My '97 Discovery stopped running yesterday. Engine just died. Would restart and run for 5 or 10 seconds then die again. Starter would not immediately turn over if you tried key immediately after engine stopped. You have to wait a few seconds. Local garage says the computer seems to not be sending a "Run" signal to the fuel pump. If they hot wire the fuel pump the engine runs fine. Any ideas? I don't want them to spend days trying to figure this out if at all possible. Thanks
The update on this problem is that the computer is not providing the necessary ground connection to the fuel pump relay. The relay and fuel pump are fine. If the garage grounds the relay the pump runs, Rover starts and runs fine. Can't do this permanently as the garage says the pump is not supposed to run continuously. The fuel system could overpressure, leak and a fire might result. As the main computer has nothing to do with the security system the garage does not think there are any security system issues. The fact that the ignition key does not immediately activate the starter makes one wonder though. Three days and still no car.............
On or around Thu, 04 Jan 2007 17:43:33 GMT, "Gordon Wedman" enlightened us thusly:
if we're talking a V8, they're talking crap. The pump runs continuously but has a cut-off via the ECU for "engine not turning", which would appear to be the signal you're missing. I forget exactly how it gets the signals on the hotwire which yours will be, it's either a signal from the ignition or from a crank sensor, to tell the ECU the engine is rotating. The ECU then switches the fuel pump. If there's no wiring fault in the bit from the pump to the ECU, then it could be a fault further upstream. right, looking at the book...
connection from coil -ve to ECU pin 39, via a 6.8Kohm resistor. You should get 9.5V +/- 1V with ignition on.
Fuel pump suppy is via the fuel pump relay and inertia switch. The fuel pump is earthed to the vehicle frame somewhere.
The fuel pump relay coil is fed from ignition live and so must be switched by earthing pin 16 on the ECU to trigger the relay. This will only happen if it gets the signal from the coil. The relay supply is battery live and the relay load goes via fuse B8 to the inertia switch and thence to the fuel pump.
The pump should run for approx 1s when the ignition is turned on, even without turning the engine. This is done by the ECU earthing pin 16. If this is not happening, then pin 16 will show battery voltage all the time, in which case the book says the ECU is suspect. If you get 0V on pin 16 but no fuel pump operation, and the pump is known to work, then there's a fault in the wiring.
If the pump runs for 1s when the ignition is turned on but then doesn't run again when the engine is turning, I'd suspect the connection to pin 39 via the resistor from the coil.
Bear in mind that I have had odd results from a pump which ran not-fast-enough. In that case though the vehicle would idle but not run when throttle was applied.
a 12V test lamp on the pump supply lead can make it easier to spot if the pump supply comes on.
At Land Rover's suggestion the garage replaced the HBB relay unit and reset the computer. The car started up and I drove it home yesterday. This morning it would not start:
-no Check Engine light a key position 2
-sometimes cranked but no start
-sometimes would not crank I understand there is a TSB that covers this sort of intermittent starting problem. Check some connections and also reprogram the 10AS ECU with the
1998 security settings. I went back at noon and it started. I drove it back to the garage and asked them about this. They don't want to do any more work unless they do a full tune-up. Don't believe its a security issue. Any thoughts? I may have to take it to the LR dealer 160 km south of here.
Yes, in fact there is a technical service bulletin on this issue. It says to check a few connections and to try reprogramming the spider to the 1998 security protocol. I talked to my garage about that but he does not want to do anything unless he first does a complete tune-up: new plugs, plug wires, etc. Since the car is now starting up as normal I'm going to hold off on the additional expense for now. Its awkward driving around with your fingers crossed but I guess that's what you have to put up with if you wish to drive a Land Rover.
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.