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Discussion Starter · #1 ·
Well I took my 85 6M in today for a test only smog check and it wasn't good. :x

Here are the results:

15 mph, 1799 rpm, 13.73 CO2%, 1.28 O2%, 77 HC PPM, .03 CO%, 2374 NO PPM
25 mph, 1827 rpm, 13.71 CO2%, 1.36 O2%, 68 HC PPM, .03 CO%, 1465 NO PPM

What is causing the NO to be soo high. I need to get this fixed soon. Any ideas?
 

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EGR passage ways are likely clogged up. Common problem on our cars that shows up at smog check time. If you take care of that, and run some high octane fuel for the next check, you should be good to go.

Edit: you might also change your plugs too while you're at it. I run plain old ND copper plugs in my car. It runs smooth as silk.
 

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NOx being high is EGR you have a 6m. does it have an egr system? i'd try cleaning the egrcm. lil brown thing. i cleaned mine out it was fucking NASTY. filled with carbon and the filter on it was disgusting.
 

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Absolutely, your EGR system is plugged up (assuming your in Cali and swapped your 5m intake and EGR like you're supposed to). Seen this over and over again. Everywhere exhaust flows through the EGR system gets clogged up with soote just like a chimney for your fireplace. You'll need to knock out an 18mm freeze plug on the top of the intake plenum and unscrew the allen head plug from the back of the plenum and ream it out really good. A shotgun cleaning rod and 20gauge brass bristle brush works great for this. Next you'll need to take off the EGR valve itself and clean it out including the pressure port for the vacuum modulator. Tricky part is the vacuum modulator itself. If the pressure port on the bottom of it is plugged, then you can try to dig it out clean with a wire or drill bit or something but there's no guarantee you'll get it clean enough to work again. Last you'll want to take the EGR tube loose from the EGR cooler on the back of the cyl head and ream out the cooler with the shotgun brush. Exhaust needs to pass freely through the whole system. Put it all back together once its cleaned.

To test, with the engine warm and idling, the engine should stumble or even die when you apply vacuum directly to the EGR actuator (use vacuum pump or short circuit directly to vacuum source on the intake.) That proves the valve operates and the passages are clear. If nothing happens, then the system is still plugged or the valve is faulty. For the next part, you'll need a vacuum gauge and 5-6 feet of hose but they're cheap. Disconnect the vacuum hose from the actuator itself and connect the hose to the vacuum gauge, then tape the gauge to the windshield so you can see it while driving. (I find the high idle test in the TSRM doesn't always work - engine needs to be under a load.) When the engine is idling, vacuum should be zero. When you step on the gas part throttle and accelerate normally, you should see 10-20 inches. When you lift your foot off the throttle, the vacuum should snap back to zero instantly. When you floor the accelerator pedel, vacuum should fall to zero. If you read anything else, there's a problem in the vacuum system, most likely the modulator. If you never have vacuum, its the solenoid or the temp VSV (which basically are there to disable the EGR system while the engine is warming up or the ECU otherwise thinks it needs disabled) - test those as in TSRM.

Once the EGR system is working, you also need to make absolutely sure the timing is 10 degrees. If they let you get away with 8, even better. Then reset to 12 or whatever you had set before after you get your sticker. And of course make sure the cat converter is hot, etc.etc. Good luck.

Phil D.
(Texas - another smog nazi state)
 

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pdupler said:
When the engine is idling, vacuum should be zero. When you step on the gas part throttle and accelerate normally, you should see 10-20 inches. When you lift your foot off the throttle, the vacuum should snap back to zero instantly. When you floor the accelerator pedel, vacuum should fall to zero. If you read anything else, there's a problem in the vacuum system, most likely the modulator.
actually at idle the vacuume should be about 15-20 inches if your hooked into the actual vacuume system. the hoses coming out of the top of the throttlebody aren't true vacuume connections. they are vacuume connections that only get vacuume at part throttle. hence why the egr system uses them so it isn't going at wot and not at idle either. they are before the throttle plate not after it. if your hooked to a true vaccume connection the higher the idle the higher the vacuume until you can't revv any higher. but it'll only be higher if there are no exhaust restrictions and the engine is at max revv for that throttle opening.
 

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True, but I guess I wasn't very clear. Reading should be taken at the EGR valve actuator (after the vacuum modulator) under normal acceleration. It only takes a few inches to hold the EGR open so thats why its designed the way it is. Basically you are only testing for the presence of vacuum at part throttle with the engine at operating temperature. If you have vacuum there under any other condition or no vacuum at all, something is wrong.

Phil D.
 

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Discussion Starter · #7 ·
Thanks for the input. I figured it had to be related with the EGR since the HC levels were not high also, saying the cat is doing something.

Strange thing is that they test to see if the EGR is functioning correctly. He must have not caught it.

I did change the cap, rotor, & plugs with NGK iridiums and the oil is clean. I run premium all the time so that is what it had when it was tested.

Here you have to have the timing set to specs so it was set to 10 deg.

Yes, I swapped all the 5M stuff over to the 6M including the EGR system. I cleaned it all out when I installed the 6M but that was 6 years and well over 60K miles ago. I also installed a new EGR valve at that time.

Can you get that freze plug from Toyota or Autozone?
 

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you have to have your car tested here but they didn't do it...i had my powersteering disabled and when they saw that they just wrote that that was the problem. so when i brought it back later with powersteering they checked it it worked and they gave me the stickers lol! they didn't write that it hadn't been tested for anything else.
 

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The exact same thing happened to me in September. Every thing was fine except for the NO which was sky high. I was told you should probably drive it around for a while then take it in while the engine is still hot. So i drove down the freeway for a bit and back, had her re-tested, and passed with flying colors :)
 

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This may sound stupid, but check the ground for the mas. My friend replaced just about all of the parts in his 87 untill he took it to toyota and they said he was missing a ground. after he installed it it passed. his car ran fine before had also. hope this helps!
 

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pruner said:
The exact same thing happened to me in September. Every thing was fine except for the NO which was sky high. I was told you should probably drive it around for a while then take it in while the engine is still hot. So i drove down the freeway for a bit and back, had her re-tested, and passed with flying colors :)
you have to take it in to be tested hot because the egr system doesn't come on til the engine is about 180degF. make sure they test your car right away. some places leave the car sitting a couple hours then just start them up and oh! wow they don't pass! they need 400 dollars in repair!
 

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Just prepping my car for a e-test. Checking my EGR Vacuum Modulator filter element. Its pretty much in 3 pieces. Is it recommended that I get a replacement?
 

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as long as it flows, mine is dirty as hell and in three pieces, i just held it all together and got an air hose and blasted it, put a new cat one (since my old one was dead) and vwahala passed
 

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Josh, I would even retard the timing more say down to 8 or 6 degrees instead of 10 if thats allowed. Also the HC seemed a bit high (rich) maybe a new O2 sensor is needed. And is the AFM in stock configuration??

I would try running some Emisson Test additive. CRC and Octane 104 both make additives for smog testing :wink:

My 86 smog figures from last test in '03 before SMOG II:
idle rpm 0.01% CO 25 HC PPM
2500 (2650 actual) rpm 0.03% CO 16 HC PPM

jr85mk2 said:
Well I took my 85 6M in today for a test only smog check and it wasn't good. :x

Here are the results:

15 mph, 1799 rpm, 13.73 CO2%, 1.28 O2%, 77 HC PPM, .03 CO%, 2374 NO PPM
25 mph, 1827 rpm, 13.71 CO2%, 1.36 O2%, 68 HC PPM, .03 CO%, 1465 NO PPM

What is causing the NO to be soo high. I need to get this fixed soon. Any ideas?
 

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Discussion Starter · #15 ·
Arch,

I just got the car smogged yesterday and it got by, not by much but it passed. The EGR vac modualtor was dead so that made the EGR functional and the NO came way down. Not as low as it should be but enough to pass. Funny thing is that the HC went up this time around. I think the cat is getting tired. The O2 sensor is a couple of years old.

There is no way I could change the timing any, here in CA they make you set the timing to the specs under the hood and it has to be perfect or they will not pass it. My mom had a car that was of by 2 degrees and had to be changed. Perhaps you can get away with 1 degree off but I don't want to push it. I have the AFM loosened about 3 teeth and with 210 injectors on a 6M with Thorely headers. I only took off the K&N and the RC intake pipe for smog testing. The car was sitting around for many months so the gas in the tank may also have been old enough to make a difference.

Here in CA they put the car on a dyno and load it down to test it. That is why it says 15 and 25 MPH. With the Thorley and the 2.5" brullen exhaust it really make a roar getting tested. The other normal cars you can't even hear, not my car! :lol: Of course being FWD cars the exhaust is out into the street not facing into the building like when they have for RWD cars.
 

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With the Thorley header, your O2 sensor is not in the exhaust stream, and barely works. Do the measurements. It makes a lot of difference when you get it in the exhaust stream and the system starts to work again. With your 6M you would really like it. It surely woke up my 5M, and that motor is really tired.
 

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Josh,

I reading your post as I have the same problem and am considering buying a new EGR vacuum modulator but I'm not sure this will solve my problem.

Did you end up replacing this?

thanks

Tom
 

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thanks pdupler
that was very informative. I have to do this to my car. I was planning on just cleaning the tube and vale. I don't want to take the plenum off or knock out any freeze plugs if I can avoid it. before I just cleaned out what I could with carb clean towels and a hanger.

Also... In CA our cars can pass timing from 7 -13 degrees. It must be within 3 degrees of 10 unless otherwise stated by manufactuar ie hondas- +or- 2 degrees
 
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