1981 cj7 no crank

[Griffen Amadon]

I have a buddy who has a 1981 jeep cj7 that was retrofitted with fuel injection by the previous owner. It has the inline 6 cylinder in it. The issue is that a few weeks ago, the starter decided it wanted to stay engaged to the flywheel and burned it out. To cover all bases, since they were really old and worn, he replaced the ignition starter switch, the starter, starter solenoid, and the ignition lock cylinder. All brand new. Now it has no crank whatsoever. Has the 4 post solenoid, with 12v going into one end, and nothing coming out other side to starter when you turn the key to start. The two wires on top of solenoid, blue and red(with black stripe), the blue one has 12v when key is turned to start. The red one has 5.8v, which catches my interest because doesnt that have to be 12v also for the solenoid to engage? My question is why that wire is only getting half voltage? And where does that wire come from? I try and trace it into the harness and lose it halfway through. Any help is appreciated. Also, does the solenoid have to be grounded? Im not sure that it is, i could be wrong though. Not too familiar with jeeps. Thanks in advance

 

[greg92jeepxj]

The bendix drive stuck in the out position and and fried the armature , that how it's sounds from where I'm sitting. Ok , good to replace all the worn stuff. Now to get it working. First check that the solenoid is working correctly ; remove the wires from the small posts and jump the battery positive side of the solenoid ( large stud) to the small stud closest to it . The starter should engage. A bit late to strain the eyes on a 1980 CJ wiring diagram but the two wires your referring to for the small posts are from the neutral safety and ignition switch. Providing the ignition switch under the column is a match for the new one from the old , all wiring should be right. When key is in START position , the 12 volt wire should energize the SOL (solenoid) position to engage starter. Make certain this wire is only live when key is in START. The other wire should go to the IGN terminal (ignition) which energizes the coil positive for , you guessed it , ignition . The 5.8 volts is on a resistor circuit . That is so the ignition coil doesn't burn out due to over saturation (too much voltage). Originally , these were set this way for points and condenser but adapted for solid state ignition. The solenoid will go round about from the key ( ignition switch) to NSS ( neutral safety switch / auto trans) or clutch start switch ( manual trans). One wire will be live with ignition on and the other in start position only. The solenoid should be marked but if not , the small post closest to starter should engage starter. To be sure , with only the two big studs hooked up ( one from battery positive and the other to starter) , find the one that is live with key on . That's to coil positive. The other is to engage starter. The large studs are polarized so make sure not to put wrong cable on wrong side or the starter will engage when battery is connected with key off. It happened to my brother on a ford truck. Confusion mounting the solenoid and posts were unmarked. The metal bracket should ground the solenoid . Make sure it's bolted to a clean and unpainted surface. Check all connections with a voltmeter first if unsure before making final connections since things are not currently working out for you. If you must , unplug the coil harness and see if there is continuity from coil positive wire to the wire that goes to small stud next to battery large stud on solenoid. The other wire should fire the other small post to engage starter. Please make certain of your connections so the solenoid works right.

 

[drewbuddy]

Just thought I would throw this out there, I find it strange that your fuse or relay never popped or cut out before being engaged and holding enough to "burned it out"
Maybe something to check out

 

[69jeepcj]

Could have blown a fusible link. Its like a fuse but built into the wiring. no relays on a 81.

 

[Tison78_CJ5]

Possible the 5.8 volts, is the real fault.
If the solenoid did engage, that could keep it on.
It sounds like a wiring issue. Something shorted.

Also, I would recheck the ignition switch, against the electrical drawing...

 

[Griffen Amadon]

Ok thank u for all the replies. Ive checked all the wiring. It seems like all of it gets what its supposed to and has solid connections. I tried jumping the solenoid like you said to, and nothing happened. At all. That means bad solenoid, correct?

 

[greg92jeepxj]

Return policy on electrical parts is a problem in most stores. If you know of anyone who has a known working solenoid , try swapping it in to see if it works to confirm fault.
note: make certain to use small terminal closest to battery positive for SOL (solenoid) connection . This is the trigger in START position. It's only live when key held in START. The other wire should be live when key in ignition position . If you get the engine to crank but won't run , we will have to look up the ign 1 & 2 wiring. There are two circuits , one is to supply voltage to coil while cranking and the other is to supply voltage in run.

 

[greg92jeepxj]

I thought I would post this picture of a starter solenoid. It is basically what is found on a jeep (AMC) . The only wiring to confirm on your 1981 is the ignition circuit. We may have to differentiate the ign 1 & 2 circuit.

 

[Griffen Amadon]

Ok. Sorry for delay. Have eliminated all parts being bad. It is a wiring issue. The blue wire gets 12v when ignition is in crank position. The red wire with the stripe only gets 6v in the on position. It does not switch to 12v or anything when you go to crank. Now the diagrams ive looked at it shows that wire being tied into the coil for the distributor, but the previous owner somehow disconnected it from there and tied it into another wire or something when they retrofitted it with fuel injection. I am completely lost on this one. We know the starter, ignition cylinder, and ignition switch on column work. Tested all wires and put out proper voltage. We cannot get the solenoid to run at all, due to something wrong in the wiring somewhere. It has to be the 6v red wire, but i have no idea how to diagnose it. Any help is greatly appreciated

 

[greg92jeepxj]

This may seem left field but is relevant in terms of where voltage starts and ends up and where it may be not getting through. I didn't ask if this jeep has a manual or auto trans , only mentioned a clutch start switch ( manual) or neutral safety switch ( auto). You'll want to be sure that both are functioning . Had a look at a wiring diagram I have for 1980 models to find where the ignition module is wired with the crank circuit . The two wires on the small plug are part of the wiring to the starter solenoid. The lt. blue will come through the firewall from a bulkhead connector from the ignition switch and the red w/ tracer will go back to the solenoid and splice with the ignition coil positive and to the firewall bulk head connects to the tach . The connection to the ignition module is what we are interested in. But before we get too concerned with the module figuring path of voltage , you mentioned the blue wire puts out 12V in crank . At this point the control side of the starter solenoid which acts like a relay to close the connection between the starter stud and battery stud should be activating the internal plunger to connect . If your receiving 12 volts at crank position , it sounds like the red w/tracer wire is part of the problem. Either the solenoid isn't properly grounding or the module may be at fault. Check for clean ground at solenoid mount bracket and try to get a voltage reading of the two wires from the module small plug ignition on and cranking. Please post your findings.

 

[greg92jeepxj]

Two things come to mind . The initial problem the jeep had with the starter staying on with the key released which would mean the the circuit is still energized after starter circuit should not be live which would mean the module is back feeding the solenoid and shouldn't be and where is the fuel injection module getting its feed from ? The ignition switch or the dura spark ? You want it live when the ignition is live but should have its own power source . It should be powered from the ignition switch and not the dura spark. Please check the wiring of the fuel injection module .

 

[Joedirtaay]

Makes me think of my first car. 68 nova. It was a automatic that the shifter from the column was routed to the floor with a speed shifter. If the column wasn't lined up into park it wouldn't start.

 

[greg92jeepxj]

Has there been any progress or issues found ? Basically , the dura spark dosen't know the ignition switch is in CRANK position therefore it is not sendinding 12 volts to the ignition coil which is why your only getting 5.8 volts as it should when in RUN . I'm not faulting the dura spark just yet but we need to know if the solenoid relay is faulty . A simple check is to pull the two wires ( the blue and the red w/tracer ) off and jump the battery side post ( large stud ) to the solenoid post ( small post ). This should crank the starter if the solenoid is good. If so , the only check is to confirm the status of the dura spark. The wiring harness harness from the distributor ( four wire ) to the dura spark must be in good order and communicating signal for the dura spark to know the engine is cranking . The START position will feed 12 volts through the blue wire for CRANK and the red w/tracer wire will feed 12 volts while in START position until the ignition switch returns to RUN. This is what needs to be verified . If the blue wire is only live ( as it should be ) in CRANK , the ignition switch is working for that circuit . If the red w/tracer wire is not going to 12 volts in CRANK, there may be a fault in either the ignition switch if it is not sending 12 volts through this wire for CRANK. This leaves only two things to consider ; is the ignition switch defective or wrong application ( realizing it was replaced ) or possibly a fault in the dura spark circuit where the two wire plug comes out of. Wondering if all parts installed are mis matched for your application . I do not know if this is possible but if there is a difference from an ignition switch from an earlier year ( non dura spark ) and is not feeding the solenoid right , you may not be getting the 12 volts in CRANK that you should . That being said , is the solenoid actuating the internal plunger ? I would say NO since the "I" ( ignition) terminal on the solenoid relay is only receiving 5.8 volts and most likely can't fire the internal plunger with only 5.8 volts. It is likely the solenoid may be good and you only need to find out WHY the full 12 volts is missing frrom ignition terminal at CRANK. The RUN circuit is feeding the solenoid "I" terminal 5.8 volts at CRANK which sounds like something's up with the ignition switch IF the dura spark internal circuit is working correctly. Question : what does the "I" terminal on the solenoid in terms of voltage read in RUN position ? It shouldn't read anything . The ignition switch should feed the ignition coil in RUN. What are you getting ?

 

[Griffen Amadon]

Ok i figured it out and i wanna smack my head against a wall for what it is. The damn neutral safety switch. It wasnt sending a ground signal to the bottom of the solenoid so the voltage going to it wasnt really doing anything. Oh and who's bright idea was it to make it so when you change the neutral safety switch, all the trans fluid has to come out. So dumb. Anyways, problem was the switch itself. I tested it by grounding out the bottom pin on the solenoid to the frame. Fired right up first time, so thus switch was bad. Thanks for all your help guys, couldnt have figured it out without you.

 

[greg92jeepxj]

Your most welcome Griffen. Glad we were able to help out. But I really feel you deserve the tech award here for being a trooper and seeing the diagnostics through to completion and success . That is rewarding in itself. The feeling of getting it done and finding the solution without having to take it in for service. We really thank you for sharing your repair with us and your membership with jeepz.com too. Guys like you is what this forum is all about . Really happy for you and its owner . Regret it was out of service so long but I know you'll keep it rolling 'cause I know you can . Best of luck and enjoy one of the finest jeeps ever built . A CJ ! Stop by anytime . Have a great summer ! Greg