ajscotty 4x4 Posted October 5, 2009 Share Posted October 5, 2009 My 1996 Range Rover Classic seems to be overfueling. It has had the front bulkhead repaired and the engine changed. The replacement engine is not new but low milage and had been sitting idle for a year or two. The softdash was removed when the bulkhead was repaired and all the wiring was protected from heat and welding effects. When the engine was started it was using fuel heavily and running very rough. The air flow meter has been changed for a reliable one with no change. The ECU has also been swapped for a known good one with no change. New plugs have been fitted with no change. New temp sensor fitted with no change. Could anyone suggest where the issue might be or had similar symptoms......What is the most common cause of overfueling ? What symtoms would sticking injectors cause ? How are the injectors triggered, is there a speed sensor that tells the ecu how much fuel for a given road speed or engine rpm ? Could it be the fuel pressure regulator ? Possibly unrelated : The engine load relay buzzed and the fuel injection relay would not energize the pump. The relays have since been changed. Also if the battery is left conected it goes flat after a couple of days sitting idle, it is a new battery and no interior lights are on. I am based in Hertfordshire UK and would appreciate any constructive help Quote Link to comment Share on other sites More sharing options...
DC_ Posted October 5, 2009 Share Posted October 5, 2009 No expert by far, but when i first got my RRC i had rough running too./ Turned out to be a combination of things. Mostly poor patrs. Have the Dizzy cap and rotor arm been replaced with genuine ones? Leads? Timing? Coil? You say you have changed the CTS (temp sensor) that was also a factor in the poor running of mine. Quote Link to comment Share on other sites More sharing options...
ajscotty 4x4 Posted October 5, 2009 Author Share Posted October 5, 2009 Coil is original LR product,.... leads, distributer cap are supplied from Rimmer bros. Rotor arm is original LR product. I will do checks on the throtle position sensor tomorrow. Thank you for the reply Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 5, 2009 Share Posted October 5, 2009 Technical archive -> hotwire EFI diagnostics guide. Most likey culprits: coolant sensor, airflow meter. Quote Link to comment Share on other sites More sharing options...
Ally V8 Posted October 5, 2009 Share Posted October 5, 2009 Or they have swapped the plugs over on the coolant temp and fuel rail temp sensor. Quote Link to comment Share on other sites More sharing options...
Bille Posted October 5, 2009 Share Posted October 5, 2009 Just been having similar problems on my '93 RR, after a lot of head scratching, asked a lot of people, finally think I've got it nailed by replacing the Temperature sensors (Both). I initially replaced only the horizontal (2 wires $AU20) no difference so replaced the vertical one ($AU35) up near the fuel rail and after 150klm that looks like it has done the trick....I hope. It started off just seemed to be running a bit rich, idling a bit high (1000rpm) then occasionally started cutting out when it got up to temp and I was in a line of traffic and went to move off....could 'nurse it' along if I kept revs above 1200rpm. I was given heaps of good advice but was reluctant to change everything at once because I wouldn't know what the actual problem was so adopted a slowly slowly approach. Good luck...hope this helps. Quote Link to comment Share on other sites More sharing options...
JEP Posted October 6, 2009 Share Posted October 6, 2009 Be sure to check the relays again, especially the fuel relay. It needs to be of correct type as it also supply 12V to the oxygen sensors when fuel pump is running. Wrong type can supply fuel pump with 12V but NOT the oxygen sensors and vice versa. This happend to my 1990 RR 3.9 Hotwire. I replaced the Bosch fuel pump relay with a Lucas relay. Fuel pump did run. Found out that the oxygen sensors had 12V only when fuel pump did NOT run. 0V when pump ran. ECU goes in limp home mode = running very rich. Good luck! John-Erik Sweden Quote Link to comment Share on other sites More sharing options...
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