Need to know what's broken and maybe how to fix it ? Post here
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Have just finished building megajolt unit and am after a map for LPG and petrol for a 3.9 efi , also where can I get a bulkhead fitting to fit vacuum pipe to box of megajolt (v2 model map sensor in box), can you test vr sensor with out it connected up .
I think Roger is away somewhere, I would think he'd be the best person to get maps from.
For the bulkhead connector, PC watercooling suppliers might be a good option, something like this perhaps...
You can test a VR sensor using an oscilloscope but the best thing to do is just get it all hooked up and see if you get a spark. I've never known a VR sensor fail, the only thing that causes problems is when you get it wired in reverse - in which case simply reversing the wires will fix it.
Not sure if you would want my maps - they are not at all optimised, but I will post them tonight and you can use them as a start point if you like.
WRT setting the system up, most things are obvious, but there are a couple of points worth noting:
0. It's best (IMHO) to get the system running well without the MJ (ie just with EDIS in limp-home mode) and then connect it up after - obviously this is preferable for troubleshooting, and you might be surprised by how well it runs on a steady 10deg advance!
1. Check that the TDC mark is actually TDC by poking something down the plug-hole.
2. Check that the EDIS system (without MJ connected) gives a spark at 10deg BTDC (if not then you will need to 'shift' something (the maps, the trigger-wheel or the VR sensor) to compensate)
3. In my experience, it's best to use 4 diodes and a zenner to feed the flyback voltages from the coilpacks to the ECU lead from the original coil - that way it retains the OE inline voltage-limiting resistor.
4. Use the switched fuel-pump supply to feed voltage to the switching terminal on the MJ to automatically switch maps from petrol to gas (and vice-versa) Does this require a current limiting resistor? Can't remember, but I suspect so...
WRT the vacuum tube, I just ran one tube all the way from the plenum chamber to the MJ unit through a grommeted hole in the bulkhead.
Hope this helps.
The zener rated voltage needs to be just a bit higher than the normal voltage could ever reach so in theory 15v should do it, but to allow for tolerances etc I chose an 18 volt unit. There is no need for any power handling so a low powered unit is fine.
When I did it I assembled the "four-diodes-and-a-zener" on a small piece of stripboard, but I now believe that a better way would be to assemble them "in-line" and seal them in with heat-shrink, potting or self-amalgamating tape. Might be an idea to make two while you are at it since this is probably going to be the most likely source of any breakdown..
One more point I forgot earlier - if you can't get your strobe to flash (or it is intermittent) then put the pickup on No6 lead. Strobe pickups appear to be polarity sensitive, and with the wasted spark system one lead is positive and the other is negative WRT earth, and since 6 and 1 are on the same coil, they spark at the same time so either will do to trigger the strobe.
BTW - Sorry - didn't get time to sort out the maps last night - I'll do it tonight or tomorrow. Yes - I know they should be backed up on the computer...
As I said - not optimised in any way, but appears to work, and doesn't pink.
err - can't do it, it says that the extension mjlj is not allowed (same if I change them t .txt) so here they are as text - paste them into notpad then save with an mjlj extension.
Hope this helps...
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