lamda sensor(O2) or amm possible, but if you are having probs as other thread do that first

 

We used to be able to trick the EPA emissions machine by ritarding the timing (or maybe it was advancing; can't remember which ) a few degrees. Ask around. Somebody will know.

Now Missouri doesn't require the emissions test for cars built before 1997 which is why I forgot. This trick won't compensate for a bad AMM, 02 sensor, or needed tune-up. But it's gotten my cars passed more than once. A "friend" at the inspection station told me how to do it.

 

Yeah, I tricked a few cars into passing by retarding ~5 degrees. I believe that addressed nitrates NO. CO and CO2 or whatever else they measured, was the EGR usually for the tests they performed here. Another good trick is to run premium gas and make sure the car is up to temp. Although that all appears to be covered already.

 

Exactly HOW did you fail? That may make our obsevations more useful. Target numbers VS real numbers would help a lot. Also do a regular tuneup, it could help a lot. Filters, air and fuel. That's a start. AMM cleaning, and whatever else you can think of that hasn't changed since last test.

 

I was having a thought about this all the other day and was considering fuel grade. If high octane fuel is "less volatile" the low grade fuel - thus preventing detonation by burning slower, would it not make sense (especially for NA's) to use a low octane fuel that burns faster and possibly more completely. I know that the a common thing to think would be to use a the highest octane "better" fuel you can buy to go for an emissions test.

Any thoughts? How might this be different on NA & Turbo cars as well?

 

Agreed with the question above, knowing which measurement failed is critical to this question.

Jetman: If you fail on volatiles (aka hydrocarbons, HC, VOC), any change in fuel (even one brand to another, possibly) is a potential "fix" because, as you state, more or less would be burned in cylinder and/or in the cat. Changing formulations or changing the timing (as Corgan has mentioned) will vary that amount and may get you a pass. One of the reasons that different brands may come into play is that the cat is selective and will oxidize (burn) certain volatiles and not others. If one gas has a different balance, you could get different results. On the other hand, changes in combustion could result in high temperatures that will inch your NOx numbers higher or could change the CO and CO2 levels. Naturally, if you pass on CO and CO2 with a lot of margin, why not use some of the margin up to pass on the HC measure?

I got a very clean bill of health myself.

http://www.saabsunited.com/upload/i...009/09/eng_convertible_update_--_good_start/inspection report Saab 1991 900.jpg

 

Timing is checked in Cali, must be in spec +/- 1 degree......
-use new plugs (correct ones and gap)
-run low octane
-run car for at least 20 minutes to get the motor and Cat up to temp.(driving)
-post results

good luck!

 

Timing is checked in Cali, must be in spec +/- 1 degree......
-run low octane
good luck!

I was always under the impression that the low octane burned less clean since the atomizers and other ingredients were skimped on, I guess I need to look into that again.

 

Thanks all...........

I was going to post the inspection report, could not find, it was on my scanner...............failed on low speed HC measured 156 max 118
NO measured 2502 max 799 CO measured 0.55 max 0.75 Got to get it running now? but thank for all the help!

Ron

 

I was going to post the inspection report, could not find, it was on my scanner...............failed on low speed HC measured 156 max 118
NO measured 2502 max 799 CO measured 0.55 max 0.75 Got to get it running now? but thank for all the help!

Ron

Generally, your car is running very poorly in terms of efficiency and is not completely burning the fuel. I'd start with checking the O2 sensor, then the plugs and inspect their gap along with cap and rotor. As suggested, clean the AMM as well. The N/A is equipped with EZK ignition control, which minimizes the chances that timing is much of a factor, but you may want to be sure that the distributor is as close as possible to ideal.

 

I agree with mmoe, but I'll tell you, that NO number looks as if you need a new cat. Even running poorly the catalyst should convert most of the NO.

I just got a new cat on my '88 (RIP) a couple of years ago for $200 at a muffler shop, NBD.

 

... that NO number looks as if you need a new cat. Even running poorly the catalyst should convert most of the NO.

+1 elkparts

 

high NOx is usually a culprit of the motor runnin too hot. although in this case it may have a lot to do with it leaning out, possibly related to his fuel problem?

 

Thanks for all the help.....

As you know the car is dead as we speak, and I suspect the fuel pump. I believe it has been running lean, its been pinging. I'm going to check the tune up parts first and the o2,(i replaced it two years ago with a ford one) and go with an after market cat. I'll keep you posted. thanks all. I just redid the head liner and the car was getting very fun to drive, I'll be back!