Looking back through this thread there was a lot of information, so I decided to compile it for anyone who may need it.
Initial Problem: Purchased the 1998 Discovery for $600, spark was intermittent and it would not start (engine turned over).
Discovered fuse blown in the engine compartment, and dash, and fuel inertia cut off switch was unplugged. Once fixed it would crank and run but miss. Took it to auto parts store and had codes read:
P0300 Random/Multiple Cylinder Misfire Detected
P1187 Variant Selection (O2 sensor)
P1313 Misfire Rate Catalyst Damage Fault - Bank 1
P1314 Misfire Rate Catalyst Damage Fault - Bank 2
P1316 Injector Circuit / IDM Codes Detected
P1447 ELC System Closure Valve Flow Fault
Cylinder 4 Missfire
2nd Problem: Drove it for a day and it started to run horrible, would stall and finally got to the point it would not crank.
The fuel temperature sensor located on top of the tank next to the fuel pump plug was shorted somehow and after unplugging it, it cranked and ran but still missed, and finally wouldn’t crank again.
Replaced the camshaft position sensor (guessing it was taken out by the short in the fuel temp sensor) and it again would crank and run but still missed. I found all this information in forums.
3rd Problem: Using a timing light I was able to see that 8&5 and 3&2 were missing, 4&7 fired correctly, and 6&1 did not fire at all.
I purchased a computer and matching alarm computer (you need both from the same rover or they will not work, the alarm computer is green). Once this was replaced 6&1 and 4&7 fired correctly, but 8&5 and 3&2 missed. The only code I had was P1193 (O2 sensor).
4th Problem: 6&1 and 4&7 fired correctly, but 8&5 and 3&2 missed. I was certain this was an electrical issue from what I had read, combined with the intermittent miss. It did not miss all the time, sometimes it would miss in time and other times it would run fine for a minute, I did however notice it almost always missed when the accelerator was mashed to the floor. My logic was if it was mechanical then it would be a consistent miss.
I went through several steps to find the problem. I swapped the coils to see if the problem followed the coil (it didn’t), I changed plugs, and wires. Replaced crankshaft sensor, checked all plugs for a short in the wiring testing the computer side to the plug. And cleaned every ground I could find under the hood, and inside the rover. None of which solved my problem. I then discovered there are tabs that the crankshaft sensor reads to fire each coil. I removed the inspection plate on the bell housing and had my son bump the starter so I could see if any tabs were bent. I saw no damage to any of the tabs, except one was missing. It was the inside tab (there are two at each location they fly by both sides of the crankshaft sensor which tells your engine to fire). It took a long time searching the intranet to find a picture of one. A lot of folks had discussed the gap as missing teeth. There is a gap, but it is missing both teeth. I located it however I was still missing just one tooth in a different location. I had a friend who is a very skilled tig welder weld a tab (that I made by grinding down a piece of steel to match the missing tab/tooth. I saw were others had massive damage from gears grinding off the flywheel from starting the rover, but mine had zero damage other than one tooth gone. Welding the tooth on fixed the missing, and from what I gather, the one tooth must have been causing the crank sensor to see it sometimes and sometimes not which caused the intermittent miss fire and drove me insane trying to find it. The main issue I had discovering this problem was nothing fit, most folks who have had this problem have several teeth missing from a foreign object getting inside and tearing up a bunch of teeth. It should also be noted, I did not pull the flywheel to fix this. I pulled the oil pan (drain it 1st) and turned it so I we could get to the missing tooth, and turned the motor over slowly to get the pin in the best position. We also took a dremel with a flex shaft and used a cutting wheel to clean up the welds.
5th problem: I have a high idle now in Park or neutral. I have cleaned the intake and IAC, and replaced the air filter that had a huge tear in it, but have not been able to solve it. I have read were the new computer may need to be reset to fix it, but for now I am going to start working on other cosmetic (interior, leaking sun roofs, etc) before dealing with the engine again.
I also wanted to mention, I am a shade tree mechanic and have mainly worked on Jeeps since I can remember helping my dad growing up. I read a lot of folks discussing the difficulty of land rovers and how they are completely different from other vehicles. I must admit I was beginning to feel the same way working on it; however looking back it is not very different from other vehicles. I found a lot of items on forums from Chevy’s to Fords that were almost identical issues that helped me to work through these issues I described. So don’t be afraid of the land rover, but to save money USE A JUNKYARD for parts!!! One thing I read that was correct is that every part on these are almost double the cost of the average vehicle. Hope this helps someone! Also I don’t cruise the forum much but if you PM I will get an email and get back with you. I would be glad to help anyone if I can.
