Electrical problems

[TerryMason]

Trying to finish up my tub swap, and I can't get my engine to start. Even with starting fluid in the carb, is doesn't even spark (Done turn over, just never "catches").

I've also noticed that the fan motor and windshield wipers don't seem to work. Any ideas where I should start?

Terry

 

[Inspector-Gadget]

Perhaps others know the details of your Jeep, but I don't. Generically guessing....do you have +12 to the primary side of the coil on crank and run positions of the ignition key (or the equivalent if you have modified or upgraded)?

Gadget

 

[TerryMason]

Sorry, 85 Jeep CJ7. 258 with the carter Carb.

I am 80% done with a tub swap, so this is something that I forgot to wire, or wired up incorrectly.

 

[Inspector-Gadget]

Hello Terry,

My suggestion stands...unless you installed a non-metal tub.

My son owned an 82 CJ-7 with a fiberglass body. We had to go to extraordinary lengths to provide good chassis/body/dash/etc. grounds for everything on that Jeep.

Regards,

Gadget

PS: You might have less than +12 volts applied to the coil in the run position of the ignition key if the resistance wire is still in the coil primary circuit. So many Jeeps. I hope I am not mixing up my memories. As I recall -- approx +9 volts. Then again, I can't remember lunch anymore.

 

[TerryMason]

You may be right about the grounding.
I've got 11.5v on the coil with the ignition in on position.
My lights and turn signals work, but no horn, heater, or wipers. I'll try running a ground wire from the dash to the battery

 

[Inspector-Gadget]

Good idea!

Even on an all metal Jeep, the grounds can get "iffy" after 18 years.

Gadget

 

[MudderChuck]

There are two wires supplying voltage to the coil, one for start and one for run. Check the voltage, at the coil with the motor turning over (started engauged). The wires join up somewhere between the ignition switch and the coil, there is usually only one wire connected to the + coil (sometime two) that supplies two different voltages depending on wether the key is in the start position or the run position. The wires come together, sometimes at the starter relay, sometimes at the ignition module, depending on model and year. There is usually a resistor in the run circuit to lower the voltage some. The starting circuit is usually battery voltage.

 

[chinard]

Don't know if you checked this already, but is your carb getting fuel?
It might be possible that your tub swap may have pinched the fuel lines.

Take off the air cleaner and look down the barrel while you move the throttle and see if its squirting any fuel into the carb.

If your still not sure about the ignition coil getting juice, you can buy an inductive spark plug wire tester. Theyre these little gadgets that look a little like a disposable razor with a little light inside that glows when it detects a current.
I used it on my jeep when i upgraded my ignition.