PO420, P0171 Need Help Please

[NCHornet]

Don't have to many salvage yards around here. Plus at least with buying a new or rebuilt EGR I have a 12 month warranty. Go buy from the salvage yard and the warranty runs out before you get out of the parking lot.
I was reading another thread where some have run cheaper EGR's off some GM vehicles. They said the EGR looked identical and the plug was even the same, but I can't find the thread any longer and don't remember what model they got it from. I think it was a mid 80's or 90's Grand Am, but the part number was different too. I might as well just stick with the one the book calls for.

[Cat Fuzz]

The seal is near the top of the plug tube. The oil leaks down and puddles at the bottom of the plug tube. When you remove the plug, the puddled oil leaks down the threads and into the cylinder as it's coming out. If the oil was fresh and oily still, this is probably what's going on. Oil getting into the combustion chamber will usually burn off and leave gunky deposits on the plug, not oily oil.

[NCHornet]

OK, maybe you are right. Yes the oil looked very fresh and dark black. I believe I know the rubber seal you are talking about. Is this the piece that the spark plug tube goes through and it sits just below the coil pack? Where can I get 6 of these? Maybe I will switch it with another cylinder and see if the oil residue dries up.
I sure appreciate the help. I was starting to think the motor was dusted.
Thanks Again
NCH

[NCHornet]

I was able to look at the Chiltons book today and I see the seal you are referring to. At least I think I do, it looks like it is actually under the valve cover and spark plug tube actually goes through it but it wasn't the one that is under the coil pack above. It looks like I need to pull the valve cover to get at those three. Is the valve cover gasket reuseable? Do these spark plug seals come with a valve cover gasket or can I get them separately? I guess I can find that out by calling the auto parts store. I am so thankful I found this forum and thank you for your time and sharing your knowledge. I thought this motor was soon to go. Maybe I will end up keeping her for awhile. My daughter really likes it. If I can keep the CEL light off it would be a win win. Thanks again.
NCH

[Cat Fuzz]

The spark plug tube seals come with a valve cover gasket set. You have to remove the valve cover to change them so you may as well install a new vc gasket while you're at it.

[NCHornet]

Thanks Fuzz. That will be my next project. Doesn't appear to be to difficult. I am just waiting now to see if the EGR sets a code again. I am expecting it to.
I mentioned this before but is it normal for this engine to take 100-150 miles to set the CEL? My wifes highlander had a O2 sensor go bad and I would clear the code but it would reset the CEL before I ever got down to the street? Just curious if others have had these long times between CEL's.
Thanks Again
NCH

[Cat Fuzz]

There are different times for each CEL code depending on what it is. For example, the PCM will not set a misfire code unless it detects a certain number of misfires within a specified time frame. Some fault codes require the PCM to see the fault more than once in a certain period of time before it will set a code. Sometimes a code will set right away, like a plugged EGR passage will throw a code as soon as you start driving but not at idle since the EGR valve is normally closed at idle.

[NCHornet]

ok, finally got the new EGR valve on today. Before I cleared the codes I checked them again and the P0420 bank one is back along with the P0452. I feel like I am running around in circles. The p0452 is pointing back to the FTP sensor, which I already replaced a few weeks ago. The P0420 code is pointing to a bad converter or a bad 02 sensor. I have monitored both upstream 02 sensors and they both are switching between .1 and .9 volts fairly rapidly, so they appear to be working as planned. Like I said I put the new EGR valve in and cleared the codes. Will see what pops ups. I may end up getting a for sale sign for it. Thanks Cat Fuzz for all the help.

[NCHornet]

Update,
Well the Mass Air Flow sensor and new EGR have cleared up some codes, but I am still getting the P0420 code and P0452 code. I have already changed the fuel pressure sensor above the fuel tank, so I don't know what else it could be?
I think I may also need a new converter. The 02 sensors are working as designed. I can see the upstream sensor flunctuating and the downstream sensor is more of a steady output. My scan is giving a description of the P0420 code as Catalyst System Efficiency Below Threshold Bank One. The freeze frame data for the P0420 code was this, Calculated load 9%, short term fuel trim bank one 0%, Short term fuel bank two 0%, Intake manifold Absolute pressure 13.3 in h.g
Coolant temp 180 F, Long term fuel trim bank one 3.12%, and long term fuel trim bank two 3.12%, engine rpm 834.
I didn't do a live data run today of the 02 sensors, but I remember when we got the P0420 code last time the Freeze Frame had a value for the short term fuel trim bank one and two and now it is giving me a zero for both. Not sure what this means? But I sure appreciate all the help y'all have given me especially Cat Fuzz.
Thanks
NCH

[Cat Fuzz]

Actually, those fuel trim numbers are very good. 0% is actually ideal. This article does a pretty good job explaining.

http://www.omninerd.com/comments/10664

http://www.obd-codes.com/p0420

The p0420 could still mean there is a problem with the catalyst on bank one. Even though you can see the upstream sensor switching and the downstream sensor staying flat, it may not be within spec enough to satisfy the PCM. The PCM's of OBD2 cars are pretty good at telling the difference between a bad cat and a bad O2 sensor. If the O2 was just slow switching, that would be another code entirely. If you wanted to find out for sure, there is a test that can be done but it requires a mechanic that is VERY well versed in emissions repairs. They can actually drill a hole in front of the cat and one behind the cat and get actual readings of the exhaust stream with a 4 or 5 gas analyzer and compare the before and after cat readings and tell you for sure if you need a new cat.

For the p0452 it could be a lot of things. A stuck open solenoid, a bad vacuum line, bad gas cap, etc. Check the easy stuff first, all the fuel evap lines, vacuum lines and maybe buy a new gas cap just for S&G's. If that turns up nothing, I'm afraid the next step is a smoke test, which is also a specialized emissions repair procedure requiring a pro equipped with the proper tools to perform.

[NCHornet]

I can't remember right now but are there two cat's on the Passport? My daughter is at school so I can't verify, but I remember both sides going through a single cat. But I could be wrong. I can get a universal cat for around $100 and a sensor for $60. This would probably be cheaper than finding a place that has the equipment to perform these tests. I live in a small town so I would have to drive 45 min to the city to find a place. Could I swap the bank one and two sensors and if the code switches to low effiency bank two we would know it is the sensor and not the cat? Just a idea. I am leaving town for 10 days to 2 weeks so I will dive into this when I get back home. I can't thank you enough for all your help.
Kevin

[Cat Fuzz]

Yeah, switching the O2 sensors around is a good way to eliminate the O2 sensors as a problem.