Dumb question about electrics

[Guest]

73 TR6.

Looking for a spot to connect a part that requires current while cranking as well as running. From the Advance diagram it looks like the +ve hookup to the coil (where Pink/White and Yellow/White join) will do the job. I want to double check two things:

1. Did I misread it?
2. Is there a better spot? - part is in the engine bay.


/ubbthreads/images/graemlins/cheers.gif

 

[Tinster]

Alan- what kind of part are you trying to connect?
I have finally completed the total re-wire harness
of the Crypt Car and the wires are still fresh in
my mind. Also, is your wire harness 1973 or replaced
with new?

Maybe I can help ya out.

d

 

[macino62]

are you putting an electric fuel pump in? (saw you were injecting). i connected mine through the ignition switch.

 

[Guest]

No - the ECU. Requires connection that has power for both crank and run modes. FP comes off ECU relay board.

Stock harness.

Looking for a tap without disturbing the ignition switch - had some problems already with that this year!

 

[macino62]

Out of curiousity, which ECU are you running?

 

[Guest]

MegaSquirt 2 - wanted something cheap and easy to start with before getting too exotic. Just want the car to run at this point...

Hence it'll be bank fired using a pertronix as a pickup from the distributor for timing.

For a *really* easy install I guess I could just do fuel and the -ve coil pickup a la MS1. Might do that 1st.

 

[Keoke]

[ QUOTE ]
No - the ECU. Requires connection that has power for both crank and run modes. FP comes off ECU relay board.

Stock harness.

Looking for a tap without disturbing the ignition switch - had some problems already with that this year!

[/ QUOTE ]

Hi Alana,Lets see if we can define your power requirement for the ECU.
1] do you need only 12V on the line when the ignition switch is on?
---------------------OR
2] do you need both voltages seen at the coil's Positive terminal: The one presented during Cranking and the latter one presented during the run sequence. ----Keoke?

 

[Guest]

I need 12V both at run and crank - That's why I picked the coil, it seems like the most obvious place.

My question was more whether there was a 'better' place to tap in. It's for sure dead easy to get them there...

 

[Brosky]

Alan, never tie into the coil for anything but the distributor. Pick a 12V source from the fuse block that is constant and fused. JMHO.

I'm at the office and just saw your email & pics about the other topic that we discussed. I'll get back to you from at home later on. Thanks.

 

[Keoke]

[ QUOTE ]
I need 12V both at run and crank - That's why I picked the coil, it seems like the most obvious place.

My question was more whether there was a 'better' place to tap in. It's for sure dead easy to get them there...

[/ QUOTE ]

Yep ,But, connecting into the Ignition circuit may introduce more problems than it's worth. Generally, all the white wires at the fuse box are switched power. You can verify this with a test light. Consequently, IMOP that would be the safest place to connect the ECU's power lead.--Fwiw---Keoke

 

[LastDeadLast]

Alan,

I'm going to suggest another route. I think you need to make a small board, to house all the electronics for your FI system. Use relays off of the fuse panel but drawing power directly from the battery (fused, of course). This way, all of your new stuff is segmented from the old and the only thing you're taking from the old harness is a small drain to activate the relay.

I would suggest calling Mike Masters. You can purchase all the relays, and very high quality wire. NFI, but I have purchased parts from him and I found his stuff of very high quality.

 

[DNK]

I agree with Shannon. Have them build you a panel maybe with relays and all that.

 

[Guest]

I bought one. I just need to find a way to power it...
12v cranking AND running.

 

[Keoke]

OK you are good to go now.--Keoke

 

[DNK]

After studying the Master's diagram. I think you might need to feed off the ignition switch and then to your panel. But then again, An electrician I ain't.

 

[Keoke]

The switched power at the fuse block feeds off the ignition switch.---Keoke

 

[DNK]

But does that shut off during cranking?

 

[Guest]

Right, the brown wire going into the fuse box in fuse #3, but is it powered when you are cranking?
That's my dilemma.

From looking at the diagram it seemed that I needed KW and WY, hence the coil tap but I'm prepared to be proven wrong.

I *could* drag my ass out into the garage with a voltmeter and just check, but its cold out there tonight.

I thought someone might know...

 

[Keoke]

Brown wires are generally always hot and are not switched.---Keoke

No DNK if you get the right lead.

 

[Guest]

Ack - typed without thinking.
I meant to say the white one at #4.