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#4552053 - 10/23/17 02:38 PM Air Intake Temp & MAP #'s help
Iowegian Offline

Registered: 01/05/17
Posts: 273
Loc: Iowa
I have a 2011 Equinox with 2.4l.
Not a turbo but is GDI.

Pistons and rings just replaced for oil consumption, thank you GM.

First I'm a bit ocd and I'm alwsys looking for problems when there are none. So please check me on this. Is this a problem?

AIT: car sits entire weekend in the garage. Key on and engine off gives me these temps
Engine oil and coolant temperature were both 66.2 deg. Garage temp was 64 deg.
And the AIT was 69.8 deg.
I found it interesting that the oil and coolant matched each other perfectly.
AIT is part of MAF and is located right behind filter very close to mouth of intake system.
It always read 6 deg higher than ambient while driving. Engine heat should not have too much effect due to the location.

MAP: My Map read 14.2 psi (28.9 inHg) with key on and engine off.
Local airport showed barometric pressure was 31.1 inHg. Found out that weather station readings adjust for altitude to make all readings comparable. Rule of thumb is adjust inHg down by one for every 1,000 ft of elevation. I'm at 960 ft above sea level.
So actually the barometric pressure was 30.1 inHg.
MAP is supposed to read actual barometric pressure but it is off by 1.2 inHg.

Are either of those off enough to bother with?

No codes but I have experienced occasions where no codes but there was a problem....
Sucking down 1.5 quarts in 2k miles and no code.
Thermostat starts to open at 160 deg and with top temp at 180 deg and no code. Replaced and now temp goes to 195 deg.

I have been experiencing some hesitation/stall when I let off the gas for stop light and step on it when it turns green before I get there. Also once from a complete stop. I was hoping it to be the transmission (I have a $100 deductible warranty and these transmissions suck.)

But now beleive it to be the MAP and combined, to a lesser degree (pun intended), the AIT.

Thank you ahead of time for chiming in abd any experience.

Also, here are a couple of articles on this.
You may not see any of the charts without downloading the pdf at the bottom of the article.
2011 Equinox, 2.4l
2009 Sienna, 3.5l

#4552168 - 10/23/17 04:50 PM Re: Air Intake Temp & MAP #'s help [Re: Iowegian]
StevieC Offline

Registered: 08/21/08
Posts: 17116
Loc: Ontario, Canada
I think your sensors are fine, some variation is normal. My coolant, oil, battery, mass air-flow temperatures senors are all within a few degrees of each other.

As for the hesitation/stumbling/stalling. I'm surprised it's not showing codes for this. But check the obvious. Coils, Plugs, Dirty Throttle Body, Upstream Oxygen sensor voltages / responses. Check for voltage problems with the Throttle Position Sensor for dead spots.

Or take it back to GM under warranty and let them figure it out. Should be running properly.

Edited by StevieC (10/23/17 04:53 PM)
'15 Dodge Journey - 90,000 KM's - SSO 5w20
'06 Hyundai Santa Fe - 535,000km - SSO 0w30 (R.I.P)

#4552205 - 10/23/17 05:18 PM Re: Air Intake Temp & MAP #'s help [Re: Iowegian]
mk378 Offline

Registered: 09/27/15
Posts: 1450
Loc: USA
Car sensors aren't laboratory grade instruments. That's what fuel trim is for.

#4552319 - 10/23/17 06:48 PM Re: Air Intake Temp & MAP #'s help [Re: Iowegian]
Iowegian Offline

Registered: 01/05/17
Posts: 273
Loc: Iowa
It's what O2 sensor is for.
In the 2nd article, the guy moves the voltage up and down on the map sensor to see how much it would take before his Honda's O2 sensor would lose any control over the fuel trim. Didn't take much.
2011 Equinox, 2.4l
2009 Sienna, 3.5l

#4552327 - 10/23/17 06:55 PM Re: Air Intake Temp & MAP #'s help [Re: Iowegian]
Iowegian Offline

Registered: 01/05/17
Posts: 273
Loc: Iowa
"The barometric pressure seldom goes above 31 inches or drops below 29 inches. Normal sea-level pressure is 29.92 inches."
2011 Equinox, 2.4l
2009 Sienna, 3.5l

#4552329 - 10/23/17 06:57 PM Re: Air Intake Temp & MAP #'s help [Re: Iowegian]
Iowegian Offline

Registered: 01/05/17
Posts: 273
Loc: Iowa
I do have new plugs and the throttle body has been cleaned. When i first bought it last year it was very dirty. Significantly help the idle and response.
2011 Equinox, 2.4l
2009 Sienna, 3.5l