Failed Emissions Test Twice

TXBII · Dec 11, 2013

Hey guys.. pretty new to the forum and looking for some help. I bought a 1989 BII and have been getting it ready to be road ready. After getting it running, I thought to be pretty decent, I went to have it inspected and it failed on the Emissions Test. Nox(ppm) to High.
1st Test Run results:
HC (ppm) 17 High Speed 23 Low Speed PASS
C0 (%) .02 .02 PASS
C02 (%) 14.4 14.4
02 (%) 30.2 27.1
Nox(ppm) 2920 (standard 1161) 2623 (standard 1262) FAIL
Dilution 14.42 14.43 PASS

So from the recommendation from the Inspection Guy, Muffler Shop, and Mechanic I had a new CAT put on and they said that would fix it. Well it didn't. The numbers a little better but still way to high..

2nd Test Run results:
HC (ppm) 20 High Speed 20 Low Speed PASS
C0 (%) .02 .02 PASS
C02 (%) 14.5 14.4
02 (%) 33.9 31.3
Nox(ppm) 2328 (standard 1161) 2419 (standard 1262) FAIL
Dilution 14.52 14.42 PASS

After I had the CAT installed I drove the BII straight to my house (7 miles) to pick up the paperwork for the retest and then 15 miles down the highway to the inspection place. I never turned the BII off so it had been running since I left the Muffler shop. Was told to do that to get the CAT nice and Hot.

The only thing I have noticed is while at the Inspection shop sitting on the dyno it was idling smooth and then all the sudden acted like it started missing. And it does have a little "ping" to it when you stomp on the gas, maybe slightly out of time? Any help would much be appreciated, not all that mechanical but trying to learn as much as I can. Thanks guys!!

TXBII · Dec 11, 2013

Something else I just noticed..was going to check the timing. With it running I pulled the "Spout" and nothing changed as for my idle. From what I was reading, by me pulling the "Spout" the idle should have dropped right?

ab_slack · Dec 11, 2013

Yes pulling the connector should have caused idle to drop. The ignition would have retarded from the operating point. If the timing and idle didn't change at all, it means that it probably wasn't making contact to begin with or maybe intermittent.

If this BII hadn't been running for some time, one thing that will help is just getting driving miles on it. Burn out any junk. Maybe run a tank thru it with injector cleaner.

Also the Cat requires a certain amount of oxygen. If the O2 sensor is messed up and you aren't getting O2 to the cat, it can't convert the bad stuff like it is supposed to. You can try unplugging the O2 sensor and see if it changes how the car run. If it doesn't change at all, or it runs better you may have an O2 sensor issue.

I don't know how they determined it was the cat. Back pressure test? Or just opinion based upon the emissions results. I am pretty confident the 89 didn't have both in and out sensors to check performance. A bad O2 sensor or something causing it to run richer than it should can cause a problem with the cat.

I assume you aren't getting a CEL indication, but do you know if the CEL actually works or not (like nobody pulled the bulb or bulb burnt out).

So get the timing sorted, the initial timing set right and make sure with the SPOUT connector it advances properly. Make sure the O2 sensor is doing its thing. Then run the vehicle as I said. I learned my lesson the hard way not do run off to get it inspected right away after doing a bunch of work. Let it get all the crap that might have gotten in while sitting and working on it out.

alwaysFlOoReD · Dec 11, 2013

http://www.aircare.ca/repinfo-ere-causes-nox.php

adsm08 · Dec 11, 2013

Another thing to do is a top-end cleaning. NOx is a compound only produced above 2500F. While the engine runs around 200, the combustion can get above 2500. A few things can cause higher temps during combustion. A poorly performing cooling system can cause it, as well as a lean fuel mix. In a gas engine lean actually burns hotter than rich. An incorrect A/F calculation from bad inputs can cause a lean mix. Hot-spots from carbon deposits can also cause a high combustion temp.

I would start by doing a home-brew top end cleaning. You can either spritz some water into the throttle while running her hot and wide, or you can run some seafoam through the intake.

RonD · Dec 11, 2013

Yes, high Nox is usually EGR(exhaust gas recirculation) related.

Nox levels usually increase when cylinder temps get above 2,500deg, this should only happen when engine is under load, but lean fuel/air mix can raise cylinder temp, so nox levels as well.

Pinging is a sign cylinder temp is too high, fuel/air is igniting from the heat instead of the spark.

The EGR system cools the cylinders under load, yes sounds odd, lol, but that is what it does.
So the EGR system reduces pinging and lowers Nox levels.
The EGR valve and tube get carbon build up which lowers the flow of exhaust gas, you often will notice the start of this build up as pinging when it didn't ping before.
But easy to clean EGR valve and tube....usually

Run some Seafoam or similar injector cleaner in the fuel tank, this can help prevent lean mix from dirty injectors.
Also check for vacuum leaks, extra air means lean mix.

adsm08 · Dec 11, 2013

RonD said:
Yes, high Nox is usually EGR(exhaust gas recirculation) related.

Nox levels usually increase when cylinder temps get above 2,500deg, this should only happen when engine is under load, but lean fuel/air mix can raise cylinder temp, so nox levels as well.

Pinging is a sign cylinder temp is too high, fuel/air is igniting from the heat instead of the spark.

The EGR system cools the cylinders under load, yes sounds odd, lol, but that is what it does.
So the EGR system reduces pinging and lowers Nox levels.
The EGR valve and tube get carbon build up which lowers the flow of exhaust gas, you often will notice the start of this build up as pinging when it didn't ping before.
But easy to clean EGR valve and tube....usually

That would be great, if the 89 BII had EGR.

RonD · Dec 11, 2013

adsm08 said:
That would be great, if the 89 BII had EGR.

Maybe there is an '86 or '87 2.9l in there

adsm08 · Dec 11, 2013

RonD said:
Maybe there is an '86 or '87 2.9l in there

True.

I guess I am more fixated on fixing the OP's problem right now.

stegomon · Dec 11, 2013

if you have a car over 20 years that still runs good e nuff....screw this smog sniffing. just let the old cars go

adsm08 · Dec 11, 2013

stegomon said:
if you have a car over 20 years that still runs good e nuff....screw this smog sniffing. just let the old cars go

Agreed.

The way I see it, once a vehicle hits the 15 year mark just do a visual anti-tampering inspection. If the emissions stuff is all there and looks like it could work, let it fly.

TXBII · Dec 11, 2013

Thanks for all the replies.. Will start to run that stuff down.. One question, how can I test the Spout connector. If I want to make sure my timing is correct I need this to be working correctly and right now it seems to do nothing when I unplug it, the timing/idle doesn't retard or slow down. Just want to make sure my timing is right before I start messing with everything else.. Would you guys think this is the correct approach?

Road Angels · Dec 12, 2013

With the spout conn. out set your base timing as per spec then plug it in and see if there is a change, then rev the engine up to steady 2k or 2.5k check for advance, also did you change your plugs if not do so but go one range colder since newer plugs are a broad heat range design, go 2 ranges colder if you can get them, put fresh gas in it, I dont know if they are doing a timing check but many times pulling the timing back will reduce nox say 4 degrees, you can even go to a colder thermostat but only one range colder the sensors need the heat to send the correct signals and keep the cat lit up

Road Angels · Dec 12, 2013

One other thing is when I did inspections in calif. before the camera and dyno, some times I would tell the customer to put a bb in the vac. adv. line, and bring it back if other emission standards where well in range this would bring nox down but would raise some of the others, but still pass, I have passed turbo lasers with the timing pulled back as much as 12 degrees total advn. to the point the car had no power but was clean running

adsm08 · Dec 12, 2013

Easy way to test the SPOUT and see if it is working right just throw a timing light on it. If the SPOUT is working properly the timing will jump all over the place with the slug in and lock in place once it is pulled out.

You won't always notice a drop when it is pulled. It depends on running conditions. I can tell you from experience, if the circuit is open the vehicle won't be all that drivable. It will run great down low, but as soon as you try to get out of second gear it will fall on it's face.

Failed Emissions Test Twice

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