Please Help: 3rd Fail at CA Smog Ref with 3.6L conversion
 

I have read numerous threads in the forums about emmisions, catalytic converters, MAF, O2 sensors, etc in attempt to figure out my current issue but really need some help and advice, please. The car is very close to passing but I can't figure out what needs to be done. I was hoping those more knowlegeable than me can provide some help to me and others that may be in similar 3.6 conversion CA smog issues or those thinking about a 3.6 conversion in the future.

Here is the background: My car is 1978 SC with a 1989 3.6 964 motor. The motor was built and installed by Mark K. in San Diego. It runs great and goes like a stabbed rat. It has the plastic "air intake" from a 94, drilled factory air box, K&N air filter, AutoAuthority chip (will change to Steve Wong once I complete smog), S-Car-Go headers, new 3 wire O2, new CA legal Magnaflow Cat (193-86-36105-0109) and small resonator muffler immediately after the Cat. Not sure this is important but hose from oil tank returns to intake to pass visual inspection instead of a catch can/breather as originally configured for the 3.6 conversion.

1st test:
Before I took the car to the referee 3 wks ago I did a pretest at a Gold Shield station and the car passed. The next day I took it to the referee and the car passed visual and functional parts of the test with no issues. During this test the AutoAuthority chip was still installed and the car failed emmissions.
http://forums.pelicanparts.com/uploa...1354908555.jpg
I showed the pretest to the referee and he pointed out the the Gold Station entered the car as a 1978 SC so the limits were higher for Nox so it passed.

Went back to Mark K to discuss results and potential causes. He said CO indicates car running lean so he adjusted MAF 1 click CCW to richen mixture and showed me how to do it. The Cat is brand new and had less than 200 miles on it and nearly at the end of the exhaust system so we thought the Cat needed to be "run in" a bit more and ensure appropriately heated up prior to the test. I also put some CRC Guaranteed to Pass Smog additive in the tank and drove it around until almost empty tank.

2nd Test:
AutoAuthority still in DME and MAF gear 1 click CCW (from discussion with Mark) to richen mixture in attempt to cool down chamber temp and reduce 15mph Nox. Referee quickly did visual and functional, still passed. Emission test failed, even with MAF moved one click to richen mixture, CO still low but Nox increased with MAF one click richer, run in of Cat and CRC additive through 1 tank of gas.
http://forums.pelicanparts.com/uploa...1354910363.jpg
Referee said car looks to be running lean and chamber temps high producing high Nox. I told him I know how to adjust MAF to richen mixture in attempt to reduce chamber temp and Nox. He said he had time so we went for it, two more times. Each time moving MAF gear one click CCW to richen mixture.

1 more click richer (total 2 from original setting) results:
http://forums.pelicanparts.com/uploa...1354911043.jpg
15mph HC and CO drop (don't understand this) as well as Nox but still fail. 25mph HC almost the same, CO increase slightly from richer mixture and Nox significantly decrease.

1 more click richer (total 3 from original settings) results:
http://forums.pelicanparts.com/uploa...1354911438.jpg
15mph HC and CO sudden jump above limits and Nox reduction but still over limit. 25mph HC and CO sudden jump and Nox up also, but still under limit. (really don't understand this). Nothing appears linear with regard to HC and CO with once click of MAF.

Back to Mark to discuss. We decide to put a stock chip in DME and tack weld a small neck down at the tail pipe to increase back flow in attempt to lower chamber temp as well as heat the Cat a bit more. We move the MAF back 2 clicks leaner. I take it for a pre-test and make sure the tech entered it as a 89 3.6L. Failed but really close.
http://forums.pelicanparts.com/uploa...1354912546.jpg
HC pass for both 15 and 25mph, Nox pass but CO at 15mph high and at 25mph at the limit. I move MAF back one click to lean it out, so now the MAF is now at original setting when we started the smog tests, but now the car has a stock DME and more exhaust back pressure.

3rd Test:
Referee doesn't the quick visual and functional, still passed. Emissions fail, only change from pretest is one click leaner on MAF as mentioned above and full tank of 91 octane gas.
http://forums.pelicanparts.com/uploa...1354912959.jpg
Slight increase in HC at 25mph, CO decrease at both 15mph and 25mph due to leaning MAF one click, but Nox jumps at 15mph almost 300ppm and almost 800ppm at 25mph. Does this make any sense? How can one click of MAF cause such a swing in results?

Referee says he has time for one more test if I want to try to richen MAF because we have a little room at HC and CO. I move the MAF one click to richen and emission fail again.
http://forums.pelicanparts.com/uploa...1354913557.jpg
15mph HC increase 33ppm and over limit, 15mph CO up over limit, but both 15mph and 25mph (barely) pass.

As I said, car is very close to passing but I don't understand the wide swings in HC, CO and Nox with one click changes in MAF. As I said, O2 sensor and Cat are new, stock chip in DME and more back pressure. Not sure what to do now.

Do these result point to anything in the system as being suspect? I am going to change the plugs and thinking about an oil change to reduce potential effect on HC and or CO of dirty oil fumes going back into intake. Please let me know if I am missing anything obvious or not so obvious, suggestions, advice, etc:confused:. Would really like to get this car to pass CA smog.

Thanks in advance.

Can you have someone like Steve Wong program you a "smog chip" designed to run at the lowest possible emissions?

How about disable one fuel injector! So that cylinder becomes a "fresh air" pump into the exhaust stream!

PM sent

So why does the breather return to the intake instead of a catch tank? In my experience, which includes passing cars through BAR refs in CA, the emissions equipment needs to be identical to the later spec of the engine swap, and not done according to how it was originally done.

I mention this because it very well could be the source of your dirty reading. If you ran that dirty oily air into a tank instead of combusting it, it might be the difference between pass and fail.

So, why do you say you had to do it this way? It's backwards from what I am used to doing. I have had to add tanks to cars before because the ref expected to see one (not on Porsches, BTW).

Thanks for the responses guys, please keep them coming. Looks like not too many people want to open the thread, probably bring back bad memories:

McLovin, I was thinking about asking Steve about that but wanted to check to see if there is something else that I am missing. Theoretically a stock chip with good O2 sensor and Ca legal Cat should not need customized fuel mixture maps, but that is just theoretical. You suggestion is definitely a consideration and option if everything else fails.

Matt, I am definitely not an expert but I put the oil tank breather line back into the intake (edited, I previously wrote "exhaust") based on recommendation from my motor builder because he though it would not pass inspection with a collector tank/breather. Not sure how the original 964 was set up but I think the oil fumes/vapors were some how put back into the intake but perhaps "filtered" first. If what you say about taking the oil tank vapor line can out of the intake and into a collector/breather will pass visual, then I think it could make a difference. If I could only find a Gold Station that would not mind me paying for time on their machine and "experiment" to debug the issue. I could pre-test with oil tank breather hose out of the intake and see what happens to eliminate a possible cause. Most Smog stations are so afraid of a sting operation they don't even want to perform a pre-test on a conversion. The referee is really helpful and gave me his phone number so I could tell Gold Stations to call him to explain that we are trying to pretest to fix the emissions and pass the engine swap. I am going to try to find a friendly station, but first I'd like to know which other knobs to try to turn to fix the problems.

Again, please keep suggestions coming and if you guys know other Pelican members who may have some info that could help, like Steve Wong, Wayne, Instant G, and others, please direct them to this thread. This is a challenge I want to overcome not only for my car but others in CA who want to do or have a 3.6 conversion.

Thanks

Just spoke with the Ref about catch can/breather for a conversion. Car will not pass visual inspection if the oil tank breather line is in a catch can with a breather vented to atmosphere or just terminated at the catch tank. He said if I want to put a catch tank in line of the oil tank breather line prior to the intake to separate oil from vapor that is okay, but he doubts it will help my car with the emissions issue.

Suggested putting the MAF on an analyzer to see if the output voltage curve is smooth and no evidence of step functions, spikes or dips. Also suggested to check the O2 sensor to ensure it can swing in range of voltage output in fraction of a second. He says the closed loop system is working but varying in non proportional manner so probably not a mechanical problem. Also provided some info about Cat regulations that I should read up on. I will check it out and report back in case it could help other pass smog with a conversion.

Thanks

Wasn't sure if the cannister would matter or not. I also wasn't sure on what was stock for a 964 since I am a vintage guy. My direct experience is Subaru and Honda based where they have engine mounted charcoal cannisters. They also have PVCs and EGRs and all kinds of emissions stuff that only are installed on certain years and certain ECUs have different tunes based on that stuff. It was just a shot in the dark. If the ref says it won't help, I would trust him over me any day of the week.

In all my go arounds with old cars and smog, high NoX is either bad/inoperable EGR system or if no EGR, then a weak cat.

From the sounds of you making either HC or Nox but not both pass/fail, my guess is that your 'new' cat isn't doing jack.

Can you fit a good used factory cat?

(imo on the breather, my Jeep smokes like a locomotive out the breather and still gets through smog)

What gears are you testing in? I know this sounds strange but on another car I had it had the same outcome, 3 times, 3 fails. Then I said to the guy to try in different gears and it passed. First three times, second and third gear, gears that passed, first and second.

Can you install a stock 964 cat? I'm not familiar with the cat you're using but I do know the 964 metal based cat is very efficient. It might make difference

East bay and Dan J, I do have access to a used factory cat but but I am not sure it will fit my current exhaust set up. My car has S-Car-Go equal length headers that tie into a y-pipe that bends toward the passenger side then up under the bumper and then reverses direction towards the drivers side where the cat and small resonator terminate at a small curved tip. My other concern is that the Cat is so far at the end of the exhaust chain that it is just not getting hot enough to work properly. Even if I try the factory cat, I wonder if the location and the age of the Cat will work to reduce Nox enough, but its worth a try. I will ask my motor builder for it.

Tobluforu, the Ref is really helpful, he runs the test in 1st and 2nd. For 15mph he even goes to the lowest speed allowed i.e. 14mph in attempt to reduce chamber temp.

I found some interesting information regarding CA Cat requirements. I think it is well known that if we in CA use an aftermarket Cat, it needs to be 50 State (i.e. California compliant) certified and be marked with an appropriate number indicating CA legal, like 193-86, the part number appropriate for the car/engine type and date of 0109. However, the Ref told me that as long as the CA code is present (193-86) he is not required to confirm the Cat part number associated with the car/engine. What this means is if there is a more effective and efficient CA legal Cat, e.g. for a larger displacement car, that can be fit into the exhaust system, the Refs cannot reject it. Ref said this is a potential area to gain margin in system's ability to knock down Nox numbers.

I'm going to call Magnaflow and Walker on Monday to see if their engineers know of a more efficient Cat than the one specified for the 89 3.6L that is installed in my car.

Cat...
 

I have been down the California REF thing with my Vanagon Subaru 3.3 conversion and my 87 gti 16v (notorious high emitter)

Assuming there are no other issues with ignition my experience is its the cat efficiency. aftermarket cats are not as good a OEM. I have learned that one the hard way and also make sure the engine is well warmed up.

Good luck Daron

You live in CALIFORNIA I can tell you how without adjusting anything from
this point 'forward' ;)
SmileWavy