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Emissions HELP

12K views 27 replies 12 participants last post by  OhSueCQ 
#1 ·
I have an 85 cutlass supreme. This means I still have to pass the emissions test.

So of course I go to get my car inspected, safety passes fine but I fail emissions.
Does anyone know an easy way to lower the emission the car produces.
I went to a shop and the guy said it could be the timing chain, and that would be pretty expensive to fix.
Does anyone have any other ideas that can help me pass emissions.

Thanks for any input
 
#2 ·
try these 3 things just before you get it tested,
1st always change the oil before you get a car tested, because it will have a certain amount of gas contamination in it and will cause your cars to fail at times.
2nd either change the air filter or take it out (just for the test) that way it sucking in cleaner air.
3rd. this is a cheater but remove the PCV and just lay it on the valve cover BUT still attached to the vacuum line, this also will let your car suck in cleaner air.
i did these thing on my 84 burb because it had failed BADLY, & by doing these thing it passed w/flying colors..........joe
 
#3 ·
Cutsupreme,

As long as you do not have any internal problems like burn valves or bad rings, try pouring in a bottle of "Guaranteed To Pass".
I put it in my 76 Sprint and followed the directions to the letter and I passed with now worries. They say on the bottle that if you do not pass they will pay for your testing. Check it out.
I would not try to cheat the system because if you get caught you may have to go to a "Check Only" station everytime from then on. I don't think it is worth the headache.
Also set the timing to factory specs, even if the car runs like trash. The machines that test go by factory settings so stick to them until you get your OK from the state.

Keep it clean
Scholman
 
#7 ·
A NOX failure is often caused by a faulty EGR (not opening or clogged passage) but because of the opposite reason Jmark gave. NOX failures mean that the combustion temps are too high. This is caused by lean mixtures. You have provided almost no worthwhile info to help you out (base timing, vacuum advance hook-up, etc.) A lot of the routine suggestions may help. Leave your PCV hooked up but pull it out of the valve cover so it's sucking in fresh air. Get your base timing set correctly, as mentioned retarding the timing kills performance but often helps pass emissions testing. If your vacuum advance is connected to manifold vacuum switch it to ported, this will allow your timing to stay at base timing when idling. After making all adjustments last but not least set your idle on the high side, not high enough to fail for excessive rpms but just below the max allowed. As far as properly tuning your carb, that I will not get into over the internet. Another major factor you have not mentioned is whether or not your car is fuel injected or carbed. Either way if it is a computer controlled carb with a M/C solenoid or fuel injected just changing the O2 sensor could get you a passing test.


 
#8 · (Edited)
Actually if you think about it, the EGR's job is to richen the mixture. That's why when it isn't working the engine runs too lean, usually pings, and fails for NOX due to increased cumbustion temps. What's interesting about his failure is that a failed CO could often mean different things in different applications. Any poor combustion could raise CO's (incomplete burn of fuel mixture) but his high NOX also tells a story of a lean mixture causing high combustion temps. Were his readings at idle, at elevated rpms? High combustion temps caused by excessively lean mixtures due to a faulty EGR could also cause poor combustion events causing CO's to increase. There are a lot of variables to this kind of stuff, it's not always as simple as 2+2=4. I agreed with the possibility of a faulty EGR as a possible cause but not because it causes a rich condtion. Rich conditions lower NOX readings.

PS. I don't think anyone said to un-hook vacuum advance, and yes if he is in a state that requires openning the hood like during an IM240 test he must leave pcv in the valve cover.

 
#9 ·
I hate these emissions systems on the newer cars

My newest ride is a 74 Dodge PU truck. I really love NOT having to get tested every other year. Sorry to hear about your problems, don't forget to get the timing chain repair done as soon as possable.



Todd



Rat Rods Rule!
 
#10 ·
Well I guess some of this will forever be interpretational. EGR gasses lower the total volume of combustable gasses in the cylinders. I guess I interpret the fact that these gasses reduce the amount of clean air(combustable oxygen) that can enter the combustion chamber that it is almost the same as richening the combustion mixture since the inert exhaust gasses are lacking in burnable oxygen. That may not be the most acurate analogy. And EGR's are designed to allow an exact amount of flow as well, to much is as bad as too little. I could dump raw fuel down a carb at idle to and it would stall, not because its too lean. I would also like to quote this from a manual..."Carbon monoxide (CO), is incompletely burned fuel or to be more precise are hydrocarbon molecules that split apart but don't burn in the combustion cycle. Hydrocarbons (HC) is simply unburned fuel that escaped the combustion cycle." Sounds like incomplete combustion to me, molecules that are split apart but didn't finish burning. HC is fuel that never even got started. The reality is this guy could pass with just a simple timing adjustment but we can't diagnose that over the internet. But what hasn't been mentioned is that if you look past the EGR as a problem that advanced ignition timing is also a cause for high NOX readings. This guy might just need a timing adjustment or a timing adjustment and a little carb tuning. The possibilities are endless without seeing how the car reacts to any changes. Another funny point is my chart for common emission failures shows a partially restricted exhaust system for both CO and NOX failures. Who knows?



 
#14 ·
was the engine fully warmed up? The catalitic converters efficency is direclty related to the temperature..... A least that what my chemistry teacher tell us. He said his car failed when he just drove it to the shop to have tested. His mechanic told him to drive it for 30 minutes and try it again. sure enough he passed.
 
#15 ·
Sean N said:
was the engine fully warmed up? The catalitic converters efficency is direclty related to the temperature..... A least that what my chemistry teacher tell us. He said his car failed when he just drove it to the shop to have tested. His mechanic told him to drive it for 30 minutes and try it again. sure enough he passed.
There is truth to your post Sean. Some people keep shutting their cars off and restarting them while waiting on line. This forces the computer to keep going from closed loop to open loop operation and doesn't allow the cat. converter to reach optimum temp. for catalist eficiency.


 
#17 ·
I had allot of experience with emissions problems when I had to get my 78 350 powered camaro to pass. It had a 600 CFM Holley with a 204-214 .420 .443 cam and single exhaust with converter still in place.

Usually all it took to pass was leaning out the mixture screws to the point it would ALMOST miss at an idle. Running the highest allowable idle seemed to help too, I always shot for around 850-900. I never had to retard the timing and it did not have egr in place. Always passed and they never did underhood checks, I lived in WPB, FL.

They always gave me some BS reason why it didn't pass if it didn't make the first pass. They once told me I needed new piston wrings or a carb overhaul. I pulled into the parking lot adusted the carb idle mixture a little leaner drove it back through and it passed, they didn't like it but oh well!
 
#18 ·
Hey Jmark are you still checking in? After taking some time to sit back and re-read through the posts (especially your looong one) I have come to the conclusion that I owe you an apology. I will admit I really didn't take the time to thoroughly read through all the posts well enough initially but afterwards took the time to read through again. Aside from cutsupremes troubles after re-reading your posts I started re-thinking my EGR thoughts. I had originally formed the analogy that the EGR in a sense richened the mixture because I knew that the already burnt exhaust gasses lacked combustable oxygen, somewhere along the line someone must have worded it like that and I just never really analized it. After reading through what you wrote I guess you could say that technically the EGR doesn't really richen or lean out the mixture since as it's allowing less fresh air(oxygen) into the combustion chamber it is also allowing less fuel at the same time. The carb is still going to mix whatever ratio of fuel to air it is designed to do but the EGR just allows less of that mixture into the cylinders. Then I'm also thinking maybe at idle when we manually crank open the EGR we maybe aren't technically leaning her out as much as we are just totally depleating the cylinders of combustable gasses. What do you think???? I respect what you have to say or I would not have even wasted my time thinking this over and posting this reply. Maybe I should have read a little more thoroughly and typed a little less the other night but here we are and what's done is done. Hope you can accept this apology, Don.

 
#19 ·
Failed emissions test

I have a 94 Chrysler LHS and live in Ohio. I failed the Emissions test today on HC 200.5 (Limit 114.0) and CO 6.78 (Limit 0.63). Any suggestions as to what can be wrong? I just noticed today that my car seems to be using a lot of gas. It runs great, but has a little shakiness at idle sometimes.

Sue
 
#20 ·
Lot of things could be wrong here Sue. Dont know if your car is OBDI or OBD II. Should be stated on the emission decal under the hood. Possible O2 sensor, high fuel pressure, MAP or MAF, ect. It can get expensive guessing at parts. Have the codes read and go from there........... I dont think its the EGR!
If this car has run with these kind of readings (rich) very long it could have damaged your cat.
BTW Don and Jmark - good discussion! I did smog check for 20 yrs here in Cal and I still dont completely understand all the ramifications and interactions of emission controls and testing. I smogged my Maxima today and the HC limit was 112 and I passed with 112.
 
#21 ·
cutsupreme said:
I have an 85 cutlass supreme. This means I still have to pass the emissions test.

So of course I go to get my car inspected, safety passes fine but I fail emissions.
Does anyone know an easy way to lower the emission the car produces.
I went to a shop and the guy said it could be the timing chain, and that would be pretty expensive to fix.
Does anyone have any other ideas that can help me pass emissions.

Thanks for any input
Get an oil change, use some G2P formula or other de-carbonizer. Before you take it in for emissions drive the car for about half an hour. Also set the carb to run lean before they hook it up to the machine. Always works.
 
#22 ·
Map Sensor?

Thanx for your quick reply! The car as I said, runs great. I just got the E check yesterday and just noticed it was using a lot of gas a little bit later the same day (I know I wasn't having this gas useage problem prior to the E check). I've replaced 2 map sensors, one of them was replaced Aug 2001 and the other one July 2002 (it was under warranty). The only other problem I've ever had with this car is my check engine light has come on twice in the last 3 months. As soon as I shut the car off and restarted it, it stayed off and as I've said, there have been no other problems with the car, it runs like a dream. Come to think of it, the last time the map sensor went out - prior to that my check engine light came on a few times but went right back out and I didn't notice anything wrong with it until a month or so later when it was running really rough.

It had a full tune up and the works last October (2002), spark plug wires, the works. I've probably only put maybe 5000 miles on this car in the last year. I've changed the oil regularly but guess it's time for that again. And I'll have my mechanic replace the air cleaner when he does that (I replaced it last October too).

So could the map sensor alone be responsible for the failed HC and CO readings? The last time the map sensor went out, I thought something was wrong with my transmission because the car would barely go into reverse when I tried to back it out and it was running rough, I could barely get it to my mechanic. He serviced the transmission and as I said found that second bad map sensor. The time before when my map sensor went out the car wouldn't start at all. I'm wondering if the map sensor slowly goes bad and that's why the check engine light comes on sporadically but the car still runs? I do have a mechanic and thankfully he's the only mechanic that's ever worked on this car, he's going to check it out after the first of the year (I have until Feb 16 to pass the E check).

Again, thanx for your help, this is a great Forum.

Sue
 
#24 · (Edited)
Hi Sue, your car should be OBDI. Like 2-manytoyzs said it could be many things. Any sensor out of range could fool the computer into delivering the wrong amount of fuel. If the 'check engine' light came on there should be a code stored even after it shuts itself back off. As mentioned by 87442lover, a O2 sensor is a good guess (but still just a guess!). If she has high mileage the sensor could be what we call 'lazy' meaning she's cycling too slow. If your mechanic has a decent scanner he should be able to verify the sensors cycle rate. I would start with getting codes pulled and then look into your O2 sensor. Both good suggestions by the other members. The code check is important because even a bad coolant temp sensor could 'fool' the computer into thinking the engine is cold all the time and cause her to run rich.


 
#25 ·
DMorris is right, Sue, your car is OBD-I. The O2 sensors are a very good guess. They get into a vicious cycle where they get lazy, the injectors run rich, the rich mixture makes them even lazier, and so on. I believe your model only has 1 sensor, its down by the collector. I don't believe they started putting one after the cat until a couple of years later, but you might check as they would both likely be cooked.

Good luck and Merry Xmas!

Bluesman
 
#26 ·
02 Sensor & E Check

I'm back. I did the check engine light flash sequence where you insert the key without starting the car and turn it on, off, on, off, on, and count the flashes. It gave me a code 51, which according to the computer code list I found on the internet for my car (94 Chrysler LHS) means that the oxygen sensor is stuck at lean position. I realize that if I've driven it this way for a while, it could have damaged the catalytic converter. But wouldn't I have noticed something if it's been this way for a while? And why does it always give you the # 12 code first (Memory Standby Power Loss - battery cable disconnected)? Is it because I initiated it by doing this procedure and that's the code you should get first? I checked it a few times and each time I had 1 flash, pause, 2 flashes, pause, 5 flashes, pause, 1 flash pause, 5 flashes, pause, 5 flashes pause.

I'm still taking my car to my mechanic, hopefully this week if he can work it in, but I'm trying to get a handle on repair costs, especially since I just finished with all the Christmas expense. How accurate is the key code procedure? How expensive are catalytic converters? Lastly, could some other malfunctioning part be causing this? Where is the 02 sensor located, is it easy to get to as in, can my hubby replace this part or are we better off just taking it in and hoping it doesn't lead into a lot of parts having to be replaced? I know that when the map sensor went out it was right on top, easy to get to and looked like I could even change that part myself.

Thanx for all of your input.

Sue
 
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