[Damian]

He looked around just to make sure everything is there. My cat isn't stock at all and he didn't even look at it. I don't think they are gonna go over everything with a fine tooth comb on a car like that, maybe if you had other stuff that wasn't stock on it.

[kdracer73]

Originally Posted by Damian

The STAR program is already going, the Typhoon falls under that category. That was earlier this year too. I'd just get the Magnaflow one and go to the same smog shop I went to over by Costco.

The Star program is running, but Star is more for rating shops and technicians.. The OBD changes have not taken effect yet... the smog machines still use dial up modems! They are 1997 technology and the new machines are not out yet. Our shop has been selected for Beta testing, and we still don't have the equipment yet.

[kdracer73]

Originally Posted by Vettezuki

Sounds good. Do they poke around under the hood at all, or just plug in?

They still are supposed to do a visual inspection. The problem is the Aveo cat is a cast piece that bolts to the manifold. If a cat is welded in, not in stock configuration, it is considered modified. We are supposed to inspect the part numbers etched into the cat, record them, cross reference them with the state database for OE certification . But some (MOST) techs are lazy ( hence the Star program rating ).

I have cars all the time that fail for illegal cats , come in the shop.

[Vettezuki]

The Magnflow is supposed to be a zero mod direct fit, bolt in. Part no 49352 is supposedly built to CA emissions spec on top of that. I don't know what the OE piece looked like exactly, cuz what's in there isn't it I don't think, but the Magnaflow should look right (bol tin) and pass the sniffer fine.

[enkeivette]

Ya, I welded my old Corvette magnaflow cat on the Neon when I upgraded to 3" pipes, no one noticed.

[Vettezuki]

Sort of making progress. . . slooowwly.

Received cat yesterday. Put brand new cat and brand new OE correct O2 sensors on. Reset codes and started driving. Mostly "felt" ok, except the O2 Heater Code still got thrown. More on that in a bit.

So got a chance to run it diagnostically today, and the emissions are all over the damn place, rich, lean, high HC ok HC, hi NOX, ok, NOX, rich, lean. The ECU is apparently struggling to control the A/F.

Took it home, drove around a little more monitoring upstream down stream O2 voltage. Upustream is between .1 and .8 which seems correct, and downstream seems pretty stable around .1 HOWEVER, the upstream swings almost randomly between .1 and .8., very rarely does it settle on anything, including while cruising under a constant steady load. This seems very strange to me. What say you? Normal, or damage to wiring and or ECU somewhere???

The heater circuit for the O2 seems to be driven by the ECU, not on a fuse or anything, so maybe that's just toast and why I keep getting P0038 and P0039.

The fan has not been working, on the dyno, she overheated pretty quickly given that it was under load, but with no air. Fortunately, that was just a bad connection. Some monkey broke the connnector so it's just the prongs stuck in the ECU connect side for now, but it works correctly, and comes on low as I'd expect around 190, with AC at any temp, etc. Also got the timing belt cover on, which wasn't too bad.

So, very slow progress but something. Anyway, what ya's think about the O2 voltage?

NOTE: The plugs look ok, and I'm not getting any misfires. The air filter is not clean, but not filthy either, so I don't think either of these are really causing grief.

[kdracer73]

The up stream o2 sensor should range from .900-.100 fairly quickly. Most inexpensive data streamers don't have a fast enough refresh rate to keep up. We look at the data in milliseconds on a good scanner.

When we ran the Aveo on the dyno, the Co and Hc was extremely high. Passing spec is around .40% and the readings where 4.0% and the second time I ran it, the hc and co where low, but the Nox was over 1000 parts per million.


For the cat conv to work, the mixture has to change. The cat stores o2 (reducing Nox) when lean, to burn off the carbon monoxide and hydrocarbons ( co is partially burnt fuel-hc raw fuel,simply) when rich.

I will do some research when I get back to work Monday....

[Vettezuki]

Originally Posted by kdracer73

The up stream o2 sensor should range from .900-.100 fairly quickly. Most inexpensive data streamers don't have a fast enough refresh rate to keep up. We look at the data in milliseconds on a good scanner.

When we ran the Aveo on the dyno, the Co and Hc was extremely high. Passing spec is around .40% and the readings where 4.0% and the second time I ran it, the hc and co where low, but the Nox was over 1000 parts per million.


For the cat conv to work, the mixture has to change. The cat stores o2 (reducing Nox) when lean, to burn off the carbon monoxide and hydrocarbons ( co is partially burnt fuel-hc raw fuel,simply) when rich.

I will do some research when I get back to work Monday....

Ok, well, definitely it was oscillating in that kind pattern, though my refresh rate was slow. Now, when you had it on the dyno, did you say the upstream was just sitting at .1? Anyway, that's NOT what I'm getting, but my rate is probably only a few times a second at most.

My biggest concern at the moment is damaging the brand new O2s and Cat. By the same token I wonder if the total learning "circuit" just takes a few hundred miles. The ECU definitely had some miles on it from a terrible condition, so maybe it's still "learning" those away?

[Damian]

It should still see good working O2 sensors and correct itself rather quickly. It will take some time to correct its fuel trims though, but even then, that should only take about 15 miles to adjust itself.

Some things to consider is coolant temp sensor, MAP sensor, and even TPS. Coolant temp sensor is really cheap to change out of the 3. You wouldn't happen to know what the A/F ratio is do you?

A dirty air filter could cause it to have unburnt fuel too since the ECU can only pull so much fuel, but then Id think you would get a system too rich code if it was too bad.

[Vettezuki]

Originally Posted by Damian

It should still see good working O2 sensors and correct itself rather quickly. It will take some time to correct its fuel trims though, but even then, that should only take about 15 miles to adjust itself.

Some things to consider is coolant temp sensor, MAP sensor, and even TPS. Coolant temp sensor is really cheap to change out of the 3. You wouldn't happen to know what the A/F ratio is do you?

A dirty air filter could cause it to have unburnt fuel too since the ECU can only pull so much fuel, but then Id think you would get a system too rich code if it was too bad.

Unfortunately this ECU does not support AF measured only commanded. That's why I was gonna borrow Adam's LM2 so I can at least see what it is sitting there, which should be dead balls on stoichiometric.

I'll change the plugs even though they look ok, since I have a new set and the air filter just to remove those as parameters. There is no indication anything is wrong with the coolant temp sensor. I do wonder a little about the MAP sensor, this system does not use a MAF. Also does a brand new cat take any time to "burn in"? I wouldn't think so, but figured I'd ask. This is a Cali-spec cat from Magnaflow, direct fit, looks OEM, so I don't think there's anything wrong with that, the O2s are OEM NTK direct fit.