From: jake.pinneberg on 9 Dec 2008 22:48 Yesterday my '95 Camry V6 passed its seventh smog test in a row. But the HC reading was 83 at 15 mph. The max permissible is 84. Two years ago it was half. All other tests were fine. The car is very seldom driven. Could that be the problem? What needs be done? Gas additive? Long trip? ... ? Thanks, Jake
From: johngdole on 11 Dec 2008 21:26 High HC means you have unburned fuel in the exhaust. Retarded timing (stretched timing belt), valve gap off spec, old spark plugs, vacuum leaks, valve carbon buildup, etc etc can contribute. Oxygen sensors can also be the culprit. Use Bosch *planar* type if necessary. These newer designs are more resistant to contamination. Oxygen sensors, like spark plugs, are actually wear items. The minute amounts of sulfur in the gas (plus other combustion contaminants) will gradually degrade the performance. http://www.boschautoparts.com/Products/OxygenSensors/PlanarO2 But if it's seldom driven then first try Chevron Techron fuel system cleaner with fresh tank of gas (gas deteriorates fairly quickly sitting around). However, with a dirty tank it may dislodge buildup and may require you to change the fuel filter. But as general maintenance a fuel filter should be replaced if you haven't done it since 95. I don't believe the lifetime fuel filter, ATF, coolant type of marketing. But "lifetime" means different things to manufacturers and owners. On Dec 9, 7:48 pm, jake.pinneb...(a)gmail.com wrote: > Yesterday my '95 Camry V6 passed its seventh smog test in a row. > But the HC reading was 83 at 15 mph. The max permissible is 84. > Two years ago it was half. All other tests were fine. The car is > very > seldom driven. Could that be the problem? What needs be done? > Gas additive? Long trip? ... ? > > Thanks, Jake
From: ransley on 12 Dec 2008 07:20 On Dec 11, 8:26 pm, johngd...(a)hotmail.com wrote: > High HC means you have unburned fuel in the exhaust. Retarded timing > (stretched timing belt), valve gap off spec, old spark plugs, vacuum > leaks, valve carbon buildup, etc etc can contribute. Oxygen sensors > can also be the culprit. Use Bosch *planar* type if necessary. These > newer designs are more resistant to contamination. Oxygen sensors, > like spark plugs, are actually wear items. The minute amounts of > sulfur in the gas (plus other combustion contaminants) will gradually > degrade the performance. > > http://www.boschautoparts.com/Products/OxygenSensors/PlanarO2 > > But if it's seldom driven then first try Chevron Techron fuel system > cleaner with fresh tank of gas (gas deteriorates fairly quickly > sitting around). However, with a dirty tank it may dislodge buildup > and may require you to change the fuel filter. But as general > maintenance a fuel filter should be replaced if you haven't done it > since 95. I don't believe the lifetime fuel filter, ATF, coolant type > of marketing. But "lifetime" means different things to manufacturers > and owners. > > On Dec 9, 7:48 pm, jake.pinneb...(a)gmail.com wrote: > > > > > Yesterday my '95 Camry V6 passed its seventh smog test in a row. > > But the HC reading was 83 at 15 mph. The max permissible is 84. > > Two years ago it was half. All other tests were fine. The car is > > very > > seldom driven. Could that be the problem? What needs be done? > > Gas additive? Long trip? ... ? > > > Thanks, Jake- Hide quoted text - > > - Show quoted text - Oil is a HC then why couldnt he be burning oil, but yes a regular Tune Up like one that everybody normaly did would locate these issues, nobody maintains cars anymore.
From: johngdole on 12 Dec 2008 22:01 How's the HC reading over the years? Gradually increase? A sharp increase in the last test? etc etc Sure, oil leaks could do it too. Did you cahnge oil/filter before the test? On Dec 9, 7:48 pm, jake.pinneb...(a)gmail.com wrote: > Yesterday my '95 Camry V6 passed its seventh smog test in a row. > But the HC reading was 83 at 15 mph. The max permissible is 84. > Two years ago it was half. All other tests were fine. The car is > very > seldom driven. Could that be the problem? What needs be done? > Gas additive? Long trip? ... ? > > Thanks, Jake
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