Ignition Grounding

[dagr8tim]

Quick question. I'm trying to get my 75 started and I don't have a key. I have the ignition in the dash. I was wondering if the ignition grounds through the dash or if it grounds through the starter solenoid.

I'm going to have to run a jumper wire to try to start it and I don't want to have to reinstall it in the dash if I don't have too.

 

[BusaDave9]

How to hot wire a jeep.
Not sure if I should be answering this. The key switch should be grounded. The solenoid should also be grouned to the fender. But there are more wires than that.The key also needs to supply 12 volts to the ignition. Thats a separate wire from the blue starting wire.

 

[dagr8tim]

How to hot wire a jeep.
Not sure if I should be answering this. The key switch should be grounded. The solenoid should also be grouned to the fender. But there are more wires than that.The key also needs to supply 12 volts to the ignition. Thats a separate wire from the blue starting wire.

There are 4 terminals on the back of the ignition. ST, BAT, IGN, ACC. I know bat has power at all times, and that the other terminals get power out of them depending on where the key is located in the ignition.

But my question was if the ignition lock/switch was grounded through the dash because it's pinched between the collar on the ignition and the ring to tighten the ignition in the dash.

 

[BusaDave9]

There is a ground in the ignition switch for accessories. If that ground wire is bad or broke the jeep will still start.

 

[dagr8tim]

Cool, hopefully I won't have to fish the ignition back up and install it.

 

[mstar]

There is a ground in the ignition switch for accessories. If that ground wire is bad or broke the jeep will still start.

Could you elaborate on that a little.I am just having a hard time visualizing that.Is this specific to a certain model jeep or all vehicles in general.I know you are well versed in auto electric systems so this caught my attention.Respectfully Mike S.

 

[BusaDave9]

The ignition switch has 2 parts. The top connector in this pic goes to the fuse box. If it is disconnected accessories won't work but the jeep will still start.
I think this applies to all AMC CJs

 

[dagr8tim]

For what it's worth, mine is the 4 terminal ignition in the dash. The terminals are "Bat", "Ign", "Acc", & "St". That's why I figured the ground was through the body of the ignition to the metal dash.

I ordered a new ignition today, so hopefully this weekend I can put everything together and try another attempt at starting it.

 

[BusaDave9]

No I don't think there is a ground on the ignition switch. It switches on the voltage.

 

[csuengr]

There is no ground on the switch, it just switches power.

 

[dagr8tim]

There is no ground on the switch, it just switches power.

Ok, I tried to jump from bat to ign and then provide power to the two input terminals on the starter solenoid. I got it to turn over, but no spark. I assumed it was a ground.

I broke down and ordered a new ignition, because I didn't have keys for the current one. Hopefully that fixes the no spark issue. Otherwise this could be fun......

 

[csuengr]

To start, do this. Hook the + side of the ignition coil to the + side of the battery. Jump the starter solenoid to the battery. Don't run it that long like this because you will ruin the ignition coil.

 

[dagr8tim]

To start, do this. Hook the + side of the ignition coil to the + side of the battery. Jump the starter solenoid to the battery. Don't run it that long like this because you will ruin the ignition coil.

That brings me to my next question.

Can you use a square style modern coil in place of the older cylinder style? I've got an aftermarket "performance" coil from a 98 XJ in the garage. I'm wondering if I can get a stronger spark.

 

[csuengr]

With a bit of rewiring, you can. The coil wire on your Jeep right now is a resistor wire. It drops the voltage at the coil to around 8 volts. XJ's don't have a resistor wire, so the coil gets full voltage.

 

[dagr8tim]

With a bit of rewiring, you can. The coil wire on your Jeep right now is a resistor wire. It drops the voltage at the coil to around 8 volts. XJ's don't have a resistor wire, so the coil gets full voltage.

So doing away with the resistor would allow me to use an XJ coil?

 

[BusaDave9]

So doing away with the resistor would allow me to use an XJ coil?

Yes, some coils (especially older ones) need a resistor. Most newer coils don't need the ballast resistor.