So I went had got the initial registration smog check and it failed the 15 mph NOx but passed the 25 mph. Here's the breakdown:

Test HC(ppm) CO(%) NO(PPM) Results
15 mph max meas max meas max meas
108 87 0.71 0.15 767 839 Fail
25 mph
83 72 0.58 0.23 706 633 Pass

If anyone has any insight into this, please let me know. The car is a 1990 5.0 tpi so it's the speed density intake not the MAF.

 

I'd back the timing off about 6 degrees and try again. That will lower both the NOX & HC (which is also a tad high).

RBob.

 

Thanks RBob, now I just need to find out how to adjust the timing. Relatively new to this whole 3rd gen TPI thing, It's nothing like My LT-1. So if anyone has a step by step on how to adjust the timing and what I need or if anyone that lives in San Diego could give me a hand, It would be greatly appreciated!

 

Get a timing gun. Attach the clip thing to the #1 spark plug wire, aim timing gun at balancer and find out what your timing is at. Then loosen your dizzy (there's a bolt or two, i cant remember, around the base of the dizzy) then turn the dizzy accordingly until you get the right timing.

 

Okay just for giggles I went and tried to pull any trouble codes from the ECM and I got code 32. Which I believe has something to do with the EGR...... I was reading up a little bit in my chilton and It says that the EGR valve keeps NOx levels down by injecting exhaust gases into the combustion chamber. Could this be why I failed the 15 mph? But still why wouldn't it fail the 25 mph as well.

 

Depends upon the conditions in the combustion chamber at each speed. If you've got "hot spots", they may be more of a factor at the lower RPM. Or, the PROM timing table may produce higher combustion temps at the lower RPMs - backing off the base timing may improve that situation.

 

With the timing, if your timing isn't set within a degree or two of factory spec they would have failed you for that as well. The print-out they gave you will should tell you where the timing is at. If it matches the sticker under the hood then you can't adjust it or they will fail you for that too. If it doesn't match the sticker then you need to adjust it until it does.

You might want to post this on the SoCal regional board as well. Being a major concern in SoCal many of the members there fully understand what the numbers mean and what you might need to do to fix them. Good luck.

P.S. Don't go back and try to smog again w/o making a significant change. The state keeps track of how many times you fail and you don't want to be classified as a gross polluter.

 

Slow91, I didn't realize CA checked the timing for emissions. They are tough out there.

Formula_racer, when you check the timing need to disconnect the EST connector. This will put the distributor in bypass mode which is when the timing can be properly adjusted.

If there are EGR problems, such as shown by the code, this will make both the NOx and HC levels high. With a double wammy at that. As Chiltons stated the EGR keeps the combustion temperature down which reduces NOx.

The double wammy happens when the EGR system isn't allowing as much EGR into the engine as the ECM thinks it is. When EGR is active the ECM adds timing and pulls fuel. Without the proper amount of EGR this action produces more NOx and HC then if the EGR system didn't even exist.

On vehicles with as many miles as the typical 3rd-gen the EGR passages can be clogged with carbon.

RBob.

 

Well the print out say the timing is set at 6 BTDC unfortunately the emissions sticker under the hood is gone so I don't know what it should be set at for a 90 5.0 TPI w/5spd. Oh and where is the EST connector???

 

That's where you need to be.

Yeah, they are! With one of the smog bills passed a few years ago there was something in there that allowed for "test only" testing. A percentage of cars, somewhere between 10%-30%(I don't remember the exact %), were to be randomly selected for "test only" test stations. I don't know if they have this where you are, but these stations are not allowed to make any repairs to any vehicles with the idea that they'll be less likely to cheat. As for the random part, I don't know anyone with an OBD1 car that doesn't get the "test only" notice from DMV.

Having said that, I believe that I read somewhere (I think on the results page of my last test) that if your timing is with in 1 or 2 degrees you can pay the "test only" tech a state set fee of $15 or $20 to set it correctly for you so you can pass. If it's off by more than 2 degrees you automatically fail (the tech isn't technically allowed to fix it) or if it's within 2 degrees but you don't pay to have set properly you fail. Lucky us, huh?

California's not all bad though, a couple weeks ago I went snowboarding on a Monday and Kayaking in the ocean on Saturday, you just take the good with the bad.

 

"TEST ONLY CENTERS" as stated are NOT allowed to adjust or repair per BAR laws. Even an unplug vacuum hose cannot be replug by the technician. That's right, he would be in violation. The only thing they can do is replace the gas cap if it fails the pressure/vacuum test.

As for the timing:
1.)If the vehicle underhood label says 6*BTDC @ 750RPM, it is allowed +/-3* and +/-50rpm. In other words, it can be between 3*-9*BTDC and in between 700-800rpm.
2.)If underhod label says 4-6*BTDC @ 750 then it has to be what it says.
3.)If underhood label say no timing adjustment, factory preset then you don't even check timing. It could be idling at 1750rpm that would still pass. However if it's idling that fast, chances are there is a vacuum leak and may possibly have the MIL on.

Formula_racer,
It is not that simple to diagnose your car just by looking at those numbers. What I mean is that to diagnose the vehicle and fix it with flying colors, not just barely passing. But at least it give me some ideas. What is the CO2 and O2 numbers? Those are an indicators if it's in fuel control. You car did not fail that bad. How old is the O2 sensor? Also, how many miles on the clock? Most likely it has carbon build-up in the combustion chamber especially if you use high octane gas. Carbon build-up in the combustion chamber is like raising the compression and raising compression raises NOx. Hope that helps. Feel free to call if you need help.

 

Well the %CO2 was 12.8 @ 15mph and 12.6 at 25mph and the %O2 was 2.8 @15mph and 3.1 @ 25mph. Maybe you can tell me something more by these numbers. The car has about 97k on the odometer, engine was replaced about 6k miles ago as well as most of the sensors. O2 sensor, knock, temp, IAC, TPS.... all the goodies. Don't know if the EGR was replaced, doesn't appear so though as it's pretty rusty.

I went out and looked at the vacuum lines from the EGR and soleniod have started to crack and split so I'm going to replace those this weekend and then check to see if the EGR is operating properly.

If someone can take a picture of the emissions sticker from a 90 5.0 TPI so I know what everything should be set at or if anyone knows where I can buy a new sticker????

Travis

 

The next time, you might want to consider a pre-test.

 

How do you get one of those, better yet where?? I haven't heard about that, what do they do?

 

I think any place that can perform a smog test can do a pre-test. Check the sign at the smog check station.

They identify problems so you can take care of them before the test.

 

how much does that usually cost to get done?

 

when we use to have that BS out here in MN we could apply for an emision exempt permit for the car about 300 dollars then it did not matter. the only thing they checked was that the block in the car was the same one on the aplication

maybe CA has something like this===

PS
i miss socal


later and
GB

rick

 

I don't recall, but it is reasonable. It only gets expensive when you have some problems that need to be a repaired before you can pass. But then, that's the purpose for it.

As Slow... mentioned, you don't want to be a gross polluter.

 

OK, directly out of the Smog inspection manual (rev. 6, Sec 1.2.0)

Technically, we can replace Fuel caps and even do oil changes if we chose to do so, but most Test-onlys don't because of the whole inventory thing. If you dont sell tangible stuff, you don't have to worry about inventory on it.


BTW, as long as you don't have tampers on the vehicle, you qualify for the state giving you $500 in emissions related repairs.

 

Since I've got a carb (1985 LG4) I get sent to a test only station every two years. But, and this is a big but, before I go to that test-only station, I go get a pre-test from somebody that can do repairs. Then I go to the test only station.

 

So what exactly does the state consider "Tampers"....... cuz I could sure use that extra funding right now. Socal is pretty expensive and smog repairs are never cheap!

 

Tampers are anything that physically and/or functionally change an emission control system.

If you have any vacuum hoses routed wrong, any hoses/wires to sensors/emissions equipment missing or changed, then you have a tamper. Basically, as long as you have the stock setup, or have an E.O. number for ANY kind of modifications, then you are OK.

Does it say temperd anywhere on the inspection Report that the station gave you?

 

No it doesn't say tamper anywhere on the inspection report they gave me, everything says PASS or N/A. The only part I failed was the NOx at 15 mph, Max is 767 and it registered an 839. HC's were also pretty high, 87 out of 109 max.

 

A technician can probably tell you what needs replacement/repair by looking at those numbers. Dyno Don, if you are out there, what do you think?

 

Not trying to put anyone down, but a good technician can still only guess at what a vehicle needs just by looking at the numbers. I have seen it where a vehicle is failing for NOx and the timing is advanced 10*, the tech that did the work was positive that setting the timing correctly would fix it, so he set the timing to specs. When the car came back, the timing was dead on, but now it's Gross polluting for NOx. Strange occurrence, but I've seen it with my own 2 eyes.

Yes, an experienced tech can make a damn good guess, but an experienced tech will also know better.

 

(Quote)

I went out and looked at the vacuum lines from the EGR and soleniod have started to crack and split so I'm going to replace those this weekend and then check to see if the EGR is operating properly.
Looks like he identified most of the problem himself

 

Thanks, Don. You the man!

 

Damn California sucks to own some muscle.

 

http://www.superchevy-web.com/tech/0501sc_smog/
Smog Legal Stroker.