Emissions testing... I hate it..

[arnauts]

Howdy,
I'm having a little problem with my Fleetwood again, seems my insuance runs out on the 7th, and I don't have the nessesary emmisions testing to reinsure it. (I was running on one time only 3 month insurance before)

The car runs rich, which I've always known by the way the catalytic converter gets red hot (litteraly red hot) after several hours of idling. The cat smokes, and the car gets about 12 MPG, based on a conservatively, and cautiously driven tank. I passed all but one of their insane requirements, which failed terribly. I passed the hydrocarbons nicely, and passed the carbon monoxide nicely, on both the driving and idling tests, the only thing that got me was the oxides of nitrogen (N0x) which hit 2772.0, while the allowable maximum is 1700.

So, I will adjust the idle mixture on the carburator, which is (hopefully) responsible for the the red hot cat, and excessive N0x. Where are these idle screws located on the carb? Also, what kind of role does the catcon have in
N0x emissions?

What do you think?
Thank ya'll kindly.

[lochenjons]

well i dont know about a cadillac carb but im guessing its the same as a chevy. on the left side of the carb, there should be a small screw that when you turn it while the engine is on, the idle will change (duh). i don't know if adjusting the idle is going to fix anything though... i would change spark plugs, map sensor, o2 sensor, and go down to autozone or kragens and buy some of that "guaranteed to pass" smog stuff (ask they'll know what your talking about). recently just had the same problem on my '87 suburban and it passed after switching out parts and minor tweaking. hope this helps

[Old Fleetwood]

I wish you luck with your inspections. That will be one of the hassles with me getting Benzilla's Gorgeous, White Coupe.
Connecticut has a really sticky emissions program which has been scandal-ridden. In fact, at the moment, the Connecticut State Police are BEING INVESTIGATED BY THE NEW YORK STATE POLICE FOR CORRUPTION.
So I'm paranoid as all get out.
I ran into this when I got my cousin's Dodge Wagon from New York some years ago. It had one bulb out in a side marker and the old fart doing the safety inspection gave me a real hassle until a younger guy saw what was happening and took over.
It was actually comical and was a rare time that some justice was done.
But in the past, I "modified" an AMC straight six and dynoed an additional 30 hp and it sailed thru emissions.
Yet I'm sure it was dirty as hell.

[The Ape Man]

I dunno if your test is done at idle or if it is a simulated road test. If it is the latter then take a good look at the EGR valve and it's vacuum circuit. A good trans fluid or seafoam cleaning followed by some spirited driving can't hurt either.

[Gwokable]

NOx means the heat inside of your cylinders is getting far too hot, allowing the nitrogens in the air to oxadize. This kills your mileage since it increases the speed atwhich the reaction occures; this means more pressure while the piston arm is at a higher degree angle relative to the crankshaft. That means knocking and weird shit; very bad for the engine.

What you need to do is make sure your EGR (Exhaust Gas Recirculation) valve is hooked up properly and that it works. EGR sucks exhaust fumes from the exhaust pipes and circulates it into the cylanders; this slows down the reaction and causes it to happen slower, boosting mileage and engine life at the cost of some low and midrange speed.

Detach the EGR valve vacuum hose and start up the car, then put it in drive, nuetral, or reverse with the parking break on. This will disengauge the solenoid holding vacuum from getting to the EGR valve. Then check for vacuum on the valve. If there is none, then start from the carb and work your way through vacuum lines and the solenoid.

To test the EGR valve itself, you find it and push in on the diaphram (it's underneath) and hold your finger over the vacuum intake line and see if you can create suction when you stop depressing it. Any loss of air means a bad valve, and if the valve doesn't depress easily then it may also be bad. To check the passageways inside of the engine, put it in park and depress the EGR valve manually; if the car idles very roughly or shuts off, then you know the internal passages are in good shape; if it doesn't, then you need to pull the carb, get yourself some piano wire or guitar wire and a can of air, and a drill. Attach the piano wire to the drill, insert it down and start drilling the passageways clean. Then use the can of air to blow em' fully out then run the car.

More than likely, fixing the NOx issue will cause an issue with CO but that's still to be seen.

[The Ape Man]

Originally Posted by Gwokable

NOx means the heat inside of your cylinders is getting far too hot, allowing the nitrogens in the air to oxadize. This kills your mileage since it increases the speed atwhich the reaction occures; this means more pressure while the piston arm is at a higher degree angle relative to the crankshaft. That means knocking and weird shit; very bad for the engine.

What you need to do is make sure your EGR (Exhaust Gas Recirculation) valve is hooked up properly and that it works. EGR sucks exhaust fumes from the exhaust pipes and circulates it into the cylanders; this slows down the reaction and causes it to happen slower, boosting mileage and engine life at the cost of some low and midrange speed.

Detach the EGR valve vacuum hose and start up the car, then put it in drive, nuetral, or reverse with the parking break on. This will disengauge the solenoid holding vacuum from getting to the EGR valve. Then check for vacuum on the valve. If there is none, then start from the carb and work your way through vacuum lines and the solenoid.

To test the EGR valve itself, you find it and push in on the diaphram (it's underneath) and hold your finger over the vacuum intake line and see if you can create suction when you stop depressing it. Any loss of air means a bad valve, and if the valve doesn't depress easily then it may also be bad. To check the passageways inside of the engine, put it in park and depress the EGR valve manually; if the car idles very roughly or shuts off, then you know the internal passages are in good shape; if it doesn't, then you need to pull the carb, get yourself some piano wire or guitar wire and a can of air, and a drill. Attach the piano wire to the drill, insert it down and start drilling the passageways clean. Then use the can of air to blow em' fully out then run the car.

More than likely, fixing the NOx issue will cause an issue with CO but that's still to be seen.

Good information but the vacuum part doesn't apply to this vehicle. EGR gets ported vacuum through a temperature switch on '80 368. Don't bother putting the car in gear. Check to see if diaphragm on EGR opens up when you crack the throttle on a warm engine. Careful not to burn yourself if you check the EGR with a finger.

[ewill3rd]

You need to go to square one with this car.
I'd recommend fixing it rather than "getting it to pass".
If you have a glow in the dark catalyst then something is majorly wrong and turning some screws on the carb is not going to fix it.
In fact it will likely make it worse.

NOx doesn't have much to do with fuel mixture anyway, it has to do with combustion temperature heat. The fact that your cat is glowing could be the problem or an indicator thereof.
Nitrogen is inert but if you get it hot enough it will react and combine with the oxygen left in the exhaust stream forming NOx, that is why you are failing.
The EGR system is the best place to start, don't touch the carb or you will end up failing on everything instead of just NOx.

Is this a two speed idle test or a loaded dyno test?

[arnauts]

The test is composed of a driving test on a dyno, at which it's simulated at 40 km/h for a period of about a minute, then idled for about the same time. When I inspected the EGR system today, I found a ball berring shoved in the vacuum line, and removed it. There is vacuum on the end of the line. I took it through aircare and failed, producing 2300 oxides of nitrogen, which is an improvement from 2700. (The limit is 1700) This was running the guaranteed pass formula, and after some spirited driving on the highway.

So, if the tempreture inside the cylinders is getting too hot, would retarding the timing rediculously, so there are less reactions per given time help the readings? Also, if I enrich the fuel mixture, would the excess fuel entering the cylinders help to cool them down?

I hate to beat around the bush and go for a quick fix, but I'm out of a daily driver right now and need something to get me around.
Thank you again

[ewill3rd]

The quickest and cheapest fix would be to pinpoint the EGR problem and get it fixed.
Usually when the EGR system is working right NOx goes away immediately.

It sounds like you should pull the EGR valve off, check the passages in the intake to be sure they are not carboned shut and maybe even replace the EGR valve itself.
Be sure to look at the old one, there should be an 8 digit number on it and a P or N to indicate if it is positive or negative backpressure.
The parts guy will need that to get you the right valve.
Aftermarket valves have kits in them to help you install it properly so don't lose the old valve.

Make sure the vacuum lines are all connected properly and then you should be able to retest it.
Changing the timing and changing the fuel mixture is just going to cause HC and CO problems, and I doubt it will help the NOx much.

Good luck.

[arnauts]

Well folks, I'm happy to say that I've passed emissions testing.. with outstanding excellence thanks to your help. Only 190 oxides of nitrogen! All thanks to a new EGR valve, which cost me $97 (Lordco quoted me $135)
Also, no more glow in the dark catcon. The EGR valve on there wasn't stock, so I'm assuming that it's been replaced before. I gave the intake manifold one hell of a spraying with intake medic, so hopefully it got rid of all those nasty carbon buildups.
Anyway, I'm ridiculously happy now..
Thanks again~

[ewill3rd]

Glad to hear you got it fixed!
It is amazing what that little valve can do when you can actually see the results.
I am very relieved that you didn't fiddle with the carb. Your car will love you for it.