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Quesiton on smog test result.

I have a 2000 4Runner with 31000 miles. I took it to a smog check and passed. However, some of the readings of the result are higher than average particularly in the HC testing ( what is HC?)

Here's the reading:

15 MPH test 25 MPH test HC (PPM) HC (PPM) Max: 49 Max: 32 Avg: 8 Avg: 6 MEAS: 47 (amt measured) MEAS: 12

CO (%) CO (%) Max: 0.62 Max: 0.75 Avg: 0.02 Avg: 0.02 MEAS: 0.06 (amt measured) MEAS: 0.01

NO (PPM) NO (PPM) Max: 501 Max: 754 Avg: 88 Avg: 82 MEAS: 159 (amt measured) MEAS: 17

On the 15 MPH test I barely passed the HC and reading for NO is higher than the avg. The smog guy said I might need a tune-up. Another factor could be my engine wasn't warm enough during the testing.

Any idea what causing the high reading and how I should improve it? Thanks.

Reply to
rp
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HC = Hydro-Carbon, as in fuel, unburnt that is. Looks like the engine and cat were not warmed up enough before the test, that would explain the 25 test being lower than the 15 test (I assume 15 is done first then

25). Cat got hot enough by the 2nd test to start working and converting HC and NOx into other things. Just a guess though, could also be an oil change and tuneup ahead of the test would help.
Reply to
Roger Brown

On Wed, 30 Jun 2004 21:07:14 GMT, Roger Brown found these unused words floating about:

I don't know about you guys, but I always take the cars out on a 30 mile run, sustaned above 45 mph (65 - if I can). Usual driving leaves a lot of 'gunk' and with it run a bit, it usuall passes well under average.

This also lets the computer 'reset' for the particular gas you have in the car (one minute idle beforehand).

Reply to
J. A. Mc.

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