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kdog904 07-13-2013 06:16 PM

Ignition Problem
So I have tested and replaced almost every part when it comes to starting my CJ7. The solenoid is fine, the ignition switch is new, battery and starter are fine. What I believe is my problem is the ignition wire going to my starter solenoid. When I put a voltmeter to it, I get just below 12v. My ignition safety wire is getting the full 12v, so I know its not that. So my question is, is their anything short of replacing the entire wire running through the harness I could do to make this wire get a full 12v to engage my solenoid and get my starter motor spinning?

kovic 07-13-2013 06:49 PM

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What exactly is it doing?


kdog904 07-13-2013 06:55 PM

Absolutely nothing the starter motor doesnt turn, according to my dash volt gauge its sending the 12v down the ignition wire, just not enough to engage the solenoid.

kdog904 07-13-2013 07:04 PM

I have looked at the wiring diagram and I can't find where the red/white ignition wire leads to through the harness. My only option is checking for a loose connection that's stopping it from sending the full 12v.

BagusJeep 07-13-2013 07:36 PM

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kdog904, you need to fill in your Profile. No one knows which year and model you are strugging with and what mods you have. You can then get specific advice, still wrong but specifically wrong.

I have had to assume it is a 1984 plus manual 258ci with Duraspark ignition. You see the issue, "Assumption is the mother of all **** **s".

You are using the wrong method to check voltage. At the battery you may get from 11.5 to 12.5 Volts. You will then get losses through the wires, which are maginally sized by AMC. The best tool for checking for voltage is a 12V test bulb (cost $5) and some long leads. Hook one end to the battery negative and go looking for voltage. A bRight bulb is battery voltage, a dim bulb is 7V which is the voltage at the coil in a ballasted ignition.

You are talking about the red/white ignition wire in connection with the solenoid spinning. This causes all sorts of questions. The ignition circuit is indeed red with tracer (i.e. red with a white tracer stripe so you do not get it confused with the main power cables which are permanenetly live) but it does not operate the solenoid.

There are four connections your solenoid needs:

1. Red incoming power cable, big and red.
2. Red outgoing cable to the starter motor. Big and red.
3. Light blue wire going to the S tab on the solenoid. Small and light blue. It is live in Start only and comes from the ignition switch.
4. Grounding. Mostly they are fixed to steel fenders and ground through the body. Some members find problems with this arrangement and put an earth cable on the mounting bolt and wire it back to the main grounding cable from the battery. Up to you but if it is not grounded you can feed as much voltage as you like to it, there is no circuit and it will just sit there.

You will note I have not mentioned a red wire with white tracer. This wired DOES NOT operate the solenoid. It is connected to the I tab on the solenoid and is a passive recipient of voltage in Start.

Why? Because you have a ballasted ignition circuit. The key feeds battery voltage down the red with tracer wire in Run and Start to a resistor (in diagram just above the SPLICE where it says 1.35 Ohm) which lowers the voltage to around 7V at the coil. A ballasted coil normally runs at 7V, does not get too hot and does not melt the innards of the ICM

In Start the solenoid feeds full battery voltage to the other side of the resistor, giving the coil a thrilling 12V whilst starting which gives a much stronger spark.

If you were to disconnect and measure just the red with tracer wire at the solenoid you would see less than 12V. Seems normal.

So to summarise, you need to find the light blue wire. Check with the test bulb that it is live in Start only. Connect to S tab.

If this does not work check the grounding of the solenoid.

One test is to bridge across the incoming BIG RED wire with the S tab. If it clicks then the solenoid and ground are fine.

Here are a few diagrams which may be helpful, more helpful than the straight wiring diagram. They are for a 1984.

kdog904 07-13-2013 08:17 PM

I really appreciate the help Bagus and I filled in my profile as best I could from memory. I know the light blue wire that connects to the S terminal, accept in my case it's green. It does receive 12v when the key is in the START position. I looked at the coil (which after tracing the wires from the solenoid I found they lead there). Next I noticed the connectors on the top of the coil were pretty chewed up, so I cut the red and, in my case green, wire and patched them up. I'm still getting the same volts from the red and green wire as I got before, so is it possible my coil is the problem? Sorry for the confusion i'm kind of learning as I go with this.

kdog904 07-13-2013 08:25 PM

Also, a little background as to why I decided to start screwing around with this was because for the past few years this jeep has had trouble starting. In most cases it wouldn't even try the starter motor. My dads solution to this was often just tapping the posts of the battery with a hammer or jumping it by bypassing the solenoid. A few days ago the jeep kept what seemed like turning the starter motor on and off very fast, causing it to grind. So I replaced the solenoid thinking that was the problem. Also a few days ago my radio was flickering in and out, which is why I replaced the ignition switch and since then it has stopped. Sorry to ramble I just hope some of this can help figure out whats wrong.

kdog904 07-13-2013 10:33 PM

I did a test and found my reverse lights dont come on when I have the key in the ON posistion and am in reverse. Does this mean the NSS isn't letting my starter solenoid ground out?

kdog904 07-13-2013 10:48 PM

It was my NSS. Grounded solenoid to the body starts like a champ now. Thank you all for your help

BagusJeep 07-13-2013 10:55 PM

These old CJs can be difficult to work on when wire colours are changed.:mad:

As you can see in my ignition diagram, the light green wire on the coil goes to the Ignition Module. The red with white tracer wire at the coil is from the ignition circuit.

If you disconnect the wires from the coil (they need to be disconnected to measure, otherwise you are testing both together) the red with tracer should have about 7V (dim bulb) in Run. In Start, if the solenoid worked, it would become a Bright bulb with 12V. This is not effected by the NSS.

The light green wire at the coil is the switch from the module. What it does is ground the coil in time with the engine. It has no voltage, it is a ground. If you have it disconnected and the test bulb is lighting up there is something wrong.

To test that light green wire is giving the signal you would hook one end of the test bulb to the battery positive and the other to the wire. As it is switching from ground to open circuit you will see the bulb flash when/if your engine turns over.

However none of the above will effect the operation of the solenoid.

The Neutral Safety Switch in your auto box is just that, it is only closed when the box is in Neutral and Park. It is cunningly wired in the light blue wire to your solenoid. It does not appear in the diagram I posted earlier. However, if you have battery voltage, in Start only, at the S tab (light green or blue) in Park and Neutral it is working fine.

It sounds like a grounding problem. When your Dad (Dads are always right) was pounding the battery terminals was this because they were old, corroded or just a bad fit? It sounds like the solenoid is not grounded back to the battery. This may also explain why other systems are flickering.

There should be a large black battery cable going to the engine, often fixed to the engine block but sometimes the starter holding down bolt. There should be another strap from engine to frame. CJs are notorious for bad grounds, some twit considered that grounding a major component to a rusty steel fender which could connect to the tub which could connect o the frame which could........ I think you get the picture, electrons flow around a circuit of which only one half is in nice plastic coated copper wires and the other half is through a muddy rusty bit of steel.

The inside of the battery cable can corrode and fray, they are not indestructible.

I have a seperate ground system that links major components via copper cable back to the battery negative. You may want to try grounding the solenoid with a wire back to the battery negative and see if it helps.

As to the reverse light I believe it is a different switch on the transmission. the reverse lights I believe are powered and the switch just grounds it. If so you can get under it and find the switch you should find voltage there.

BagusJeep 07-13-2013 10:56 PM

Posts crossed.

It is not your NSS, it is your grounds.

Well done on finding it.:cool:

kdog904 07-15-2013 12:26 PM

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Just for some clarification then, I have a black wire that goes onto a 3rd post on the bottom of my solenoid and runs into the harness. I'm assuming it grounds the solenoid. To fix this whole problem I stuffed some wire into the plug, put it on the bottom post, then attached it to the screw in the firewall that grounds the battery. Does this bottom black plug go the the NSS, or just some ground point in the body?

Here is a picture of the bottom of my solenoid with the wire I used to fix it.

RWise 07-15-2013 05:16 PM

Many run dedicated grounds, from the base of the solinoid to the negitive on the battery (or a ground lug that goes to said post)
Should be 4 terminals on your solinoid 2 large high amp terminals, and 2 small terminals, 1 engages the solinoid the other feeds 12 volt to the ignition. Some have had trouble finding the correct solinoid and used a 3 terminal, (does not have the 12 volt to ignition post/terminal). It grounds back through the base,,,,,
Good luck!

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