decoder - Your #1 GM & General Motors Information Resource
it tells me the VIN is not valid =/ tried many times, with and without CAPS.

Do all Impalas with AFM have an indicator on the DIC saying wither its in 6 or 3 cylinder mode? mine has none. it only shows the current mpg on the instant economy view. I also heard that AFM for the 3900 was only 07 and 08, but my car is a 09 manufactured in Nov, 2008. Any thoughts?

I still need to make a trip to the dealer, just been busy.

 

Post a pic of the engine bay?

 

Okay,
i.imgur.com/QRG1V8e.jpg
i.imgur.com/uESt6kU.jpg
i.imgur.com/tFErkmI.jpg
i.imgur.com/2nNJe48.jpg

so what do ya think?

cause this is what i found on google...
http://i.ytimg.com/vi/G8eewd56IjY/maxresdefault.jpg
http://images.hollandersolutions.com/ACI/CT7/IFZ/CKH/4.jpg
http://static.cargurus.com/images/s.../site/2015/01/04/19/52/2009_chevrolet_impala_police-pic-379473042129232967.jpeg
http://cimg.carsforsale.com/394405/E3868AFC-AD1C-4D49-826E-B817CAED39CA_8.jpg

Mine never came with an engine cover so idk whats what lol, obviously not the last one but, I just recently learned there were more than one version of this thing...

 

Does the AFM actually turn on and off?

 

See this is a rough one because about 85% of the 3.5L and the 3.9L is identical.

 

Not sure you can tell from looking at the engine as pretty much the only difference between the 3.5 and 3.9 is a different bore and stroke.

 

Well on some 3.5L there were air resonation pipes on the intake which this one lacks but, it's not a definite tell-tale.. I was hoping to see a cover.. LoL

 

If that 2009 Impala has factory dual mufflers and tailpipes, then it was originally equipped with the 3.9 liter engine. 3.5 liter engine cars only came with a single exhaust.

 

8th digit of your VIN:

M = 3.9 Flex Fuel

K = 3.5 Flex Fuel

N = 3.5 Non-Flex Fuel