Easy first shot to check the ground strap is to use your jumpers and ground the engine block to the battery or frame.
Do you have points in the distributor? If so there is a little capacitor in there that has to be replaced.
The strap comes off the back of the engine or on the later I6 from the same mount as the ignition coil on the right side.
The wire could be gone or broken. It connects from the back of the engine somewhere to the firewall. It should be visible from under the hood.
Earle
Your engine should have one mesh strap going across an engine mount to ground the chassis frame and another going to the firewall from the back of the engine. It is top dead center so if you don't see it is isn't there.
Some folks wire them with a cable from the battery negative to the firewall or fender. The fender isn't really a good ground, too many bolts to rust up between it and the tub.
The mesh cable is also the best one for RF noise. A battery cable ground will transmit noise better.
The stereo also might want it's own ground to the battery so it doesn't use the noisy body.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 'New' frame in the works for '08. Some Canadian Bush Trip and Build Photos:I have a 1980 CJ5 Jeep, with V8 engine. I have very extreme ignition noise, of course on am only. Fm works fine.
I have replaced the plugs, and later installed high quality, carbon core plug wires.
Someone here ( I think Mike Romain, not sure) has said that a defective or worn braided strap from the engine to the firewall may cause severe ignition noise, and other problems. I am not a mechanic, but I have looked for this wire, and don't find it. Is it visible from under the hood ?
What other efforts can I try to get rid of this ignition noise ?
Thanks !
James
Bill, I have already installed resistant plugs, as well as carbon plug wires.
Earle, I have looked closely, but I cannot see a braided wire going to the firewall, from under the hood. Maybe it has indeed fallen off !!
James
bill, I had them put in about a year ago, so i would have to look. I do know that I bought them myself, and that they were touted as being specially made for rf resistance, and to deter ignition noise. I will have to consider this again, though. The Jeep is at a vacation location, so I can't even check the plug type until I get to it again.
James
My old car started to lose it's grounds and cause noise in my stereo system. I solved it by taking a wire from the radio to the equalizer to the crossover and the front amp and from there to the chassis behind the dash out to the door frame and ending up at the battery's negative terminal. My stereo never got noisy over bumps again.
Use stranded wire in mobile applications. Solid wire will break sooner from flexing.
How about a new cap and rotor?
They do rot. I solder the terminals after I crimp them on.
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