Range Rover 4.6 (GEMS) 1996 TA - Runs very rich, fault code P1187 #Archived Message
Posted by Shaun Dale on April 7, 2007, 12:23 pm
Bit of a headscratcher this one! Vehicle runs very rich, initially suspected MAF but am lucky enough to have a friend with T4. Fault code P1187 upstream Oxygen sensor heater open circuit.(sorry failed to record if bank A or B)But this would not give symptoms I'm seeing. Idle airflow showed as 18 (T4 says idle should be 20-25)Kg/hour, responds to snap throttle. It also gave an airflow figure for 5000rpm, right like I'm going to hold the engine at 5k! Bank A upstream lambda sensor was switching occasionally but bank B was stuck at 4.95V. I reset adaptive values and the engine ran a lot better but now neither lambda sensor is switching, both are stuck high. Unfortunately I am not familiar with the sensors used on these, the T4 says high is lean (as does Rave) So my feeling is that as engine is running rich and sensors are signalling lean that perhaps they have been poisoned with this batch of dodgy fuel that was around recently. Any ideas? Sorry about long post, Shaun