MSD HELP

[DHGTR]

guys, i am trying to diagnose a 'no spark' problem.

the ignition is the standard msd set up.

1. there is no spark at the plugs.
2.there is no voltage going into the coil (small red block type)

what are the minimum connections i need on the msd box to run the car ;
i'm guessin, battery live (big red), earth (big black), connection to dizzy (green/violet), positive to coil(orange), negative to coil (black) and possibly the white wire from the loom which plugs into the red wire on the msd(i assume this is ignition connection)in fact the only wire i wouldnt connect would be the tacho output.

Have i 'assumed' correctly?

if i have my pos, neg and ignition voltages i'm thinking ints basiclly the msd box 'has gone'!

has anyone else got any thoughts that might help.

cheers
dave

[rossins]

I had similar problems last year, try this site there is a test that you can run to confirm that it is the msd - www.msdignition.com/1troubleshoot.htm

Good luck
simon

[gtrclive]

If I remember rightly the white wire is not used when using there own MSD Dissy. The plug that connects to the dissy, is the signal wire, but if your not using a MSD dissy then you can use the white wire as the signal wire and even connect it to your points if you had any. So Isolate the white wire first. Then with the ignition on if you disconnect the dissy plug and quickly short the lead that goes to the msd box on and off, (that's giving the MSD Main box a fire signal) every time you make and break those cables it should spark.

PS you will never get 12V across the coil leads with this system don't ask me why, but it does say so in there notes.

[gtr-gaz]

Can't help with your problem, Im afraid Dave, but I do have a spare MSD unit you can borrow if needed.

[steve_d]

As well as the big red wire there should also be a small red wire.
The big must go to a heavy duty supply direct from the battery or you could take it from the starter motor. The small red is ignition switched.
As Clive said, if your dizzy is using the green/violet then the white must be isolated. The instructions also indicate that grounding this wire can be used as a security feature.

Steve

[davefiddes]

Be careful if you are putting a meter across the coil. The MSD box generates over 400 Vac when it fires which is likely to fry a domestic meter...

[luckyp]

I can just second the white wire note. I read the instructions for the MSD after the first failure at SVA. I now use the white wire with a key switch as anti-theft.

I don't suppose you have the white wire incorrectly connected meaning that it cuts the spark permanently?

Pete

[DHGTR]

Thanks for the replies guys all very interesting. i shall be going back to have a look at the car again on Friday (Lees GTR = black/silver trim/cream leather) and i shall keep you all posted.
Simon - thanks for the link
Clive - i was looking for 12V on coil seemed a good idea at the time
Gaz - i may nip down and borrow the box at the weekend if you are around, i'll be in touch. thanks
Steve/dave/pete - thanks for the extra info, car has been running so i'm assuming wiring was correct.

cheers
dave

p.s. if it was a red car it probably wouldnt have a problem pete/wayne. oh and it would go faster as well

[stig]

Does this help?

[DHGTR]

had another go at the msd last night. found big red and black ok but switched 12v was decked. cut wire and ran another 12v to msd but still no sparks. think the 12v shorting to ground has probably taken out the msd. dont know where Lee took this supply from so i will have to run a new wire for the switched 12v - odd but no fuses blown???
Gaz if the offer of a borra is still on, i will take you up on it please.

dave

[gtr-gaz]

DHGTR said:

Gaz if the offer of a borra is still on, i will take you up on it please.

dave

No problem Dave. Give me a ring.

[DHGTR]

Thanks for your help guys.

managed to get to the car and temporarily fitted a new msd control box (thanks GAZ).
The engined turned over for about 3 seconds and then burst into life, left it running for about 15 minutes with no problems, apart from the streaming eyes, he really should get it tuned.

i wonder if the msd being located in the very hot engine bay has got anything to do with these early failures. Does any one have their nsd located in the cockpit or perhaps with some kind of shield around and if so, have they had any problems.

i have a MegaFire ignition on my car so would also be interested if anyone is running the same , for their comments on that.

thanks again

Dave

[pb3]

Mount it as low down as you can on the rear bulkhead, the temps down there are close to ambient.