1980 Cherokee Loredo Wont Run

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Topic author
Gunthergoognar
Posts: 2
Joined: Mon Jun 11, 2018 5:49 pm

1980 Cherokee Loredo Wont Run

Post by Gunthergoognar »

Hey everybody. I am new to the forum and also new to my 1980 Jeep. It had the 360 V8, automatic, holley carburetor, 125K kiles.

I recently acquired the jeep and she cranked right up. Drove on the interstate to get home for about 20 minutes when I noticed we were starting to get pretty hot. Pulled over and noticed a cracked upper radiator hose. Then after cooling off wouldn't start again. Pushed it to a truck stop and left her there to slumber for a few days while i went to work. Came back and fixed the radiator hose and put in a brand new battery. took a few cranks and then started on up. Drove around the gas station for a little bit pulled up to fill the tank and top off the radiator off. then boom, wont start. Engine cranks, of a weak nature, but wont start. Fuel is getting to the engine but not starting. A few times is gurgled as if it was gonna start and then dropped off on me.

anywho, towed her the rest of the way home and have been tinkering around with it. upon drop off from the tow truck she did the gurgle thing again but would kick on. Let it sit for 12 hours and then same thing. Every once in awhile she wants to start but only the gurgle. Cleaned up the carburetor and such and tried her again...yup you got it gurgle. Recently turned the key and had the starter turn the engine. sounded like it was having some trouble then boom...it loosened up and spun for a solid three seconds strong. then lagged again. I'M STUCK! HELP!

Thanks for all the input and opinions in advance!

Jonathan

annnnd one last time! GURGLE
Jonathan
1980 Jeep Cherokee Loredo

letank
Posts: 4009
Joined: Wed Oct 03, 2012 9:16 pm
Location: SF bay area

Re: 1980 Cherokee Loredo Wont Run

Post by letank »

Gunthergoognar wrote:Hey everybody. I am new to the forum and also new to my 1980 Jeep. It had the 360 V8, automatic, holley carburetor, 125K kiles.

GURGLE
gurgle, like hiccup? you mean trying to fire or backfire?

seems like you have gas, but you can still drop gas down the the carb top opening -aka air horn- and try to see if it will start

next step is electrical, in the shade, pull one of the spark plug cap, connect another spark plug, no need to remove one from the engine yet -we are doing a quick and dirty check here- have an helper crank and see if you have spark?

if no spark, see if the coil is giving you a spark -forgot how to do it because of the 80ish you have the duraspark... of course do you have the duraspark, with the module on the driver's side inner fender close to the brake booster

Image

you could have some third party HEI instead -disregard the coil(s) this is my test system-

Image

or this one which is cleaner -no center lead wire to coil-

Image


Otherwise found this:

Test Equipment Required:

12Vdc Test Light with extended leads (12Vdc Lamp bulb w/6-foot leads)
Spark Gap Tester < $15 (or spare spark plug) 6-Foot ground wire w/spring clip
Jumper Wires (Jumper the connector from Distributor to ICM)
D-Cell Battery with Leads (used to test ICM transistor circuit)
Multimeter

Here is how a properly functioning system works:

The Ignition Control Module (ICM) in our Jeeps replaces the Points of the older ignition systems.

The Ignition Coil’s Positive/Negative terminals are the Primary winding.

The Positive terminal delivers the voltage to the coil winding. The Negative terminal connects to the ICM.

The Secondary side of the Ignition Coil is the high-energy spark plug wire from the Ignition Coil to the Distributor’s center cap.

One side of this winding is always grounded; the other side is the Ignition Coils spark plug wire of the Ignition Coil.

During the following tests, do not let the Ignition Coil heat up excessively!

When you turn the Ignition key to the “ON’ but not Start position, you are supplying voltage to the Ignition Coil and the ICM. A transistor inside the ICM acts as a switch, connecting and disconnecting the Negative Terminal of the coil to ground, when the engine is cranked over.

Just like the points distributor that the ICM replaced, the ICM grounds the Negative side of the Ignition Coil to charge the Primary winding and opens it to collapse the Primary winding's magnetic field inside the coil.

When the engine cranks, the coil pickup tells the ICM to open and close that transistor switch by the Pick-up coil, along with the Distributor rotation.

The ICM opens and closes an internal switch (transistor) connected to the Negative Ignition Coil terminal.

Place a 12Vdc Test Light on the Negative Terminal of the Ignition Coil with its other end of the test light to the same ground as the ICM.

Bump the ignition key to turn the engine over without starting. This should produce a light that pulsates.

When the ICM switch is closed there will be no light, when the ICM switch is open the lamp bulb will light.

This confirms that the pick up coil is functioning and telling the ICM to ground and open the Negative side of the Ignition Coil.

A spark gap tester will determine if the spark is strong, weak, or non-existent.

Unplug a spark plug wire and insert the Spark Gap tester into the spark plug wire, use the extended cable that you made up with spring loaded clamps to connect to the metal part of the Spark Gap tester, connect the other end to the Negative battery terminal. Repeat this test for all of the spark plug wires.

If you see a healthy blue spark as you crank the engine, then you have just tested the Ignition system. You have confirmed that the Pick-up coil inside the Distributor is sending the signal to the ICM. You know that the ICM is switching the Negative Terminal of the Ignition Coil to ground and then opening that ground connection. You know that the Ignition Coil is sending a strong spark to the Distributor and you know that each of the spark plug wires in you Jeep is delivering this spark energy to the individual spark plugs themselves. You can test plugs individually, if you have a need.

You also now know what all of the tests look like for your Jeep’s ignition system.
Michel
74 wag (349 Kmiles... parked, next step is a rust free body)
85 Gwag (229 Kmiles... the running test lab)

twisted frame
Posts: 637
Joined: Wed Mar 27, 2013 9:41 am
Location: Massachusetts

Re: 1980 Cherokee Loredo Wont Run

Post by twisted frame »

Wow, letank, you covered it! The only thing I would add is make sure your battery and starter cable connections are clean and free of rust or corrosion. The slow cranking followed by a more healthy-sounding cranking makes me wonder if bad connections are preventing full power from reaching the starter.
73 J4000. 360, MC 2100, T18A, D20, stock closed knuckle Dana 44 front, 60-2 rear. Warn Lock-O-Matics, Warn/Belleview electric winch, true duals with glasspacks, old-school front diff skid plate, used 265 Toyos on 16" AR wheels.

Topic author
Gunthergoognar
Posts: 2
Joined: Mon Jun 11, 2018 5:49 pm

Re: 1980 Cherokee Loredo Wont Run

Post by Gunthergoognar »

Thanks letank. Incredibly extensive and particular feedback! Awesome! I will be troubleshooting on Monday for sure. Hopefully sort it all out and be running in no time. Then the project truly begins. Will certainly check back in with results!

As for the gurgle. It’s turns over and is trying to run. Sounds like combustion is happening but not very consistent and certainly not enough to full motor run.

Thanks again,
Jonathan
Jonathan
1980 Jeep Cherokee Loredo
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