78 replies to this topic

[mike.]

Well its got 12v at the middle pin on the coil, but I took a plug out and couldn't see it sparking (was thinking it was because the plugs might earth through the block)

Also tried putting a nail into the HT lead and holding it close to a head stud to see if I could see a spark but that didn't work either. Whats the best way to see if i'm getting a spark?

[liirge]

If you have access to a colourtune, you can see if its sparking

[The Matt]

You tried reversing polarity on the VR?

[l_jonez]

One thing to check is the the 12v supply is constant when the starter is cranking over.

I made that mistake, on a mini when you engage the starter the 12v to every thing else is removed.

Edited by l_jonez, 07 December 2011 - 06:52 PM.

[mike.]

Yep tried reversing the wiring on the VR.

Not got a colourtune either...

I'll check that the 12v is constant whilst cranking, but it should be as its powered from the starter solenoid via a ignition switched relay.

[l_jonez]

but it should be as its powered from the starter solenoid via a ignition switched relay.

in that case theres a good chance the relay will drop out when the engine is cranking. theres no need for a relay as even the coil pack is a fairly low ampage you just need a switched supply (which is constant when cranking ) iirc i took my feed from the original coil +12v wire. (pink/white)

[mike.]

Sorry should of explained, i've fitted a second fusebox to run all my ancillaries off which runs through a relay off the solenoid. That fusebox is what its all power off through a 15 amp fuse at the mo.

But how can that relay drop out if its powered from the solenoid? The solenoids gota have power whilst cranking, otherwise it wouldn't turn over - or an I missing something.

[l_jonez]

might be the way i read it, i thought you meant the the +12v for the megajolt comes off the the solenoid but via a relay which is operated by the ignition.

what i was trying to say is that when a starter is cranking power is cut to every thing other than the coil and the starter

[mike.]

Right i'll just have to check i'm getting voltage then.

But the relay is switch by the ignition, so the relay is on and powering the MJ from the second click of the key - Just need to check its still receiving that whilst cranking

[l_jonez]

Right i'll just have to check i'm getting voltage then.

But the relay is switch by the ignition, so the relay is on and powering the MJ from the second click of the key - Just need to check its still receiving that whilst cranking

yep

[l_jonez]

I've got 12v on mine. either way you need a constant supply.

Edited by l_jonez, 08 December 2011 - 08:03 AM.

[mike.]

Just to update this, the plugs i'm running are NGK R BCPR6ES with the gap set at approx 0.70mm

[mike.]

Ok, spent a while testing today and found a couple of problems.

PIP and SAW connections are ok, EDIS to VR are ok, however I think i've got the 2 outer pins on the coil plug wired back wards. I think whats confused me is from this wiring diagram:

http://www.autosport...ule_harness.png

Since its labelled coil, i've wired it as I look at the coil. When infact thats supposed to represent the plug for the coil...

So going of this photo of my plug, with pins for 1,2,3 from left to right:



I've got pin 1 going to pin 12 on the EDIS, pin 2 going to my hard rev limiter through my MJ, and pin 3 going to pin 10 on the EDIS.

I'm unsure if this is right, as if you imagine that wiring diagram as looking directly at the coil as its labelled my wiring is right, but if its supposed to be how the plug is wired them its wrong...

Also Jonez is right about 12v whilst cranking! I'm getting 12v to the coil and the power supply i'm powering the whole lot off, but whilst cranking this drops to 0.9v!

I don't understand why this is happening though - Here is how my second fusebox is wired:



1 large gauge cable coming straight off the solenoid, through a 60 amp fuse, through the relay. After the relay are then 6 cables, each rated at 17 amp, one for each fuse of my second fusebox. The switch for the relay is off the top fuse on the original fusebox.

So the relay must still be getting power as its bolted on to the solenoid which is obviously getting power whilst cranking, but with Jonez's info in mind - Will all power to that top ignition switched fuse drop out whilst cranking meaning the relay loses its switch power and turns off?

If thats correct - Why am I still getting a reading of 0.9v at the coil whilst cranking? If the relay switches off whilst cranking I should be getting 0v shouldn't I?

This will also be a problem for my fuel pump, as that is wired through my fuse box, so will also not be getting 12v whilst cranking!

[l_jonez]

its simple a relay needs a trigger in your case its the top fuse on the original fuse box but as i said when you crank the supply to most of the car is lost (including top fuse) so with out a trigger the relay will drop out regardless and hence you loose power to your secondary fuse box.

dont worry about the 0.9v its one of the strange things that happen in automotive electrics

[l_jonez]

as a test remove the the relay and see if it starts but be aware that its permanent live so the only way to then stop the engine is to pull the coil connector or remove the supply completely