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My 49er usually run at 40lbs at 50mph. Lately, it's been fluctuating. Runs at 20lbs then goes up to 40lbs when I let off the gas. Sometimes near 0lbs at idle. Is the pump getting tired? Is the gauge going crazy? Does oil viscosity have a role in the pressure? I'm confused? Thanks for any advice.
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Mechanical gauge or electric?
67 Coronet 500 - 9.610 @ 139.20 mph
Owned Since 1981
Daughter's Car
67 Coronet 500 Street Car with AC
13.300 @ 101.75 mph
69 GTX clone - build in progress........
Posts: 3,151
Threads: 296
Joined: Jan 2013
It sounds vacuum/crankcase pressure related. Not knowing how those motors vented the crankcase, (this is way before PCV) I'd make sure any breather tubes, crankcase vents are clear.
I love Mopars so much I'm date coding the skid marks in my underwear.
The conventional wisdom says 10 psi for each 1000 rpm. I would first take out the oil relief valve and make sure the spring in it is not broken. Do you have a manual? Pretty simple job.
