1992 Ford Taurus Emission Problems

Hi,

Hi Everyone,

I'm hoping that someone in the forum can help me. It looks like a great place to get some answers. Just glad to be here!!!!


I live in Canada, and have a 1992 Ford Taurus 4d car. I'm looking for any help in maybe trying to solve the reason its not passing emissions testing.

The only part that does not pass the emissions test is the NOX?

The limit at a fixed speed of 40km per hour should be .450 and our vehicle is coming in the .825 ?

I have another question that no mechanic will freely answer and that is, if there was a problem with the egr valve or any of its parts, would the "check engine" light come on?

Or do i assume that since we have had not check engine lights come on, that the egr system is working fine?

Any help would be greatly appreciated...


Where running out of time.

Hi,

Hi Everyone,

I'm hoping that someone in the forum can help me. It looks like a great place to get some answers. Just glad to be here!!!!


I live in Canada, and have a 1992 Ford Taurus 4d car. I'm looking for any help in maybe trying to solve the reason its not passing emissions testing.

The only part that does not pass the emissions test is the NOX?

The limit at a fixed speed of 40km per hour should be .450 and our vehicle is coming in the .825 ?

I have another question that no mechanic will freely answer and that is, if there was a problem with the egr valve or any of its parts, would the "check engine" light come on?

Or do i assume that since we have had not check engine lights come on, that the egr system is working fine?

Any help would be greatly appreciated...


Where running out of time.
the most likely cause for high nox emissions in you car is a faulty egr system. such as a a valve stuck in closed position.clogged egr ports. or your egr valve is not getting vacuum therefore not opening.not positive on this but i dont think your vehicle has a dpfe sensor which is the sensor that measures egr flow.i know that the newer cars have them especially all those equipped with obd 2.that would explain why your check engine light does not turn on. because certainly if your vehicle was equipped with a dpfe sensor and you had restricted egr flow then you would indeed have a check engine light on.the second biggest cause for high nox is carbon build up in the combustion chambers.and of course there are many other causes for high nox such as lean conditions,incorrect heat range on your spark plugs,engine overheating,etc.... i believe your car is equipped with a two way catalytic converter and not a 3 way. 2 way converters help to reduce hydro carbons and carbon monoxide while 3 way converters also help to reduce nox.therfore i would count out the catalytic converter as a culprit.hope this helps.

Hi Manuel!

Thanks so much for your reply. Just last night my husband and a friend of his, who is a mechanic took the egr valve off, and did a pressure test to it. You could see the little piston inside moving up and down freely and it would also hold pressure? My husband also blocked the manifold (i think thats what you call it- its the part that the egr is connected to) and then we started the engine, it has soo much vacumm he couldn't remove the piece covering that spot until we turned the engine off!

Many people have said that it is the Catalytic converter, but then others say that the hydro carbons would be high in the emissions test if the cactalytic converter was no good?

We are getting no """Engine""" lights on at all???? Everyone has been guessing but no one has the answer. This car runs awesome, it doesn't misss, or anything, it passed 2 years ago no problem, its just this NOX problem has got us stumbled.

Any other ideas would be greatly appreciated.

Thanks again for replying.

99mallard
the most likely cause for high nox emissions in you car is a faulty egr system. such as a a valve stuck in closed position.clogged egr ports. or your egr valve is not getting vacuum therefore not opening.not positive on this but i dont think your vehicle has a dpfe sensor which is the sensor that measures egr flow.i know that the newer cars have them especially all those equipped with obd 2.that would explain why your check engine light does not turn on. because certainly if your vehicle was equipped with a dpfe sensor and you had restricted egr flow then you would indeed have a check engine light on.the second biggest cause for high nox is carbon build up in the combustion chambers.and of course there are many other causes for high nox such as lean conditions,incorrect heat range on your spark plugs,engine overheating,etc.... i believe your car is equipped with a two way catalytic converter and not a 3 way. 2 way converters help to reduce hydro carbons and carbon monoxide while 3 way converters also help to reduce nox.therfore i would count out the catalytic converter as a culprit.hope this helps.

Hi Manuel!

Thanks so much for your reply. Just last night my husband and a friend of his, who is a mechanic took the egr valve off, and did a pressure test to it. You could see the little piston inside moving up and down freely and it would also hold pressure? My husband also blocked the manifold (i think thats what you call it- its the part that the egr is connected to) and then we started the engine, it has soo much vacumm he couldn't remove the piece covering that spot until we turned the engine off!

Many people have said that it is the Catalytic converter, but then others say that the hydro carbons would be high in the emissions test if the cactalytic converter was no good?

We are getting no """Engine""" lights on at all???? Everyone has been guessing but no one has the answer. This car runs awesome, it doesn't misss, or anything, it passed 2 years ago no problem, its just this NOX problem has got us stumbled.

Any other ideas would be greatly appreciated.

Thanks again for replying.

99mallard
so it sounds to me like your egr valve is in working order and that the egr ports on the manifold are not clogged.one thing you didnt mention is if anyone checked if there was a good source vacuum. i believe it gets vacuum from an egr actuator.trace the green vacuum line thats on the valve to see if it does indeed go into an actuator.this is what provides vacuum to the egr valve under certain conditions.if this part is bad ,and ive seen more than a few of them go bad, then you will not be getting vacuum at the egr valve.can you feel any vacuum at the line going to the egr valve? check it at a high idle like 1200 rpm.ideally it is best to use a vacuum gauge to record vacuum but you might be able to feel suction on your finger.however ideally it is best to check vacuum during a roadtest as i do with a vacuum gauge and long hose attached to the vacuum line because the greatest vacuum will be achieved at a cruise with a light engine load.and it is hard to diagnose a problem by just relaying messages back and forth.if you decide to replace this actuator it is a relatively cheap part.like less than 20 dollars.also about the catalytic converter,my fellow mechanic who specializes in this stuff says that your vehicle should be equipped with a 3 way cat.and that a break down in the reduction catalyst would cause a rise in nox while not affecting "hc" and" co" because those two gases are affected by a different catalyst within the converter.so it is very possible to hav a bad converter as well.also you might want to have your mechanic friend run a can of decarb to clean off carbon in the combustion chamber as in my experience this usually helps to lower nox by a couple hundred parts per million dependin on severity of the carbon build up.hope this helps.

Hi Manuel,

Well it turns out our vehicle is not equipped with the acutator, and ours is a 2 way catalytic converter.

This one has everyone stumped?????

Any other help would be appreciated!!!!!!!!

Thanks so much!!!!!!


99mallard




so it sounds to me like your egr valve is in working order and that the egr ports on the manifold are not clogged.one thing you didnt mention is if anyone checked if there was a good source vacuum. i believe it gets vacuum from an egr actuator.trace the green vacuum line thats on the valve to see if it does indeed go into an actuator.this is what provides vacuum to the egr valve under certain conditions.if this part is bad ,and ive seen more than a few of them go bad, then you will not be getting vacuum at the egr valve.can you feel any vacuum at the line going to the egr valve? check it at a high idle like 1200 rpm.ideally it is best to use a vacuum gauge to record vacuum but you might be able to feel suction on your finger.however ideally it is best to check vacuum during a roadtest as i do with a vacuum gauge and long hose attached to the vacuum line because the greatest vacuum will be achieved at a cruise with a light engine load.and it is hard to diagnose a problem by just relaying messages back and forth.if you decide to replace this actuator it is a relatively cheap part.like less than 20 dollars.also about the catalytic converter,my fellow mechanic who specializes in this stuff says that your vehicle should be equipped with a 3 way cat.and that a break down in the reduction catalyst would cause a rise in nox while not affecting "hc" and" co" because those two gases are affected by a different catalyst within the converter.so it is very possible to hav a bad converter as well.also you might want to have your mechanic friend run a can of decarb to clean off carbon in the combustion chamber as in my experience this usually helps to lower nox by a couple hundred parts per million dependin on severity of the carbon build up.hope this helps.

Hi,

Hi Everyone,

I'm hoping that someone in the forum can help me. It looks like a great place to get some answers. Just glad to be here!!!!


I live in Canada, and have a 1992 Ford Taurus 4d car. I'm looking for any help in maybe trying to solve the reason its not passing emissions testing.

The only part that does not pass the emissions test is the NOX?

The limit at a fixed speed of 40km per hour should be .450 and our vehicle is coming in the .825 ?

I have another question that no mechanic will freely answer and that is, if there was a problem with the egr valve or any of its parts, would the "check engine" light come on?

Or do i assume that since we have had not check engine lights come on, that the egr system is working fine?

Any help would be greatly appreciated...


Where running out of time.

The older diagnostics (pre 1994) most probably could not determine an EGR problem. The newer models (OBD II) include components that check the status of the EGR valve.

If it appears that the valve is functional from your vacuum tests, I agree with the suggestion to check the vacuum line to the valve. From what I know of these guys, the EGR valve is shut (no vacuum) when idling and opens up when the car is at some predetermined RPM. A failure mode is the valve stuck open, and that results in a very rough start from a standstill. If stuck closed you get no perceptible performance problem but will fail the emissions test on a dynamometer.

The older diagnostics (pre 1994) most probably could not determine an EGR problem. The newer models (OBD II) include components that check the status of the EGR valve.

If it appears that the valve is functional from your vacuum tests, I agree with the suggestion to check the vacuum line to the valve. From what I know of these guys, the EGR valve is shut (no vacuum) when idling and opens up when the car is at some predetermined RPM. A failure mode is the valve stuck open, and that results in a very rough start from a standstill. If stuck closed you get no perceptible performance problem but will fail the emissions test on a dynamometer.
Hi,

Thanks,

The egr valve is working perfectly, my husband has removed it and applied vacuum to it and you can see the valve open and close easily and it holds pressure with no problems. This car runs great, it starts perfectly with no hesitation, it hasn't run this good in a long time. Someone, a friend suggested retarding the timming back 4 degrees to make it pass???? Any thoughts on that one???

I know we have to do this with my sisters car every two year, if we don't retard her timming back, it fails, we bring it home and retard it and take it right back and it passes with flying colours.

Some people say this is the only way to get some vehicles to pass?

Thanks for your input.

99mallard

Hi,

Thanks,

The egr valve is working perfectly, my husband has removed it and applied vacuum to it and you can see the valve open and close easily and it holds pressure with no problems. This car runs great, it starts perfectly with no hesitation, it hasn't run this good in a long time. Someone, a friend suggested retarding the timming back 4 degrees to make it pass???? Any thoughts on that one???

I know we have to do this with my sisters car every two year, if we don't retard her timming back, it fails, we bring it home and retard it and take it right back and it passes with flying colours.

Some people say this is the only way to get some vehicles to pass?

Thanks for your input.

99mallard
yes ratarding the timing will reduce nox but if it is retarded too much it will cause a rise in hc as well. also you mentioned that the egr valve is working accordingly however you failed to mention if there is a good vacuum source going to the valve.by vacuum source i mean the vacuum line(i believe its green in color) that should be attached on the top portion of tha valve. also i looked at a wiring schematic from a mitchell service manual for a 1992 taurus 3.0 ohv v6 and it shows an "EGR Solenoid" for this particular engine.so if your vehicle doesnt have one does the vacuum line go directly from the egr valve straight to the intake manifold?well ive done all i could to help you with this problem, if anyone alse has any suggestions please share them.

yes ratarding the timing will reduce nox but if it is retarded too much it will cause a rise in hc as well. also you mentioned that the egr valve is working accordingly however you failed to mention if there is a good vacuum source going to the valve.by vacuum source i mean the vacuum line(i believe its green in color) that should be attached on the top portion of tha valve. also i looked at a wiring schematic from a mitchell service manual for a 1992 taurus 3.0 ohv v6 and it shows an "EGR Solenoid" for this particular engine.so if your vehicle doesnt have one does the vacuum line go directly from the egr valve straight to the intake manifold?well ive done all i could to help you with this problem, if anyone alse has any suggestions please share them.
Hi Manuel!

Thanks so much for your continuing effert to help. No, there is no green vacuum line on this vehicle, its just a regular 3L V6 engine. It does however have the solenoid, and my husband has replaced that just the other day.

Again, thanks for all your input, its much appreciated.

99mallard

Hi Manuel!

Thanks so much for your continuing effert to help. No, there is no green vacuum line on this vehicle, its just a regular 3L V6 engine. It does however have the solenoid, and my husband has replaced that just the other day.

Again, thanks for all your input, its much appreciated.

99mallard
well it might not be green in color but there has to be a vacuum line going to the egr valve otherwise how will it open?if there is no vacuum line attached to the egr valve then it will not open thus not fulfiilling its job of lowering nox.not having a line going to the egr valve might be your problem here.maybe it somehow got disconnected,find it and connect it to the egr valve.so as a final bit of advice, your egr valve needs a vacuum source so it can open properly( unless you have an electronic egr valve, which i seriously doubt a 92 ohv v6 taurus will have) SO FIND THAT VACUUM LINE AND CONNECT IT TO THE EGR VALVE.

well it might not be green in color but there has to be a vacuum line going to the egr valve otherwise how will it open?if there is no vacuum line attached to the egr valve then it will not open thus not fulfiilling its job of lowering nox.not having a line going to the egr valve might be your problem here.maybe it somehow got disconnected,find it and connect it to the egr valve.so as a final bit of advice, your egr valve needs a vacuum source so it can open properly( unless you have an electronic egr valve, which i seriously doubt a 92 ohv v6 taurus will have) SO FIND THAT VACUUM LINE AND CONNECT IT TO THE EGR VALVE.
Yes there is a vacuum line, there has always been a vacuum line but just not green, and yes it is connected and working well.

thanks for all your help.

99mallard

Yes there is a vacuum line, there has always been a vacuum line but just not green, and yes it is connected and working well.

thanks for all your help.

99mallard

Hi All,

Just wanted to let you all know that we finally got the car to pass the e-test.

Thanks for all your help.

Hi All,

Just wanted to let you all know that we finally got the car to pass the e-test.

Thanks for all your help.
good to hear that. was was the actual problem? did the timing do it?

good to hear that. was was the actual problem? did the timing do it?

Yep! retarted the timing 10 deg so that the car ran like crap, and the test came out perfect. It passed with flying colours!!!!!!!!!!!! Doesn't that just make you sick!!!!!!!!!!!!!!!!!!

Every element of the etest was even better then before, even ones that passed before, were almost perfect this time???

go figure!!!!!!!

Thanks for all your help!!!!!!!!!!!

There is an octane adjustment you can do to reduce NOx. Instead of manually retarding timing, you remove the shorting bar and it adjusts things properly for the PCM. It is located under the hood towards the firewall just under the plastic cover on the passenger side near the distributor. It's a wire connector that looks like it has a plug in it. Pull the plug and your done. That should help for a more permanent fix, plus it will run smoother.