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Wacky oil pressure gauge...
- Thread starter ODXJ97
- Start date
Rick Anderson
NAXJA Forum User
- Location
- Lusby, MD
Well, the oil pressure should go up and down with engine rpm.
It should NOT go to ZERO if the motor is running. You should have at least 10 PSI at idle, a good condition motor will have 15-25 PSI at idle.
The motor should make more than 40 PSI at upper rpms, like 3000rpm or higher, 55 PSI is a good figure here. Often the pressure relief valve will limit the pressure to 50-60 PSI and it won't climb higher even if the motor rpm increases.
How long has the oil pressure gauge been doing this? If its a recent development, have you changed the oil and filter? Filters sometimes can malfuntion or come apart and clog up the oil system.
It should NOT go to ZERO if the motor is running. You should have at least 10 PSI at idle, a good condition motor will have 15-25 PSI at idle.
The motor should make more than 40 PSI at upper rpms, like 3000rpm or higher, 55 PSI is a good figure here. Often the pressure relief valve will limit the pressure to 50-60 PSI and it won't climb higher even if the motor rpm increases.
How long has the oil pressure gauge been doing this? If its a recent development, have you changed the oil and filter? Filters sometimes can malfuntion or come apart and clog up the oil system.
I've changed the oil twice since I baught it a couple of months ago. It does move back and forth with engine rpm. However, when I come to a stop it goes to zero and the dash reads "check gauges"... then when I excellerate it'll go back up to 20-30-35 etc..
Boatwrench
NAXJA Forum User
- Location
- Petaluma, CA
Same thing on my 2000. Replace the sender unit, use OEM dealer part. It's located on the oil filter housing.
Tom
Tom
Dr. Dyno
NAXJA Forum User
- Location
- Al Ain, UAE
ODXJ97 said:I've got a 97'. The oil pressure gauge is all over the place.. 0-40-30-0 again. I cleaned the contacts... then replaced the sending unit... and checked for pressure. It's still doing the same thing. Any help?
Get a new OEM replacement sending unit. If the gauge still drops to zero, change the oil and filter (especially if it's a Fram). Don't use Fram filters. If that doesn't improve things, remove the oil pan and inspect the oil pump pick-up screen. The likelihood is that it's clogged but rather than just clean it, replace it a new oil pump/pick-up assembly.
Don't neglect it otherwise you'll end up replacing bearings or worse, rebuilding the whole engine. Did I say don't use Fram oil filters?
Dr. Dyno said:
Before diving off in all of this I would check it with a mechanical guage. Like I said mine did the same thing on the guage but was rock solid on a mechanical guage. My dash guage says hot idle is like 5psi and with a real guage its 25 psi, dash says 30 cruise psi real guage says 60.
Dr. Dyno
NAXJA Forum User
- Location
- Al Ain, UAE
BlueCuda said:
That's fine except that if he hasn't got one, he'll have to buy one so for what it's worth, he might as well buy a new gauge sending unit instead. If that reads the same as the old one, it's highly unlikely that both sending units will be duds so it'll be time to investigate the things I mentioned.
Sounds like you also need a new sending unit.
Dr. Dyno said:
I have had two of them
. The problem seems to lay somewhere between the sending unit and the guage. I breath easy about it because what the guage is doing is for the most part mechanicly impossible as long as its full of oil. This did bother me for quite some time, as it didn't really start to happen until my new stroker had about 5K miles on it. You should have heard the sigh of relief when I fired it up with the test guage on it and it had 25psi at hot idle and 60psi at just over 2500RPM lol. Its a 97 with 205K on it now, the wiring must be a little bit pissed off. I would really like to mount a good guage inside the cab but no one makes a good setup.
zfinger
NAXJA Forum User
- Location
- Boulder, CO
I also have a 97 that HAD the same problem. What was happening was the distributor cap was somehow arcing to the oil filter or sending unit right beside it. On the suggestion of a guy at work I did a new cap, rotor, plugs and wires and it fixed the problem.
Try that, I bet it solves your problem, and its good, regular, and cheap maintenance.
Try that, I bet it solves your problem, and its good, regular, and cheap maintenance.
zfinger said:
Well, that sucks because a new MSD high output setup was just installed about 6 months ago... It's hard to believe that all of these magic tricks will fix such things (oil fliters, distributor caps) but hey, if it works.. it works. I'll try it. :confused1
zfinger
NAXJA Forum User
- Location
- Boulder, CO
So did it work?