Author Topic: Smog gurus  (Read 1726 times)

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Re: Smog gurus
« on: May 31, 2019, 01:47:46 PM »
Where's the NOX column?

No NOX measurement requirement in my county, yet.

So, your truck passed the test, right?

Yes, by 2 HC's below the limit, which is extremely unusual for any of my vehicles, even the '86 22r w/300k+ only runs in the 50's with HC's at 2500rpm.

With only a little over 1000 miles in 2 years it could be an issue with the fuel system. Injectors can get gummed up without being used on a normal basis. How much of the fuel was fresh? Old fuel burns slower after the lighter components boil off. Even in a decently sealed fuel circuit the more volatile chemicals escape. Unless you use the vehicle regularly a good long trip with fresh fuel and cleaner would be a good idea.
Does sound like a cold cat though.

While only 1000 miles on it in two years, it runs at least once a month around my property hauling a trailer, and the occasional trip to the trail or town.
Not remembering when I put gas in it last, likely it was February, I went ahead and removed all but a few gallons then filled it with 16 gallons of 89 octane, and drove about 20 miles to the shop, so there should have been nothing but fresh gas in the lines for the test.

The only thing simple that it could be if it wasn't due to being cold, is that when I put the cat on, and fired it up, I thought I felt slight leak at the rear flange just ahead of the 2nd O2 sensor.  I couldn't hear a change in putting my hand on/off the top of the flange, but it felt like there was a slight puff-puff with the engine idling.  Being lazy, I just ran a bead of sealant around the flange, and after a heat cycle to cure the sealant, I couldn't feel the leak anymore.

I figure I will drive the truck more regularly and check the mileage, if there is a sensor or injector dumping excess fuel into the system it should be pretty clear in the mpg's, I know an aged coolant temp sensor in my 3.0 caused teh HC's to be a lot higher, nearly 3 times as much at idle and about twice as much at 2500rpms, compared to a new one that was installed between tests w/just 600 miles on it between the two tests.
'90 black X-cab mod'd 3.0, 33's/4.88's, rear ARB, custom bumpers, sliders, safari rack, etc.
'91 Blue X-cab 22re, 35's/5.29's,Truetrac front, ARB rear, dual cases, and custom Safari flatbed, bumper, interior.
The money pit '87 Supra resto/mod


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