My 1996 Discovery 1 had a fuel injector leaking down, a bad MAF, #4 cylinder with a regular misfire, an iffy fuel pressure regulator, and oil leaks from the valve covers. Despite all this, it ran OK but got poor mileage. I’ve rebuilt a number of engines and I understand EFI in general pretty well, so I ordered parts and dove in. It was probably a mistake to replace everything at once from a diagnostics point of view, but I was in there cleaning everything anyway, so I did a lot of replacements. Long story short(er), I got everything back together with 19lb fuel injectors from a Mustang ( a perfect fit minus the clips,) new TPS, valve cover gaskets, pressure regulator, new hoses everywhere, two new ignition coils (one for #4/7 and one for another I thought was iffy,) and a MAF sensor. It wouldn’t idle at all, nor rev up. After figuring out how to reset the idle air control, it was running, but crappy. Checking for spark using a timing light, I saw that #4 and #7 were not firing. Using a meter, I saw the primary side of the coil was “open.” I replaced it with the one I had that was only suspect. “Maybe just a bad one”, I hoped. Ran great! I went for a test drive and it was feeling wonderful for about 2 miles and then went bad again. I immediately checked the coil and it was dead again!

What could be causing my coils to blow up? The only thing I can suspect is a bad ECU. Anyone heard of this happening on the GEMS ECUs? I’m afraid to try another coil - throwing away money is not cool for me. The spark plugs are the same ones that were in there and have about 5,000 miles on them and the HV wires are fairly new and look good, so that are the same as they were before the trouble. I can get an ECU, and I don't think I even need to match it with the alarm ECU on this truck (I hope - I REALLY don’t want to go to a dealer. If I can’t fix a truck myself, it’s worthless to me.) This Land Rover is challenging that thought right now.

Any advice appreciated, short of “take it to a shop.” I should be able to fix this with all of your combined experience.

If not, I’ll have a 1996 Discovery for sale in Taos, NM. Offers considered….

Thanks,

 

disconnect the battery and remove the ecu ......take the covers off and see if any moisture has gotten inside....or if the connectors are corroded...this is a fairly common issue with these. you can blow dry it out and reseal it. moisture in there can cause all kinds of trouble.....personal expeience..lol

 

Thanks for the suggestion. I'll take it apart on Thursday. The connectors are clean, as I had earlier cleaned them and used dielectric grease. When I originally bought the truck, the individual wire connector on the ECU going to the fuel pump was wonked, so I wired it directly internally through a little hole I drilled in the case and then sealed with epoxy. So, I've already had this ECU apart once. (And I think I used gasket maker to seal it back up.) In any case, I'll look for moisture and a burned transistor. I hope I find a bad transistor, because that can easily be replaced. Great suggestion. I appreciate the response.