Spike0907

That's the annoying thing - the first thing I did when it wouldn't start was to get someone in with an Autologic - there were no error codes. He just suggested swapping out the pump for a manual one but I didn't want to do that. So I've been searching for some electrical issue since.

I am continuing my investigations with my voltmeter, and have found something odd. I am using this wiring diagram from RAVE, https://imageshack.com/i/idHBj9Oej The curious thing I have found is that, with the K116 Engine Control Load Relay unplugged so that I can probe the socket, there is 12V at pin 30 (as expected), and 0V at pin 86 (not expected). Surely there should be 12V at both as thay come off the same splice. The other thing I've found is that pin 85 of the K116 relay is supposed to go to pin 15 of the Engine Control Module, except that pin 15 of the ECM is empty - there is no metal connector, so it is not used. Am I using the wrong wiring diagram? Is so how can that be? My vehicle is a 1998 Disco 1 300Tdi auto with fly by wire. Thanks.

Thanks for the replies. The reason for changing the security control unit? For a few months I had been getting the Check Engine light coming on for a few seconds at a time, with the engine going into half power mode. Otherwise the engine was a brilliant starter, one flick of the key and we were off. Then one morning the engine refused to start - it turned over on the starter just fine, but there was no fuel at the injectors - I've taken the pipe off injector 1 to check. There's no power going to the shutoff solenoid from pin 3 of the EDC, and no clicking. The lift pump and fuel filter are good. The engine still doesn't start even when I put a fused link direct from the battery to the stop solenoid, the solenoid does click, though. I've spent hours searching the loom for loose connections or damage etc. I removed the security control unit and the EDC, opened them and searched for bad solders with a magnifying glass. I have found that it is possible to open the throttle potentiometer unit down by the accelerator pedal and clean the contacts, but a working engine is required to adjust it before re-installing it, so I'm leaving that until the engine is starting again. But apparantly, a faulty throttle potentiometer shouldn't stop the engine from starting, it just puts the Check Engine light on. I've also checked every relay I can find for correct operation. Eventually, it was a choice of changing either the security unit or the EDC. Investigations suggested that the EDC hardly ever goes wrong, so I plumped for the security unit, even though the central locking works OK. So now I've got the replacement security unit hanging from the connectors and its key fob hanging on the keys, and the central locking works OK. I'm waiting for someone to come and reprogram the new security module to work, but if the vehicle still doesn't start, what should I try next? Change the EDC? Thanks for any suggestions. I've certainly learned a lot about Discovery electrics lately!

I wonder if someone can give me some advice. I've just changed the AMR6429 module - the green security module in the passenger footwell - on my non starting 1998 300Tdi auto FBW. The key fob is programmed to the module. My problem is that the Disco is still not starting, the engine turns over fine, but there no power to the stop solenoid or injector pump. My question is this, do I need to get someone to program the new 6429 module to work in my vehicle, before it will start? Thanks

Thanks for that fireblade. I'm going to persevere with finding the fault for a while longer, but if all else fails how much do you want for the pump? Also, do you have the 4 injector pipes, 4 injectors (although I think my existing injectors will do), throttle cable, and the kick-down bracket. Thanks

My 1998 Disco 300Tdi Fly By Wire is refusing to start. It worked fine the previous evening, then next morning it cranked over just fine, but refused to fire. I tried a jump lead to the fuel shut off solenoid, and I could hear it click but still no start. Thinking it must be a loose connection or dry solder joint, I have taken out every "box" behind the dash, opened them and checked them for dry solders, pushed home every connector I can find, put it all back together, but I haven't made a scrap of difference. It turns over beautifully, but won't start. I have noticed that the Check Engine light is illuminated while the engine is cranking. I don't remember that being the case when the vehicle was starting OK. There is no Spider behind the radio, instead there is an AMR6429 unit in the passenger footwell. The central locking works OK, everything works OK, except that it won't start. Does anyone have any idea what might be wrong? It seems absurd to be changing the injector pump for a manual one, just to cover up a possibly trivial electrical fault elsewhere. Thanks