I Challenge Anyone to Solve this Discovery No Spark Issue!

1998 Land Rover Discovery LSE– not sure the series but it does not have a distributor (wish it did!) best I can tell it is a discovery 1.
4.0L automatic transmission has 150K miles on it, does not have catalytic converters.
I purchased the rover over two months ago for my son who turns 16 this Thursday. I have rebuild jeep engines (258 inline 6cly), and swapped a fuel injected 94 5.0 Ford engine into a 1979 CJ5 jeep so I am not ignorant of mechanical work but I have had my struggles with the electrical side. This is my 1st time messing with a distributor less system. When I purchased the vehicle I was told the owner had swapped out the spark plugs, wires, ECM, alarm, MASS, Crank Position sensor, camshaft position sensor, and coil packs and the vehicle still had a miss and backfire problem. I have spent countless hrs researching on the intranet this issue, and new issues….I found exposed wires on the camshaft position sensor plug going to the engine harness. I taped them up, and drove the truck around and it seemed to run great and I thought I fixed the problem. The next day I drove the truck to work and it started missing again. Thinking the tape came loose I went ahead and put tags and insurance on it and retaped (tape looked good) the plug again but it didn’t help. I drove to auto zone and had the codes pulled:
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
TWICE
Cylinder 4 Missfire
It also had a camshaft position sensor failure code; however I cranked the truck with it unplugged when I was retaping it to see if it made a difference (it did not), so I figure that is why it showed that on the scanner when I drove it to AutoZone. It continued to act up to the point where it would shut off when I slowed down so I parked it. My plan was to clear the codes by leaving the battery unhooked and the key in start all night (autozone guy said it would clear the codes). It rained that night and the next day at lunch I went to crank the truck and drive it to autozone to get new codes and it would turn over but not start, it did run horribly a few times backfiring and spitting but not well enough to even get it in gear. That afternoon it wouldn’t even do that anymore. Since then it has been down. Using a timing light only cylinders 8 & 7 were producing spark. Sometime after that none are producing spark, but every now and then it will fire one randomly. I have checked compression on all cylinders (150psi on each). I also ohmed the coils several times (1.1 on all primary’s and 13.5 on all secondary’s), and cleaned all connector wires with cleaner and used electrical grease and plugged back up. I did notice on the coils that one side is a copper color and the other is silver, the gold was a little tarnished, so I hit it with a little sand paper lightly and sprayed the heck out of it with electrical cleaner, put electrical grease in each one and reconnected everything. I also cleaned all the wire connections on the coil pack. I have turned it over in the dark looking for jumping spark several times. I also traced the wires from the coil plug back to the ECM and the crank sensor plug back to the ECM. I replaced the crank sensor (no change), removed the inspection cover on the bell housing and I don’t have any teeth broke off that the crank sensor reads. I cleaned all grounds, and even tried a jumper cable to ensure the engine and chassis were grounded. I replaced the ECM and Alarm ECM with a matching pair (no change). I also disassembled the “main relay” (black box with two plugs next to the ECM) and found the relays to all be working correctly. I cleaned all the fuses in the main panel and greased and reconnect (panel on the left side that hooks to the battery under the hood). I also cleaned all fuses and greased under the steering wheel fuse panel. At this point I have tried everything I read on multiple forums. I have also started threads on two other forums without much new ideas coming in. I cannot download the RAVE because the only computer I have is my work computer and it will not let me download. I do have some electrical schematics that were passed on with the truck and bits and pieces of info I have found on these forums. Another notable piece of information is that the tachometer does not move when cranking, I do recall it working when I could drive it. My son was very excited to get this Rover but I really don’t know what else to try on this thing. Please help me out. I am willing to try anything but don’t want to randomly start purchasing $500 sensors with no clue if it will fix anything.

I also found the knock sensor on the drivers side wires were completly melted together. I rewired the sensor and reconnected, but it made no change as well.

Maybe you got it all wrong and the cars full electric

Ummmmmmmm no.

Ok I read and looked everywhere read everything even read doing a cold boot connecting the negative and positeve battery cables would reboot the ECU,,,doesn't work. There are a bunch of comments stating if you disconnect the cables and connect them for 10 mins it resets the ECU. Not true, It will reset the alarm though.

Unfortunatly its one of two things.

Ether its the Crank Positioning Sensor, also know as the CPS, or like in my case melted wires that went to the CPS.
Replacing the CPS is a pain to get to because of the location behind the exhaust manufold. It can be done with out removing the exhaust but its tight.
The only way to really tell if the CPS is bad is to disconnect the wires running to it and check the voltage. The CPS creats its own voltage when the engine turns over about 3 to 4 volts DC. Connect a volt meter to the two wires if its a D1 and three if its a D2. Turn the engine over and watch the voltage on the meter. If its a bad CPS then you will not have any voltage showing at all as you turn the engine over. (make sure the CPS is well grounded to the housing. If its all oily you may not get a good ground to the bell housing. The CPS grounds to the motor when bolted in. The CPS is simply a mini generator.

If its not the CPS then you need to reprogram the ECU.

If the CPS is bad you might be in luck and the ECU will sense the new CPS and recalculate the position of the engine again. If not then you have to find someone with a test book and reset the ECU.

Its the one thing you can't do without the program being reset.

Don't buy a used ECU or a rebuilt one because you still have to program it with Test book for your rig.

Try to reprogram your original. ECU first.
Also try to find a mechanic with a Test Book that is not the dealer, they are too expensive and they don't know very much farther then to sell you new parts.


good luck

thanks for valid input Mark. I did swap ECM's with the matching alarm box. I was told you don't have to reprogram them if you do both. I will ohm out the crank and see if wires are fused I will also try and test it with the motor turning over.

Ya not true about buying the ECMs together. They have to be programed to your vehicle on Test Book. Check the Oms and crank the engine to see if you get 3 to 4 volts. If you get a signal from the CPS then drag your rig down and get the system programed. The ECM is designed to shut down the spark when there is a problem that could cause the engine to fire out of time. Even if you fixed the problem the ECM will stay in safety mode until the Test Book is hooked up. Trust me I tryed every way around it to keep from going down and having it hooked up. I found a mechanic in my area that works on British cars and he had a test book to reprogram my ECM. He called me next day and it was ready.

Good luck.

regarding all the missfire codes it shows your cats are bad, if you havn't already change the cats and all 4 O2 sensors. if its not a head gasket then that should clear up the codes.

BTW install the original ECM and have the mechanic boot it on their test book. Most likely the original ECM is still good and just needs a boot. If not leave the new one with the shop. You may have fixed the problem and have been chasing the failing spark problem. I bought another ECM and it didn't work same as yours.

school of hard knocks. Check the CPS if its working then wave the flag and boot the ECM.

How does the crank sensor ground to the bellhousing? Mine is all plastic that touches the bellhousing. I ohmed the wires and they are not showing to be touching, but they did ohm good back to the ECM plug. I will hopefully get to try to get a voltage reading tomorrow. It got late tonight and I didn't want to attempt it in the dark. Thanks again for your replies.