dave88sw Posted November 2, 2014 Share Posted November 2, 2014 I don't know if this has been done before or if it's even possible but please bear with me. I have a 96 V8 Discovery that runs very well but i think the distributor is getting a bit worn, it isn't particularly smooth with power delivery and it feels very much like a timing issue. I'm also not a fan of distributors and would like it to be a little more water proof. I am however, quite pleased with the Injection system, it seems to run very well on the 14CUX and isn't too thirsty. As i don't want the car off the road at all, i'm thinking of keeping the 14CUX and just replacing the Distributor with Megajolt. This should allow me to fit up and test the Megajolt before commiting myself to it as the distributor can stay in place. Is this a reasonable idea or am i barking up the wrong tree? Can i mimick the signal to the ecu that would normally come from the coil so that it will inject? Thanks for any thoughts Dave Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 3, 2014 Share Posted November 3, 2014 Yes you can do that quite easily, to mimic the signal you use 4 diodes and a zener wired to the coil packs feeding the ECU wire.... works well and reliably, I have done it a couple of times. If you do a search you will find it Quote Link to comment Share on other sites More sharing options...
elbekko Posted November 3, 2014 Share Posted November 3, 2014 Can't you just use the EDIS (if you're using that) IDM signal to the ECU? I'm assuming it's looking for a spark event signal? Quote Link to comment Share on other sites More sharing options...
dave88sw Posted November 3, 2014 Author Share Posted November 3, 2014 Thanks for the replies guys, really reassuring. I think this is the route to take for me as the Disco is otherwise completely standard and i'd like to keep it that way (she's never been welded believe it or not). I'll do some searching (although so far i've found very little on megajolting an efi V8, only carbs) and if i get stuck i'll shout. Cheers Dave Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 3, 2014 Share Posted November 3, 2014 I don't think the IDM signal is sufficient, yes it is looking for spark event, but I think it was out of spec from the IDM. http://forums.lr4x4.com/index.php?showtopic=75572 You need to remove the resistor in the white/black wire when doing this Quote Link to comment Share on other sites More sharing options...
elbekko Posted November 3, 2014 Share Posted November 3, 2014 According to this it should work: http://rockledge.home.comcast.net/~rockledge/EDISDiagram.jpg Not sure in what way in would be insufficient? Quote Link to comment Share on other sites More sharing options...
aniesigh Posted November 3, 2014 Share Posted November 3, 2014 If you buy the megajolt kit from triggerwheels, they do a 'tacho driver' to go with MJ which will provide the signal for the 14cux to squirt. Was only about a tenner and for me saved time of making one with diodes etc, but as boothy said you can make one yourself Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 3, 2014 Share Posted November 3, 2014 elbekko, I think it was voltage, it has been discussed before, I forget why it wouldn't work. I am sure it is right, as they wouldn't bother making the tachodriver box, or post it in the megamanual otherwise! Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 3, 2014 Share Posted November 3, 2014 Just found a bit of info, the pulse from the IDM is only 512us long, probably too quick for the poor old 14CUX to keep up with -it is looking for coil flyback voltage which would be quite long in comparison. Quote Link to comment Share on other sites More sharing options...
dave88sw Posted November 3, 2014 Author Share Posted November 3, 2014 Thanks guys , great info, i'm completely sold on the idea so now just to find the necessary bits. Thanks again Quote Link to comment Share on other sites More sharing options...
zardos Posted November 3, 2014 Share Posted November 3, 2014 Just found a bit of info, the pulse from the IDM is only 512us long, probably too quick for the poor old 14CUX to keep up with -it is looking for coil flyback voltage which would be quite long in comparison. Yes and it also does - When the engine is stopped, but the Key is turned on (KOEOff), the EDIS module emits a 64us pulse every 262.144ms to indicate proper operation. Which might confuse the ECU as well if it can detect it (thinking it is firing very slowly when not actually running) My digital dash ignores this extra status pulse when used for RPM signal Info from http://www.dainst.com/info/edis/edis.html Quote Link to comment Share on other sites More sharing options...
elbekko Posted November 4, 2014 Share Posted November 4, 2014 Just found a bit of info, the pulse from the IDM is only 512us long, probably too quick for the poor old 14CUX to keep up with -it is looking for coil flyback voltage which would be quite long in comparison. Hmm, interesting. May have to use the PIP after all then, will have to see what a BeCM makes of it Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted November 4, 2014 Share Posted November 4, 2014 You could splash out and buy a full Megasquirt and use it to run ignition-only until you get brave enough to switch the fuelling over too, makes it a much easier job down the line when the 14CUX gets flaky as you will have done the hard part (coils & trigger wheel) already. Also Nige does a lovely collection of coil brackets etc. that make the job sooo nice. Quote Link to comment Share on other sites More sharing options...
mickeyw Posted November 4, 2014 Share Posted November 4, 2014 I did this with my old Ninety. I was running gas mind you, so the 14 CUX didn't do much anyway. I just left the old dizzy in there to send a signal to the fuel system. All worked fine. Quote Link to comment Share on other sites More sharing options...
dave88sw Posted July 26, 2015 Author Share Posted July 26, 2015 Sorry to bring this back to the top after so long but i've only just got round to making any positive steps towards megajolting! Can somebody confirm exactly how to wire the signal to the 14cux ecu? I've just re-read this thread and the ones linked here and there seems to be a difference of opinion. Should i use 4 diodes connected straight to the original signal wire in the engine bay (therefore going through the factory fitted resistor to the ecu) or Should i use a zener/resistor as per the diagram and omit the original factory fit resistor or should i use the zener/resistor as per the diagram and retain the factory fit resistor? Thanks Quote Link to comment Share on other sites More sharing options...
mickeyw Posted July 27, 2015 Share Posted July 27, 2015 Just gone through this exact process with my 110 and a '95 Disco engine. I have removed the factory resistor, and used the tach adapter circuit, same as Autosport Labs can supply (4 sets of diode and resistors in parallel). This is not the same as the circuit in the Megamanual (4 diodes into one Zener) but both will work fine with the 14 CUX. Quote Link to comment Share on other sites More sharing options...
dave88sw Posted August 16, 2015 Author Share Posted August 16, 2015 Having wasted half my Sunday messing about deep in the 14cux loom, i can tell you that on mine, the wire to the ecu for the trigger from the coil is not White/Black as the wiring diagram suggests, it is white with a blue trace and it is on pin 39 of the ecu plug (couldnt read that on the diagram i found as it was too pixelated). I do however now have everything wired ready, all i need to do is get down to the scrapyard for a pair of coilpacks and a vr sensor and i should have it running. Fingers crossed by next week i will be able to smash the distributor to pieces and rid the car of the misfire it has had for the last few months. Cheers guys Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted August 16, 2015 Share Posted August 16, 2015 You mean that's when you find out it is fuel related? Quote Link to comment Share on other sites More sharing options...
missingsid Posted August 26, 2015 Share Posted August 26, 2015 I had horrendous issues with my admittedly carb V8, poor running, no running, barely running. Added MJ and it all went away! Good luck and enjoy. Marc. Quote Link to comment Share on other sites More sharing options...
dave88sw Posted October 12, 2015 Author Share Posted October 12, 2015 I can now FINALLY finish this thread off. After months of having no spare time to get to the scrapyard, i finally found a spare 10 minutes last Monday and actually found 6!! coil packs. Fitted it all this weekend and it fired up first try, after a test run, i found it wouldn't rev over 3500 rpm and after a bit of head scratching, found the rev limiter was set to 3500, so upped that to 5500 and had another go. It is absolutely fantastic, it pulls right through the rev range and is silky smooth. By far the best mod i have ever made to a car and i have no doubt in my mind now that i will be fitting it to my series 2.25. Thanks for all your help guys Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 12, 2015 Share Posted October 12, 2015 Great stuff! How long until you Megasquirt it Quote Link to comment Share on other sites More sharing options...
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