1978 F100 Ignition

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Mar 27, 2016 | 03:39 AM

BGF100

Thread Starter

Mountain Pass

Joined: Jul 2015

Posts: 182

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From: Queensland, Australia

1978 F100 Ignition

Hi,
I have a 78 F100 V8 351.
I think it is missing. It has electronic ignition.
So I am guessing it can only be a spark plug or HT lead?

Is this correct or can it be other?

I am a newbie to this.

Thanks,

Mar 27, 2016 | 04:26 PM

Filthy Beast

Postmaster

Joined: Mar 2011

Posts: 2,698

Likes: 7

From: Taxachusetts

If it's missing, you'll know it. Hold it about 2K rpm.....if a plug is shot, fouled, etc, you won't have a smooth, steady hum to the engine. Change yer plug/coil wires, plugs (set to the correct gap) and check all wires for clean, snug connections.

You could also set a glass of water on yer air filter and watch the ripples (if any) - that will show a shake like if you have the DT's.

Mar 27, 2016 | 04:47 PM

dlburch

Cargo Master

Joined: Jul 2005

Posts: 2,311

Likes: 366

From: Kansas

a quick way to tell which cylinder is missing (if any) is to pull each spark plug wire one at a time to see how the engine changes...when you come to one that causes no change, it's most likely that cylinder(s). If you wires are old/cracked just be careful because you might learn what that little blue spark feels like!
many things can cause a miss on an individual cylinder besides plugs/wires/cap/rotor:
vacuum leak affecting one cylinder
burnt/sticky valve
broken push rod
bad lifter
worn cam
bad compression rings
etc...