[toobroketoretire]

I have been using my fuse block's "IGN" terminal for the last 6 months to power my Carter 100 gph electric fuel pump that draws 4-1/2 amps. Well, two days ago my fuel pump suddenly lost it's power and left me sitting at an intersection with a dead engine.

After getting my engine restarted and having it die about 6-7 more times I finally made my way to an area where I could check it out. My IGN terminal was dead and I suspect that terminal isn't capable of delivering that many amps.

I ended up connecting my fuel pump to the 30-amp circuit breaker on my firewall and I doubt I'll have any more trouble.

 

[toobroketoretire]

The point I'm trying to make is there are other places that are more suitable to draw power from. For something that draws very little amps the IGN terminal is okay but for anything that draws much more either use one of the terminals on the horn relay or the circuit breaker (used on the earlier C3's).

 

[Big T Machine]

Sorry to hear about your problem, but glad you were able to fix it. Toobroke, what I did in my '73 was to use that same IGN terminal, but I ran a relay off it to a small auxiliary 4-fuse fusebox mounted uder the dash by the factory fusebox, and I have stuff powered from that. Nothing that draws as many amps as your fuel pump but it still makes a nice place to add low amperage components I want powered with the ignition. I forget now what all I had added, I think just my aftermarket radio may be hooked up to it now, but it seems to have worked well for me.
I'm just adding the info, not trying to say my way is better.

Big T

 

[toobroketoretire]

Sorry to hear about your problem, but glad you were able to fix it. Toobroke, what I did in my '73 was to use that same IGN terminal, but I ran a relay off it to a small auxiliary 4-fuse fusebox mounted uder the dash by the factory fusebox, and I have stuff powered from that. Nothing that draws as many amps as your fuel pump but it still makes a nice place to add low amperage components I want powered with the ignition. I forget now what all I had added, I think just my aftermarket radio may be hooked up to it now, but it seems to have worked well for me.
I'm just adding the info, not trying to say my way is better.

Big T

I think your way is also a very good way to reduce the load on the ignition switch. As I had a spare fuel pump relay for my '82 I considered using that but then realized my 30-amp circuit breaker was easier to use as it's right above my oil pressure switch that I am using to send power to my fuel pump.

The point of my post is the IGN terminal is a handy-dandy place to draw power from but it has it's limitations as far as how many amps it can pass. Better to use the horn relay, the circuit breaker, or an additional relay (like you did) to provide power.

I went to the coast with my daughter about a week ago and on the way my 6 month old fuel filter got plugged almost completely. When it got plugged it no doubt forced my fuel pump to draw a LOT of amps and I think the additional amps fried the insides of my ignition switch. The Valero I buy almost all of my gasoline from had been drilling "test" holes for a week before I filled up and I suspect they hit the 91 octane tank or the line leading away from it.

 

[buster]

The point I'm trying to make is there are other places that are more suitable to draw power from. For something that draws very little amps the IGN terminal is okay but for anything that draws much more either use one of the terminals on the horn relay or the circuit breaker (used on the earlier C3's).

I am still having intermittant problems with stalling and think it may be the power source (IGN terminal) I am using for my Pertronix Blaster coil. Could I run that off of the horn relay instead?

It only happens at idle and I find that wiggling the IGN terminal after a stall is what seems to allow me to start the car again.

I have looked into replacing the fuse block but that can only be done with a complete harness rewire on my '73 as the wires and box are not available seperately.

 

[cor66vette]

Not sure if it's the same on your year but on my '75 the IGN cavity is fed from the 10a fuse to its right.

 

[toobroketoretire]

Not sure if it's the same on your year but on my '75 the IGN cavity is fed from the 10a fuse to its right.

On my '71 the IGN terminal gets hot when the ignition switch is turned on.

 

[cor66vette]

On my '71 the IGN terminal gets hot when the ignition switch is turned on.

Correct, same here. But the feed comes from the fuse to its right when the ignition is on. You'll notice in my case the 10a fuse powers the gauges and they are ONLY on with ignition.