Newbie with Aveo in need of timing belt/head help

[JusteR]

The one mystery wire that I can't find a place for. If I remember right it's on the same section of harness that goes to the alternator. Not very long and I can't find anywhere it could reach to. It's pretty clean so I'm sure it was plugged in before. Anyone have any ideas or pics? Driving me nuts.

My guess is: Power Steering Pressure switch. idle should come up a bit when you steer while not moving

[JusteR]

+1 on the VR6 swap

[DRG2003]

My guess is: Power Steering Pressure switch. idle should come up a bit when you steer while not moving

RPMs very slightly drop when turning the wheel when idling. Does that confirm that's what this plug goes to? Any easy way of explaining where it connects? I'll poke around next time I get under the car and see if I can get this last thing done. Thanks!

[Dustin]

Isn't there a two wire (coolant temperature?) sensor on the firewall side of the head between the first and second runners of the intake manifold? If the temp guage works that might not be what it is, unless there is one for the guage and one for the computer to calculate fuel map magic. Just my $.02. Good luck.

[JusteR]

It could be a coolant temp sensor as well; however, if disconnected your car would fuel as if the engine is at -40F. I was thinking about this the other day and it could also be for an AC pressure switch _or_ intake air temp sensor. I think I'll actually go and look at mine and see what I see.

BTW, DRG-- If you don't have hydraulic power steering don't worry about it. The reason you want idle to go up under high PS load conditions is to keep the engine from stalling with the AC on during parking lot maneuvers.

hthy, more info to follow as it comes to mind...

[JusteR]

Dustin, you are right, there is a sensor on the head betw. the intake runners; and it is listed as the coolant temp sensor. I am also showing a purge solenoid going on that bracket behind the alternator. I always thought the coolant temp sensor was down on the block, firewall side near the timing cover(I have coolant-y scale on mine). *edit* 1 wire on the one down low; must be for the gauge. (And I'm thinking: seperate sensors on a 2008?) I am going to try and find the power steering pressure switch on mine...

I found my purge solenoid, it is high up on the intake manifold stay bracket. And, it is a red 2-wire connector!

Alternator is towards the bottom and photo is taken looking up. HTHY

FWIW, I couldn't find the steering pressure switch on my car. I don't think it has one. I apologize for any confusion caused by my earlier guesswork.

[DRG2003]

That was it!! Thanks for finding it for me! Once I saw your picture it was obvious once I got back under the car. In just enough of an inconspicuous spot that I couldn't see if without knowing what I was looking for.

Of course a little bad always has to come with some good... now that I have plugged that connector in it wants to randomly stall out when idling? Ran perfect before. Check engine light was on before (and before this whole rebuild) and is still on... I will have to scan and see what codes are coming up. Any ideas?

[JusteR]

I think the car is trying to run the evaporitive emissions monitors. I know that is vauge, but read up on it. I'm not sure if the manifold pressure sensor is used to estimate purge flow [in this setup], but in a speed-density car it is used in conjunction with throttle position to estimate the airflow and thus, calculate the injector pulsewidth. HTHY. Sorry you are stalling now

[DRG2003]

Seems to be fine now! Maybe the solenoid was sticking from not being used for a while? Started the next day and it was fine... left it alone for a few more days and it was fine again today. I read they can stick open or closed and cause varying symptoms depending. From what I understand it's an emissions thing... the ecu monitors the fuel line/tank pressure and when it gets to a certain pressure it opens the solenoid and vents it to a charcoal canister instead of the environment.

Still got that check engine light on but so did the previous owner intermittently before any of this happened. Also haven't driven it any considerable distance to give it a chance to reset. My gut tells me it's either the fuel cap not sealing or an o2 sensor. I need to find a good generic scantool program for my laptop/cable. I have the VW program but that's no help on the Chevy lol. Thanks again for all the help!

[JusteR]

When I test those, I energize them 25-50 times to make sure they don't stick at all. once will throw a code and two in a row will set a light IIRC.