Brian, good information. It always helps to understand how the system is supposed to work. It helps in the diagnostic process.
Chris, I agree, I think, retarding the timing might work, but its a risk. I'm pretty sure the EGR is working well, though I'll take a harder look there too.
Here are the numbers from the test. They test at two speeds, 15 and 25 mph, both at 1975-2000 rpm. The HC measures 15 and 10 (max is 121 and 101, with average 35 and 24). CO measures 0.02 at both speeds (Max is 0.70 and 0.90, with average 0.11 and 0.09). The NO measures 1046 and 935 (max is 1006 and 866, with average 332 and 274). So, its doing great on the HC and the CO, and just a bit over on the NO. But thats all it takes to fail.
The engine might be running a little lean? I thought that was controlled by the ECU. How can I adjust that? The ECU is deffinitely a CA model, btw. When I had the throttle body off I was after another objective. I didn't adjust anything or specifically clean anything. Yes, I'm adjusting the idle with the rear-facing screw.
Last night the idle seemed to be better, more consistent. Perhaps the dirt or whatever, cleaned itself out with driving. Is that possible?
Jerry, I'm always happy to see your replies. The timing was right on, 12?btdc. You're right, I shouldn't have to fiddle with it to make the Trooper pass smog, but I'm willing to do it if I know it will pass. I can always reset it afterwards. The large air duct, going from the air filter to the I-TEC unit, does have a hole in the bottom. I've plugged it up with some gorilla snot a long time ago, but I'll check that. The TPS adjustment? I'm used to doing that on my truck (F-350 diesel), and was able to do it on the 2.8 Trooper (sort of), but I have no experience on the 2.6 Trooper.
So, lets start with the basics. Where is the TPS on this engine? What is the adjustment procedure? My manual (Haynes 1641) makes no mention of the TPS that I've been able to find.
Would the Cat possibly cause the NO to be high? I replaced it once, 5-6 years ago, along with the rest of the exhaust system. Could it be that time again?
In looking back over my records, this same thing happened in 2003. It failed with high NO numbers, and passed 11 days later with average numbers. The only record I have of maintenance I have for those 11 days is replacing the O2 sensor. But that was only about 7000 miles ago. Could it need replacing again? Might I have damaged it or its wire lead during the head replacement? That O2 sensor lasted 3+ years, 20,000 miles.
Gerry, good point about the Cat. I wasn't aware that you could determine its effectiveness with a point and shoot IR unit. I see in the latest ad that PepBoys has an Actron unit at $50. That should be good enough for my purposes.
I've rambled long enough, asked more questions than I should in a single post. Still hoping for some input, though.
Ken
