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Discussion Starter #1 (Edited)
Yesterday I installed my MSD-Unit on a 25th Anniversary.

To check all wires I went through the wiring diagram and found the K-Terminal of the Coil to be connected with the fuel pump relais.
On the MM-Box/Coil the B-Terminal of the Coil is connected with 12V, the middle Terminal with ground and with the K-Terminal the ignition Box inducts the spark at the Coil.

But where is the sense to connect this with the fuel pump relais?
Since we got current even without this connection...
Is it to cut of the fuel when the rev-limiter stops the spark?

My car runs without this connection since I installed the MSD-Box.

Raymond
 

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Is it to cut of the fuel when the rev-limiter stops the spark?
this is correct, the rev limiter also shuts off fuel by shutting down the pumps. reason is if you shut off spark but continue to supply fuel, when the spark returns there would be a tremendous amout of unburned fuel that could and would ignite causing quite the explision in the exhaust system. Kaboom..:)
 

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Discussion Starter #3 (Edited)
John,

great/glad to know this, since my rev limiter is at 8000rpm and I never reached this limit so far I never had this problem.

What is strange, the MM box has this white wire to the coil and the coil is connected to 12V directly, how does it work...
On this white wire cannot be a constant current or how would the spark be inducted at the coil/distributor?

Raymond
 

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it's sunday morning so remember I din't have my books and cars in front of me


it's possible you are talking about the wires for the timing retard relays that are in the left frame rail in the front trunk? or the Air Pimp Clutch control relay ?? The countach wiring is craziness...only discover the what, not the why or you will go crazy like the wiring...:)
 

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Discussion Starter #5 (Edited)
John,

I found the reason of my confusion, my carbed QV does not have a fuel pump relais, therefore I don't have this connection between the K-Terminal and the relais.
I suppose it's from the 1988.5 cars on which have a different relais box.
The 25th is also a carbed german car, anyhow it should also run without any problem without this connection, since the rev limiter will also be set at 8000rpm...

Oh yes, the wiring is a really funny time consumer, since I have the 25th wiring diagram it's easier to understand what effect the relais, wires and whatever are supposed to have... :whip:

I was definitely not talking about the retard and the air pump relais, these two I know well...
As I know this so called retard relais takes the two magnetic pickup signals and makes one out of it, which is then supplied to the box.

Raymond
 

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Raymond/JRV,
As i intend to purchase a MSD box for my injected 86QV I have some questions:
1) Can I use the MSD box bought directly from MSD with V12 conversion specified?
2) Raymond, when you purchased your first MSD unit from Burtoni, did you specify in your order that it was for a carbed QV?
3) Is there a difference between the MSD units for a FI car and a downdraft when bought from Burtoni?
Hope you can help!
Cheers,
Bjoern
GLA12982 ;)
 

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Discussion Starter #7 (Edited)
Bjoern,

there is no difference in the Box itself, you simply have to know how to attach the wires to get the fuel pumps working...

As you know I'm selling the MSD Conversion box for about 45% of the price of Burtoni's Unit, ready to install with all wires and instructions even a total non mechanic can follow...

The Box I prepared this weekend goes to Sofia in Bulgaria for a LP5000s.

Don't think you will get the Box cheaper at MSD directly, they bill you more than $700 only for a box, without coil, the needed wires and the mounting plate for the car. It takes you some hours to wire the box and produce a fitting plate, nobody seems to estimate this...

Raymond
 

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Discussion Starter #11 (Edited)
Burtoni costs $2500 plus shipment, I paid almost $2700 for my first box (import taxes, shipment etc) ...

As I said, don't forget the work you have to do, producing a mounting plate exactly for a specific Countach-Model, wiring accordingly etc.
If you think 900 Euro is too expensive you're free to do your own experiences...
$580 at summitracing, nice but don't forget the conversion and the Coil you need, shipment costs and finally the import taxes... Also some of these lowcost dealers have no warranty.

Raymond
 

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Discussion Starter #12
Today I installed the MSD again in the 25th and messed around with the wiring.
Damned, I didn't think it might be that hard...
But know I understand the mess and and know why what is running...

It's just not as simple as one thinks, specially if you have a car with fuel pump relais like the Injected cars have and also all Anniversaries...

Took me again 2 hours to get the running properly, now the owner tests the box and will for sure keep it...

Raymond
 

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Discussion Starter #14
Well, it was really tricky to find out the way the fuel pump relais works, also I was fooled by a wire I thought was attached to the ignition key but wasn't, first it had current and suddenly no more...

I just took the unmounted MM-Box to pieces and remarked a brown stuff under this Alu-plate, it's like grease but brown and doesn't smell at all.

Any idea what that could be?

BTW the owner wanted my box because his MM-Box went made and cut of the engine at 4000rpm.

Raymond
 

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Countach MSD Box- Fuel Pumps not working

Hi Guys,
I am in Australia and recently purchased a QV5000 FI from Texas.
Suddenly the fuel pumps are not working.

I need some help to diagnose the problem.

This car has had all emissions removed, Air Pump, Cannisters, Cats.

Also the Bosch Injection system ECU plugs are in the rear RHS trunk, but no ECU's.
How the hell does the injection system work?


There is an MSD Box installed.
Can anyone advise me how these boxes should be wired specifically for a QV5000FI? I think the wiring has been done incorrectly and there are some wires simply twisted together resulting in bad connections.

The fuel pumps momentarily came to life when i jiggled some wiring near the coil.

I have gone through all the wiring and checked for poor connections, bad earths etc.

Next is to check the fuel pumps.
Where are the pumps?
How do i get to the pumps?
I do not have a lift at home to raise the car.

Below is a picture with some specific information.
Any help or suggestions would be appreciated.


Regards

Dean
 

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