Chevy Colorado

[fasterthanyours]

Anyone know where the O2 sensor is on the exhaust?

I think mines bad, because the engine doesn't idle at 800 RPM, it idles at 500.

[MrDude_1]

the one you want is in the exhaust manifold, near the collector. there is a second O2 after the cat to verify its working. the 2nd one does not effect fueling.


that said, im 99% sure thats not your problem. first thing id do is look at the IAC counts with a scan tool.

[fasterthanyours]

Cool thanks, i was doing some reading on the Colorado trucks site and they suggest cleaning the throttle body.

[MrDude_1]

Cool thanks, i was doing some reading on the Colorado trucks site and they suggest cleaning the throttle body.
thats also a good place to start.. if you IACs are maxed, then thats where i would go.

your "base" amount of air is set by the amount allowed to leak around the blade, plus there may be a small hole in the throttlebody.

that amount is then fine tuned by a computer controlled valve.. the pathway to this valve is in the throttlebody.

if the "base" amount of air is too low, then the computer can have the IAC valve open all the way.. and the engine still doesnt have enough air at idle.

if you take it off the car, brake cleaner is quick and easy... good time to clean your MAF too.

[Mike]

Seafoam :wtg:

[fasterthanyours]

Yeah the guys on the site said seafoam and carb/brake cleaner.

[MrDude_1]

Yeah the guys on the site said seafoam and carb/brake cleaner.

brake cleaner leaves no residue.
carb cleaner leaves a light oil behind. (to prevent corrosion)

if you clean the MAF, DONT use carb cleaner.. the oil may damage the MAF.. or at the veryleast.. you still dont have a clean MAF.

seafoam works ok on some intake parts.. but it wont get the edges of the throttleblade very well, and will miss the IAC passageway.

[fasterthanyours]

What is the MAF?

[OriginalOne]

mass air flow sensor

[fasterthanyours]

Thought so, I'll probably get into next weekend

[MrDude_1]

MAF is in the red box:
http://www.jfdavidson.com/truck/01First.JPG

[Professor Fate]

Warranty. Should be covered by dealer.

[mccutch2u]

Seafoam :wtg:

I agree but check the carbon build up on the throttle body and clean with carb cleaner as needed............right around the throttle plate there will be a ring of carbon that reduces the air gap and thus effects idle only

[fasterthanyours]

Well I think you guys or right. I'll get on that next weekend.

Out of warranty, 95,000 Miles

[OriginalOne]

I agree but check the carbon build up on the throttle body and clean with carb cleaner as needed............right around the throttle plate there will be a ring of carbon that reduces the air gap and thus effects idle only

+1... except don't use carb cleaner on the throttle body, use throttle body cleaner or brake cleaner.

[mccutch2u]

we had a thunderbird come in the shop one time wouldn't even stay running all they wanted was an oil change, so I checked the throttle plate and saw the carbon build up and cleaned it and the car purred like a kitten afterwards

[mccutch2u]

another thing you can do is find a vacuum hose and get a piece of hose to make it longer and have somone keep the car running while you have the hose dipped in the can of seafoam and that will clean the carbon from the intake and head.What sucks is that I don't know of anyshop that cleans the fuel injection the way that I have always done it. I always disconnect the fuel line and tap into the fuel system with some fuel injection cleaner so that the car runs off the cleaner and not the gas. It does alot better job. Most shops will do a three part cleaning by 1:adding a cleant to your gas,2: cleaning the throttle body and 3: cleaning your intake system the way that I described above....................if you do clean it the way I described then you will need to take it out and drive it to finish burning the carbon off and it will smoke for a little bit depending on how much carbon build up you have