I just bought a 1997 240 a couple weeks ago. It has a stock KA with some bolt ons but nothing special. The CEL is on and before I get my tag I have to pass emissions so I took it to get the codes checked and came up with this:
P325 Knock Sensor issue - the guy looked at the knock sensor and said it had a crack in it so just replace the sensor and done.
P136 O2 Sensor issue Bank 1 Sensor 2 - the primary O2 sensor has been replaced and I wasn't even aware of the secondary one so I am assuming if the previous owner was also unaware of it then it has never been changed. Again, no big deal.
P400 EGR System issue - this is the one that worried the guy. He told me that the EGR systems on these cars are a pain to diagnose and work on.
So if anyone has any suggestions about the EGR passing emissions please let me know. And if you know where to get a knock sensor and O2 sensor for cheap, also let me know.
buy the knock sensor on ebay you can find them for $30, O2 will be a bit more expensive because its a 3 wire heated O2 you can buy the least expansive one that comes without the connector and just solder and heat shrink it to the connector from the old sensor. It is a bitch to work on the EGR for the S14 KA, I just removed mine, since there are no emmission check in Florida. Im not too familiar with them so I'll just leave that up to someone else.
Yeah, I figured out a while ago that eBay is the best place for parts like O2 sensors and knock sensors. Saved me about $100 last year when I replaced both O2 sensors on my 300zx.
The EGR is the problem. I don't know where to begin or what to do. I need someone who has been there and done it.
Is there a difference in the fat and skinny O2 sensors? Reading the info about some of these suggests they are different but I thought that was just the housing from different brands. Ebay information isn't the most reliable so I wanted to check.
Another question: Could I use an O2 sensor from my 1990 300zx? I replaced them some months ago but the car isn't drivable so they are still new and they are both 3 wire.
So I was looking around and I found a place that sells brand new EGR valves. Would replacing the valve solve the problem or is there alot more to the EGR system than the main valve?
I have a question that I need answered pretty soon:
If a 3 wire O2 sensor is wired wrong and driven that way for a while, will it damage the sensor or can it just be rewired correctly and be fine?
I ask because I crawled under my car this afternoon to change the O2 sensor only to find that the sensor was a replacement already but was wired with the sensor wire connected to one of the heater wires. Instead of using the new O2 sensor I have I just rewired that one and the car seems to run smoother but I don't know.
I have installed a new knock sensor and fixed the O2 sensor (hopefully) and now the only issue is the EGR so I am still waiting for suggestions.
the egr valve is a problem on all 240's. Like the poster above said, check the 90* hose coming off the valve as it tends to degrade over time. Another good way to test the egr valve is to press the little diaphragm upward while the car is running (in neutral). If the car stutters and chokes, it's working properly, and it's not atcually the valve that's the problem. In terms of getting your egr problem to pass emissions? In CA it's nearly impossible to pass (legitimately) with any sort of modification on your car. I'd recommend checking the entire egr setup (all hoses, the valve, the place where it bolts on to the back of the intake mani, and the feed from the exhaust. Look for leaks, vacuum ports without hoses, or hoses with cracks. Other than that (or replacing all of it - the pricey option), you can try clearing your codes right before you go to get smogged, and hope that little bastard stays off. OR, if you're feeling fiesty, you could get yourself a little resistor (wish i could recall which one, i think it's a 1/4w 10k ohm resistor, but you'll want to look that up - search "240sx egr resistor") and wire it into the egr temp sensor harness. this modifies the signal that is sent from the ecu, sends it back to the ecu with the proper voltage to say "EGR is OK". Viola. This is the solution that people who do the EGR delete use. Depending on your local emissions laws, modifying your emissions systems in any way, shape, or form might be illegal. it is in CA.
At any rate, if you can do a decent job wiring that resistor inline, it doesn't even really look like it's there, and you can move on with your life. Good luck getting your hands in there to actually get at the sensor harness, though, because unless you have tiny carnival worker hands, it's a pain.
I doubt that GA emissions laws are as strict as CA but they are still pretty bad. I have taken a look at the EGR and I noticed 2 things that I wondered about.
First, the small hose that goes from one diaphram to the other, the one about 3" long, seems to be crimped or something so I wanted to replace it with a new hose.
Second, the threaded bung on the back of the first diaphram has nothing attached to it and I think it has been welded shut but I'm not sure. What needs to go there or what should I do about it?
look for another vacuum feed, possibly coming off the back of the motor. there's one vac feed that is really really hard to see, you should feel around, and see if you can feel one. I know that's not a good description, but it's the only way i know to tell you how to find it.
i missed this one when i put my emissions back on last year, and it ran like crap. if it's not running poorly, you're probably not suffering a vac leak, but you have to check.
Well the CEL never came back on so even though I have good reason to believe that the EGR isn't completely hooked up I took the car to get emissions done and it passed without a hickup the first time.
When I have time I am still gonna go over the EGR good so I won't have anything to worry about next year but for now I am ok. I passed the test, got my tag, and the title is officially in my name now so I am happy.
I'll post here if I find anything else about the EGR but for now, thanks for all the info and help everybody.
devil, based on your saying that the bung on the back of the diaphragm has nothing attached leads me to believe that your EGR tube that should connect between your EGR valve on your intake manifold and your exhaust manifold might be missing. This tube routes behind your head, between the back of the head and the firewall. If it's not, you're most certainly getting a code due to the fact that EGR temperature sensor is not sensing "HOT" exhaust gas in the tube (that may not even be there).
Use the resistor trick outlined above to solve this. What I did is wire two resistors of cold and hot values and a relay that would switch between. I think I wired the signal that went to the EGR vacuum solenoid to the relay, thereby switching the relay on and off. This way when the ECU decided it wanted EGR it would assert the EGR Vacuum signal which would actuate the relay and close the "HOT" value resistor to the EGR Temp sensor signal back to the ECU. When the ECU decides to turn off the EGR, it'll see a COLD value on the EGR Temp sense line.
Devil, based on your saying that the bung on the back of the diaphragm has nothing attached leads me to believe that your EGR tube that should connect between your EGR valve on your intake manifold and your exhaust manifold might be missing. This tube routes behind your head, between the back of the head and the firewall. If it's not, you're most certainly getting a code due to the fact that EGR temperature sensor is not sensing "HOT" exhaust gas in the tube (that may not even be there).
Use the resistor trick outlined above to solve this. What I did is wire two resistors of cold and hot values and a relay that would switch between. I think I wired the signal that went to the EGR vacuum solenoid to the relay, thereby switching the relay on and off. This way when the ECU decided it wanted EGR it would assert the EGR Vacuum signal which would actuate the relay and close the "HOT" value resistor to the EGR Temp sensor signal back to the ECU. When the ECU decides to turn off the EGR, it'll see a COLD value on the EGR Temp sense line.
This has worked for me for over three years.
That seems like alot of effort just to get rid of the EGR. But I couldn't be getting a code because the car passed, unless I misunderstood something. I thought you wouldn't pass if you had any codes.
I don't have a problem with the EGR being there and I'd rather just hook it back up and not have to worry about it. But no, there is nothing attached to the threaded bung and it has been welded closed so I guess I need to replace it and reconnect the pipe you are talking about.
Maybe I should find someone who has just removed theirs and get it from them so I know its all there.
Can you find the EGR tube that should be routed behind your engine block (between the back of the head and the firewall)? If there is no tube, check your exhaust manifold. Is there a corresponding un-hooked up bung there too? You may need to feel kinda back and behind your exhaust manifold to determine this. Obviously do this when it's cold. I can't remember how easily the EGR tube is to see from the exhuast mani side.
240SXforums.com is in no way affiliated with Nissan Motors Co, Ltd.
All Trademarks are property of their respective owners. 240SXforums.com is an enthusiast community for the Nissan 240SX (Silvia).
AutoGuide.com
Truck
European
Import
Domestic
Manufacturer
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.
