Electrical Gremlin

DRR Sportsman

posted

quote:
Originally posted by markemark:
quote:
Originally posted by David_D.: I have a fuse block that is powered directly to the battery, and a fuse block that is powered by ignition switch ON. Neither of those are through a relay. All of my accessories are triggered through relays.

I don’t understand how this is wired and would need to see a diagram to make sense of it. This being your design, you have more knowledge of it.

The statement below from your initial post is the part that is the most confusing and I’m guessing goes back to the Ign ON wiring method.

*Random instances of shutting the car off with the ignition switch and the car doesn't shut off unless I flip the master disconnect switch. Then it acts normally again.

This very well could be an issue with either the alternator wiring or potentially a bad relay.

David Deming
1974 Chevy Nova Custom Hatchback
Horsepower Innovations E85 Carb

Posts: 338 | Location: Nampa, ID | Registered: October 25, 2006

Ignored post by David_D. posted

markemark

DRR Pro

posted

Is this a street car that turned into a drag car and some of the street wiring/ fuse box still is being used? It sounds to me like your wiring method although working prior, is incorrect. Ignition On powering multiple relays is not correct. Ignition On supplies the +12v signal for “only” the ignition device to become active.

An inexpensive permanent fix to your problem and improvement to what you presently have could be as easy as installing THIS .

Posts: 2722 | Location: 53056 | Registered: December 30, 2009

Ignored post by markemark posted

DRR Sportsman

posted

Update: after changing many things, I ended up unplugging the crank trigger and going directly from the ignition box to the distributor and everything worked. Apparently I’m getting some EMI from something at higher RPM.

David Deming
1974 Chevy Nova Custom Hatchback
Horsepower Innovations E85 Carb

Posts: 338 | Location: Nampa, ID | Registered: October 25, 2006

Ignored post by David_D. posted

CAD

DRR Trophy

posted

Put a shielded pickup cable on.... the benefits of the crank trigger outweigh using the distributor.

I think it is about $125.

Posts: 151 | Location: Omaha NE | Registered: October 31, 2009

Ignored post by CAD posted

1leg

DRR Trophy
Picture of 1leg

posted

quote:
Originally posted by David_D.:
Update: after changing many things, I ended up unplugging the crank trigger and going directly from the ignition box to the distributor and everything worked. Apparently I’m getting some EMI from something at higher RPM.

I have seen crank trigger sensors have this issue. I think they just break down over time. Just replacing the sensor fixes the problem, sometimes.

Meziere Tech.
Make sure your water pump is on whenever you check your coolant level.

Posts: 271 | Location: Escondido | Registered: July 01, 2011

Ignored post by 1leg posted

DRR Sportsman

posted

quote:
Originally posted by CAD:
Put a shielded pickup cable on.... the benefits of the crank trigger outweigh using the distributor.

I think it is about $125.

I have a shielded cable. Swapped it and had the same problem.

Removed the alternator and the interference was better, but not gone.

David Deming
1974 Chevy Nova Custom Hatchback
Horsepower Innovations E85 Carb

Posts: 338 | Location: Nampa, ID | Registered: October 25, 2006

Ignored post by David_D. posted

DRR Sportsman

posted

quote:
Originally posted by 1leg:
quote:
Originally posted by David_D.:
Update: after changing many things, I ended up unplugging the crank trigger and going directly from the ignition box to the distributor and everything worked. Apparently I’m getting some EMI from something at higher RPM.

I have seen crank trigger sensors have this issue. I think they just break down over time. Just replacing the sensor fixes the problem, sometimes.

Replaced the pickup and still had the same issue.

Car has run quicker than it ever has plugged into the distributor, so even though it wasn’t noticeable, I’ve likely been having issues for a long time.

David Deming
1974 Chevy Nova Custom Hatchback
Horsepower Innovations E85 Carb

Posts: 338 | Location: Nampa, ID | Registered: October 25, 2006

Ignored post by David_D. posted

markemark

DRR Pro

posted

If you haven’t already, the 12v +/ - feeds for the ignition box should go directly to the battery not sharing wires with any other device. You can try checking the trigger wheel magnets strength with a paperclip. The paperclip should have the same amount of pull to remove when attached to the magnet. Sensor gap should be set to .065”. As I posted prior, consider a relay board and rewire.

Posts: 2722 | Location: 53056 | Registered: December 30, 2009

Ignored post by markemark posted

DRR Sportsman

posted

quote:
Originally posted by markemark:
If you haven’t already, the 12v +/ - feeds for the ignition box should go directly to the battery not sharing wires with any other device. You can try checking the trigger wheel magnets strength with a paperclip. The paperclip should have the same amount of pull to remove when attached to the magnet. Sensor gap should be set to .065”. As I posted prior, consider a relay board and rewire.

I plan on running wires for the ignition box directly to the battery. I'll also check the magnets on the wheel for strength. I think my relay board is good, but I'll consider it.

David Deming
1974 Chevy Nova Custom Hatchback
Horsepower Innovations E85 Carb

Posts: 338 | Location: Nampa, ID | Registered: October 25, 2006

Ignored post by David_D. posted