How to fix a faulty eletrical oil guage!!!!!!!!!!!!!!

[396_WAYS_TO_SPIT]

I primed my engine today and the guage was showing way over 80psi. I then unhooked the guage and hooked up a different one and the same thing. I then bought a new sending unit and the same thing. I then switched the wires and the guages goes well past zero. So it goes either way over 80 or way under zero. What the hell is going on here? I ran a mechanical to break the cam in but I think its acting up too. Help,Help,Help,Help,Help,Help,Help,Help,Help,
396
[ June 12, 2003, 06:34 PM: Message edited by: 396_WAYS_TO_SPIT ]

[Eric455]

what ever you do done run mech. it wil break under vibratoin and you will loos tht motor. is ur sending unit matching with ur gauge. each gauge reads differnt with different senders. 80+ or 0- does not sund right. check ur grounding. before you start it should read 0 with open key. when you start the motor is shout get pressure. does the gauge read anything below 80 after the oil gets warm?
eric

[Jim Hall]

Mine does the same thing! I have not changed it yet but I heard that there are different sender's
ie: rated for varying psi. I hve not checked on this yet, need to ask auto parts guy.

[Hallett19]

I know guys that run elec on the dash, mech on the block, just in case .....

[Eric455]

Hallett19:
I know guys that run elec on the dash, mech on the block, just in case ..... i had that set up on my olds long time ago "just in case" on the BBC's we really dont need it cuz we always get good oil pressure. lol
eric

[Maxey]

Assuming that the sender and dash unit are compatible: Most electrical dash gauges have three
terminals. Ignition feed, sender, and GROUND. The
ground terminal is usually in the center. W/O a
good ground, the gauge will not work properly. Hope
this helps.
Maxey

[396_WAYS_TO_SPIT]

I figured out my problem. I had the wrong sending unit. I found out that you cant use an automobile sending unit in a boat! I had to buy one for a marine application which only ran $20. I started it up and she was reading good as new wink I am going to plumb in a mechanical one just for insurance.
396

[1Bahnerjet]

wait a Minute, I have a Mechanical one,(you know Plastic tube) from motor to dash is this Bad? Just asking.
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Thats BANNER with an H

[Eric455]

1Bahnerjet:
wait a Minute, I have a Mechanical one,(you know Plastic tube) from motor to dash is this Bad? Just asking.
-------------
Thats BANNER with an H no not as bad as a copper tube most people who have them use. plastic should be okay but you get a better reading with an electric. a good investment would be to change to the system to electric. what rwadings are you getting.
eric

[1Bahnerjet]

Most often 70-80, this for 454
-----------
Thats BANNER with an H

[Eric455]

1Bahnerjet:
Most often 70-80, this for 454
-----------
Thats BANNER with an H thats pressure to me. i would leave it the way ot is for now. check for leaks once in a while on the block and @ the gauge.
eric

[79Hawaiian]

396_WAYS_TO_SPIT:
I figured out my problem. I had the wrong sending unit. I found out that you cant use an automobile sending unit in a boat! I had to buy one for a marine application which only ran $20. I started it up and she was reading good as new wink I am going to plumb in a mechanical one just for insurance.
396 Have the same problem, I am currently running an auto sender. Where did you get the marine one? Did a quick search and found nothing.
Nevermind, just found them at CPPerformance.com
620-25470 Oil Pressure Sender 0-80 PSI, Hardin Gauge, VDO, Medallion
[ June 12, 2003, 11:01 PM: Message edited by: 79Hawaiian ]

[Rexone]

The only thing that's important is that the sender matches the gauge. Auto or marine has little do do with it. Some manufacturers that make both auto and marine gauges have senders that work on either. Sender and gauges are manufactured with various calibrations. Wrong sender with wrong gauge = bad reading.
Mechanicals are fine depending on the quality of the gauge. That's why many racers run them vs. electrical. Cheap mechanicals just like cheap electricals will break.
:)
[ June 13, 2003, 04:19 AM: Message edited by: Rexone ]

[396_WAYS_TO_SPIT]

I am running a factory hardin marine guage. THe readng is the same as the mechanical one, so I know it works.
396

[gnarley]

Eric455:
you get a better reading with an electric. a good investment would be to change to the system to electric. what rwadings are you getting.
eric Eric, I will say your wrong. A mechanical gauge is more accurate & more likely to show the actual pressure than an electric!
There is nothing wrong with either & the electric may be easier to install in some cases if you already have all the wires present but you have more to trouble shoot if the electric gauge starts getting weird on you like a ground or power or the sender not working correctly or the gauge itself. With a mechanical you only have the gauge to worry about & maybe the feed line, what could be easier & more accurate?