Almost there with MegajoltV3

dalbro69 · Post by **dalbro69** » Sat Oct 04, 2014 1:21 pm

Hi everyone, Im finally in the process of fitting megajolt(v3,MAP) onto my 97' 3.9 EFI V8 serp,lpg discovery.

Ive done the basic fit and everything seems to be running in just EDIS8 mode. Finalising everything off but found the lead i had for the pc to megajolt to be wrong ( i hope its that anyway).Just a few queries im hoping you could help me answer

1. What ampage fuse should i put on the system?. ive run both coils and Edis and MJ into its own fuse box so i can give each its own fuse but not sure what size.

2. For the MAP, can i take it from the original advance take off for the dizzy on top of EFI plenum?

3. I have a standard V8 3.9 EFI mj spark map that someone kindly sent me, but can anyone point me in the direction of a suitable LPG map...i use this 90% of the time (96'-3.9-V8-serp-MAP-MJV3)

4.For the megajolt v3..Is it as simple as adding a negative trigger to switch maps (to switch to lpg map)

5.i have a basic single point LPG system that doesnt link into the lamba atall(is that open loop?). Where is the best point to now trigger the lpg system. It currently has a trigger wire going to the coil.

I do appreciate any help you can give me on any of these points. Ive scoured the site and cant find any answer to these...if i have missed them then i am sorry

Thanks in advance for your help
Darren

toenee · Post by **toenee** » Sat Oct 04, 2014 1:37 pm

1. Seem to remember it does mention somewhere on the site, a 5amp fuse is used for the megajolt. Anyway thats what I've got on mine.

2. The vacuum advance take off will be suitable, as long as it provides it isn't covered/wrong side of the throttle plate at idle. A common problem on later carb equipped cars, it was all to do with reducing emissions when idling.

Can't help with 3, sorry.

4. Yep you just need to run a switched wire to earth to enable the switch.

5. Again can't help, sorry.

dalbro69 · Post by **dalbro69** » Sat Oct 04, 2014 1:44 pm

wow...thanks for a quick responce..right..5amp for the MJ... brill. I was thinking of give the coils 30 amp as im guessing they use a lot of juice and 10 amp for Edis...hope that sounds about right.

I think the advance take off is the wrong side of the butterfly on idle...bugger !!

excellent news for the map switch..think i might be able to put that via a relay when i flick over to LPG (wasnt sure with it being a V3mj

great help so far...cheers buddy !!!!

im getting nearer lol

toenee · Post by **toenee** » Sat Oct 04, 2014 2:32 pm

This should help:
http://www.autosportlabs.net/MJLJ_V3_ve ... tion_guide

dalbro69 · Post by **dalbro69** » Sat Oct 04, 2014 2:36 pm

cheers, i have been working from that, just couldnt get the answers for these few questions, except the confusion on the map switch as the write up says it needs a 12+ ??? got confused with that as i had heard i could do it of a negative trigger

toenee · Post by **toenee** » Sat Oct 04, 2014 3:15 pm

I might have been talking shite, as I hadn't noticed your on the V3 model. Mines actually the V4, think we'll need to wait until someone else gives you the correct info.

dalbro69 · Post by **dalbro69** » Sat Oct 04, 2014 3:49 pm

no problem, still youve sorted a few things out for me...cheers again lol

dalbro69 · Post by **dalbro69** » Sun Oct 12, 2014 8:10 pm

well ive finished the install.

Ive used 15amp fuses for each coil, 10amp for the EDIS8 unit and a 5amp for the megajolt V3.

Ive used an output i found on the back of the plenum so thats sorted my MAP sensor

im not going to bother with the map switch as the LPG map seems to run petrol as good as LPG.

I still havent found out what to do with my LPG trigger yet. It currently is connected to the negative side of the coil and im asuming it reads the pulses and kicks in LPG as 1250RPM. Not sure where to connect up on the new coils or how. Ive still left the old ignition system on the car so using the old coil to swap to LPG lol

Anyone any ideas how to connect up this trigger atall.

Cheers

Post by **brentp** » Thu Oct 30, 2014 10:55 pm

Hi,

Can you tell us a bit of the purpose of the LPG trigger? does it trigger based on RPM?

dalbro69 · Post by **dalbro69** » Sun Nov 02, 2014 5:15 pm

sorry for the late reply, been away. Yes as you say, when the RPM's hit 1250, it automatically switches over to LPG from petrol and then stays on the fuel when the car returns to idle.

I have found that i can connect it to pin 2 from the edis unit which is good and works, however i lose the ability to select manual start on lpg if i do that

Post by **brentp** » Sun Nov 02, 2014 9:16 pm

Got it, thanks. You could make a combination of switches to force a manual mode, if you need to.

dalbro69 · Post by **dalbro69** » Sun Nov 02, 2014 9:52 pm

to be truthful, at the moment im having to leave the whole original ignition system connected . Reason being as soon as i disconnect any of the 4 wires from the coil, it wont allow the engine to fire up atall. Looks like the ECU receives some sort of signal from the coil to fire the engine. bugger lol

dalbro69 · Post by **dalbro69** » Mon Nov 03, 2014 10:40 am

After reading and reading, my heads about to explode. Ive found the solution, but need someone to identify a component mentioned in the installation guide. If i use the solution for driving a tachometer, it will also solve the non firing solution when the coil is removed.

I can identify the 1N4004 per coil (thats the actual name), but i cant identify the 15-18V zener...

Nothing seems to match that component name.

Can someone help atall