Failed Smog Test

[thomcycle]

Today I had to get my safety and smog check done on my 94Q. It passed safety but failed HC & NOx hi/lo. It was 30-40% above required levels. Since I haven't seen any of the warnings on the dash I'm wondering what might be causing this; EGR system, cat, etc.? The car runs smooth and has had good acceleration with no signs of smoke. I'll be doing some research today but thought some of you experts might point me toward some of the more likely causes.

Thanks :help

[BadQ45t]

It could and probably is one of those any things you just described. I don't know what state you're in, but what I've done in the past when I have not passed smog is give it to my trusted mechanic and said "make it pass" and than had him figure out what was failing. He has the smog test equipment, albeit not hooked up to the state since he gave up on the tests years ago, but uses it to test cheap repairs or adjustments first before he starts to replace EGR values, O2 sensors, cat converters etc. If you don't have a good mechanic along with the smog equipment it becomes a crap shoot and you start replacing stuff you may not really need to....or maybe you do but you at least know you had to do it.

What state you in?

[Stoneage_Turbo]

HC & NOx hi/lo. It was 30-40% above required levels

i was told when my 86 lebaron would fail that high HC levels inicated unburnt fuel , coarse it had a blown headgasket , was 8 degrees out of time and pumped oil like it was a produceing memeber of OPEC

[thomcycle]

I'm in Texas (Dallas - Ft Worth area) which "just" started doing the smog inspection in May. I though the first thing I would do is to take the Q into the Infiniti dealer and have them run diagnostics to help narrow down the alternatives. I'm willing to do the work myself but the state only allows 15 days prior to a retest so I do not have a lot of time.

Thanks,

[BadQ45t]

Maybe someone could suggest a good aftermarket mechanic in your area. The dealerships are okay but you're going to pay all the way for anything they do. My private mechanic has the non-offical smog station so he can keep running my car over and over again. They will probably charge you a full fee every time you run the thing through, could get expensive.

than again, if they seem cool and maybe the computer they own can help narrow down the problem quickly, it might work.

[PalmerWMD]

Q45's are very clean running cars when running properly.

Look at this failed smog test as a low lowel diagnostic for your engine .Unless your cats have been poisoned by say a previous owner running avgas, its almost certainly a sensor or another that your dealer should easily find.

Keep us posted.

Fred...

[thomcycle]

Update: I took my Q to the dealer in Dallas (Sewell) and their first recommendaton after the diagnostics was to replace the plugs and do a fuel system flush. Based on the records I have for the car it has been 60+K since the last tune-up. It has 113K and I bought it at 103K. The injectors and fuel pump have been replaced in the last 40K. The only thing I have done so far has been to replace the air and fuel filters, changed oil/filter twice, and drain and fill the transmission.

BTW, since the 120K service calls for what they recommend and includes several more service items- I opted to do that ($600).

[Q45tech]

During the 120k they'll clean the big lump of carbon/oil crud blocking the EGR from getting into the plenum! [high NOX]......the cats have nothing to do with NOX.

$600 is pretty low for a real Full 120k they won't be spending much more than 4 hours at most........make sure they change your differential fluid [extra $50] and flush the coolant not just a 4 quart rad drain [extra $$$] same with brake, ps. TCS not just a suck out and refill the res.

Time to think about vacuuming down the AC and replacing the dryer to prolong system life [check for minor leaks [o rings, etc].

What you do at 120k means lots of savings later on!!!!!!!!!!!!!!!!

Injectors replaced at 60k [all? underwarranty?] what kind of horrible gas got in there? Are you changing your fuel filter annually? I would start! Fuel pump at 104K? too soon...hopefully someone looked in the bottom of tank with a flashlight? Too much to ask I guess.

[thomcycle]

Since all I can go by is the Infiniti service record printout, all the injectors were replaced. Why I don't know? When I talked to the service rep he said the 120K service would only be $100 > than what the minimum they would have done to get it back into smog spec. He mentioned oil/filter change, radiator flush, air/fuel filter, belts, in addition to the new plugs and fuel system flush. I'm picking up the car tomorrow and so I'll find out what else was included in the 120K service.

Next DIY is shocks all the way around and possibly the brakes.

[Q45tech]

You have to read the fine print and ask questions about EXACT proceedures!To almost all dealers a "fuel injection service" means pouring a can of BG44k in the gas tank.Same with radiator or coolant service--- let 3-4 quarts - [30-40%]drain out and refill. Same with transmission service.Same with brake fluid or PS just suck out -- what is easy.

These half assed proceedures make the client feel good, are inexpensive, and do prolong the system life just enough to get the systems near 100k on a lux car with good designs. Less on a typical car with a 3/36k warranty

Full Total Fluid exchanges and any system filters cost more but do more especially when begun early. Like at 5k or 10k.

The problem is most new car buyers sell their cars around 60k and leasees, want to minimize their maintenance cost.A dealership is just not set up [mentally] to deal with an owner who might want to buy a new car and keep it for 200--300,000 miles.

The major 30k and 60k services are money makers because the techs buy tools and develop short cuts to speed their time and it is repeative as every car gets it......thus they might make an extra $20 or $40 or $60 compared to parts replacement work which may be squuezed as to the allocated time.

Getting to know and using the same tech [you can demand so and so only work on your car]. Explain what you want extra and discuss with the tech and service writer how to get it . Economically!An extra hour cost the tech $25-$30 it cost you $75-$85-$100.

Remember all shops [management] expects to gross $150 [parts and labor] or more per real hour expended. They [dealers] have a 50-100% margin on parts so even though a 60k service has few parts [plugs, filters, fluids......maybe $75-$85 at cost including all the spray lubes and brake/throttle cleaners BG, etc]........

If the tech takes longer than the book time it is on HIS NICKEL as flat rate pay is the norm.....every extra hour costs him $20.

Hopefully I am getting thru......you must figure a way to supplement the tech not necessarily the management.

[thomcycle]

Yup.....ditto.......ditto

Pretty much like you said......replace stuff.......said they flushed the cooling system. Inspected brakes, suspension, fuel lines etc..

No indication of pending problems like 60-70 worn pads/disks, shocks not effective, etc. Other than oil and coolant, no flushes brake, steering, differential, or refrigerant fluids/gases.

Had to talk them back down to $600 from the $900 they had listed with the cashier!

Back to DIY.

[BadQ45t]

For my buck, avoiding the dealership and finding someone that cares is the answer. T3 for those folks in the ATL is great, but for us west coasters, a 6,000 roudtrip is kinda a long way to go for a tune-up. I just don't have the time or skill to be a DIY so I find good mechanics that CARE about my car and take pride in how my car runs. I live in the Bay area but take my 300ZX back to LA to have my trusted mechanic work on it. I found a place in Ventura that really cares about my Q so I drive it down there for services, using my warrenty up north if something goes wrong (so far at 67k my 97' is bullet proof).

I always start off with a local mechanic with some smaller jobs and then get bigger and bigger once I trust them with my car and my money.

[DAEDALUS]

I have yet to find a good mechanic in the LA area. Please give us SoCal people info on this outfit! Jerry Tucker is a lot closer that T3, but still too far for me.