1990 S13 KA24E auto Stock with ~205k miles.

Results:

Stumped on this one. I had (and apparently still have) a code 32 for the EGR for a while now. The mechanic I went to said it tested ok. I personally haven't tested it myself for vacuum. Pressing up on the EGR does cause the engine to stumble if that matters. The other day I decided to go do my smog test (figured it would fail. Just wanted the test results). Drove around for about 30 minutes then stopped home to pick up some stuff. On a whim, I checked the vacuum lines for the EGR system again and this time I discovered one of the lines coming from the EGR solenoid popped out all this time. I really thought I finally figured out my EGR woes. I managed to hook it back on, clear the code, and drove around for 5-10 minutes to see if the CEL came back on. No light, so I went to the test station. Well, as you can see from the picture, CEL came on during test and 25 mph just passed while the 15 mph failed.

The car was shut off for about 20 minutes while I found out about the vacuum line. Maybe I didn't drive it long enough afterwards to heat up the cat?

I run 87 gas. Reading around the web, people were suggesting running 91/93. I'll definitely will do that for the next smog test.

CAT converter was replaced almost 2 years ago (less than 6-7k miles). O2 sensor was replaced 10-15k miles ago. NGK plug/wires have less than 10k miles. Same goes for fuel filter. Oil change was done 2 months ago. Cleaned MAF sensor 2 months ago (using CRC MAF cleaner).

Smog guy said I may be running too lean and suggested replacing the O2 sensor.

In terms of how the car runs, the major issues I can think of is poor mileage and sometimes the car feels like it has no power at low RPM. When I really gas it, the power picks up. edit: Forgot to mention that the fan clutch is seized. Car sounds like a truck. Already purchased a replacement. Waiting for it to ship home.

Car idles fine.

Im planning on seeing another guy to finally get this EGR issue resolved, but wanted to get your guys' thoughts.

edit: Also, no EGR deleting. This is CA

Is the 2 year old CAT a CARB certified cat? If not, that could be your issue. Also, next to the EGR valve is the BPT valve, check that as well. There's a vacuum line underneath it that may seem fine but one little hole in it and it'll fail. Check it. A new O2 sensor could also help. Also, keep running the 87 octane fuel. Add some denatured alcohol (1 quart to a 1/4 tank, then fill the rest of the tank to give it a nice mix), that will help a ton.

There's a couple things you could do. First would be to run a higher octane gas. They tend to burn slower and a bit cooler. The other is to retard your timing a bit. Your HCs will go up, but your nitrous oxides should drop.

Also, +1 on adding alcohol. A gallon or 2 of E85 shouldn't be enough to cause any damage, just make sure you drive around for a while first so the ECU can richen everything up appropriately.

You already know your EGR exhaust path is not clogged badly. To test mine I put a "t" in the vacuum line feeding the EGR valve so I could watch a vacuum gauge as I cruised at low speed. This will tell you if the EGR is operating normally at moderate throttle under load.

For timing, I'm in CA and I retarded my timing to -15 on a timing light. I was never this aggressive before, since I was worried they would fail me for being more than 10% off spec (-20). The smog shop reported my timing at -19 even though I know it's -15. I'd try 15 BTDC.

Also, disconnecting the detonation sensor MAY help. It would be great to get a more informed opinion on that trick but I think it helped me.

My EGR system wasn't working. It wasn't clogs, it was the valve system. Figuring out the vacuum lines and making sure there are no leaks was a start. Messing with the valves finally pointed me to the electronic one on the back side of the engine block. I replaced that with a similar one from a junkyard and all worked fine afterwards. I did think it was the BPT valve, because it seemed to leak, but it turned out I did not understand it's function and it was working properly. You'll want to drive around a while to make sure your systems checks are in order and that you're not going to throw a code during testing. What the others said about reducing your NOX sounds helpful. I've never had to do 'tricks' like that to pass smog in CA with mine though.

PS - I've read bad things about cheap aftermarket cats and even high flow cats. That they use the least amount of precious metals as possible and can lose their effectiveness in just a couple of years. That they are only good for passing smog once. I don't understand that completely, but I have read it in several places. Did you get a good, 2 or 3 way CAT from a reputable manufacturer? With a warranty perhaps?

I would inspect every part of the egr system, such as egr-valve, egr-bpt, egr-bpt tube etc. You said that pushing up on the diaphragm causes the car to stumble and almost stall, then it looks like the valve works. Could be that the passages are clogged with carbon leading up to the valve and not giving it enough pressure. There's a few small diameter tubes that connect to the egr system, so they could be clogged. What you could do is place a camera near the egr and record if that diagram is moving while you are under load.

Check for any worn rubber hoses like the 90 degree rubber hose hose that connects from the bottom of the egr-bpt to the bpt tube.

Also check for a vacuum leaks before the cat as those can increase nox. Finding a shop that has a smog machine will easily help pin point the leak.

High nox is common issue for the 240 causing smog check fails. I've dealt with it ever since california started measuring it in smog checks.

Good ole' smog. I found a very good solution to this issue (and many others) but it isn't for everyone.

Step one: Put a bunch of stuff in your car, like everything you own
Step two: Drive north
Step three: Live in Oregon

Again not for everyone, but I highly recommend it.

DMan II-40 wrote:
Step one: Put a bunch of stuff in your car, like everything you own
Step two: Drive north
Step three: Live in Oregon

I LOL'd.

Ha ha. I did that! Then I started to hate Oregon, so I moved to Arizona!

I'll be updating this thread in the coming month since it's a smog test year. So in 2016, I was never able to figure out what was wrong. Flash forward to around mid-2017, I had some free time so I decided to revisit this issue. I double-checked the EGR system again -- this time the EGR solenoid. I took it off the motor, tested it, and found out it wasn't activating (it wasn't clicking). Went to a junkyard and luckily they had a 240sx with an EGR solenoid still available. Took it off, went home, and tested it and it passed (click click click). In my mind, Im like "Is this it? Is it finally fixed?"

I've had a EGR/code 32 issue for years and was never able to pass smog legit. I hooked it up, reattached the lines, reset the code and drove the car like normal. Since then, the code 32 hasnt returned. The car no longer has a CEL constantly on . I also replaced the thermostat, radiator, o2 sensor, and CTS during that same period. Dont know how much that will help, but they were due for a replacement anyway.

We shall see if this is truly fixed in a few weeks. Going to do a tune up first before I go in for a smog.

DMan II-40 wrote: ↑

Tue Aug 30, 2016 10:41 am

Good ole' smog. I found a very good solution to this issue (and many others) but it isn't for everyone.

Step one: Put a bunch of stuff in your car, like everything you own
Step two: Drive north
Step three: Live in Oregon

Again not for everyone, but I highly recommend it.

You could also live in Florida, or Oklahoma...but I hate both of those states. However their car/smog related laws are amazing. They're nonexistent! Go into the DMV, pay your fees for a tag, and done. Renewing registration is a breeze, you can just send in your fee through the mail. God I miss that living here in NC where you have to go through the bureaucratic wringer just to get a title transfer, then "inspections"...ugh.

**UPDATE**

I went in for the smog test today and I passed. I even made the mistake of not filling up the gas tank and my technician let me know about it. Passed with flying colors.

The EGR solenoid was the answer this whole time. This small part that's hidden under the intake/throttle body area. I thought it would be difficult to remove because of the location, but once I started working it was much easier than I expected. Saved a lot of money and the part itself was like $4 at the junkyard. Compared to the EGR valve, it is much easier to remove. Thankfully the EGR isnt defective or clogged.

EGR solenoid:

The solenoid is what activates the EGR valve to go where it needs to, can't work without it.

NOx is created by TEMPERATURE and more pressure, and anything that lowers HC generally raises NOx. In the '70s the retarded ignition timing (ATDC) was how they passed it, retarding lets less mixture burn to raise HC but the temp drops off and so does NOx. Anything that slows the burn (what EGR does) lowers it.