The AZ testing is a little easier to understand than the CA ones I've seen posted, fortunately. My truck passed the equipment portion of the test, but failed the tailpipe sniffer.

Hydrocarbons (HC) in grams/mile= 2.19, std. is 3.00=pass

Carbon Monoxide (CO) in grams/mile=34.05, std is 25.00=FAIL

Oxides of Nitrogen (NOX) in grams/mile=8.01, std is 4.50=FAIL

Wish I could have seen Oxides of Nitrogen at Woodstock, but I was too young. Anyway, can I get some advice on what to do? This truck is all stock and I believe everything is connected correctly. It has 141,000 miles on it and the factory exhaust, complete with pre-cat is intact. Muffler had a few little holes in it, but some muffler putty took care of that.

Thanks in advance!

John B.

141k? Maybe it's time for a new cat?

Maybe. This state has a function now at the emissions testing online site that allows you to pull the vehicle history. It has a tradition of failures, then retests where it passes. It did pass last fall, with slightly fewer miles on it.

I printed the vac hose diagram from the ASA program. Things don't look so familiar. I did find one line that was connected wrong, and two ports that were uncapped and potentially drawing vacuum, so I put tape over them for now. It doesn't seem to run any differently, but that's not very revealing.

Then I got to staring more closely at the engine. Keep in mind, it's 105 outside and I have no garage or shade and the truck's been running, so I limit my time under the hood. One glaring thing that struck me, and I don't know why I didn't see this before: the engine should have a thermo-valve below the thermostat area with vacuum lines connected to it. It's broken off, as in, there are no lines anywhere near it, and no place to attach them. There is a fitting screwed into the place where it should be, but nothing else. What's even stranger is that there aren't any lines that look like they should go there.

This is quite odd. Investigation continues.

John B.

Even more interesting about the AZ Dept. of Environmental Quality site is that you can print the trace of the actual graphs from the dyno/roller test. Just my layman's eye on the CO graph tells me something is jumping the mixture around. While the speed runs roughly the same during the first half of the test, then ramps up to a higher speed for the last half, the CO readings are up/down all the way across. The same goes for the NOX graph, huge spikes, huge valleys.

I'll scan these and post them, it's mildly interesting and I've not seen it done on here before. The graphs are not overlaid, but it still gives you an idea of how they relate.

John B.

Here's the link to the test to see it more clearly:

JohnnyB's Emissions Test

O2 sensor's on my short list.

John B.

Thermo sw controls egr, along with other controls for same.

Egr helps keep NOx low (you missed one hell of a band when you missed the Oxides of Nitrogen. Explosive sound.).

High co and passing HC indicates lean running (vac leak, maybe from missing lines), and lean out will make NOx high, too, as NOx comes from high combustion temps which are caused by too lean a mixture.

What's odder still to me is how somebody found a way to connect all the vac lines even though there's no thermo switch. It doesn't look like it happened recently, but who knows? Guess I'll next look back into ASA to see if that part is common between other years with the 2.6 so I can start looking for one in a junkyard.

Thanks again, FE.

John B.

Fudgesicles! Got the NOX down to pass, HC was still under limit, but the CO is still high.

I threw in a new O2 sensor today, as the old one was looking pretty gunked up, plus I reset the timing as I had it a bit over-advanced (like at 12 BTDC instead of 7 which is spec). After I plugged the vac leaks I'd found and did the sensor, it liked to ping lightly on the freeway at moderate load, which one of my old Raiders did when I had a touch too much advance.

But that all wasn't the fun part. Before I even got to emissions, my battery hold-down decided to come undone, allowing the battery to slide towards the engine, melting part of the positive cable and severing it, while subsequently starting a real live fire! I put it out and just sort of rested the cable on its other half and it sort of stuck there. I figured since I was a block from emissions, I'd just go through anyway. At least I made it home.

Here are today's numbers:

HC....2.48/3.00 = pass

CO....46.96/25 = fail

NOX...3.17/4.5 = pass

Sigh...help?? Suggestions? Push off cliff?

John B.

I like Fudgesicles.



That is all...

Is your secondary air working?