Need a New Starter Relay

[AeroMoto]

I think. Here's my starting procedure:

Push the gas pedal to the floor once and let it off. Then push it in about 1/4".

Crank it for 3-5 seconds, let go of key and then it kicks in slowly.

The ignition system checks out good via Busa Dave's sticky, and I have new plugs and wires. Starter fires up just fine, and the battery is good and strong.

So brainstorming, it shouldn't be an ignition switch, because there is only one wire from the "I" terminal to the starter relay. And if the switch was bad the relay wouldn't even kick the starter on.

So I think the relay is going bad, specifically the "I" terminal on the relay. Am I way off on this?

If I need a new one, I'd prefer one in which I could upgrade to electronic ignition in the future (that shouldn't matter, should it?). And I'd also like to do JeepHammer's dual battery/dual solenoid upgrade.

Dual battery/isolated batteries/winch/welding - JeepForum.com

Thanks in advance!

 

[JR74CJ5]

Ok I'm interested...

I think. Here's my starting procedure:

Push the gas pedal to the floor once and let it off. Then push it in about 1/4".

Sounds Normal so far...

Here's where you get me...

Crank it for 3-5 seconds, let go of key and then it kicks in slowly.

Please explain... I'm lost on this... What is actually the problem? Starter wont engage or jeep wont fire?

So I think the relay is going bad, specifically the "I" terminal on the relay. Am I way off on this?

You can test this by bypassing it. Make sure parking brake is on (or tires blocked) and jeep in N. Hook alligator clip test wire up between the 12v power side and the "I" terminal. Then use another to jump from 12v power again direct to the "S" post and starter should immediately jump. Jeep should also start (relatively quickly) If does, and all the wiring is clean and ok, then yes maybe the solenoid is going out, though they rarely "half" work. Mostly either work, or don't.

If that doesn't work, you either have some wiring / ground issues, or your starter is maybe jamming a little?

But again, I may have completely missed what the actual problem was here...


~ Jr

 

[AeroMoto]

The engine won't start until I release the switch. Instead of catching like normal with it in the start position, it only starts when i put it back to the "On" position. I can crank it for 30 seconds or more and it won't start. But as soon as I crank it for 3-5 seconds and let off it it'll start.

 

[JR74CJ5]

I think you have an issue with wiring...

If possible, have someone check voltage on the coil with key on, then crank it and see if it drops while cranking. (or you can do this at the solenoid / relay)

If I'm understanding correctly, Is sounds like the jeep will only send spark to the engine when you let off the key and the starter just barley kicks it enough still to start it.

Sound feasible?

though you may be on to something that the solenoid is going bad. First I've heard of it like this, but I guess it can happen! Try the jumper wire between the 12v positive side and the "I terminal. This should bypass the key on section. Then try to start it like normal and see if it fires right up without having to let key loose. (just remember to take the jumper wire off when you are done testing )


~ Jr

 

[JR74CJ5]

wait a min... I think I am wrong on the wiring terminals... I have to check something real quick...

 

[JR74CJ5]

ok so in this post from Dave he shows the solenoid in detail and the wiring.

http://www.jeep-cj.com/forums/f99/engine-wont-start-troubleshooting-guide-19494/#post158738

make sure you are wired like this:

 

[73CJ]

How about a bad resistance wire?

| Repair Guides | Wiring Diagrams | Wiring Diagrams | AutoZone.com

 

[AeroMoto]

Looks like you both are right. So the wiring question had me intrigued, do I decided to investigate further. For some background, I've only had the jeep for a month or so, and I'm trying to iron out the POs wiring issues.

He had the coil wire wired to the accessory terminal on the ignition switch. So that's why it was only catching when the key position was on run. So I ran a jumper wire from the solenoid to the coil and it starts, but won't run. I'm missing a ballast resistor, so Ive been reading up on it and I think that's the problem.

Are these easy to find? And where does it terminate, just to ground? On the schematic it just disappears in the next page.

 

[jdarg]

75 CJs doen't use a ballast resistor on the coil primary. Look elsewhere. They also don't have a wire from the I terminal of the start relay to the coil as the ignition switch itself (assuming its working/wired properly) provides power to the coil on both Run and Start.

My hunch is that your coil primary is only getting 12V in "Run" but not "Start" key position. You can put a meter on it and check this pretty easily. If that's the case either PO has one of the connectors in the wrong place on the switch or the switch is bad.

If you jump the I terminal to the battery, it will have no effect on a 75 because the I terminal isn't connected to the coil primary. Jumping the coil primary to the battery would be a better test. Be careful how long you do this though, or leave the key in the Run position. The prestolite box loves to heat up and fail, sometimes in just a few minutes, if you leave power to it w/ a non-running motor: if you feel the box getting hot disconnect it and let it cool down again while you are troubleshooting this.

 

[AeroMoto]

I'm just going to take the coil wire from the ACC terminal and plug it in to the IGN terminal on the ignition switch so that it'll always have power. Only problem is I'm waiting on connectors to arrive so I can't do it tonight.

 

[JR74CJ5]

Missunderstood OP's last response... move along... nothing to see here...

 

[jdarg]

Sounds like a bad idea. Does the coil have power in Run and Start? Only one? Neither?

 

[JR74CJ5]

I'm just going to take the coil wire from the ACC terminal and plug it in to the IGN terminal on the ignition switch so that it'll always have power. Only problem is I'm waiting on connectors to arrive so I can't do it tonight.

Missunderstood OP's last response... move along... nothing to see here...

That's probably not a good idea for a number of reasons.

That's what I was thinking / saying too, but after I re-read it, it appears he's just going to move the incorrectly hooked up supply voltage from the acc terminal to the ign terminal to always provide power when the key is in the on position.

Did I read that wrong? That would be correcting the problem right?

At first I thought he was saying he was going to jump a wire between the acc and ign terminals on the switch, which I agree was a bad idea.

 

[jdarg]

At first I thought he was saying he was going to jump a wire between the acc and ign terminals on the switch, which I agree was a bad idea.

That's what I thought.

Kinda hard to decipher the situation without knowing the results of the coil + test at Run/Start so I'll have to trust OP knows what he's doing if he's making changes to the wiring now.

 

[AeroMoto]

Haha, no jumping of wires between ignition terminals here. Just going to rewire the ignition coil to go off the IGN terminal, not the ACC terminal so it will get power when I'm trying to start it, not after I start it.

 

[Hedgehog]

You shouldn't need to actually rewire it, just unplug from the Acc. terminal and plug into the run terminal. The jeep as most vehicles is set up so some parts of the jeep are OFF when the starter is turning. More available power/amps for the start/ignition systems. Lights, radio and other needless electrical draw is OFF when the starter is engaged. Obviously your jeep had the ignition wire on a terminal that was OFF during starter engagement ..... and you already figured that out.

 

[73CJ]

Well 1973 v8s and I6s had points.

They
Do not have a ballast resistor, but a re stance wire. I6 was 1.8 ohms and the V8s were 1.35 ohms. It goes from the Ign terminal of the ign switch.

St (start) of the ign switch goes to the S on the solenoid.

I of the solenoid goes to the coil.

Ref fig 56 page 3-30 in the 1973 TSM.

View image in gallery​

 

[jdarg]

OP, does your 73 have points? If not, there should indeed be no ballast resistor or resistance wire. 73's had a midyear change from points to electronic ignition. The Prestolite electronic ignition has the resistor built into the module.