[milkster]

I recently did a timing chain and balance chain replacement on my 2012 Terrain with 213000+ km. I used the timing chain kit found on rockauto from Cloyes (94201SBWP) which comes with the water pump and balance chain. I got it all replaced and car runs fine, no more chain slapping but the average milage reported on the dash is very high.

Before I did the timing chain, the car was reporting 12.3 L/100km - now after driving the car for about 150km the car is reporting 13.4 L/km (mostly city driving). I thought I would be getting better milage after the change but so far that is not the case.

Will this getter better the more I drive? Have I made a mistake putting things back together? I followed the Mitchell On Demand instructions along with the video from Cloyes.

Any advice on what I should check next?

 

[Colt Hero]

@milkster : might want to plug in an OBD-2 reader to check your Fuel Trim numbers. O2 sensor(s) may need replacement...

 

[milkster]

@milkster : might want to plug in an OBD-2 reader to check your Fuel Trim numbers. O2 sensor(s) may need replacement...

What values should I expect with the trim levels?

Also, both O2 sensors are about 2yrs old. I did plug in a ODB2 reader and I was getting values from both sensors.

I have torque pro so I'll see what else I can monitor with it.

 

[rednox301]

What values should I expect with the trim levels?

Ideally fuel trim numbers should read 0% during closed loop.
Realistically numbers of 10% to 15% plus or minus are common on an older engine with high mileage.

 

[milkster]

I took the car for a 20km round trip and setup some graphs in Torque app. This is what I saw:

The only thing that stands out to me is the short term fuel trim MAX value of +34. Not sure when it hit that value because while driving the values stay around +/- 10%. Is this an indication that I have a vacuum leak?

Would you recommend I monitor some other sensors?

 

[repairman54]

At idle STFT B1S1 should read between plus and minus 3 normally if no vacuum leaks. Driving readings will vary due to throttle inputs. Is sensor B1S1 a GM sensor? Aftermarket sensors are not reliable. Sensors are known to get ''lazy'' and erratic. Lazy may not respond quickly yet set no failure codes.
MAF sensor cleaned lately?

 

[Colt Hero]

@milkster : Does TorquePro allow you to put multiple points on a Trend Display, or is it only one point per trend?

It would be nice to see Short-Term Fuel Trim superimposed with

1.) OPEN/CLOSED Loop status
2.) Engine Load
3.) MAF Sensor
4.) Upstream O2 Voltage (Sensor #1?)
5.) Throttle Position
6.) Air-to-Fuel Ratio (that 14.7 number above)