No CEL, but failed emissions test

[DSM1G90]

Now, it's my turn to ask for a "little help":

Our part of the state of Idaho passed a law to begin an emission testing program due to the neighboring county got into a bit of trouble with the EPA in having the air standards higher than the average that they set in certain airshed areas.

..and our two counties fall in the same airshed area

Thus, got the notice in the mail that I needed to get my car sniffed (the two-speed idle testing being a '90 ...), so I head on down to the place that does the sniffing and, "lo and behold", the car failed miserably in the test...

...my idle mixture was way too rich.

New air filter just put in two weeks ago. Timing's dead on a 5*BTDC, EGR valve hooked up...

...but the CEL light isn't on during operation. Light goes out a few seconds after motor startup...

Motor sits right at 750rpm at idle and is very quiet and smooth. ECU beep test comes out with all short beeps meaning normal operation-all sensors are in the closed loop....

..or, are they?

Would I have a gimpy Ox2 sensor that is keeping the CEL light off, but still having fun with the ECU to shoot more fuel than needed, or something else?

My exhaust is stock - no mods here .. actually, the entire car is bone stock .. just not interested in doing any form of mods...

any clues or tips would be great .... and thx as always. DSM

 

[91GVRFOUR]

I am not sure what you have done in the recent past as far as general maintenance, but here are a few suggestions.

- Clean the MAF.
- Change the plugs and wires.
- Change the oil and filter.

If all that doesn't work, I would move onto the O2 sensor and fuel pressure regulator. If all else fails, you may have to take a look at the catalytic converter.

That's too bad that Canyon County finally cracked down on emissions. I live in Ada County where i already had to comply.

 

[hhuricane]

When's the last time you changed the o2 sensor. Unless they totally fail they usually won't set the CEL. They are tune-up items just like plugs and should be changed around 80,000 miles. Also do the what 91GVRFOUR said.

 

[my dreamt dsm]

Will my nephew had problems with his gst spyder. He failed the first one, I forgot the reason why. He went out and bout those guarantee pass stuff at the auto store. And to our surprise he pass!

Yeah it sucks, I just want everyone to feel what we feel out here in cali, hehe!

 

[InfiniteGSX]

Your questions are right. Your O2 Sensor doesn't need to be shooting accurate information. It just needs to shoot information period! If it doesn't, then, only then will you get a CEL.

Things I could do:
New Spark Plugs gapped properly (BPR6ES)
New Wires
Clean Grounds or Install New, Better Ground Wires
New or Clean Air Filter
Have Injectors Cleaned Professionally
New Fuel Filter
Oil Change
Clean MAF Sensor, Or borrow one from someone that your sure is good.
New O2 Sensor.

IF you do those things, at least most of them, I would unplug your positive wire on your battery, touch and hold it to your ground terminal for a lil while to completely depleate all power from the system and reset the ECU. Then plug everything back up, Prime the fuel system before starting it just so it starts up fresh with no issues. Then Start it up and let it run for like 20 minutes at idle.

It should have no reason to fail.

 

[my dreamt dsm]

Hey ever think they just want you to go back for your money?

What you fail on co2? and i forgot the others!

 

[DSM1G90]

Thx all for the replies. I got this thing back in 2008 and it then had 161k miles on it (motor has been replaced-a JDM VR4 motor ..) ... now has 184K on it.

This summer - did oil change, air filter and the NGK plugs gapped at .028, new battery and will try to clean the MAF

True though..I'm also pointing to the O2 sensor since I don't know if it has ever been changed out or not....and with 184K miles on it, it's prob well due for a changeout.

thx-DSM

 

[NightRiderSRT4]

a bad 02 sensor should be throwing a CEL...weird. id swap them out anyways. i was DEAD EVEN passing my emissions w/ my talon. allowed 150 pts or whatever it is and got 150 exactly! talk about a close call

 

[Squirrel8811]

a bad 02 sensor should be throwing a CEL...weird.

That is true for an OBD II car. Really the only time the light comes on in OBD I cars is when something is so far bad that the car thinks its unplugged. OBD I cars on start up it basically does a circuit test and if it sees sensors in all areas it thinks its good to go.

 

[NightRiderSRT4]

That is true for an OBD II car. Really the only time the light comes on in OBD I cars is when something is so far bad that the car thinks its unplugged. OBD I cars on start up it basically does a circuit test and if it sees sensors in all areas it thinks its good to go.

ahhhh si

 

[toofast82]

That sucks they just implemented emissions for obd1 cars in your state.
Illinois doesn't test obd1 anymore as of the past 3-4 years. They used to put them on something almost like a dyno and put through different speeds. It was causing things to break on cars at the emissions place and people were filing claims against them, .

Do you have a logger you can use to see that they o2 sensor is cycling and functioning normal?
Is all your emissions stuff hooked up and functioning properly? Evap,egr,etc

 

[steve]

Even if the O2 is cycling, it can get lazy and require the ECU to add or subtract more fuel than a good sensor which can cause higher emissions. Every time I failed testing I had to change the sensor to pass. I've never seen a O2 sensor CEL pop up even when the sensor was flatlined.

 

[DSM1G90]

UPDATE: got the o2 installed and still pooched the sniff test.

I'm supposed to have a 220 on the idle readings and I won the glorious, rich mixture award with 2740. And even on high idle, I pooched that one as well, but not as as bad.

But, "dang", sailed through the other two tests with flying colors...

SO, where to begin to look - what are the basics to dive into to find the culprit that is causing my mixture problem so I can get this all leveled out so I don't lose my registration in two months....

thx again - DSM

 

[50trimgst]

Well for starters a old cat can cause these problems as if your exhaust is stock it's probly burned out. Now this does not mean it will make a noise or be plugged up. Also check to be sure evap canister is hooked up and working properly. Also check the PVC valve as it is suposed to let a certain amount of exhaust gas back into the intake to reburn and cool the combustion chamber down witch lower your nox2 gases which is probly one of the gases you're failing. That is when nitrogen gets so hot it binds with o2 witch can be the most deadly gas coming out of your tailpipe. Let me know if all this is hooked up also the egr is working to. Also I'm a PA certified emissions inspector so I'm not blowing smoke here. Lol smoke

Also make sure your car is fully warmed when they test the car

 

[steve]

Also check the PVC valve as it is suposed to let a certain amount of exhaust gas back into the intake to reburn and cool the combustion chamber down witch lower your nox2 gases which is probly one of the gases you're failing. That is when nitrogen gets so hot it binds with o2 witch can be the most deadly gas coming out of your tailpipe. Let me know if all this is hooked up also the egr is working to.

I think you got the PCV and EGR mixed up. It's the EGR that does what you described.

 

[DSM1G90]

..Yeah, wondered on that one as well ... I did pull the PCV and it rattles okey in which I even shot starter fluid in it to really clean it out.

BUT, a bit odd is that after 23k miles on the PCV, it wasn't that all slimey inside of it as with other PVC's that I've seen with that many miles on it-like it's really not doing anything too well. Wonder, even though the turbo gauge (which I heard aint the most accurate thing on the dash) shows 0 to negative pressure during steady runs, that the PCV valve is staying closed like if constant postive pressure is always in the system to keep the PCV valve closed.

Since I have the dual line EGR valve, would the vacuum lines be crossed to keep the valve not opening, or does it make a difference? the vacuum lines each have the red and green stripes on them.

Thus, I wonder if something in the loop is running in an open condition with giving me this rich mixture - like MAF, Temp Sensor, IAC and TPS.

How would one check for leaky injectors if it's pointing to excess fuel in the bores during idle?

Thx for all the help ... - DSM

 

[Tanro]

So glad I live in a state that doesnt require emissions. If they ever try and pass dumbass emissions laws here its gonna be a over my cold dead body type of thing. Vehicles produce and insignificant amount CO2. You want to crack down on emissions? Ban cows.

 

[DSM1G90]

I would love to move to the other side of the state where emissions tests are not required, just the two counties that are listed in our area ....but my job and family is over here ... oh well ... gotta keep moving on ...

 

[steve]

I did pull the PCV and it rattles okey in which I even shot starter fluid in it to really clean it out.

BUT, a bit odd is that after 23k miles on the PCV, it wasn't that all slimey inside of it as with other PVC's that I've seen with that many miles on it-like it's really not doing anything too well. Wonder, even though the turbo gauge (which I heard aint the most accurate thing on the dash) shows 0 to negative pressure during steady runs, that the PCV valve is staying closed like if constant postive pressure is always in the system to keep the PCV valve closed.

The key thing for our PCV valves is that they seal under boost. You have to pressure test them to make sure nothing leaks from the intake manifold side to the rocker cover side at at least your boost pressure. That means having a source of compressed air to test them.

Since I have the dual line EGR valve, would the vacuum lines be crossed to keep the valve not opening, or does it make a difference? the vacuum lines each have the red and green stripes on them.

I double checked the 90 manual but it shows the same green and yellow vacuum lines as the 91+ manuals so perhaps the manuals are wrong or your car is hooked up wrong. The book doesn't show the ports on the TB very well but it looks like the yellow goes to the front top port and the green to the rear top port on a 90 TB. At the EGR the yellow line goes to the body and the green to the top. At the thermo valve the green is closest to the threads and the yellow on the end. The thermo valve blocks the connection between the two ports when the temp is over 176F. It's vacuum on the green line that opens the EGR valve. The thermo valve applies the vacuum to bottom of the EGR valve and disables it opening when the coolant temp is low.

Thus, I wonder if something in the loop is running in an open condition with giving me this rich mixture - like MAF, Temp Sensor, IAC and TPS.

How would one check for leaky injectors if it's pointing to excess fuel in the bores during idle?

If the O2 is cycling your in closed loop. The coolant temps have to read above ~109F on a 90 ECU to enter closed loop and above 186F to update the long term fuel trims.

 

[SwampRat]

Well I have a 95 and thank god they recently changed the sniffer test here in MA for 96 and newer because I always had a hard time passing. New exhaust, cat, EGR verified working, plugs wires, clean MAF you name it. I replaced the stock upstream O2 with an Innovate wide band and I monitor it with the LED gauge and it's also tied into a Greddy E01 Profec and everything is right on the money. In researching as to why it would fail unless I ran the tank dry and used basically dry gas to get it to pass I cam across a few articles about DSM and Saab turbo cars failing because the factory sets them to run fat in order to prevent detonation and thus less warranty claims. When the cars were new they didn't have the sniffer test so it was not an issue. The last year when they used the sniffer on my car I was about to go to the Registry of motor vehicles to get an exempt waver for the sniffer because they know of the problems with the DSM and Saab turbo "actually they just say stock turbo equipped vehicles" but they changed the law and I no longer qualified for the sniffer test.
All I can say is from my personal experience is good luck and you might need to look into seeing if you can get a waver from the RMV is worse comes to worse.

 

[DSM1G90]

UPDATE: pulled the rail off with the injectors intact and did the fuel pump test connector in the harness, jumper wire to battery trick to run the fuel pump so I can check for leaky injectors and no drip from any of them when I touched the battery and felt the pressure being built up in the fuel return line after the regulator (even the fuel pressure popped out one injector from the rail ... ), so I'm good there with "dripless" injectors.

Check my MAF for resistance and temperature and good there as well..which brings up the next thing .. is MAF cleaning:

Being a Karman Vortex type of MAF, what would get dirty for my MAF wasn't that all dusty and can one use starter fluid to clean out the MAF since it's a pretty high evaporating sort of fluid?

thx-DSM

 

[steve]

There's not really anything to clean. It's not like a hot wire MAF where the wire gets dirty.

 

[DSM1G90]

2nd UPDATE: I did quite the bit to the car: changed out the MAF that I got from a yard, found that my timing did slip a good 7 degrees to retard ( I must have didn't get the ECU grounded correctly on my previous test) EGR was dirty-cleaned that out and got the colors of the vacuum lines to the right connections along with two vacuum lines with slight cracks in them causing leaks. But the biggest thing was that the clamp down on the turbo end had worked loose pulling in outside air after the MAF causing the MAF not to function correctly.

Got that all pieced together and my sniff test was a lot better:

HC RPM IDLE old was 1379. new at 524 with the limit at 220 - FAILED
HC RPM 2500 old was 371. new at 92 with the limit at 220 - PASSED
CO IDLE old was 1.12. new at 0.23 with the limit at 1.2 - PASSED
CO RPM 2500 old was 0.84. new at 0.24 with the limit at 1.2 - PASSED

..still failed the test though ...

Technician recommended that I'd do an oil change then come back for the sniff since I last did my oil change a few months ago and the motor goes through a quart every 1200 miles, for the oil could be contaminated with fuel and the PVC is pulling the vapors up to reburn-why the high HC's.

See what happens ... thx DSM

FINAL UPDATE: Finally got the car to pass (barely) after an oil change (the old oil was pretty rank smelling where it was prob full of hydrocarbons) and I didn't use any trick tank fluid or even a couple of gallons of E85.

My HC number did drop real good on idle, but just 30 points below the required 220 limit. Even the fast idle was higher, but still barely 19 points under the 220 limit. CO was excellent-.33 where the limit is 1.2 .

Now, I have two years before the next test and I would like to get those HC numbers somewhat lower. What would be the trick then to accomplish this?

Thx all - DSM