The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - Electromagnetic interference with speedometer

Dead Parrot · 09-07-2020, 11:34 AM

A couple of general ideas.
Double check grounds. Did all of the engine to cab/frame ground cables get re-installed? A bad/missing ground might cause current to try to us some of the signal wires as a circuit path.

Run the truck in the dark after your eyes have adjusted and look around all of the ignition wires for any escaping sparks. Possible one of the wires has a defect and is letting some of the fire escape. It doesn't take many 30k volt electrons to mess with computer level signals.

09-07-2020, 11:34 AM	#2
Dead Parrot Registered User Join Date: Aug 2012 Location: Oklahoma City, OK Posts: 2,484	Re: Electromagnetic interference with speedometer A couple of general ideas. Double check grounds. Did all of the engine to cab/frame ground cables get re-installed? A bad/missing ground might cause current to try to us some of the signal wires as a circuit path. Run the truck in the dark after your eyes have adjusted and look around all of the ignition wires for any escaping sparks. Possible one of the wires has a defect and is letting some of the fire escape. It doesn't take many 30k volt electrons to mess with computer level signals.