My 97 disco is cranking but not starting again. I had this problem a few weeks ago and solved it with new plugs. It happened again.
The error codes I got are as follows:
P1187
P1314
P1313
P3999

I had the P1187 last time and it went away after fixing changing the plugs. P1314 and P1313 are indicating misfires and P3999 I'm not sure of. I'm guessing the problem is the spark plug wires but I'm checking in here to make sure.

 

Checked the spark plug wires and their fine.The spark plugs are all full of carbon just as they were a few weeks ago when it stopped starting. I don't know what causing these plugs to go this quickly. Help.

 

3999 is your code reader not able to read something. Not a valid GEMS code.

1187 is code for heater circuit fault for one of the front O2 sensors.

 

How did you check your wires, how old are they and what brand? The reason I am asking is they can only be tested by using an OHM meter to each one.
As for your fault codes, the 1313 and 1314 indicate that both cats have been damaged, which will not cause a no start but indicate that your engine has a real rich run past which killed the cats.
As already mentioned the 1187 is an upstream 02 Fault, so how many miles on the engine and when were all 4 02 sensors changed?

 

I replaced the spark plugs to get it running. The codes are cleared after the new plugs. I checked the spark plugs wires with a OHM meter, they're fine. I'm wondering why the plugs went bad after two weeks. They were full of carbon.I'm going to do an engine flush and see what happens.

 

For: P1187
Description of Fault code P1187
FUEL TANK TEMPERATURE (FTT) SENSOR CIRCUIT LOW VOLTAGE

Possible failuer of Fault code P1187

• Signal line short
• Sensor failure

Diagnostic Procedure using AutoHex auto Scan tool tester

• The data isn t obtained because B-CAN Frame can t be received.
• The B-CAN System doesn t actuate.

Test Conditions using AutoHex Scan tool tester

• When B-CAN Data is sending

Clear Fault codes Conditions

• The data isn t obtained because B-CAN Frame can t be received.
• The B-CAN System doesn t actuate.

MIL Status

• Keyless Access Indicator ON

 

Does not apply to this truck, there is no fuel temp senor inside the gas tank.

You're running to rich, either because the FRONT O2's are bad or the engine temp sensor is bad, one of the two.
The FRONT O2's control engine fueling, the rears only let you know if the cats are working or not, and since they are telling you the cats are bad, the rear O2's are working, so save your money and leave those alone.
When the engine temp sensor fails it will not throw a code, but your ECU will think the engine is at -40*F and the ECU will run it as rich as it can because a cold engine needs more fuel than a hot one.
If you hook up a live data scanner you can see the actual engine temp to find out if your engine coolant sensor is bad or not.
You can also watch the voltage on the FRONT O2's to see if they are working or not.

 

Mr. vipercarcom,

Please find attached the GEMS engine ecu manual. They wrote the book on codes, and the programmers of your scanner did not read it, they used generic data from another source. When the factory shop manual is available, it is always best to use that. Frequently Rover codes are confused in definitions by code readers. You could say that Rover charts a path where there are no roads.

You'll find P1187 on page 47, along with an in-depth explanation of how that code is generated, how many drive cycles it takes, etc.

If you can point out the location of a fuel tank temperature sensor on a Discovery 1 vehicle we would be interested.

 

Sorry, i just want to help, that is what i found in my country, For: P1187 , apologize for wrong information.

 

Not to hijack. But I just got the code 1314. I have new plugs,wires, oil,etc.. Now it spudders and won't go pass 55. The heat also rose up...