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Discussion Starter #1
I have a 2014 Equinox with 2.4L 4 cyl, 165,000km. If the engine is restarted after being off for about 2 hrs it starts and idles rough, until some closed-loop control takes over, and it idles smoothly. It also smells strongly of gasoline when this happens.

Here is a video of a start; it is hard to hear but runs quite rough as you can see with the tach, the engine vibrates quite a bit.

This is new (maybe after changing plugs at 150k), or else it was so subtle I didn't notice before. I thought it might be the gas tank was very low, or the oil was very low, or gas from one particular station, because when these were changed it started smoothly, as it did for the first 5 or so years. The rough start returned after some time though.

Cam Phaser recall was done long before this condition was noticed.

Is this a plug problem, a fuel pressure problem, or injector leaking problem? It started after about 150k or more.
 

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When idle smooths out it's the system going to closed loop controlled by the O2 sensor after it heats up and starts functioning. Also could be a faulty engine temp sensor sensing too cold engine temp. and over fueling engine until O2 takes over. MAF intake temp. sensing could be off also affecting cold start mixtures. Lots of variables and sensor feedbacks need to be looked at.
Smelling richness has me inclined to say it's one of the above, scan tool reading of fuel trims and sensor feed back is the only way to see what's going on. Without a quality scan tool to check system everything is a guess.
 

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I forgot to say that some time ago I would get CELs about the second O2 sensor not reading well, at the same time as the rough running being really bad; I changed gas stations from the discount one to Esso or Shell, and the CEL hasn't come on since, but it still can start rough after being off for 30 or 60 minutes.

Here is what the scan tool I have shows. It was 6C outside at the time:



Nothing looks too strange, unless the IAT is wrong by a few C, maybe. ?
 

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Which control circuit is taking over when the misfiring is cleaned up? Ignition timing?
That's where I should start looking to troubleshoot.
 

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Look at the ECT after sitting cold overnight. Engine Coolant Temp. . Should be close to actual temp and IAT , Inlet Air Temp. should be close also. A couple of degrees difference is OK, not a big gap. When the O2 sensor finally heats up after running some it takes over controlling the system, goes closed loop and actually monitors and controls engine fueling.
That is normal as system has a fixed fuel map to run a cold engine until O2 takes over control, that's how closed loop works. Closed loop uses O2 sensor to control engine fuel mixtures along with load, rpm, temp, etc..
When engine is cold it's in open loop mode and ECM controls engine by reading off ECT , IAT, baro to control fuel, timing, etc. by a fixed map in the ECM depend on temps. reported to it.
If ECT is reading cold engine it will richen fuel to keep it running until O2 takes over control.
This is the basic way how computer engines run, ECM has a myriad of maps in it for different conditions and uses them by according to sensor feedback.
At 165000 km your ready for new sparks plugs BTW if they haven't been changed. That has a direct affect on cold starting/running.
 

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Discussion Starter #6 (Edited)
It was 2C today and ECT says 2C as well. IAT still says 11C or 12C sitting overnight though.
People online have said replacing this cured their rough starting problem, maybe I should just do that. It's only $30 + my free labour.

 

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It was 2C today and ECT says 2C as well. IAT still says 11C or 12C sitting overnight though.
People online have said replacing this cured their rough starting problem, maybe I should just do that. It's only $30 + my free labour.

Funny you should mention changing the IAT sensor, I didn't catch which engine you have.
A few years ago I was changing my engine air filter on my V-6 and the MAF is right there in the air box and I noticed something strange.

The MAF had eight wires going to it.
I have changed many MAF sensors and they usually have 3 or 4 wires.

The reason is in my 3.6L the IAT sensor and MAF sensor are combined and it is called a Multifunction Intake Air Temp sensor.
 

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Discussion Starter #8
It's the 2.4. After changing the plugs last year it idled much more smooth and quiet. If any store opens again soon I can get some non-MAF-destroying spray to clean it.
 

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rednox301 , actually the MAF sensor, the one with 8 wires, has about 5 sensors built into it. It has the MAF, IAT1, IAT2, Humidity, and Baro sensors all in one unit. And the 2 IAT sensors may show slightly higher readings after a period of key on - engine off. This is due to heat generated by the MAF and humidity sensors. ( engine off = no air flow )
 

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rednox301 , actually the MAF sensor, the one with 8 wires, has about 5 sensors built into it. It has the MAF, IAT1, IAT2, Humidity, and Baro sensors all in one unit. And the 2 IAT sensors may show slightly higher readings after a period of key on - engine off. This is due to heat generated by the MAF and humidity sensors. ( engine off = no air flow )
Thanks for that info.
I need to look into that again, I'll post back if I find anything interesting.

I was chasing a Baro sensor code a while back and I couldn't put my finger on the Baro sensor.
So I assumed the Multifunction sensor was the problem, replaced it with a AC Delco, cleared codes and the Nox ran great no more codes.

Je, your 2014 2.4L uses the same Multifunction sensor.
Never had much luck with just cleaning the sensor, runs good for a month or two and problem comes back.
 

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I have a 2014 Equinox with 2.4L 4 cyl, 165,000km. If the engine is restarted after being off for about 2 hrs it starts and idles rough, until some closed-loop control takes over, and it idles smoothly. It also smells strongly of gasoline when this happens.
.
Smell of gas might be purge valve stuck in the open position


The canister purge solenoid — also referred to as an EVAP canister valve — is responsible for “purging” the EVAP system by acting as the switch that allows the vapor into the engine. When the purge solenoid fails, it will cause problems for the EVAP system, which will affect the vehicle’s emissions output levels. Usually, a bad purge solenoid will display any of the following symptoms that can alert the driver of a potential problem in need of servicing.
1. Rough Idle
One of the first symptoms that a faulty canister purge valve may produce is a rough idle. In this case, you will notice the car running inconsistently while stopped or driving at low speeds. If the canister purge valve fails and sticks open, it will create a vacuum leak that can affect the engine idle speed and quality. A vacuum leak can also be caused by a broken or damaged purge solenoid or any of the hoses attached to it. It needs to be addressed as soon as possible, as it could lead to your engine stalling completely.
2. Poor Engine Performance
On top of a rough idle, a vehicle with a failing EVAP canister purge valve will display signs of poor engine performance. The engine may feel like its running “weak” and won’t generate sufficient power for acceleration. Accelerating will feel like you’re pressing the pedal down and moving slower. The disrupted combustion process caused by the failing purge solenoid will lead to slow acceleration that needs to be addressed for repairs right away.
 

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Had a customer bring me a car presenting with almost exact same issue. Only no CEL present. There regular mechanic three plugs at it and a crankshaft position sensor including a relearn.

When I got it I was given permission to make it my daily driver in order to experience/monitor issue. After a couple hours of watching several systems, I noticed the commanded value of both the intake and exhaust VVT solenoids verses the actual values were way off. I replaced them both with Delco OEM (horrible experience with aftermarket) and result was instant. All good I must admit it was my first experience of this without setting a trouble code. The dealership I use for parts informed me that the failure rate of the original solenoids is nearly 100%. They stock and sell these thing like candy store sells Skittles. The redesigned units are far more resistant to failure and seem to "react" to PCM commands smoother and faster than their earlier counterparts.

So if you can watch actual vs commanded values and see a big discrepancy, I think you found your culprit(s).

Also, even if only one is off, replace both.
 

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Had a customer bring me a car presenting with almost exact same issue.

I noticed the commanded value of both the intake and exhaust VVT solenoids verses the actual values were way off. I replaced them both and result was instant.

seem to "react" to PCM commands smoother and faster than their earlier counterparts.

Also, even if only one is off, replace both.
Very well done using your scan tool!

Respectfully, to be clear,.......
does exact same issue include smell of gas and stalling?

And my 2 cents, STUMBLE
The replacement of the 2 solenoid is often a solution to stumbles, which as you described
is when the car computer tells VVT solenoid to advance or retard timing, and because the filter screens are so plugged up,with gunk, that the response time to PCM commands to advance or retard the timing is slow....

Because the crankcase PCV system is so poorly designed, engine oil fumes and piston blowby and crankcase PRESSURE
The crankcase COOKS the ingredients depositing gunk all over crankcase including on the solenoid filter screens.
And yea, that is why the VVT solenoids often are replaced.

Finally, the "design change" on the VVT solenoid, IS IT? (did u do a visual comparison?)
is it the change on the screens on the solenoids going from a nylon monofilament mesh to a stainless steel mesh screen, or is it a change in the size of the holes in the screen,
that is are the holes in the "cigarband" solenoid filters larger then what they were before?

STUMBLES
There is a post on called "Traverse Stumbles on light acceleration No Codes"
where a brilliant "testbob" disassembled
Then cleaned the filter screens on the 2 solenoids....
( one solenoid Retards the valves, the other solenoids controls the advancement of the intake and exhaust valves)
He actually has 2 separate posts on the same topic, look for them, read his comment and his solution, he fixed his problem. Here is One post
https://www.traverseforum.com/threads/2013-traverse-stumbles-on-light-acceleration-no-codes.19479/
His 2nd post is a detailed summary of his findings.
He cleaned the cigar band filters on these solenoids... and fixed the stumble problem
 

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Picked up a scanner myself, car is running decent right now but still random rough idle/stall and very rare rough shift. No codes. Evap purge solenoid seems possible. Not sure what $7e8 is or how to track any of this down. I can get more info if I know what someone would need.
 

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Picked up a scanner myself, car is running decent right now but still random rough idle/stall and very rare rough shift. No codes. Evap purge solenoid seems possible. Not sure what $7e8 is or how to track any of this down. I can get more info if I know what someone would need.
I am unable to see your scanner pictures...
 

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Picked up a scanner myself, car is running decent right now but still random rough idle/stall and very rare rough shift. No codes. Evap purge solenoid seems possible. Not sure what $7e8 is or how to track any of this down. I can get more info if I know what someone would need.
I am unable to see your scanner pictures...
Started a new thread.
 

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Stalling yes. Smell of gas, I would say "kind of". The PCM although not setting a code yet for the issue, was attempting to compensate for the variances. It was running rich, then lean. So if was a calm day, I assume I could have smelled unburnt fuel, however ir was rather windy here in Vegas when it landed in my hands.

The receipt from the shop that tried to correct issue showed poor MPG as one of the complaints. So maybe did have same issue of fuel smell, but I personally didn't experience it
 

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car is running decent right now but still random rough idle/stall
and very rare rough shift. .
Rough shift could be transmission responding to delayed VVT solenoid response
 

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car is running decent right now but still random rough idle/stall
and very rare rough shift. .
Rough shift could be transmission responding to delayed VVT solenoid response
Checked those a few months back, clean and operational.

Cars running like trash again. O2 bank 1 reads as low as .09v floats more consistently around .2-.4v think that's my next step. Bank 2 is .7v and that appears to be normal
 
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