Failed AirCare

[Tony Leong]

I’m wondering if I could have attained “better” scores if I drove the Talon a little longer and not had 0.5 litre of Methyl Hydrate in the tank before going for AirCare testing.  In the past, I have always finished a long drive before AirCare.

I searched for “fail aircare” and found a lot of useful advice.  Always seeking a second opinion and just to be sure, I took the Talon to an AirCare Repair Centre.  Sure enough, the Repair Centre came up with the same recommendation … replace the catalytic convertor.  No misfire was detected either.  So thank you BC DSM, search works!

The Talon had the following readings:

Hydrocarbons 0.7415 - FAIL, need less than 0.5000 to pass
Carbon Monoxide 4.5530 - PASS, need less than 9.3200 to pass
Oxides of Nitrogen 1.8781 - FAIL, need less than 1.2400 to pass

Before the AirCare inspection, the Talon had been driven under 20 minutes at city speeds.  From what I’ve gleaned from the BC DSM search, this might not have been long enough to get the high-flow cat to operating temperature.  Also, the half a litre of Methyl Hydrate (I always fill up with Chevron 94, but wanted to clear out Winter’s condensation) may not have helped.

Other details:

141,200 kms, stock except for …
2.5” stainless steel downpipe to Buscher Racing no-name high-flow cat (installed 2008)
3” s/steel cat back with one s/steel Vibrant resonator and s/steel, Vibrant dual-tipped 3” muffler
163/161/164/168 psi cylinder compression ; leak down at 10-15% (“very good” last July)
BPR6ES – new, gapped at 0.028”and put in last May, less than 10,000 kms ago
New K&N filter was installed in January/February 2011
Valve timing should be good – T-Belt done November 2010
EGR – if the AirCare Repair Centre checked, then they did not write it down anywhere

So, do you think I could have bettered my HC and NOx readings with a longer drive and not putting Methyl in the tank? 

Thanks.

[Brett Haviland]

i think a good highway (spirited) and then a quick pull in to a aircare center could definalty get you a lot closer to passing...

From looking at the test results tho, and if the engine is not misfiring and the o2 sensor is working properly i would definalty put a new cat in it..    if the o2 sensor is cycling good... and the cat is doing its job with no misfires im sure it will pass no problem.

[John Hartman]

+1.

Tho, the HC readings are high.  Usually a good car will be closer to .25 or so, maybe even lower.

Maybe have your injectors professionally cleaned?  Valley Fuel injection does it out here, but I am sure there is a closer place for you.

They will test them, sonically clean them, test them again and compare results.  They will put in new strainers, new tip covers(I forget the name for those) and new o-rings too.


A new cat will most likely take care of it tho, but I suspect something else not quite right with that much HC.

Is your ignition timing set correctly?  Or does your year even have a way to set it?

The other thing that will cause both high HC and high NOx is carbon build up in the cylinders.  The carbon will soak up fuel and release it on the exhaust stroke, and of course that is unburned hydrocarbons.  As well, it can raise the compression, causing more NOx.

[Brett Haviland]

There is no way to adjust ign timing on a 95....  so it cant be that unless the valve timing is out a tooth... and if it idles good and has good power i would not suspect that. 

Maybe check your plugs as just a quick check... with only 10 000 km's im sure they are fine... but cant hurt to check.


but yeah its your choice... Drive the $&*# out of it  and try and take it through again.. see if that helps...  OR get a new cat in there and take it through again...

The first choice might be cheaper if it does indeed pass.... and if it doesn't then ur only out $23 or whatever for a retest.. and then u can go get a new cat put in.

[Tony Leong]

Thanks for your suggestions Brett & John.  Much appreciated. 

Every now & then, when a I start the car with a warm engine, the idle speed is very low, about two dashes above the 0 RPM (guessing 400 RPM).  The engine seems to hunt around trying to get up to normal idle (750/800 RPM), but does not stall. 

Also, I have noticed that I have a linear acceleration.  Before, I used to get the <2,000 RPM kick, which then ran out before 4,500 RPMs, then a second wind would start around 5,500 RPM.  Now it pulls nicely from 2,000 RPM and drops off at 4,500 RPMs.  No second wind.

I'll look further into the injectors, timing belt and EGR if the Talon should fail a second time.

I've ordered a new cat and a set of plugs.  I'll probably drive out to Abbotsford to get the whole exhaust system up to operating temps (and clear out some carbon deposits) before getting AirCare'd a second time.  Sure helps that I can renew my insurance for another 90 days.

I'll post my results after the second AirCare test.

Thanks again Guys.

[Jordan Kruger]

Dont know if you have a logger, but check the position of your TPS.   should be at 10% closed.

[John Hartman]

also check the coolant temp sensor if you have a logger/scantool.

Check for restrictions on the intake side and exhaust system.

Also for shits and giggles, pull your upper timing cover off and have a look to see if anything has jumped in there.  If its off a tooth, it can exhibit those symptoms.

I know it ran and pulled fine when I was done with it, but parts fail and people make mistakes.  Better to get it now than when something really slips or fails.

[Tony Leong]

Jordan, no logger, so skipped while Aircare troubleshooting.

John, will get the T-belt inspected later.

[Tony Leong]

Result:  AirCare PASS.

Replaced the cat with a high-flow unit.  Also, replaced the NGK BPR7ES's even though the old ones had 8,300 kms on them (and all electrodes were tan/ash in colour from in-city, stop/go driving.  A 0.034" wire gauge would not slip past the gap, but a 0.030" would - no, I don't have wire gauges between the two ranges).  Also ran the Talon up to Squamish to get that new cat hot.

The Talon had the following readings:

Hydrocarbons 0.2467 - PASS.  Previous was 0.7415 - FAIL, need less than 0.5000 to pass
Carbon Monoxide 0.9728 - PASS.  Previous was 4.5530 - PASS, need less than 9.3200 to pass
Oxides of Nitrogen 0.2840 - PASS.  Previous was 1.8781 - FAIL, need less than 1.2400 to pass

This was the first time since AirCare was introduced that the Talon failed AirCare.  To summarize my steps before getting the next AirCare experience:

                             Install a new cat + Chevron 94 - Methyl Hydrate + drive to Squamish + new set of plugs

Thanks for the tips Everyone!

[Ryan Singh]

Congrats buddy!
I'm curious as to how much meth you used for a full tank of Chevron 94?

[John Hartman]

continuing on that point, alcohol fuels can cause more NOx, especially when lean, so don't go to far on adding methanol/ethanol.

Tony, your plugs were probably ok, unless you are actually getting a misfire, plugs GENERALLY don't cause a failure.   They can cause higher boost issues, but not generally an aircare failure.

[Tony Leong]

Ryan, I bought a litre bottle of Methyl Hydrate.  I put in half a bottle, then topped up with C94 (the Talon's usual diet).  When the tank hit half full, I emptied the rest of the Meth bottle into the tank and filled up with C94.  A couple of hundred kilometers later, I then did about 20 minutes driving from a cold start, took the AirCare test and failed.  For the second AirCare test, I had filled up several times without any Meth.

John, I thought the plugs were okay too.  Since I had an extra four pack, I swapped them out anyways as the old ones were just over a year old.

Everyone, I had a typo in my first post.  I had BPR7ES plugs in there before AirCare, not BPR6ES.

[Brett Haviland]

yeah i noticed that my 4g63's run a bit smoother with the BRP6ES then with the BRP7ES installed...

mostly at idle and on decelleration i notice it.  under full power there is no difference really... but im sure the 1 heat range colder helps at higher boost levels