Fiat Bravo 1999 1.6 182A4 - High lambda reading #Archived Message
Posted by Phil Dunmore on March 6, 2007, 7:39 pm
Failed it's MOT due to Lambda slightly high. Came to me after garage that tested it gave up. Dont think they tried to hard.Had a bad misfire, sorted that by replacing tatty leads & plugs. Small exhaust leak at joint repaired, thought that would sort it.
CO 0% HC <5ppm O2 1-2% CO2 14.5-15% L 1.035-1.04
These readings change little at idle or fast idle.
No codes Sensor is switching at 1hz on scope and live data All other live data looks sensible. Checked exhaust for pressure leaks.
As I understand it(open to correction) if 02 sensor is switching mixture must be correct. Therefore excess o2 must must enter after sensor. Could incorrect valve timing cause this? Its a little overdue a new belt, another that needs special tools to set.