Failed Emissions AGAIN!

SON240sx Automotive
1

First time with super advanced timing (car was overheating randomly after changing waterpump, cooling system needed to be bled further):

NOx: 3069 ppm (485ppm limit)
CO: 0.00ppm

Don’t remember HC, but it was about half the limit.

2nd attempt with timing brought down to stock or just below stock:

NOx: 1500ppm (485ppm limit)
CO:0.00ppm

HC was slightly lower this time, no overheating, all was well with the cooling system.

When I push the EGR diaphragm up, the engine stalls. 2 years ago, the EGR tube was cleaned out for carbon deposits clogging it. I cleaned IACV with TB cleaner through the vacuum line going to it. Idle is still rough and finicky.

What could be causing such high combustion temperatures? Am I running lean, leaking injector on a particular cylinder screwing up AFR readings for O2 sensor, timing too avanced, vacuum leaks? The dilution for the ASM 2525 test said 14.4, and idle was 9.8. I’m assuming these are AFR’s. I get SHIT gas mileage & weak low end torque too, tune up done, new plugs, wires, dizzy cap, rotor, high-flow cat & O2 sensor. Car feels torquey in the first 15 mins of the drive and on really cold days, otherwise sluggish. I replaced the knock sensor with an old spare I had lying around, code 34 disappeared, now there are no codes except speed sensor circuit (loose connection, shouldn’t affect anything but speedometer cutting in and out).

Anyone care to chime in?

Thanks.

Btw, with these megan racing engine & tranny mounts, I can feel the vibration of the KA so much more. It’s rough as fuck under 2k, everything rattles. New exhaust doesn’t help either, so much resonance in the cabin at low rpms. At high rpms, everything seems good.

2

^lol thats normal with stiffer mounts thats all i can say i run cuscos … just a step bellow solid retardation… meh… i enjoy it… sort of lol… at least on the track i do :smiley:

in regards to emissions i have no clue

3

Retarding the ignition reduces nox, not advancing it like you did. Retard the timing down to 10 degrees or so (from 20 stock), to the point where there is no power but still runs pretty smooth. Also, I have luck running seafoam through the vacuum lines. If there is carbon buildup in the engine that causes elevated nox. The other thing I have seen causing a nox failure is an o2 sensor. Try the carbon cleaning and the retarding first, if it still fails, then have a closer look at your o2 sensor. I just noticed you had a high flow cat, that is a big part of your problem, in a word they suck, and are usually only good for one emission test if you are lucky!

4

so you didn’t run any funny fuel…

no tululene, Xylene, etc…

5

The fuel system cleaner seems to help. run it through a full tank. Fill with fresh gas, go beat the fuck outta it. keep tuiming at stock, remove air filtre too for when they do the test, make sure they bring it in right after you bring it in smoking hot.

Should be good.

6

if you’ve got an aftermarket cat its likely a 2-way, doesn’t bring down the nox emissions. need a 3 way for that. Like other people suggested try retarding the timing. If you’re running “hot” and lean then bad fuel economy doesn’t really make sense.

make sure your fuel filter isn’t clogged, but I don’t see that causing an issue this bad.

7

get the exhaust super fucken hot, that’s the only reason i passed during the mine cause when i left i blew a little smoke hahaha

8

I don’t understand how I can have such high combustion temperatures to produce NOx levels through the roof, and still get shitty gas mileage and slight popping (mild backfire) around 2k rpm when decelerating. It doesn’t add up, some symptoms say RICH AS FUCK, others say LEAN AND HOT! …

I also have very little power, especially in the low end. When setting the timing, unplugging the TPS makes the rpm’s jump to like 1800rpm. I cannot adjust the idle screw, I have ABS, no access to it.

If I set the timing to 20° BTDC, then turn off the car, plug in the TPS start it again. The timing is less than 5° BTDC, not even on the marks, at idle. Is this normal, or is my ECU pulling mad timing? I have no code 34 anymore, changed the knock sensor with another one. MAF seems good too, it was cleaned recently, but no way of knowing unless I swap it with a good one.

Car is currently at the shop, they’re telling me that my cat is the cause of the NOx levels through the roof, I agree to an extent, but they shouldn’t be that high regardless. I want to treat the cause, not the symptom. Cat is welded onto my downpipe, so I can’t even switch back and forth between my 2 year old OEM style one.

Any advice other than methyl hydrate & retarded timing? lol

I want my car to run right, feel torquey, get decent gas mileage, like it was intended to. What could be wrong? All tune up items are done.

9

Clean the EGR valve. Common issue on KA 240’s as they get all clogged. A good seafoam treatment done properly will probably do the trick. Also locate the EGR diaphragm and make sure the vaccumm hose is not crumbling and collapsed.

10

Get a new o2 sensor … im pretty sure yours is done.

11

For the most part, O2 sensors only help the computer control the amount of fuel going in. Ahmad’s car is OBD1, so single O2 sensor.

He says his hydrocarbons (HC) is half of the limit, so in all likelihood his O2 sensor is fine. A bunk O2 sensor will cause an engine to run in closed loop (on OBD2 it will usually cause an oxygen sensor voltage low code). If it was running in closed loop, he’d probably get shitty fuel economy, low power, as well as a retardedly high amount of HC’s.

Yo Ahmad, clean out your EGR and put your timing back to stock. If you want more insight, send me a message on facebook.

Another note, grab a pyrometer. With the engine up to operating temperature and driven around, measure the inlet of your cat and measure the outlet. There should be a MINIMUM of a 10-15% difference in temperatures, with the inlet being cooler than the outlet. If the difference in temperature is close to the 10-15% difference, or less, then your cat’s run its lifespan. It’s no longer efficient and doing its job. Grab a Magnaflow cat from Partsource for like $85 and weld it on.

12

un plug a vacuum line for the test. will lean her out. done deallll

13

like others have said cat makes a huge difference

my truck didnt pass first try everything was jsut over the limit, changed my cat cause it had some loose metal inside, it passed with basicly all 0 and 1’s

14

Tony’s shop said the cam timing is off, and everything was misaligned, the crank pulley and the cams. I was like wtf? How is the car running then?

Quoted me $350 to do the timing, said it involves taking the front cover off. I thought you could just pop off the valve cover and do it from there, after setting TDC…

Any ideas guys?

15

Could be possible.

Try maxing you distributor out both ways See how she idles. Test drive.

If it runs better maxed out one way…then it is possible that the chain jumped.

16

This is all I can give you Ahmed

http://www.alldatapro.com/alldata/PRO%7EV153119576%7EC10015%7ER0%7EOB0%7EP2R0H%7EN/0/34870051/56619938/56620797/56620798/34853741/34850750/42063452/119615469/81101369/81101371/82090390/82090391

See what you, yourself can figure out. lol

17

lol, a dead image?

Btw, I changed the timing, advanced it a bit, she runs pretty nicely. Sounds like there’s a bit of roughness, but feels more powerful. The problem is the timing marks on the crank pulley don’t mean much if the cams were not set at TDC, right? I just timed it by ear, found the dizzy advanced makes it run better.

I honestly don’t have the time or place to work on the car, and I need it for work Monday-Friday. Otherwise I’d have the valve cover open and I’d be screwing around. lol

I really appreciate the advice guys. I can’t even tell what smooth is anymore since I got the engine mounts and exhaust. The whole car shakes like crazy, especially around 2400rpm. I can’t see through the rearview mirror, too much vibration. I know that’s not normal…maybe it’s resonance…

Gay thing is I didn’t even get an official receipt from the shop, I want to apply for the $450 conditional e-test pass.

18

Why the image is not there now…I dunno.

Pull the rocker cover. Turn engine to TDC. Look where the cams are on #1. Should be completely closed and the lobes should look like they are 180 degrees away from lifters.
The chain is supposed to have paint marks on it. That lines up with the cam gears.

19

As jowo72 said, check the vacuum line between the 2 diaphragms on the back of the intake mani, it’s common that it gets old and crusty and leaks causing the EGR not to work which plays a big role in the NOx reading.

Retard the timing, every KA 240 I’ve ever had failed horribly for NOx at stock timing, one was as high as 5000. Every single one of them passed with flying colours with the timing retarded.

20

try retarding the timing. But i don’t think that it is the problem. check the egr valve with a vacuum pump tester. it sounds like its applying though if you push on it and it almost stalls. So check for crusty vacuum hoses, if they are good maybe the chain is stretched or there is an exhaust restriction.