75 j20 wiring issues

[ClassicQueen]

VR is completely disconnected from the system, which would be wires: 40, 41,43,44.

[ClassicQueen]

Pulled ignition wiring out, are there any updates I should make to improve the wiring?



Happy Thanksgiving!

[nograin]

Pulled ignition wiring out, are there any updates I should make to improve the wiring?



Happy Thanksgiving!

No. Especially at this point in the learning curve.
Return it to stock.
If there is an electric fuel pump, get rid of it. Install a factory mechanical fuel pump instead.

The improvements you can make with what you have will be in the quality of how you fix the wiring.
Use the factory type terminals. They are mostly "Packard 56" series.
The wire crimps to the terminal with two pairs of 'wings', one for the wire and wone for the insulation. This is called an 'open barrel' wire crimp.
Buy the correct crimpers to do this.

Make sure the wires have enough length there is slack or 'strain relief' at each connection.

Route the wiring as close to factory as you can figure.
Cover the bundle (aka harness) with split wire loom, or non-adhesive electrical tape.

Support the harness runs so they aren't tugging on connections or hanging on the exhaust manifold or such.

You can buy pretty much any color combination for any gage from Rhode Island Wiring. If you have a marine supply, like West marine, near enough, they have a pretty good selection of colors and wires which can be purchased in any length. (Added benefit is that marine wire is more oil and heat resistant than general purpose automotive wire.)
If you must use a different color insulation, get a set of colored electric tape so you can at least park the ends with the right color or combination.

You may find one of more welded splices in the harness if you unwrap it. Leave them alone. 99.9% of the time they are fine. There are splicing crimps if you must make up or replace, but the welded is best.

There should be one special undersized wire coming off the junction (stud) on the solenoid. This is a fusible link. Its job is to melt if the battery is accidently grounded.

[ClassicQueen]

Working thru wiring

So I’m going thru every single wire. I’m stumped at wire 13 red w trace which goes to a welded junction yellow wire at junction goes to VR then red w trace goes to coil and then there a another red wire with trace that has been cut in the wiring diagram for ‘76 this wires connects to an electronic control unit. So the question is was there a ecu on 1975 j20s? ‘74 s diagram does not have it and I don’t se one in my truck

[wiley-moeracing]

The ecu was an emission unit normally on California vehicle models, not until later usually. Maybe a universal wiring diagram and not specific to your truck is what your looking at?

[babywag]

1975-1977 Jeep used a Prestolite ignition system, guessing that's what you're looking at?

It's a problematic system and many get replaced by folks.
The ignition module is a small box.

[ClassicQueen]

Thank you for your response. I’m actually going by ‘74 diagram but there s this one wire I cannot ID so I cross referenced to ‘76 diagram. But my best guess is that the wire goes to vacuum solenoid or prestolite ig system.
If prestolite is problematic do I just bypass it or replace it. The truck does not have the prestolite

[tgreese]

There are differences between years. No guarantee that the '75 wiring or electrical equipment will be the same as the '74 or '76 diagram or equipment.

1974 used a points (mechanical) ignition and '75 has the Prestolite electronic ignition. Again, I urge you to get the proper year of TSM and follow it. Without the right TSM, you need extra insight which a novice lacks to understand the changes in equipment and wiring.

Pretty sure a '76 with a 258 will have the Delco alternator with an integral regulator. '75 will either have the Motorola or Motorcraft alternator I believe. This will change the wiring. There were changes every year, and this makes the wiring different. Again, the proper manual will help you.

If not the Prestolite ignition, then likely it was converted or came with the Delco points ignition. Prestolite is correct for 1975.

[ClassicQueen]

Just got manual for 1975 and it is the same as 1976. The ignition control has been completely removed, with that being said do i need it?

[babywag]

The only way you would need the old prestolite wiring or module is if you have a prestolite distributor in use.

[rocklaurence]

The ECU that your referring to maybe the Spark module?

[ClassicQueen]

Just finishing up going thru interior harness. System has a Delco remy coil. Dimmer switch connectors were toasted both switch and connectors i was able to replace. Now thru my research I ve found that amp meter has been a source of problems and I

[fsj454]

1975

You can polish a turd but it is still a turd. Why would you spend time and money on something that is junk . Hope you carry a fire extinguisher. Sorry but that is my 2 cents

[ClassicQueen]

You can polish a turd but it is still a turd. Why would you spend time and money on something that is junk . Hope you carry a fire extinguisher. Sorry but that is my 2 cents

What

[ClassicQueen]

You can polish a turd but it is still a turd. Why would you spend time and money on something that is junk . Hope you carry a fire extinguisher. Sorry but that is my 2 cents

What s your reasoning behind that? Because I’m restoring it?