[Miss AJ]

Hello can anybody point me in the next direction to solve my emissions issue in my petrol 07 2 litre Grand Vitara..
Its had engine flush, fuel flush, oil filter change and oil flush, lamba sensor fitted, o2 sensor checked smallest of the two Cats changed ( new ) not recon.. Its run on high quality fuel for last 6 months Redex applied to.. They say its burning Oil.. exhaust shows black soot.. It does like to drink fuel and is a snail up a hill unless i drop a gear or two.. Ive also noticed it needs to be in 1st or 2nd gear if slow on a roundabout as it struggles to keep power in 3rd... Have enclosed Emission results.. Please help as i love my car as its immaculate inside and out and up until 6 months its run a dream... its got 110,000 miles on the clock...

 

[aquanaut20]

Changing parts without proving them faulty, may induce other parameters than what originally caused the failure.

1. Check the MAF/AIT and ECT after a cold soak, data should be similar, post results..
2. Scan the Fuel trims both short and long term for ~30 sec, at idle and 2000rpm and record in graph format.
3. Record the B!S! for ~30sec at idle and 2000rpm and record in graph mode.

 

[Miss AJ]

Thankyou for replying.. The work was done 10 months ago.. it passed emmissions.. But ive got 8 weeks till MOT runs out this year so got a Emissions test done off line to check and its come back fail.. So all of this cant of failed in a year as only driven less than 3000 miles... Cat 2 was the smallest.. Garage says it could be the big Cat? (1) could the exhaust be a issue??... They say its burning oil.. but then i dont see it using any oil or needing topping up until its changed on its service every 6 months.. Hows oil getting to wears its burning.. i just need to pinpoint the cause.. Then if its repairable i want to keep it... Its mint for its age... 🙂

 

[2013GV]

What did it actually fail on? CO? HC.? And what were the readings?

 

[Chrissybabe88!]

See the second graph on the OP.

 

[2013GV]

Ok, its failed on CO, my bad for not spotting that.

Time to graph fuel trims on all upstream and downstream sensors
Its possibly running rich as lambda is on the slightly wrong side.

Graph at idle warm engine for 40 seconds, then 30 seconds at 2500 rpm.
All S1 sensors should be oscillating between about 0.2 to 0.9V
S2 should be steady around 0.8 V
It passed at idle but not higher up, saying cats are working at idle.
im going to wait on the sensor data before condemning a cat. You would,d have a efficiency code if that was an issue.
Also grab engine temp being reported and maf in g/s at idle and 2500 rpm

 

[shs]

If engine is not fully warm it will run rich and cause this, I made a thread about it some years ago. In my case it was a faulty thermostat. Make sure the temp reaches 90C.

If you don't have a scanner check the temp gauge, it should reach the middle like in the image below. If it does it should be at least close to correct operating temp.

 

[aquanaut20]

This should be verified with a scanner as the dash temp gauge uses a different sensor that the computer ECT..