Attention Auto mechanics, failed smog help!!!

[chomorro]

My friends car wont pass smog and this is the third try after fixing misc things the mechanic has told her.

Her HC is too high. I know thats usually caused by a vacuum leak or bad spark. Im going to take a look at it tomorrow, buy some smog pass stuff at oreillys and run it on the freeway for 15 min at high speed then take it in to a guy who is super fair about smog.

Any other suggestions??

Its a 94 Toyota 4 Runner in very used condition with 180k on the odometer.

OK update, she failed AGAIN. After sea foam and oil change HC's went higher..... What am i missing??

 

[birdman2389]

Add a couple cans of sea-foam to a little amount of gas.. I work at a bike shop and all the old timers say that when their cars did not pass they would do this and then it would pass. Worth a try anyhow!

 

[RJ2112]

It would help, to know what kind of car this is, what year it is, what the mileage is, when the last tune up was done.... hydrocarbons in the exhaust are caused by one of two things. Either the fuel is not being burned up as completely as designed, or there is an oil leak into the combustion chamber(s).

Depending on the year of the car, different standards apply. I'm assuming that the correct limit is applied?

Fuel not being burned completely: Look at the plugs, and the air filter. Look at the vehicle body near the tip of the exhaust pipe. See if there is any soot on the body work.

Oil in the cylinder(s): You may have a clogged PCV valve, or too high an oil level.... it's more likely that either the rings or valves are allowing more oil into the cylinder/combustion chamber than can be burned off. A compression check to verify a good seal on all the cylinders is the best way to determine this. The shop manual (available at any public library) should give you the numbers. A VERY small range is allowed between cylinders. If one is low, that is your culprit.

 

[GTPAddict]

Looks like it's running a little rich. California is a bit crazy with the tail pipe test, aren't they? Those requirement numbers are very low.

Anyway, first thing I would try is an oxygen sensor. The O2 content is zero for the 50/15 test, meaning you either didn't have enough oxygen or you had too much fuel to completely burn all of the HCs. Be warned, leaning out the mixture could result in higher NOx. How old is the cat?

Also, (as asked above) what year/make/model vehicle is this and how many miles are on the car?

 

[ChevyFazer]

Not sure how the law goes where you live but where i live if you keep the documents showing where the work has been done and still failed 3 times the car is now exempt, for that year. If not then i second what gtp said

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[famous556]

Man, I'm glad I live in a state that I don't have to deal with this sort of thing. Good luck with your friends problem OP.

 

[chomorro]

Its an older 97 or 99 toyota 4runner with high mileage. The cat is a year old, not sure when everything else has been changed. I will check for soot etc today when i go check out the car. Sea foam stuff works??

Going to look into CA law about failing and exempt cars. I think its not possible to become exempt unless its a oldddddd car. I do know they offer monetary assistance for people who can afford to pay for a car to pass smog, i will look into that as well.

 

[Motogiro]

Its an older 97 or 99 toyota 4runner with high mileage. The cat is a year old, not sure when everything else has been changed. I will check for soot etc today when i go check out the car. Sea foam stuff works??

Going to look into CA law about failing and exempt cars. I think its not possible to become exempt unless its a oldddddd car. I do know they offer monetary assistance for people who can afford to pay for a car to pass smog, i will look into that as well.

I have a pretty clean 98 4Runner with over 100k on it. California changed the law on CAT replacement because non OEM CATs weren't doing the job. So if the 4Runner's CAT was a non OEM replacement that could be the problem.

Because of the law change and the expense of OEM CATs theft became rampant in California because a new market popped up just for CATs. So think of it this way: You have a 98 4Runner and you go to Toyota for a new one and they say $2500 to replace! I came out to my 4Runner to find the CAT half off the car one morning!

 

[ChevyFazer]

Its an older 97 or 99 toyota 4runner with high mileage. The cat is a year old, not sure when everything else has been changed. I will check for soot etc today when i go check out the car. Sea foam stuff works??

Going to look into CA law about failing and exempt cars. I think its not possible to become exempt unless its a oldddddd car. I do know they offer monetary assistance for people who can afford to pay for a car to pass smog, i will look into that as well.

Being that its in cali they probably dont have the same exemption laws but here it dont matter how old or new the car is if it failed 3 times, and you can prove that it was worked on evey time after failing it is exempt, but you have to show documentation that it has been worked on or the reciepts where you bought the parts to fix it yourself. That way someone cant just take their car that they know wont pass 3 times and be done with it.

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[FinalImpact]

95 and up have OBDII compliant ECM. Get a scanner and look at output out of the more forward sensors before the cat. Is the CEL on?

Leaking injectors could be the culprit as well as a inefficient 3way cat. But you can't jump to clonclusions as the Yodder has direct fire coils or waste direct fire coils, they went through a spell where the coils would go belly up. Car still runs and won't have the CEL on for a while but it runs bad and likely won't pass emissions testing while the energy is jumping over through the body. Even bad plug wires if it has them could cause this.

I glanced through this thread and figured I post a pic of good sensor vs a lazy sensor. Top right vs 2nd down top right. One sensor is changing state at twice the rate of the other but still working OK.

My V6 ended up getting a new coil pack and the sensors were aged so I replaced them. All is well.

http://s67.photobucket.com/albums/h305/73sport/Toyo/?action=view&current=o2logidle.jpg

Do some searching on Toyotanation.com they are a friendly bunch will help you out if search before asking the same question thats already been asked.

 

[Black_Cirrus]

And one more trick I learned is change the oil it will soak up extra HC'c I've seen it in person a few times did a diesel that was 2500 on a 180 limit filters and oil change was in the 50's. Seen it work on gasers to there were closer so emissions in a can and an oil change both passed.

 

[chomorro]

Her car turns out to actually be a 94 4runner with 180k. She had no oil in the thing so i got the oil changed and put in some sea foam in the gas. Hopefully it will still be good for her appointment on tuesday.

 

[Black_Cirrus]

Well no oil is bad :thumbup:, and that makes more since, for WA emissions after 96 all they do is scan it. unless its not communicating or something them I've had then tail pipe it before. and on a 94 you may not get enough data to trouble shoot it via scan tool been awhile since I've messed with a toyota that vintage.

 

[chomorro]

OK update, she failed AGAIN. After sea foam and oil change HC's went higher..... What am i missing??

 

[GTPAddict]

How about the O2 sensors? Hate to sounds like a broken record, but this is the number 1 cause of failed HC emissions.

I'm assuming the vehicle runs good, so I wouldn't think you had a mechanical or ignition problem. Second thing I'd go after is the cat. Where did the new cat come from? I have seen a lot of aftermarket cats that just wound't cut it, been going back to the dealer for a lot of the imports. 1994 is pre-OBDII, so the PCM wouldn't tell you about a bad cat.

 

[dxh24]

You could always move to a free state... :spank: sorry i'll behave...:innocent:
I'd have to agree with O2 sensor... one of our old cars failed once because an O2 was malfunctioning.
In the past we've always kept the stock exhaust so we can toss that back on to pass Db Emissions etc...

+1 on Aftermarket CATs being crap... bought one for an older bike.... was putting out same amount as before the install :Flip:

 

[Marthy]

Air temp sensor failure will make the engine run rich too. That's what those $30.00 black box do. Cheat the voltage on the sensor and dump more gas because the ecu think it's cold outside. Someone told me you can retard or advance the timing too... it help. Or just move in Fl! Good luck...

 

[FinalImpact]

OK update, she failed AGAIN. After sea foam and oil change HC's went higher..... What am i missing??

Like i said, if its missing for any reason at all, it will fail. Have you pulled the plugs or looked at the wires/ignition coil(s). The ECM will allow for some misfire before the Check Engine Light (CEL) comes on. Is it On:?

What engine is it?

 

[FinalImpact]

Hint: the Hi NOx says there's unburned fuel. Pull the plugs and look and or replace them while out. Hi NOx can also be from excessive carbon in the combustion chamber. Is it lugged about? Is it an oil burner? Does it ever get WOT at temperature, under load to clean it out? Does it have a small exhaust leak ahead of the cat?