96Pathfinder4x4 Posted January 1, 2013 Share Posted January 1, 2013 15MPH HC MAX: 50 AVE: 7 MEAS: 2 | CO MAX: 0.64 AVE 0.03 MEAS 0.03 | NO MAX: 508 AVE 90 MEAS 898 <---FAIL 25MPH HC MAX: 34 AVE: 6 MEAS: 5 | CO MAX: 0.78 AVE 0.03 MEAS 0.18 | NO MAX: 761 AVE 84 MEAS 235 I have no check engine light, therefore no codes. Searching the internet, it seems my system might be faulty. How do I test it? I'm searching in the pdf manual, but not finding the EGR valve test procedures. Rather not throw $150 at it and not know what the problem is. Thanks to all in advance! and Happy New Year! Link to comment Share on other sites More sharing options...
Precise1 Posted January 1, 2013 Share Posted January 1, 2013 Check the EGR system for proper functioning. Oh, apparently you know that... EGR valve inspection is EC-194 according to the index, EGRC-BPT valve inspection is EC-196 B Link to comment Share on other sites More sharing options...
96Pathfinder4x4 Posted January 2, 2013 Author Share Posted January 2, 2013 Thanks! Will be checking that out tomorrow. Link to comment Share on other sites More sharing options...
Towncivilian Posted January 2, 2013 Share Posted January 2, 2013 (edited) A bottle of Techron may help lower emissions as well (not enough to pass from those numbers I think though, so absolutely check your EGR valve). Either way, it can't hurt. Edited January 2, 2013 by Towncivilian Link to comment Share on other sites More sharing options...
Tungsten Posted January 2, 2013 Share Posted January 2, 2013 Run some carbon cleaner through the system. That should help with power too. If that doesn't help, high NO emissions means there is an issue with the catalytic converters. Link to comment Share on other sites More sharing options...
BBB Posted January 2, 2013 Share Posted January 2, 2013 Last year for inspection I had to deal with emissions problems. Mine was both HC and NO too high. Changing out the H2O temp sensor, new plugs wires and cap & rotor, and new O2 sensor helped the HC numbers. But I had to put a new cat on before it would pass. I didn't have a maint history from PO so I just replaced what I could starting with cheapest part. The guys at the emissions inspection station were cool about it, tested 3 times before I resigned to buying new cat. Then it passed. Link to comment Share on other sites More sharing options...
Precise1 Posted January 2, 2013 Share Posted January 2, 2013 From what I understand, excessive temperatures, excessive carbon build up, ERG issues and cat problems all can contribute to high NO. Like you said, the cat would be the last thing to inspect/replace... B Link to comment Share on other sites More sharing options...
96Pathfinder4x4 Posted January 3, 2013 Author Share Posted January 3, 2013 Going to check the rest of the sytem out tonight. Found this Autozone repair guide while learning what the EGRC-BPT system does. (Exhaust Gas Recirculation Control - Backpressure Transducer) http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jsp?pageId=0900c152800762d1 Link to comment Share on other sites More sharing options...
ejin4499 Posted January 4, 2013 Share Posted January 4, 2013 How stable is your idle? I had similar numbers on my pathfinder when I replaced my engine. Look for a vacuum leak. Check the hose on the back of the head get crazy with a can of brake cleaner till you find it. The smog shop had me chasing EGR problems for a month ended up i had a couple bad gaskets and a few cracked hoses under the upper intake. Link to comment Share on other sites More sharing options...
Alkorahil Posted January 4, 2013 Share Posted January 4, 2013 For high NOX issues: 1) change the oil 2) 87 octane gasoline - no additives in the tank like octane boosters, seafoam or injector cleaner! 3) before you have it inspected, make sure it is well warmed up. Drive it around at highways speeds 60+mph for at least 15 minutes before taking it to be inspected. 4) make sure your spark plugs, wires, distributor cap and rotor are all good. 5) make sure your ignition timing is correct. 6) make sure your coollant level is good and the coolant isnt old. (test it) 7) make sure your engine air filter is good. This will give you a good baseline to determine if the problem is either: 1) EGR Valve 2) O2 sensor However, based on the low HC and CO numbers posted above I would say the problem is O2 sensor. Everytime I have seen numbers like those posted, replacing the O2 sensor fixes the problem. 1 Link to comment Share on other sites More sharing options...
ejin4499 Posted January 5, 2013 Share Posted January 5, 2013 You might look into adding some denatured alcohol to your gas as well. It lowers your combustion temps. I have heard abouta qt to 10 gallons does the trick. YMMV Link to comment Share on other sites More sharing options...
96Pathfinder4x4 Posted January 5, 2013 Author Share Posted January 5, 2013 Warmed up. While revving the engine: No vacuum into EGR, no vacuum into EGRC-BPT. Good vacuum into EGR solenoid. As per the manual, I turned the car off, waited a few seconds, then disconnected and reconnected the solenoid connector. No clicking or any noise whatsoever, so I'm considering it bad. Heading down to Autozone to see about a new one. Link to comment Share on other sites More sharing options...
96Pathfinder4x4 Posted January 6, 2013 Author Share Posted January 6, 2013 Regards to the temp sensor and EGR-vacuum solenoid. Do they work independently of one another or if the temp sensor is bad, will it receive power to the vacuum solenoid??? Link to comment Share on other sites More sharing options...
sewebster Posted January 6, 2013 Share Posted January 6, 2013 You should be able to feel the EGR valve move (on the bottom) when you rev the engine. Don't burn yourself. Play around with it when cold to see how it feels. Link to comment Share on other sites More sharing options...
Tungsten Posted January 6, 2013 Share Posted January 6, 2013 The EGR valve does not work until the kill switch turns off. That's done to avoid having the EGR interfere with engine warm up. A stuck EGR in the open position will make the truck sluggish and unresponsive. A closed one will not do much on a VG engine. The oxygen sensor, coolant temp sensor, and EGR will have an effect on NO emissions but it will not have as much effect as a catalytic converter that's going bad. From those numbers it is definitely looking like a catalytic converter. Link to comment Share on other sites More sharing options...
96Pathfinder4x4 Posted January 6, 2013 Author Share Posted January 6, 2013 Warmed up. While revving the engine: No vacuum into EGR, no vacuum into EGRC-BPT. Good vacuum into EGR solenoid. As per the manual, I turned the car off, waited a few seconds, then disconnected and reconnected the solenoid connector. No clicking or any noise whatsoever, so I'm considering it bad. Heading down to Autozone to see about a new one. It's not the cat. I have no codes and no vacuum TO the EGR valve. A friend told me how to test the solenoid. The solenoid is good. I got the truck up to operating temp and the temp sensor won't come down past .5 M Ohms. I think the temp sensor reads back to the ECU, but I'm not 100% sure. Link to comment Share on other sites More sharing options...
96Pathfinder4x4 Posted January 6, 2013 Author Share Posted January 6, 2013 I forgot to mention that the truck has no performance issues. It has a slight bounce in rpms at idle. Link to comment Share on other sites More sharing options...
Tungsten Posted January 7, 2013 Share Posted January 7, 2013 Can you apply a manual vacuum to the valve and see if it holds? The engine should struggle if the EGR valve is open when it shouldn't be. That means the valve is not the problem but there could be a vacuum leak instead. Link to comment Share on other sites More sharing options...
msavides Posted January 7, 2013 Share Posted January 7, 2013 Unless they changed this in later models California models had a EGR temp sensor that would detect if exhaust gas is actually recirculating. if the egr valve were stuck in a California model the Check engine light would come on. Link to comment Share on other sites More sharing options...
Slartibartfast Posted January 8, 2013 Share Posted January 8, 2013 (edited) I ghetto tested the EGR on mine by sucking on one of the tubes, pinching it off, and then seeing if it made the valve open up. Some kind of vacuum pump would be good for this because, as I quickly discovered, EGR components don't taste very nice. Edited January 8, 2013 by Slartibartfast Link to comment Share on other sites More sharing options...
96Pathfinder4x4 Posted January 8, 2013 Author Share Posted January 8, 2013 I vacuum tested the EGR and the EGRC-BPT. Both test fine, according to the manual test procedures. No daylight work until Wednesday. I'm putting it all back together and replacing a couple of hoses...I'm thinking I have an intake leak somewhere and it's just not enough pressure to get through the EGR tube network. Link to comment Share on other sites More sharing options...
Precise1 Posted January 8, 2013 Share Posted January 8, 2013 FYI, the ERG tube its self can be clogged, especially if the vehicle has ever run rich... B Link to comment Share on other sites More sharing options...
96Pathfinder4x4 Posted January 8, 2013 Author Share Posted January 8, 2013 I stuck a wire up in the tube from the intake. I didn't get anything and the wire didn't get dirty. I've blown through all the hoses & lines. Once everything is back together, I'm going to stick a vacuum gauge on the intake and see how much pressure I'm getting. Link to comment Share on other sites More sharing options...
Precise1 Posted January 8, 2013 Share Posted January 8, 2013 Ok, it sounds like you are on it. B Link to comment Share on other sites More sharing options...
MY1PATH Posted January 10, 2013 Share Posted January 10, 2013 15MPH HC MAX: 50 AVE: 7 MEAS: 2 | CO MAX: 0.64 AVE 0.03 MEAS 0.03 | NO MAX: 508 AVE 90 MEAS 898 <---FAIL25MPH HC MAX: 34 AVE: 6 MEAS: 5 | CO MAX: 0.78 AVE 0.03 MEAS 0.18 | NO MAX: 761 AVE 84 MEAS 235 I have no check engine light, therefore no codes. Searching the internet, it seems my system might be faulty. How do I test it? I'm searching in the pdf manual, but not finding the EGR valve test procedures. Rather not throw $150 at it and not know what the problem is. Thanks to all in advance! and Happy New Year! Its possible you may be running a little lean. Have you tried injector cleaner like "Gummout Regain"? The reason I say this is because of your High NOX and Low HC. If I'm correct, Increasing fuel reduces NOX and the cat reduces HC. So by nature most engines run a little rich to reduce NOX and rely on the cat to reduce the resulting HC. FYI, the ERG tube its self can be clogged, especially if the vehicle has ever run rich... B There is also, right next to the egr, what looks like a block off plate for a second EGR valve. This is actually a HOT EGR Diverter. when you pull the plate off you will find a steel tube welded to the inside. Its purpose is to direct the EGR into the maifold without creating a hot spot in the aluminum. Anyway, this diverter is almost never checked or thought of and is commonly clogged. I'm 3 for 3 on the ones I've checked so far. Best way to clean it is to set it on concrete and hit it wit a torch until the deposits smoke and glow a little; then pick it up with a pliers and smack it on the ground to get the @!*% out. once the clog is out you can clean it more throughly with barrel brushes and carb cleaner. 1 Link to comment Share on other sites More sharing options...
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