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Unread 09-11-2008, 06:46 PM   #1
Dawgfan
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77 CJ7 Electrical / Ground Issue Problem Solved!!!!

I bought a 77' CJ7 w/ 304. Started right up and drove it home. I have started it 4 times since I got it home. Sometimes I would have to turn the key a couple of times before it would start. It sat about a week and I went to start it and I could hear the starter solinoid just clicking loud and non stop.

I replaced the solinoid and now there is a short issue somewhere so I don't think the solinoid was the issue. There are three wires going into the once side of the solinoid, (battery cable is okay, wire to alt is okay, other wire is okay except when I turn the key it reads as a groud). If I detach the little ignition input wire from the top of the solinoid and send 12v into it straight from the battery with the wire reading as a ground disconnected the jeep will turn over.

I have no clue where to look for the issue, I would assume it is somewhere in the ignition but not sure. Any help or ideas would be great. I have decent electrical knowledge and a good meter so I can test whatever I just don't know where to start.

Here is what I have done so far:

Okay, I have read everything on grounds and here is what I have done:

1) Replaced starter solinoid
2) New wire from solinoid to starter
3) New ground to engine block
4) New ground to body (I scraped to VERY clean metal under the starter solinoid and ran a ground from the battery to there)

Here is what I know:

On the input side of the starter solinoid the 12v from battery and the wire to the alternator are good. The third wire (I think to fuse block) has no reading but as soon as I turn on the ignition switch or even the head lights the wire reads as a ground. This is with or without any power to the starter solinoid . I just put one test lead on the battery positive terminal hold the other one to the wire with it unhooked from the starter solinoid and as soon as the ignition is turned or the head lights are pulled (it becomes a ground).

Jeep has no aftermarket wiring.

WHAT ELSE CAN I GROUND TO FIX THIS???? Please help.


Ben


Last edited by Dawgfan; 09-14-2008 at 11:12 AM.. Reason: Problem Solved!
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Unread 09-11-2008, 08:13 PM   #2
zachblamercj7
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wow i just bought a 86 cj7 and had the same problem i bought it and had started it like 5 times, when i went to start it about 2 days later it made a loud clicking sound, not olny was the celinoid clickin so wa the coili replace the coil and it still wouldnt start, i replace the starter and still it woulnt turn over, later i found out that a wire had shorted out and fryed my batt. and even with a jump box hooked to my fryed batt it wouldnt turn over, so maby just try a diffrent batt out of somthing and see if that works
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Unread 09-12-2008, 03:10 AM   #3
John Strenk
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I'm trying to figure out what the difference is between " No Reading" and "Reads like ground". What mode is your voltmeter in (Volts, Ohms, Amps,etc)? Where are the leads connected? What does the display indicate.

Off the top of my head I'd say you have a bad battery connection or battery to solenoid cable.
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Unread 09-12-2008, 04:30 AM   #4
HackFabrication
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Quote:
Originally Posted by Dawgfan View Post
...other wire is okay except when I turn the key it reads as a ground).
I agree with John, this doesn't make any sense. If it was truly 'grounding' (going to negative), when you turn the ignition key, you would soon have a melting wire. And a possible fire.

On my 76 CJ's harness (original I6) the alternator wire had the fusible link in it. With a 'eye' terminal. The wire is protected on either side of the terminal by the fusible link. The terminal was connected to the battery side of the solenoid and one end of the wire went to the alternator and the other to the fuse box.

Here's a not so good pic of it before I finished the install of my 5.0L:


It sounds more like a power problem to the fuse box (which would cause the intermittent crank/no crank senario), rather than a ground problem. Take your volt meter and check the voltage at the firewall side of the fuse box (where the large gauge red wire is):


It should read 12+ volts regardless of the ignition key position. If it doesn't you've possibly got a break in that wire causing an intermittent 'open' in the circuit.
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Unread 09-12-2008, 04:47 AM   #5
Dawgfan
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Trying to clear up what I am saying, if I put the positive side of the test lead on the positive battery terminal and the negative side of the test lead on the on the wire going to the fuse box from the colinoid (with that wire unhooked from the coliniod) with the meter set to Volts I get no reading. As soon as I turn the key or turn on the head lights the meter instantly reads 12.72v or so, so the wire is becoming a ground.

Maybe that helps explain better.

Ben
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Unread 09-12-2008, 06:26 AM   #6
jfwireless
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Your test does not indicate the power feed to the fuse box is ground. Once you turn on your headlights, or ignition your negative voltmeter lead is finding ground through the lights or other +12 volt loads. As you are drawing no current with this test there will be no voltage drop across your lights or +12 loads so your voltmeter does and should read +12 volts. If it was at ground potential and your battery and cables were good you would see some serious smoke and would burn up the wiring in a few seconds.

Take a few voltmeter test for us to help figure this one out.

put the negative lead of the voltmeter on the negative battery post, the positive voltmeter lead on the +12 battery side of the solenoid, try starting the engine, what voltage do you read before starting and while trying to start the engine.

If you get +12 volt for both tests above, do the same measurements with the negative lead to the voltmeter on the metal case ground of the solenoid(starting relay) What do you read both times now?

If you get +12 volts on both test above, move the positive ;ead of the voltmeter to the other side of the solenoid and make both test again. What do you read now?

Jim
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Unread 09-12-2008, 01:08 PM   #7
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Quote:
Originally Posted by jfwireless View Post
Your test does not indicate the power feed to the fuse box is ground. Once you turn on your headlights, or ignition your negative voltmeter lead is finding ground through the lights or other +12 volt loads.
What he said.

If you put the negative to the body (or - terminal on the battery) and the positive to the wire you should get +12 volts regardless of the ignition switch position.
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Unread 09-12-2008, 01:54 PM   #8
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Quote:
Originally Posted by Dawgfan View Post
Sometimes I would have to turn the key a couple of times before it would start.
When you say, 'Turn the key a couple of times', do you mean crank the engine, then let it rest, then crank the engine some more,
OR,
Do you mean you had to hit the key two or three times before the engine would start cranking, Indicating a bad ignition switch or linkage?

Quote:
I replaced the solinoid and now there is a short issue somewhere so I don't think the solinoid was the issue. There are three wires going into the once side of the solinoid, (battery cable is okay, wire to alt is okay, other wire is okay except when I turn the key it reads as a groud).
How do you know the 'Battery cables are OK?'
The only way to test the battery, and indeed the battery cable, is with a load tester.
In fact, you should load test all the starter & battery cables...

The wire going to the alternator 'BATT' terminal should read as an open circuit since the diodes are not going to let any current pass...
Unless you have the 'Sense' wire looped from the two wire plug around to the 'BATT' terminal, then it's going to read as a 'Ground'.

The second small wire will read as 'Ground' since anytime the ignition switch or lights are on, any current applied will be going to 'Ground' through what ever appliance or accessory.

Quote:
If I detach the little ignition input wire from the top of the solinoid and send 12v into it straight from the battery with the wire reading as a ground disconnected the jeep will turn over.
If you mean you jumper power from battery to the 'Lite Blue' wire terminal, or the 'S' terminal on the starter relay, that means the starter relay is working correctly,
As are the battery & starter cables.

Did you test for 12 volts from the 'Lite Blue' wire when the key switch is in the 'Crank' or 'Start' position?

If you have 12 volts, then the starter switch is working.

If you DO NOT have 12 volts with the key switch in the 'Crank' or 'Start' position, then you have something wrong, mis-adjusted ignition switch linkage, bad ignition switch, open wiring, ect. between switch and starter relay.

Last edited by JeepHammer; 09-13-2008 at 05:37 PM..
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Unread 09-13-2008, 08:57 AM   #9
Mike Romain
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I think you are missing a wire. I would look down below the solenoid for one that has fallen off.

The two small side posts on the solenoid 'both' need wires on them. One of these wires comes from the keyswitch to turn on the solenoid and the other wire 'goes' to the coil to give it power when the starter is turning.

I think you only have the wire going 'to' the coil plugged into the side and are missing the keyswitch wire from your description of things.

That 'ground' as explained needs to go back onto the main post, it sounds like it could be the fuse link connection for the headlights.
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Unread 09-13-2008, 12:27 PM   #10
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Quote:
Originally Posted by Mike Romain View Post
I think you are missing a wire. I would look down below the solenoid for one that has fallen off.

The two small side posts on the solenoid 'both' need wires on them. One of these wires comes from the keyswitch to turn on the solenoid and the other wire 'goes' to the coil to give it power when the starter is turning.
Not quite right Mike.
Also a VERY common mistake! If I'm not watching it, I do the same thing all the time!

'77 was a Prestolite year, and Prestolite used a full 12 volts to the coil and module, so there wasn't any 'Bypass' circuit used.

The ignition switch powered the module up in both 'Start' and 'Run' on the key switch also, so again, there wasn't any need for a 'Bypass' circuit.

On a '77 (Or any Prestolite year)
The 'S' terminal should have a Lite Blue wire,
And the 'I' terminal should be bare.
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Unread 09-13-2008, 02:28 PM   #11
Mike Romain
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Quote:
Originally Posted by JeepHammer View Post
Not quite right Mike.
Also a VERY common mistake! If I'm not watching it, I do the same thing all the time!

'77 was a Prestolite year, and Prestolite used a full 12 volts to the coil and module, so there wasn't any 'Bypass' circuit used.

The ignition switch powered the module up in both 'Start' and 'Run' on the key switch also, so again, there wasn't any need for a 'Bypass' circuit.

On a '77 (Or any Prestolite year)
The 'S' terminal should have a Lite Blue wire,
And the 'I' terminal should be bare.
OK, thanks, something new to remember.

Would he have an ignition fuse that may be popped?
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Unread 09-13-2008, 05:39 PM   #12
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I don't think there is a 'Starter' circuit fuse in '77.
Couldn't find one in the FSM and I don't remember any fuses in the ones I've taken apart...

This statements from him leads me to believe it's the ignition switch, but when I asked questions, they were ignored.

Quote:
Originally Posted by Dawgfan View Post
Sometimes I would have to turn the key a couple of times before it would start.
Quote:
If I detach the little ignition input wire from the top of the solinoid and send 12v into it straight from the battery with the wire reading as a ground disconnected the jeep will turn over.
If he has to 'Try' the ignition switch two or three times before it will crank, then it's probably the switch or linkage to the switch.

If when he has the key in the 'Start' position, and has no current to the starter relay 'Lite Blue' wire, then the switch isn't working or the wire is broken somewhere.
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Unread 09-13-2008, 09:07 PM   #13
jfwireless
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The mistery is why the solenoid(starter relay) chatters when he trys to start the engine when it does try to start? and the engine turns over with no problem when he removes the +12 volt feed from the output side of the starter relay? Makes me believe we have two issues, an ignition switch issue, and some type of cable/ground/battery issue.

Jim
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Unread 09-13-2008, 09:32 PM   #14
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The clicking of the starer relay is almost always low current delivery to the starter relay.
Low battery, bad connections, ect.

Some times it's the relay it's self not getting good ground, but I though the guy said he covered that...
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Unread 09-14-2008, 11:13 AM   #15
Dawgfan
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I got the answer on another Jeep site I am on . . . the headlight foot switch had a short in it. I just disconnected it and the Jeep started right up!!!!!

Thanks for all the input.

Ben
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