2016 GM1.4 L Turbo health check and diagnostic

DriveHard

DriveHard

Joined
Nov 24, 2003
Messages
4,417
Location
Middle of Iowa
BITOG friends...looking for any insight.

A handlfull of years ago we bought my mother in law a manual transmission Mini after she took a ride in my Fiat 500 and fell in love. I was looking for something a little more stable, better ride quality, and well...easier to obtain here in Iowa. Recently she has an ailment in her left foot that she can no longer drive a manual transmission car. My bride and I of course decided to buy her something new (she is on a passed away cop's retirement and living at the poverty line), and found a great deal on a 2016 Chevy Trax LT with ~127K miles on it. It is in amazing shape, the seller knows the OG, and all records seem in check. We got it for just over 50% of KBB. Now...here is why...

Good...
it leaves no spots, has no leaks.
coolant looks clean and decently fresh
engine runs "smooth" - rough for idle, but I realize this is an economy car with a very small 4 cylinder
oil is at 23% life - comment was made that none was added and it is 0.5 quart low. There is some clarity to the oil, and under the fill cap looks clean
It appears the fuel mileage has never been reset, and it was averaging 29 mpg
Body is clean and rust free...underbody is clean...for being an Iowa car, the owner must have never driven it in winter.
Interior is clean...covered in dog fur, but clean. It needs a detail, but I can work with that easily. I have an O3 machine for getting the dog smell out, and a shop vac
Evidence a mechanic that cares was under the hood
brakes are ~50%
drives smooth

Bad...
Idle is rough...but is it really? This is a small 4 cylinder, and I have never driven a GM with the 1.4L turbo. It is rhythmic and steady, just vibrates the car quite a bit.
Is throwing catalyst inefficiency code.
Shut down once on my bride was driving it...details to follow
Covered in fur
two door dings
mismatched tires - but all good tread

Health check...
Hooked the car up to diagnostics after my bride drove it and it died...here are some observations..
MAF sensor was pretty steady, and held steady when I commanded a throttle position. Intake air temp seemed accurate.
MAP sensor seemed accurate and responsive
upstream O2 sensor was normally crazy...although I did see a few 0.0xxV values and a few 0.9xx values...seemed high and low. This is with a brand new Denso O2 sensor
Downstream O2 sensor was reading between high 0.6xxV to low 0.7xxV under most conditions. Does this seem low? Would this indicate the catalyst inefficiency code?
fuel pressure was steady in the ~45 psi under all conditions
coolant temp was steady and oscillated with fan cycling
throttle position was ~7% at idle...seemed to respond normally
Load was ~20% at idle...23% when A/C cycled on
short term fuel trim oscillated between +3.1% and -3.1% almost every single reading...assuming this means it is about even?
long term fuel trim I seem to remember as .998? Guessing a value of 1 is good?

There were no indications of vacuum leaks or PCV problems from what I could read from the data that this car is known for. Are there specific tests or data I should look for? The car seems to run really good, and has no indication that it died for a few seconds as my bride describes. My first thoughts are crank angle sensor or MAF sensor for this type of failure? No codes were thrown other than the one for the Cat. I need to figure out the cause of the random dying (only happened once) or get enough miles on it not happening to make my bride happy to turn over to the mother in law. Anything else I need to look at from the engine reliability perspective? I am going to change the ATF, oil, air filter. Plugs...hummm...never dealt with a coil pack like that before and I have heard horror stories...any advice here?
 
If it’s the same as a Cruze 1.4, there’s a check valve in the intake you need to check. It’s in the intake under the corrugated tube that runs to the inlet side of the turbo. The tube is very brittle, so unclip all the clams on the valve cover, remove the 90 fitting. There should be a little orange tit facing you as you look into the hole back at the firewall. If it’s gone, change the intake and the valve cover. The check is usually gone by 80,000. The valve cover is cheap and has a diaphragm which failed causing a rough idle that will usually set codes. Theres a breather on the top of the diaphragm if you plug it and it runs smoother the diaphragm is junk.

IMG_4315.webp


IMG_4314.webp
 
Gus_Mahn said:
If it’s the same as a Cruze 1.4, there’s a check valve in the intake you need to check. It’s in the intake under the corrugated tube that runs to the inlet side of the turbo. The tube is very brittle, so unclip all the clams on the valve cover, remove the 90 fitting. There should be a little orange tit facing you as you look into the hole back at the firewall. If it’s gone, change the intake and the valve cover. The check is usually gone by 80,000. The valve cover is cheap and has a diaphragm which failed causing a rough idle that will usually set codes. Theres a breather on the top of the diaphragm if you plug it and it runs smoother the diaphragm is junk.

View attachment 232095

View attachment 232096
Click to expand...

I read about this...but wasn't sure on how to inspect. I figured there would be something in the engine data suggesting a problem. Would this set the Cat code? That is the only one I found.
 
I have 2 cars with this engine. PCV in valve cover can be a cause of rough idle issue. Also common coolant leaks from reservoir bottle, and plastic coolant manifold on drivers side of the engine. Oil drain plug is 10mm threaded into a cast aluminum pan. Take care not to over tighten as you will damage the plug. Lastly, since this is a turbo engine, keep oil full and clean.
 
Gus_Mahn said:
If it’s the same as a Cruze 1.4, there’s a check valve in the intake you need to check. It’s in the intake under the corrugated tube that runs to the inlet side of the turbo. The tube is very brittle, so unclip all the clams on the valve cover, remove the 90 fitting. There should be a little orange tit facing you as you look into the hole back at the firewall. If it’s gone, change the intake and the valve cover. The check is usually gone by 80,000. The valve cover is cheap and has a diaphragm which failed causing a rough idle that will usually set codes. Theres a breather on the top of the diaphragm if you plug it and it runs smoother the diaphragm is junk.

View attachment 232095

View attachment 232096
Click to expand...
Exactly right. Too many people will keep replacing valve covers w/o checking the intake for the root cause issue. You saved me a lot of typing!
 
Wrenchturner44 said:
I have 2 cars with this engine. PCV in valve cover can be a cause of rough idle issue. Also common coolant leaks from reservoir bottle, and plastic coolant manifold on drivers side of the engine. Oil drain plug is 10mm threaded into a cast aluminum pan. Take care not to over tighten as you will damage the plug. Lastly, since this is a turbo engine, keep oil full and clean.
Click to expand...
I keep an extra or two oil drain plugs on hand!
 
Visit the forum CRUZETALK.COM, there is a guy on there that has put together (3 versions I think) of a kit called CRUZEFIX. The version I purchased for about $75 replaces the problematic orange diaphragm in the intake with an external check valve and plumbing. Super easy to do and good insurance.
 
379KITTY said:
Visit the forum CRUZETALK.COM, there is a guy on there that has put together (3 versions I think) of a kit called CRUZEFIX. The version I purchased for about $75 replaces the problematic orange diaphragm in the intake with an external check valve and plumbing. Super easy to do and good insurance.
Click to expand...

just got the kit and a new valve cover on order. Looks easy to install, and much easier than replacing the intake manifold. I have high hopes this will solve the issue.
 
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I’ve owned three 1.4L Cruzes. They have lots of issues, but can be DIY repaired for fairly cheap. I never minded the way they drove, and never had to have one towed.

Change the coil pack when you do the plugs. I changed coils on all three cars before 100,000 miles. One a tower broke off, and the others arced through the plastic. I’d probably only use ZZP or OEM.

If you have cooling issues, change the degas bottle,the hose that go from the degas bottle to the water outlet, and the water outlet on the driver’s side of the head. It wouldn’t hurt to change the plastic housing thermostat and the water pump if it’s got over 70,000 miles on the water pump. There’s a bleeder on the passenger top tank of the radiator facing the passenger compartment. Open it cold and fill until coolant runs out.
 
Last edited:
Gus_Mahn said:
I’ve owned three Cruzes. They have lots of issues, but can be DIY repaired for fairly cheap. I never minded the way they drove, and never had to have one towed.

Change the coil pack when you do the plugs. I changed coils on all three cars before 100,000 miles. One a tower broke off, and the others arced through the plastic. I’d probably only use ZZP or OEM.

If you have cooling issues, change the degas bottle,the hose that go from the degas bottle to the water outlet, and the water outlet on the driver’s side of the head. It wouldn’t hurt to change the plastic housing thermostat and the water pump if it’s got over 70,000 miles on the water pump. There’s a bleeder on the passenger top tank of the radiator facing the passenger compartment. Open it cold and fill until coolant runs out.
Click to expand...
Other than things mentioned - I recall the battery cable lost ground to the body - that’s an easy tiny wire brush job …
 
Clean the throttle body as many times the build up of dirt causes a stalling out condition. It can prevent enough bypass air when letting off the gas and stall out.
 
Further investigation from last night...

Plugging the vent of the valve cover does not change the heavy yet stable idle quality.
The long term fuel trim of the second O2 sensor is at 99.8%...is that a problem.
Short term fuel trim of front O2 is again +/-3% so I am assuming it is "normal"
Pulling the big PCV tube off the intake obviously makes the engine stumble...when I put my thumb over it, it returns to the normal "heavy" idle.
Pulling the dip stick makes it stumble
There is no "orange nipple", or anything else down the PCV hole in the intake. I cleaned it out with MAF cleaner and a brass brush. Nothing there. I realize this would only effect the engine when at boost.
The downstream O2 sensor appears to be new...looks super clean, and wire run is not stock

I have ordered a new valve cover, the "fix it kit" for the intake check valve, new plugs, and a new coil pack. I will also re-do the grounding paths block->battery, block->chassis, and chassis->battery

I cleaned the MAF which also looked new.

In the case of random stalling I am down to the engine ECM, and crank angle sensor...

welcome any other thoughts.
 
Marcozi said:
What are you scanning the engine computer with? I recommend the OBDFusion app.

Here are some link about the app, how to set it up and how to use some of the advanced features:

OBD Fusion® - OBD2 Diagnostics for iPhone, iPad, and iPod Touch | OBDSoftware.net

OBD Fusion is the best selling OBD2 diagnostics app for iPhone, iPad, and iPod Touch (iOS). It has a ton of features and now includes support for CarPlay!
www.obdsoftware.net www.obdsoftware.net

www.e46fanatics.com

OBD Fusion

www.e46fanatics.com www.e46fanatics.com
Click to expand...


I have an iCarsoft Pro...why would you suggest I switch?

 
4WD said:
We had a 2013 Cruze for 145k - between 80k - 100k - I’d start changing some plastic - inlet/outlet for coolant - valve cover with PCV - May as well hit the plugs and ignition whilst doing the cover …
Click to expand...
Preventative or more common amongst that certain model? I remember people having issue with intake manifolds and the gaskets during the orange coolant surge era. I think people drained and went back to green coolant and issue went away.
 
Revving2Redline said:
Preventative or more common amongst that certain model? I remember people having issue with intake manifolds and the gaskets during the orange coolant surge era. I think people drained and went back to green coolant and issue went away.
Click to expand...
The hot side outlet to the radiator failed more often - so that one would be preventative - the valve cover is 100k IIRC - and it’s easy to just to plugs and the tiny ignition then (stabs right on to the plugs)
 
Done valve cover replacement, plugs, coils, cleaned MAF, checked air filter, new upstream O2 sensor and the poppet valve fix...still showing catalyst inefficiency code...considering trying downstream O2 spacer.
 
DriveHard said:
Done valve cover replacement, plugs, coils, upstream O2 sensor and the poppet valve fix...still showing catalyst inefficiency code...considering trying downstream O2 spacer.
Click to expand...

"spark plug non-foulers" are a hot seller at the parts store. So, it must work, at least sometimes!
 
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