| Failed smog - again! We need ideas! |
Subject: Failed smog - again! We need ideas! by Subman on 2009/1/20 4:23:16 Last Saturday my 91 failed the CA smog test for the 3rd time. It was 2 yrs ago that a dead short wiped out the ECM and the CCM and a 1 ½ years ago I had the last test, and had some EGR issues. A new heat tube gasket finally resolved that. But in the interim I replaced a blown radiator, heater core, trans, and a bunch of other stuff. The specs on the car are 91, auto, L-98, base model, bone stock save the 50MotorSports pinktop injectors (7 years in and no challenges), front sway bar and shocks. I took the car to a local (reputable) muffler shop to have the cat checked. I have had this done before, but it was always a pressure test. They used a simple heat sensor and found the inlet was 354* and the outlet was 251* indicating a bad cat. This cat is about 6 years old and has about 30k miles on it. I made the trip to see Andy with all the emission reports and his thoughts are these. . The cat should not have gone south at this point unless something triggered its demise. If I was running very fuel rich, makes sense. But it doesnt seem to be. The next item would be the smog pump. That was replaced (new, not rebuilt) in October along with both the check valves. Then there is AIR control valves. I think this could be a real possibility. Replacing the cat is a given, so, before I start throwing money at the car, I thought I would post on Guru and let yall take a shot at coming up with a quick, easy and CHEAP ways to test any and all things that could/would toast the cat so it doesnt happen again. Here is the 6/2/07smog numbers: 15 mph fail HC(ppm)-max-112 / mine-136; CO(%) max-0.72 / mine-0.32; NO(ppm)778 / mine-981 25 mph pass HC(ppm)-max-86 / mine-86; CO(%) max-0.60 / mine-0.06; NO(ppm)717 / mine-555 Here is the 6/16/07 smog numbers after some Seafoam and changing the plugs 15 mph fail HC(ppm)-max-112 / mine-156; CO(%) max-0.72 / mine-0.75; NO(ppm)778 / mine-1665 25 mph fail HC(ppm)-max-86 / mine-139; CO(%) max-0.60 / mine-0.50; NO(ppm)717 / mine-1355 Here is the latest smog numbers with new plugs, valve seals in (Nov/Dec) dist cap, rotor, ign. module and a pickup coil (late Oct): 15 mph fail HC(ppm)-max-112 / mine-156; CO(%) max-0.72 / mine-0.39; NO(ppm)778 / mine-1159 25 mph fail HC(ppm)-max-86 / mine-116; CO(%) max-0.60 / mine-0.07; NO(ppm)717 / mine-822 Andy will probably chime in with some more info and ideas, but dont let that dissuade anyone from puttin in their $0.02. As always, my thanks in advance to the brain trust here at Guru Subman |
