Passing emissions/smog test -- '92 Corolla DX

[karugs]

Here's a 1992 Corolla DX that failed emissions on its first try, two years after my mom bought it. NO (nitrous oxide) seems to be 1000+ and max is around ~700. CO (carbon monoxide) passed, the only thing is that NO. How do we go about it? Here's the car's current condition:

Smokes blue when driven or at idle, warmed up or cold. I'm told of valve stem seals by a trusted mechanic. Same mechanic mentioned cleaning out EGR valve. I never knew an EGR existed for this car. Any tips on removing this (what to look out for)?

Smog test shop mentioned catalytic converter replacement necessary. Trusted mechanic (mentioned above) said it's only a temporary fix, valve stem seals are the culprit since they burn oil and hence, the blue smoke. True? I think it's going to be like $1-grand to fix them.

We drove it full throttle once or twice, but it still failed. When I follow the car behind, the smell of burning fuel (or oil?) is strong. It's always running on regular (cheapest) fuel. 208,xxx miles.

Thanks. Any help is appreciated!

[Corolla_reps]

just get the catalyctic converter fix for sure u'll pass the emissions....

[cobrajet25]

If the car smokes all of the time when it is running, then chances are it has bad oil control rings. These rings are on the pistons, and when they wear out alot of oil is pumped into the cylinders with the engine running.

If this is the case, it is time for an engine rebuild (or replacement), and changing the valve stems will do nothing to solve the problem. Low-mileage JDM replacement engines can be had for around $300 if you look around. When valve seals wear out, you will get a cloud of smoke at cold start-up, but the engine will not smoke under normal operating conditions. All of that oil in the exhaust can cause catalytic converter problems...the oil tends to gum them up inside. Fortunately, aftermarket cats on these cars are pretty cheap (around $100).

Your car has an EGR system since you live in California. Cars in all of the other 49 states do not have them. Cleaning it out after 200k miles is a good idea. You might also change your O2 sensor if you have not already. This sensor is primarily responsible for your air/fuel mixture, and if you are still running the original then it is time to replace it. These too are not that expensive (@$50). Gotta keep that oil changed every 3-5k to avoid all this stuff...if you let is slide too often even Toyotas will start smoking! Good luck. Regards, Aaron

[karugs]

Corolla_reps & Cobrajet,

Thanks for replying. It seems like my mom will ask for help from the state so it might take a while. I don't know how she'll go about it, but if anything, she mentioned she can't buy a cat from another person because she needs official receipts (like from a store) to deduct costs from when help arrives. Aside from that she'll also ask our mechanic on what action is best to do (change cat, O2 sensor, egr cleaning, etc). I might check if the EGR is gummed up (I'm pretty sure it is) but given alot of tests coming this week I might have to postpone it for a while.

How much do you think it would cost to, if worse comes to worst, swap in a different engine? $300 for engine alone right? Also I'm sensing that you mean the car has alot of blow-by because of the piston rings letting oil through? How do you check? On my diesel the procedure is, you remove the oil cap and if you can collect oil on your hand (just above the cap) or if it shoots oil out then it has major blow by.

Thanks.

[cobrajet25]

Unfortunately, you can't check the 4A-FE for blow-by by removing the oil filler cap while the engine is running. The intake cam drive gear is right under the cap (sort of a design blunder on Toyota's part), and when the engine is running the spinning gear will fling oil all over the place! You might be able to check it by removing the PCV valve hose, which is the big black hose right in the middle of the intake side of the valve cover.

Somewhere around $300 for an engine is about right...maybe a little more or a little less. That is for a JDM crate motor...all of the intake and exhaust components will have to be swapped from your old engine onto the new one. I am not sure if the JDM engines have the provision in the cylinder head for the California-only EGR system or not. I can get a good used engine at the local "pick-your-part" wrecking yard for about $150, so you might consider getting an engine from a salvage yard in your area, too. Since the Cali motors are different, that may be your best bet. I know it sucks to have to change all of this stuff, but the good news is that after it is done the car should be good for another 100k, maybe 150k if it is properly maintained. Good luck and keep us posted. Regards, Aaron

[PPW-546]

if you are running the original 4A-FE motor, what you do is bolt off the exhaust manifold and you should be able to see 4 holes on the block. If they are all dry, then it's not the piston rings. If one or two are wet, then those cylinders have busted rings and those are easy to replace even without yanking out the entire motor.

Check the head too because the valveseats might not be aligned, thus not sealing properly. I just fixed my motor last week because I had the same problem.

Good luck bro.

[89molavi]

How much oil is the car burning anyways? The cat is temp fix because it absorbs the emissions from the oil. Was the car/engine warm enough when they tested the emissions, because a cold catalytic converter would not function properly.

[karugs]

Here is an image of the same engine before anything else, but it's not the actual one. 4AFE?

Aaron, there are two hoses from the valve cover. One ends on a blue thing at the end of the intake manifold, and the other ends at the throttle body/intake tube (it's origin on the valve cover is also angled). Which of these two is the one leading to the PCV valve? I understand the EGR is behind the intake manifold, somewhere between the hoses when you look at it from the front. I'll keep the engine swap in mind. I just received word that mom will leave it at the shop overnight so I'll pick her up later this afternoon.

On second look it seems there is another hose from the valve cover. Starting from left to right, there is one going to the throttle body(1), there is one going to the blue thing behind intake(2), and another going straight backwards to the intake just to the left of the throttle pulley(3).

PPW, dude are you Pinoy? It seems from your license plate you are. Kamusta? Anyway, yeah I think it's the 4AFE motor I have (see image above). By memory it seems the area below the exhaust manifold is kinda dry (and with wet spots) but I'm not sure if the wet spots are from the busted piston rings (I hope not) or from past grease spots that were never cleaned. If the car is just run then you switch it off and you see wet spots, will this be enough to tell it's piston rings? Or will that just mislead me more since it could be from another fluid (like grease on the engine block)?

Molavi, I don't think the car burns any oil. I haven't observed it that keenly yet. Seems to me that it's not but when I last checked, the oil pan seemed to be wet. But not sure if it's from coolant from previous problem we had. Needless to say, I'll go check it again when I can, as we'll leave it in the shop overnight. Yes engine was warmed up since we did some full throttle runs before testing for smog (but it still failed) and gauge was reading normal operating temps (halfway).

One more question: how do I clean the EGR valve? Do I just take it out? Nothing to worry about or expect to run across? Will soap/water do or just blow-dry it? Or just brush the insides? Thanks

Thanks for replying! I'll keep you guys updated.

[foodaa]

How is the cooling system? NOx is created when the engine is running hot. You also get high NOx if the air/fuel mixture is lean.

[karugs]

Foodaa,

We just replaced the radiator and hoses since we had a rather large leak a few weeks ago. So I suspect it's working good. Would this be related to emissions? Just wondering. I don't have the dreaded head gasket leak where coolant mixes with oil, luckily.