1998 Disco no spark issues

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#71

12-19-2014, 08:08 AM

snydesh

Three Wheeling

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Looking back through this thread there was a lot ofinformation, so I decided to compile it for anyone who may need it.

Initial Problem: Purchased the 1998 Discovery for $600, spark was intermittent and itwould 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 MisfireDetected
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 finallygot to the point it would not crank.

The fuel temperature sensor located on top of the tank nextto the fuel pump plug was shorted somehow and after unplugging it, it crankedand ran but still missed, and finally wouldn’t crank again.

Replaced the camshaft position sensor (guessing it was takenout by the short in the fuel temp sensor) and it again would crank and run butstill missed. I found all thisinformation in forums.

3rd Problem: Using a timing light I was able to see that 8&5 and 3&2 weremissing, 4&7 fired correctly, and 6&1 did not fire at all.

I purchased a computer and matching alarm computer (you needboth from the same rover or they will not work, the alarm computer is green). Once this was replaced 6&1 and 4&7fired 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 issuefrom what I had read, combined with the intermittent miss. It did not miss all the time, sometimes itwould miss in time and other times it would run fine for a minute, I didhowever notice it almost always missed when the accelerator was mashed to thefloor. My logic was if it was mechanicalthen it would be a consistent miss.

I went through several steps to find the problem. I swapped the coils to see if the problemfollowed the coil (it didn’t), I changed plugs, and wires. Replaced crankshaft sensor, checked all plugsfor a short in the wiring testing the computer side to the plug. And cleaned every ground I could find underthe hood, and inside the rover. None ofwhich solved my problem. I thendiscovered there are tabs that the crankshaft sensor reads to fire each coil. I removed the inspection plate on the bellhousing 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, exceptone was missing. It was the inside tab(there are two at each location they fly by both sides of the crankshaft sensorwhich tells your engine to fire). Ittook a long time searching the intranet to find a picture of one. A lot of folks had discussed the gap asmissing teeth. There is a gap, but it ismissing both teeth. I located it howeverI was still missing just one tooth in a different location. I had a friend who is a very skilled tigwelder weld a tab (that I made by grinding down a piece of steel to match themissing tab/tooth. I saw were others hadmassive 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, andfrom what I gather, the one tooth must have been causing the crank sensor tosee it sometimes and sometimes not which caused the intermittent miss fire anddrove me insane trying to find it. Themain issue I had discovering this problem was nothing fit, most folks who have hadthis problem have several teeth missing from a foreign object getting insideand tearing up a bunch of teeth. It shouldalso 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 overslowly to get the pin in the best position. We also took a dremel with a flex shaft and used a cutting wheel toclean up the welds.

5th problem: I have a high idle now in Park or neutral. I have cleaned the intake and IAC, andreplaced the air filter that had a huge tear in it, but have not been able tosolve it. I have read were the new computermay need to be reset to fix it, but for now I am going to start working onother cosmetic (interior, leaking sun roofs, etc) before dealing with theengine again.

I also wanted to mention, I am a shade tree mechanic andhave mainly worked on Jeeps since I can remember helping my dad growingup. I read a lot of folks discussing thedifficulty of land rovers and how they are completely different from othervehicles. I must admit I was beginningto feel the same way working on it; however looking back it is not verydifferent from other vehicles. I found alot of items on forums from Chevy’s to Fords that were almost identical issuesthat helped me to work through these issues I described. So don’t be afraid of the land rover, but tosave money USE A JUNKYARD for parts!!! One thing I read that was correct is that every part on these are almostdouble the cost of the average vehicle. Hope this helps someone! Also I don’t cruise the forum much but if youPM I will get an email and get back with you. I would be glad to help anyone if I can.

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