Just bought a 78 CJ5 304 V8 3speed and has started and driven fine for 2 weeks. Right after reinstalling the speedo cluster (not easy and couldnt avoid disturbing alot of wiring sliding it in) and testing gauges, dash wiring and fuse box with a light tester and meter, the engine turns over and starts, but immediately dies. It's always started no problem before. When I pulled out the aftermarket Sunpro fuel gauge mounted under the dash, it touched the dash and sparked. Checked fusebox and replaced cluster feed fuse and panel lights fuse. Also replaced the coil with a new one. Still won't stay running. What could I have disturbed or blown up that would cause this?
I had a 76' dodge aspen that did that. You could here the engine running while you were holding the key turned, but when you released the key to the run position, the motor died instantly. It was a bad ballast resisitor.
If you have a factory tach, you can't remove the gauge cluster without unplugging it,
And the vehicle won't run with key switch in the 'Run' position without the Tach hooked up.
The gauges are all powered up by the same circuit that powers the ignition.
If you blew the Ign. fuse when you grounded the power to the fuel gauge,
Then I'd check that fuse.
If you think it's the ignition under the hood,
Then pull the coil connector off,
Ground your test light to the battery negative,
And probe the coil connector 'RED' wire.
YOU MUST REMOVE IT FROM THE COIL TO GET A GOOD READING.
With the key switch in the 'Run' position, you should get a 'Dim' light.
This will tell you if the ignition switch, fuse, ignition resistor...
All the stuff leading to the actual ignition is working.
With the key switch in the 'Start' or 'Cranking' position,
You should get a 'BRIGHT' light.
This will tell you if you are getting the power 'Jumper' from the starter relay ('Solenoid') to the ignition.
My guess is you WILL NOT get power to the coil CONNECTOR RED WIRE,
And that will tell you right away there is a glitch in the dash wiring,
Fuse, something unplugged, something grounded that shouldn't be, ect.
With multimeter on coil positive(+) and good ground:
Key off: 0
I tried this test from the chiltons AMC 72-85 book. I tested coil to distributer cap wire pulling it off at the dist cap, placing it 1/2 " away from a good ground, result, got spark when trying to start ign.
What does this tell you guys?
I live in Louisville, KY and am so anxious to get this solved, I'm working on it on Derby Day when I could be at Churchill Downs right now! Going back out to check some thing recently posted here. Be back,
First thanks to all who pitched in to help. Found the problem(s). The aftermarket fuel gauge I mentioned that sparked when I pulled it out seemed to cause the low volts in run position. It was mounted on a steel plate and screwed in to the radio opening. I screwed it back in (which grounded itself to the dash) and thats when it starts then dies at 1volt in run. I've since taken it all the way out (after I disconnected the battery this time!) capped off those wires. I've also pulled open the dash and found 3 wires melted together! Pink 16, green 18 and red/white. All 3 go from the connector under the dash that the steering column wires connect to, up and over the steer column, either out the fire wall or in the fuse box. Ive cut out the bad sections of ea. wire and getting ready to splice in new wire. Any tips?
Thanks again for everyone's help,
Last edited by tim843; 05-07-2010 at 07:07 AM..
If you were taking voltage readings,
Then you didn't do what I told you to do.
Take the coil connector off the coil,
Test the wires with a TEST LIGHT as described above.
Probably one of two things,
You have the 'Ignition RUN' circuit grounded out with the new wiring,
(Jeep starts on a 'Cranking' or 'Start' circuit, but when you drop the key switch back to the 'Run' position, you probably aren't getting power to coil/module)
You have a bad 'Run' circuit in the module from leaving the key in the 'Run' position while you were doing wiring.
Do the tests I laid out and you will QUICKLY find the issue.
Just wanted to follow up: Finally took it too a professional. An ignition wire in the steering column had rubbed open and was shorting. Also the blue wire wasnt making a good contact on the starter solenoid post.
Thank you all for helping this Jeep newbie.
If you live in the Louisville, KY area, I highly recommend Jeffersontown Auto Electric 502-267-8558