wiring help........urgent !

[n2oxide]

Hi Guys.

MG MAESTRO 2.0 efi

I have an aftermarket ignition system ( MSD - using with nitrous oxide ) which takes is trigger/feed from the NEGATIVE WIRE from the coil. Car wont fire when I disconect this wire from the original coil. So the question is WHY NOT; I know it obviously sends a signal to the ECU to fire the car; but this is the same damn wire I need to trigger the MSD. It all works when BOTH connected, but cant really have a redudant coil sparking its guts out when there is loads of nitrous and fuel around............

HELP PLEASE; I need that wire to trigger my MSD but the standard ECU/IGNITION does not allow the car to start when I take it away and connect it to the MSD. YOU CANNOT CONNECT ANYTHING TO THE COIL APART FROM THE MSD WIRES - ask the many rolling roads who have tried and blown up their diagnostic machines !

Please guys, dont give me any low downs on pros and cons of nitrous oxide, I've been doing it for 20 years and know more about it than anyone. And no slagging off the MSD; just firing up the Maestro today its engine tone changed and screamed to its peak rpm without more than a dab on the thottle pedal. NO NITROUS, NO MSD, NO KNOWLEDGE.

Thanks

Perry

[mgdavid]

don't understand, if you fired it up today then what's the problem?

[E_T_V]

NO NITROUS, NO MSD, NO KNOWLEDGE.

Then why are you asking us for help

[digital efi]

don't understand, if you fired it up today then what's the problem?

It all works when BOTH connected

Could you explain a little more about how the MSD is supposed to work........for example, does it completely replace the standard distributor?
Or does it provide a spark to the distributor instead of the factory fitted coil?

[n2oxide]

I fired it up with both coils; standard coil missing it's king lead......................the MSD did the sparking, just did this to confuse the ECU that it is still connected to the original coil. When started, removed negative wire from standard coil and ECU shut down engine as expected. MSD working but need to confuse the ECU it's still connected otherwise it won't fire up the engine, but need to do this without a redundant coil sparking around the engine bay with it's king lead missing !

[n2oxide]

Msd is a capacitive discharge, it does not replace anything more than the spark, it keeps the coil firing hundreds of times per second at around 50,000 millijoules hence why only the msd can be connected to the coil. The standard dizzy cap, rotor arm and leads are used BUT the trigger/negative coil wire is what now triggers the MSD. It's not an amplified spark, it's capacitive and controlled by the msd.

[Chris Y]

I have an aftermarket ignition system ( MSD - using with nitrous oxide ) which takes is trigger/feed from the NEGATIVE WIRE from the coil. Car wont fire when I disconect this wire from the original coil. So the question is WHY NOT;

Sounds like you need to talk to MSD and ask them for help. I don't think many people here know much about n2o, and probably even less about weird aftermarket ignition systems.

[G Force]

Hi Guys.

MG MAESTRO 2.0 efi

I have an aftermarket ignition system ( MSD - using with nitrous oxide ) which takes is trigger/feed from the NEGATIVE WIRE from the coil. Car wont fire when I disconect this wire from the original coil. So the question is WHY NOT; I know it obviously sends a signal to the ECU to fire the car; but this is the same damn wire I need to trigger the MSD. It all works when BOTH connected, but cant really have a redudant coil sparking its guts out when there is loads of nitrous and fuel around............

Can you not just replace the standard maestro coil with an LED?

I'm guessing (& I mean guessing) that if you connect the coil neg directly to the MSD the engine speed signal to the EFI ECU is corrupted, causing no fuel injection rather than no ignition?

[n2oxide]

THATS IT !
SORTED THANKS
( as suspected, only someone with a nitromethane sucking V8 picture to his name would have an answer )

Perry

[G Force]

THATS IT !
SORTED THANKS
( as suspected, only someone with a nitromethane sucking V8 picture to his name would have an answer )

Perry

Your welcome Perry. glad to be of help.

Perhaps you could show us some pictures & stuff about your Maestro

Cheers, Gary (Gforce)