Wiring up with a hard rev-limiter...

[Tomf]

I plan to wire up my megajolt bits tomorrow, and iv been looking at the diagrams on here. Im using the MAP kit.



Clearly the basic wiring for me would just be the earth, +12v, PIP and SAW.

Now i also have the hard rev limiter installed in my megajolt, so does that mean i take the 12v feed for me ignition coil from this take off or does this mean im supposed to put +12v through this terminal aswell?

also what is the rev limit output signal used for?

[B@man]

Hi Tom,

The +12v is the feed from your ignition switch via a fuse, the coil pack(s) are then supplied from the "Coil Power" pin, mormally the 12v is routed through to the coil but when the rev limiter is activated the MJ reduces the voltage supplied to the coil.

I believe the "rev limit" output was used when the rev limiter board is fitted externally, you could probably use it to drive some other external equipment as well to show when you hit the limiter, However I would think that it's fairly obvious, I've not connected anything to this pin.

[Tomf]

Thanks for getting back to me so fast.

So if i just use one ignition fused live to the 12v pin, then i just take a wire from the pin marked coil power to what would be the 12v of the coil?

Thats good then ill just leave the rev limier output pin alone lol.

Also whilst im here what size fues should i be using for the ignition live?

[B@man]

Thanks for getting back to me so fast.

So if i just use one ignition fused live to the 12v pin, then i just take a wire from the pin marked coil power to what would be the 12v of the coil?

Thats good then ill just leave the rev limier output pin alone lol.

Also whilst im here what size fues should i be using for the ignition live?

Hi Tom,

Yep you got it !

I used a 15A fuse for the MJ and a pair of coils seems OK so far !

[Tomf]

Spot on, thank you for the help iv got it all wired up today and im getting a spark so its all looking good, im still waiting for a USC cable converter to come in the post so i can start playing with the maps though.

One thing i did notice that i thought was a bit strange though was then i was turning the engine over all the plugs were sparking at the same time... Is this normal for this system?

[NITROPIXIE]

Your spark plugs should not be all sparking at the sametime and it is quite obvious to see at cranking speed.

1) Double check your wiring from your EDIS to your coil pack. Make sure that 12v is the centre pin of the coil pack.

2) Perform a insulation check between the each of the wires with the EDIS plug and Coil pack plug disconnected. There should be a very high resistance here unless they are shorting out some how.

Hope this helps

Ryan

[Tomf]

Hmm i thought as much, thinking again, i only have my spark testers on the middle two plugs (4 cylinder) would these both be sparking at the same time as both would be at TDC at the same time. Ill put the plug testers on 1 and 3 tomorrow and check.

The spark was flicking on and off as i would have expected, and not a constant spark...

[NITROPIXIE]

Ahh that's why. Yes cylinders 2 and 3 spark at the sametime, as do 1 and 4. As this is a wasted spark ignition setup your spark plugs will now fire twice per engine revolution, one cylinder on its compression stroke and the other cylinder will be on the exhaust stroke.

I find it best to take the plugs out and rest them on the cylinder head whilst cranking as it puts less strain on the starter motor and you can see all the plugs. Just make sure all plugs are grounded when doing so and try not to hold the leads unless you want a belt