Steveastrouk Posted March 5, 2018 Share Posted March 5, 2018 I bought my 18 year old son a 20 year old NAS Discovery 1, which turned out to be a much bigger project than we expected. It was originally from Vancouver, and meandered its way from there, through California to Central Pennsylvania over the last 20 years, where I suspect it expected to rust in peace. We've put 6" of new metal virtually all around, courtesy of YRM Metal, new crossmember, new inner wings, grafted steel around the Alpines, new passenger floor, major patches in the driver footwell. And right now the bugger won't start. For much of the time. Son ran it today, and it ran like a champion for two hours. Then he tried to start it 10 minutes later, and we get lots of cranking, we get fuel rails to pressure, but we get no bangs. One interesting thing is we get a check engine light ONLY when it starts, and not when it doesn't - I am thinking ECU isn't getting power, sometimes. I'm lost for things to poke at. Does anyone have any suggestions we can look at ? Thanks a lot. I'm very grateful for any tips you can give me. Is it worth ripping it out and putting a MegaSquirt system in ? Steve Quote Link to comment Share on other sites More sharing options...
BogMonster Posted March 6, 2018 Share Posted March 6, 2018 The symptoms sound similar to the alarm spider issue (see tech archive post) but I have no idea what arrangement the NAS V8 vehicles had or even what engine, I have a vague notion they might have had a Range Rover variant of the engine by then, rather than the same motor as the old 3.9 V8 that was in the UK model Discovery so that spider info might be completely irrelevant. Most of the expertise on here is likely to be with UK vehicles. I'd say you are along the right lines, wiring issue to something. Quote Link to comment Share on other sites More sharing options...
Steveastrouk Posted March 7, 2018 Author Share Posted March 7, 2018 (edited) Thanks BM. I was under the impression, though I may be wrong, that NAS spec Landies with that engine didn't HAVE the alarm spider thingy ? Its all turned out to be very confusing, and I am very inclined to say bugger it and put megasquirt in. Thing is, sunshine wants to drive to his new uni in New Mexico, and expects to offroad it, so I want it to be reliable. Ex-pat Steve PS. Is there a way to tell from our VIN PRECISELY which engine we have ? Edited March 7, 2018 by Steveastrouk Added PS Quote Link to comment Share on other sites More sharing options...
Ally V8 Posted March 7, 2018 Share Posted March 7, 2018 I think Bogmonster has a point here, from memory the NAS spec cars had Gems injection,so no distributor,instead coil packs at the rear of the engine.I don't think they used an alarm spider like the UK models. But the Gems ecu will still want to see a valid code from the alarm ecu.And I think thats why it won't go when the check engine lamp doesn't light up.(Same deal with early P38 RR's) Do you have the two button key fobs with it ? (Google images - YWX101220 ) Quote Link to comment Share on other sites More sharing options...
BogMonster Posted March 7, 2018 Share Posted March 7, 2018 That was what I was thinking, that the NAS vehicles have the 4.0 GEMS engine out of the P38 RR at the time. I have a feeling some even had the 4.6L engine fitted. You could post up or PM the VIN and post a photo of the engine bay and see what we can find out. Quote Link to comment Share on other sites More sharing options...
BogMonster Posted March 7, 2018 Share Posted March 7, 2018 From Wiki North America The 1994 model year marked the first year that the Discovery was sold in the United States. Airbags were incorporated into the design of the 1994 model to meet the requirements of US motor vehicle regulations, though they were not fitted as standard in all markets. All North American specification (NAS) models were fitted with the 3.9-litre V8 from the Range Rover SE models, and later models saw a change to the 4.0-litre version of the engine.[6] Technically speaking, the 1996 to 1998 US models with 4.0-litre engines had the same displacement as the 3.9-litre engines fitted to the earlier 1994 to 1995 US models; the differences between the engines involved improvements to the block rigidity and pistons, and a change from the Lucas 14CUX engine management to the distributor-less Generic Engine Management System ("GEMS"). In earlier 3.9-litre US engines the fuel injection computer (14CUX) did not control the ignition, which was instead controlled by a traditional system with an ignition coil and distributor made by Lucas. The GEMS system was developed jointly by Lucas and SAGEM; it controlled both spark timing and fuel injection. Unlike the earlier systems fitted to Rover V8 engines, GEMS was made OBD-II compliant. This change was largely driven by the federal requirement (starting in 1996) for vehicles sold in the United States to meet the OBD-II specification. Quote Link to comment Share on other sites More sharing options...
Steveastrouk Posted March 7, 2018 Author Share Posted March 7, 2018 6 hours ago, Ally V8 said: Do you have the two button key fobs with it ? (Google images - YWX101220 ) I'll have to check I have a feeling we didn't. Interesing about the alarm ECU. Is that the module in the doorpost ? Quote Link to comment Share on other sites More sharing options...
Steveastrouk Posted March 8, 2018 Author Share Posted March 8, 2018 Looks like we didn't get the fobs. We had to put a new ignition switch in already, because the original was worn out. Can the alarm box be patched out, or is it chatting to the ECU all the time ? Is it realistic to think we can find and fix it, or should we just put a new megasquirt unit in ? Quote Link to comment Share on other sites More sharing options...
Ally V8 Posted March 8, 2018 Share Posted March 8, 2018 The alarm c/locking ecu is a green box about 5" long,1"thick and about 3" wide. I really can't remember where it should be... BUT... If you pm me an e-mail address I can send you a factory document that has far more data about the GEMS fuel/ignition system than in any of the original workshop manuals or Rave discs. Quote Link to comment Share on other sites More sharing options...
BogMonster Posted March 8, 2018 Share Posted March 8, 2018 Green box with Lucas 10AS on it. I think it usually lives behind the trim in the passenger footwell in a right hand drive vehicle but not sure about LHD... Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 8, 2018 Share Posted March 8, 2018 On 07/03/2018 at 2:18 AM, Steveastrouk said: I am very inclined to say bugger it and put megasquirt in. I like this guy, he can stay! Also, that's a tried and tested approach... Quote Link to comment Share on other sites More sharing options...
elbekko Posted March 8, 2018 Share Posted March 8, 2018 If it's actually GEMS, I wouldn't be too quick to throw it out and fit megasquirt. It's a good system, just the alarm integration then that'd need fixing. Annoyingly, the RAVE doesn't seem to have much info on the integration in the D1. From the electrical diagram, looks like the alarm is in line with the park/neutral switch, and also a separate connection to the ECM. In thta case, I'm a bit surprised you say you're getting fuel pressure, as GEMS normally shuts off the fuel pump. Have you checked the inertia switch? Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted March 8, 2018 Share Posted March 8, 2018 If it fails when hot, favourite single point of failure has to be ignition. If it's got fuel pressure it's priming the pump. Have you got a spark? Is it distributor or coil packs? Ignition amp (dizzy) or crank sensor (coil pack) are two single-points-of-failure that can go intermittent when hot and would prevent starting. Quote Link to comment Share on other sites More sharing options...
Steveastrouk Posted March 8, 2018 Author Share Posted March 8, 2018 Thanks for all your helpful tips guys. We have pressure, but no spark, when it won't start. Its GEMS for sure, and it has coil-packs. It doesn't ALWAYS start cold, but it never restarts warm I believe. Like I think I said, the thing STARTS when the check engine light is lit, and doesn't when it isn't. Quote Link to comment Share on other sites More sharing options...
Ally V8 Posted March 8, 2018 Share Posted March 8, 2018 The reason it starts when the CEL lights is because its showing you that it has received the correct code from the alarm ecu. If it was a P38 RR in the same situation it wouldn't even crank,NAS Discovery and Defenders with GEMS will crank and fuel,but not spark. It is a very good system,despite what some people say, I would have a good go at fixing it before tearing it out. Send me an e-mail address and I'll send you a factory document. 1 Quote Link to comment Share on other sites More sharing options...
Steveastrouk Posted March 8, 2018 Author Share Posted March 8, 2018 Are we betting on some sort of problem with the alarm box- ECU then ? Steve Quote Link to comment Share on other sites More sharing options...
elbekko Posted March 8, 2018 Share Posted March 8, 2018 Yes, or the wiring from/to it. Quote Link to comment Share on other sites More sharing options...
Steveastrouk Posted March 9, 2018 Author Share Posted March 9, 2018 Can we link something out to disable the immobiliser box ? How about the ECM main relay not switching properly ? Quote Link to comment Share on other sites More sharing options...
Steveastrouk Posted March 14, 2018 Author Share Posted March 14, 2018 Tried to put an oscilloscope on the security code wiring at the weekend, but we couldn't get the ECU to fault ! That may in itself be a clue. Quote Link to comment Share on other sites More sharing options...
Steveastrouk Posted June 8, 2018 Author Share Posted June 8, 2018 In case anyone else has similar problems, it was failure of the wiring to the ECU fuse F3. That removes power from the ECU and the top of all the coil packs. 1 Quote Link to comment Share on other sites More sharing options...
Steveastrouk Posted June 26, 2018 Author Share Posted June 26, 2018 Ah well, It wasn't the power. We can make it work always, if we disconnect the alarm box completely for 10 minutes. Does that give anyone any ideas, because I'm out of them. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted June 27, 2018 Share Posted June 27, 2018 Is this the alarm spider thing? Not my area but I know it's a popular failure and there's a whole thing about it in the technical archive section. Quote Link to comment Share on other sites More sharing options...
Steveastrouk Posted July 1, 2018 Author Share Posted July 1, 2018 No, this is a NAS spec Disco, with the GEMS 4.0 engine. Quote Link to comment Share on other sites More sharing options...
Ally V8 Posted July 1, 2018 Share Posted July 1, 2018 Sounding more like a fault developing in the alarm module. Here in the UK I send faulty 10As units to Remotekey.co.uk to be fixed. Very helpful chap,don't know if they will deal with stuff from the US though, even my Motor Trade insurance policy has a bit where it asks if I sell or provide anything to the US. Quote Link to comment Share on other sites More sharing options...
Steveastrouk Posted July 1, 2018 Author Share Posted July 1, 2018 I took the box to work, and reflowed the whole thing in our special ovens, but it hasn't fixed the problem. Quote Link to comment Share on other sites More sharing options...
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