I have a 1990 LX I purchased a couple weeks ago. For whatever reason she just cant pass an emission test. The first time it had an exhaust leak, so I went ahead and had the piping redone and changed the exhaust. I also went ahead and changed a ruptured EGR hose. She's still failing emissions tests and the mechanics cant pinpoint what the problem is/are. Another thing also the inspectors said she just barely failed the second inspection. My buddy is thinking that the O2 sensors are faulty or it could be tune up related. cat converters are still in and the previous owner hasn't done any modifications. I would appreciate any advice you guys can give me.
Emission Problems.
- Thread starter jackfrost
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Post the numbers from the test. O2 sensors are a possibility, as is other stuff.
Mine failed too. It had an exhaust leak and too much of one of the three things that test for. I forgot what one. I was not surprised about the exhaust leak as I borrowed a stock h-pipe from a friend. I got under the car and tightened up all the h-pipe bolts. I then retarded my timing. Took it back and it just passed. Ten minutes later, the stock h-pipe was taken back off.
Mine failed too. It had an exhaust leak and too much of one of the three things that test for. I forgot what one. I was not surprised about the exhaust leak as I borrowed a stock h-pipe from a friend. I got under the car and tightened up all the h-pipe bolts. I then retarded my timing. Took it back and it just passed. Ten minutes later, the stock h-pipe was taken back off.
I second that, post the numbers you got for:
HC (hydrocarbons)
CO (carbon monoxide)
CO2(carbon dioxide)
O2 (oxygen)
HC (hydrocarbons)
CO (carbon monoxide)
CO2(carbon dioxide)
O2 (oxygen)
ej95cobra
Member
Post your CO, NO, and HC numbers and the allowed limits. That will give people an idea of what the problem may be. Also, what state are you in, different states have different possible remedies if you can't pass.
How to pass emissions testing:
1.) Make sure all the emissions gear the car was made with is present and connected up properly. That includes a working smog pump and cats.
2.) Make sure that you have fresh tune up with spark plugs, plug wires, cap, rotor, fuel & air filters. An oil & filter change is a good idea while you are at it.
3.) Dump the codes and see what the computer says is wrong…
Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.
See http://www.troublecodes.net/Ford/
OR
See http://www.mustangworks.com/article...c-iv_codes.html
IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.
Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.
Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.
For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Walmart.
Or for a nicer scanner see http://www.midwayautosupply.com/det...iption.asp?3829 – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $33.
4.) Post the codes and get help to fix them. Don’t try to pass with codes not fixed. Clearing the computer just temporarily removes them from memory, it doesn’t fix the problem that caused the code to be set.
5.) Be sure to do the testing on a hot engine. Drive for 15-20 minutes prior to taking the test to get operating temps up into the normal range. Do not shut off the engine while waiting for your turn on the test machine. An engine up to full operating temperature puts out fewer emissions.
1.) Make sure all the emissions gear the car was made with is present and connected up properly. That includes a working smog pump and cats.
2.) Make sure that you have fresh tune up with spark plugs, plug wires, cap, rotor, fuel & air filters. An oil & filter change is a good idea while you are at it.
3.) Dump the codes and see what the computer says is wrong…
Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.
See http://www.troublecodes.net/Ford/
OR
See http://www.mustangworks.com/article...c-iv_codes.html
IF your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.
Codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.
Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.
For those who are intimidated by all the wires & connections, see http://www.actron.com/product_detail.php?pid=16153 for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Walmart.
Or for a nicer scanner see http://www.midwayautosupply.com/det...iption.asp?3829 – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $33.
4.) Post the codes and get help to fix them. Don’t try to pass with codes not fixed. Clearing the computer just temporarily removes them from memory, it doesn’t fix the problem that caused the code to be set.
5.) Be sure to do the testing on a hot engine. Drive for 15-20 minutes prior to taking the test to get operating temps up into the normal range. Do not shut off the engine while waiting for your turn on the test machine. An engine up to full operating temperature puts out fewer emissions.
I apologize for not posting the numbers. The inspections were done in Virginia and here are the latest resuts: At 15 mph HC ppm= 98 limit 55 at 25 mph 168 limit 60 FAIL
At 15 mph CO%=0.34 l limit 0.22 at 25mph 0.54 limit 0.32 FAIL
At 15 mph NO ppm= 414 limit 720 at 25mph 545 limit 700 PASS
Everything else passed and I got no numbers for O2 and CO2. This weekend my buddy and I are going to install a new h-pipe,O2 sensors,and clean or replace heads. I really appreciate all the help.
At 15 mph CO%=0.34 l limit 0.22 at 25mph 0.54 limit 0.32 FAIL
At 15 mph NO ppm= 414 limit 720 at 25mph 545 limit 700 PASS
Everything else passed and I got no numbers for O2 and CO2. This weekend my buddy and I are going to install a new h-pipe,O2 sensors,and clean or replace heads. I really appreciate all the help.
