Shamwari's guide to emissions failures

shamwari

Ok people, found this elsewhere years ago and plagiarised it for my own needs. It's a nice quick lookup to have for emissions problems

CO CO2 HC O2 Probable cause
High Low High High Rich mixture & Ignition misfire
High Low High Low coolant temp sensor or engine not reaching correct temp (e.g. Thermostat)
Low Low Low High Post CAT exhaust leak
Low High Low High Injector misfire with CAT OK
High Low Med / Low High Rich mixture
High High High High injector misfire, CAT defective, rich mixture, vacuum leak
Low High Low Low System normal, CAT ok

David09

If an engine was consuming oil, what would this show up as???

(Besides obvious blue smoke)

shamwari

David09 wrote: »

If an engine was consuming oil, what would this show up as???

(Besides obvious blue smoke)

Usually High CO and HC

unkel

shamwari wrote: »

Ok people, found this elsewhere years ago and plagiarised it for my own needs. It's a nice quick lookup to have for emissions problems

Yeah I like that as a quick possible cause troubleshooting guide. Thanks dude!

Armadillo

CO CO2 HC O2 Probable cause

High Low High High Rich mixture & Ignition misfire
High Low High Low coolant temp sensor or engine not reaching correct temp (e.g. Thermostat)
Low Low Low High Post CAT exhaust leak
Low High Low High Injector misfire with CAT OK
High Low Med/Low High Rich mixture
High High High High injector misfire, CAT defective, rich mixture, vacuum leak
Low High Low Low System normal, CAT ok