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Electrical question [message #371493] Wed, 18 October 2023 11:33 Go to previous message
Greg C. is currently offline  Greg C.   United States
Messages: 224
Registered: October 2019
Location: Knoxville, TN
Karma:
Senior Member
I've built an all new dash in my coach. Every since I installed the Autometer gauges, the oil pressure has shown alarmingly low. A few months ago, I installed, at different times, two different mechanical gauges plumbed directly into the engine. Pressures shown there appear to be normal, with about 40-50 psi cold and 30 or so hot at idle. The coach has about 68,000 miles on it.
The Autometer electric gauge shows 25-30 cold and 5-10 hot at idle, running synthetic 10W30 motor oil.
After consultation with Autometer, I installed a new Autometer gauge. Same readings. Same gauge bench tested with air pressure and a mechanical gauge plumbed in for a baseline shows the gauge to agree with the mechanical gauge. Autometer says that the gauge is very likely to be inaccurate if not correctly grounded.
Today, I removed my ground cable, cleaned it, and checked the resistance. It's right at .5 ohms in 39" of cable. Looking online, that seems to be about 600 times higher than it should be. It's #4, I just ordered a new custom made #2 cable with an auxillary wire on it. I found the transmission ground strap on the coach, but I can't find the front one. There was only the one cable on the engine block stud.
Does anyone have an opinion on this? Am I on the right track?


Greg Crawford KM4ZCR Knoxville, TN "Ruby Sue" 1977 Royale Rear Bath 403 Engine American Eagle Wheels Early Version Alex Sirum Quad bags
 
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