Distributor Wiring & Fuel Pressure Reg

[Guest dom_burton]

I am nearing the end of an engine change from 1600cc to 2000cc Pinto. Unfortunately I decided to re-wire the engine bay / dashboard at the same time (seemed like a good idea at the time...).

 

Can anyone help me with the following 2 questions?

 

For reference, I have a Motorcraft distributor.

 

 

Question 1:

On my loom, I have two wires that go to the small Motorcraft amplifier (plastic chip with 6 wires going to it about 100mm x 50mm) from the distributor (inductive trigger). My question is, does it matter which way round I connect these, and how can I find out? The Haynes doesn't specify.

 

Question 2:

I have a 3-port fuel pressure regular, looks like a T-piece. I know the top is the fuel supply from the tank, but how can I tell which should be connected to the return and which to the carb?

 

Any help greatly appreciated,

 

Dom

[Big Jim]

The Haynes does tell you, if you check the wiring diagram. But if you're struggling check here and decide which set up you've got.

[Guest dom_burton]

Thanks for the link - I have worked all this out with the multimeter but it is good to see someone else agrees!

 

However looking at it (http://nw.rhocar.org/inductive_ign.htm), I still don't know which way round the 2 wires to the distributor go.

 

My distributor does not have the standard semicircle connector on it, so I have two ways I could connect the Gn/Y and Bk/R to it. Does anyone know how I can find out which way is correct, or does it not matter?

 

Dom

 

PS On the subject of the fuel pressure regulator, mine is in the Haynes: fig 7.1. on page 105.

[IanS]

These wires to the pickup will work either way round.

BUT

swappping them moves the spark timing about 7 degrees.

 

Ian

[Guest dom_burton]

Thanks Ian.

 

Do you know why it changes the timing - presumably the induced voltage waveform is non-symmetric about 0 Volts (x-axis) and so the trigger point (which I assume to be at a given Voltage threshold) will vary if you swap the wires over?

 

I will let you know how I get on when I get it started...not going down to the garage next until 7th May though so watch this space!

[IanS]

The voltage from the coil is normally 0Volts.

As the 4 pointed star thing approches the pickup the voltage will move one way(depending on which way round the wires are connected) the volts goes back through 0 as the pickup lines up and then goes the otherway before returning to zero.

The whole 0,+,0,-,0 wave takes about 12 to 15 degrees of crank movement.

The trigger threshold is on the positive going part of the cycle so if the wave goes + first the timing happens early. If the wave goes - first the timing is late.

 

Ian