Emissions failure - Help Diagnosing
Cargo Master
Joined: Mar 2005
Posts: 2,790
Likes: 24
From: Mount Royal, NJ
So I hooked the live data scanner up and took it on a drive. Even under hard accel up a hill, I couldn't get fuel trim to 20%. Under idle and cruise, it was in the single digits or less.
One quick question: RockAuto lists a downstream (After the Catalytic Converter) O2 sensor. There are only two O2 sensors that I can find on my truck and they're up by the engine.
Did someone remove my downstream O2 sensor?
I should have registered this as a Diesel.
Currently only 1997 and later vehicles with a GVWR of 8500 lbs <acronym title="Page Ranking"><acronym title="Page Ranking">PR</acronym></acronym> less are emissions inspected.
Oh well, it'll get swapped over when I complete the drive train swap.
One quick question: RockAuto lists a downstream (After the Catalytic Converter) O2 sensor. There are only two O2 sensors that I can find on my truck and they're up by the engine.
Did someone remove my downstream O2 sensor?
I should have registered this as a Diesel.
Currently only 1997 and later vehicles with a GVWR of 8500 lbs <acronym title="Page Ranking"><acronym title="Page Ranking">PR</acronym></acronym> less are emissions inspected.
Oh well, it'll get swapped over when I complete the drive train swap.
You will only have a downstream sensor if your vehicle was CARB (California emissions) compliant. I posted the following on another thread:
The front and rear O2 sensor voltages should be bouncing back and forth somewhere between 0 and 1 volt. The rate that they switch should be faster on the front ones compared to the rear (after cat) sensors. That is, if you have rear ones. Most gas Excursions do not have rear O2 sensors.
Oil vapors are sucked up by the PVC and burned in the cylinders. As part of the process, Phosphorus and other junk is released that end up coating and plating the O2 sensors and the Cat plates. This makes the sensors go bad and the converter to stop doing it's job. The Sensors are more susceptible to this, so they go bad much sooner. The voltage range that they switch back and forth as they read the O2 levels gets smaller and smaller until they are pretty much stuck at a constant voltage.
Too rich of a mixture can cause the cat to overheat and melt. This can happen from a bad TPS sensor, bad front O2 sensors, misfires, or a bad MAF sensor, among other things.
Most Ex's have a OBDI emissions system. It is determined by the GVWR of the vehicle. Over 8500 lbs and the OBDII emissions are not required by the Feds.
However, California has to always be different, and they required all vehicles to be OBDII compliant. One of the things to be OBDII compliant is to monitor when the Catalytic converter wears out. That is the sole reason for the after cat rear sensor. To compare the input to output O2 to determine if the cat is bad.
Your 2003, unless it is California compliant, will have the OBDI emissions system. It uses the IBDII connector, talks with scanners on the OBDII protocols, but only has OBDI sensors (PIDS).
California emissions vehicles are fully OBDII compliant in all respects. OBDII is nice in some ways, but there are more sensors and cost to repair when they go bad.
Oil vapors are sucked up by the PVC and burned in the cylinders. As part of the process, Phosphorus and other junk is released that end up coating and plating the O2 sensors and the Cat plates. This makes the sensors go bad and the converter to stop doing it's job. The Sensors are more susceptible to this, so they go bad much sooner. The voltage range that they switch back and forth as they read the O2 levels gets smaller and smaller until they are pretty much stuck at a constant voltage.
Too rich of a mixture can cause the cat to overheat and melt. This can happen from a bad TPS sensor, bad front O2 sensors, misfires, or a bad MAF sensor, among other things.
Most Ex's have a OBDI emissions system. It is determined by the GVWR of the vehicle. Over 8500 lbs and the OBDII emissions are not required by the Feds.
However, California has to always be different, and they required all vehicles to be OBDII compliant. One of the things to be OBDII compliant is to monitor when the Catalytic converter wears out. That is the sole reason for the after cat rear sensor. To compare the input to output O2 to determine if the cat is bad.
Your 2003, unless it is California compliant, will have the OBDI emissions system. It uses the IBDII connector, talks with scanners on the OBDII protocols, but only has OBDI sensors (PIDS).
California emissions vehicles are fully OBDII compliant in all respects. OBDII is nice in some ways, but there are more sensors and cost to repair when they go bad.
Lead Driver
Joined: Mar 2013
Posts: 7,460
Likes: 85
From: Kent Station, WA
I think Housedad is on the right track. Put some Techron or Seafoam in the tank with some good gas.
Prior to that I would change the fuel filter, PCV valve, clean the MAF sensor, and make sure all the plugs were actually changed.
Prior to that I would change the fuel filter, PCV valve, clean the MAF sensor, and make sure all the plugs were actually changed.
More Turbo
Joined: Feb 2004
Posts: 727
Likes: 2
From: Seaside NJ
Good chance that will change too, with diesels falling under increased scrutiny and the increasing awareness of "rolling coal" thanks to youtube and a bunch of bad eggs smoking out the beloved Prius, I think diesel inspections will be coming, especially here in NJ
Sorry for the off topic hijak
In terms of fixing the emissions issue youre having I cant add anything other than the basics these fine folk have already covered. Seafoam is a great combustion cleaning product, I use it on my 2 stroke 250 hp boat motor periodically to help prevent carbon build up on the rings. Should get your injectors cleaned up in a jiffy
Sorry for the off topic hijak
In terms of fixing the emissions issue youre having I cant add anything other than the basics these fine folk have already covered. Seafoam is a great combustion cleaning product, I use it on my 2 stroke 250 hp boat motor periodically to help prevent carbon build up on the rings. Should get your injectors cleaned up in a jiffy
Post Fiend
Joined: Feb 2011
Posts: 26,410
Likes: 6
From: Ft. Lauderdale, FL
easier just to move
Posting Guru
Joined: May 2012
Posts: 1,758
Likes: 3
From: Colorado
My Ex failed the last test on due to Hydrocarbons. NJ is pretty stringent about the emissions test. California level. The ONLY thing they check anymore in NJ is emissions. They have to show they are CARB compliant in order to keep getting a bunch of Federal money. If it was not for the Federal money, Govorner Cristy would have shut down inspections altogether.
Pulled a couple of plugs, and stuck an electronic inspection camera in the cylinders. I saw a bunch of crud on the injectors, cylinder heads, chambers and valves that were reducing burn efficiency of the fuel.
Pulled a couple of plugs, and stuck an electronic inspection camera in the cylinders. I saw a bunch of crud on the injectors, cylinder heads, chambers and valves that were reducing burn efficiency of the fuel.
must be a secret direct injected v10 Ford slipped in..
Lead Driver
Joined: Mar 2013
Posts: 7,460
Likes: 85
From: Kent Station, WA
Agreed, assuming your refering to the CA B.S., Fortunately my truck does not have to meet those standards as I am in Seattle. 
Thread Starter
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Laughing Gas
Joined: Dec 2006
Posts: 1,008
Likes: 5
Welp... New coils, plugs, pcv, fuel filter, shook out the air filter, and changed the oil...
Ran through all the fuel till the gauge was on the red Empty line and the Distance to Empty was zero, then added 5 gallons of E85 for good measure.
Right before the retest, I took it out on the highway and floored it in 2nd gear (4000 RPM at 70 MPH) for about 5 miles...
Still failed.
100 ppm at 2500 RPM. (Passing)
226 ppm at idle. (Failed)
It's cleaner than the previous readings. (184 idle and 239 at 2500 RPM) but at this point, it's the catalytic converter.
Time to register it at my vacation house down south... Or rereister it as a Diesel...
Ran through all the fuel till the gauge was on the red Empty line and the Distance to Empty was zero, then added 5 gallons of E85 for good measure.
Right before the retest, I took it out on the highway and floored it in 2nd gear (4000 RPM at 70 MPH) for about 5 miles...
Still failed.
100 ppm at 2500 RPM. (Passing)
226 ppm at idle. (Failed)
It's cleaner than the previous readings. (184 idle and 239 at 2500 RPM) but at this point, it's the catalytic converter.
Time to register it at my vacation house down south... Or rereister it as a Diesel...
Posting Guru
Joined: May 2012
Posts: 1,758
Likes: 3
From: Colorado
Welp... New coils, plugs, pcv, fuel filter, shook out the air filter, and changed the oil...
Ran through all the fuel till the gauge was on the red Empty line and the Distance to Empty was zero, then added 5 gallons of E85 for good measure.
Right before the retest, I took it out on the highway and floored it in 2nd gear (4000 RPM at 70 MPH) for about 5 miles...
Still failed.
100 ppm at 2500 RPM. (Passing)
226 ppm at idle. (Failed)
It's cleaner than the previous readings. (184 idle and 239 at 2500 RPM) but at this point, it's the catalytic converter.
Time to register it at my vacation house down south... Or rereister it as a Diesel...
Ran through all the fuel till the gauge was on the red Empty line and the Distance to Empty was zero, then added 5 gallons of E85 for good measure.
Right before the retest, I took it out on the highway and floored it in 2nd gear (4000 RPM at 70 MPH) for about 5 miles...
Still failed.
100 ppm at 2500 RPM. (Passing)
226 ppm at idle. (Failed)
It's cleaner than the previous readings. (184 idle and 239 at 2500 RPM) but at this point, it's the catalytic converter.
Time to register it at my vacation house down south... Or rereister it as a Diesel...
E85 ????? They're not supposed to be used with E85.
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Laughing Gas
Joined: Dec 2006
Posts: 1,008
Likes: 5
It ran surprisingly well on the E85... Probably had a few gallons of E10 in it, so it was probably more like E70 or so.
No drivability problems, no misfiring, felt like it ran slightly warmer.
Yep. Had a similar problem with another vehicle in the past... Only it failed emissions due to high NOx.
Denatured Alcohol in that tank pulled HydroCarbons and Carbon Monoxide to almost nothing with a good catalytic converter.
No drivability problems, no misfiring, felt like it ran slightly warmer.
Yep. Had a similar problem with another vehicle in the past... Only it failed emissions due to high NOx.
Denatured Alcohol in that tank pulled HydroCarbons and Carbon Monoxide to almost nothing with a good catalytic converter.
Fleet Mechanic
Joined: Oct 2010
Posts: 1,997
Likes: 206
From: South Eastern Michigan
On the E fuels and passing emissions, when we had to get my dads Cobra to pass in CO, we dumped pure(ish) alcohol in with some av-gas and it passed with flying colors. Took it home, changed the plugs and drained the tank. Put some race fuel back in it and hit the blacktop. That was a fun day.
Lead Driver
Joined: Mar 2013
Posts: 7,460
Likes: 85
From: Kent Station, WA
Prior to sniff test emissions I like to go on a half hour cruise on the freeway keepeing the rpms up, stereo and accessories off and heater on. Keep it out of over drive as well. This gets everything nice and warm including the catylitc converter.
Do you run any fuel system cleaners or additives? Techron, seafoam, iso heet?
Do you run any fuel system cleaners or additives? Techron, seafoam, iso heet?
Thread Starter
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Laughing Gas
Joined: Dec 2006
Posts: 1,008
Likes: 5
Prior to sniff test emissions I like to go on a half hour cruise on the freeway keepeing the rpms up, stereo and accessories off and heater on. Keep it out of over drive as well. This gets everything nice and warm including the catylitc converter.
Do you run any fuel system cleaners or additives? Techron, seafoam, iso heet?
Do you run any fuel system cleaners or additives? Techron, seafoam, iso heet?
I did about 15 minutes of driving with the RPMs up at over 4000 on the highway in 2nd gear.
Emissions tech looked under and said it's gotta be that aftermarket catalytic converter. Aftermarket units never last long.
Lead Driver
Joined: Mar 2013
Posts: 7,460
Likes: 85
From: Kent Station, WA
Did not realize you had an aftermarket cat. Thats probably it than. The originals are not cheap and there isn't really a way to get a high flow cat for these trucks.
Edit: just re read the original post where you mentioned it.
Edit: just re read the original post where you mentioned it.
Elder User
Joined: May 2014
Posts: 547
Likes: 1
From: Southern California
Since you suspect the cat you could check inlet and outlet temp with an IR thermometer. I saw one that was cooler coming out than going in. You also could have the tech take a reading before the cat and compare to after to see exactly what it is doing but that requires putting a hole in the exhaust that would have to be fixed after.