giddyupp

Hi All.

Complete Newb here. First post so please take it easy on me. I have done a search on this problem and cannot seem to find the answer. I have an '88 with about 95k on the clock. Oil pressure gauge has been pegged high since PO. although when I first got it the gauge did move once in a while (not any more). I have checked all the connections that I can see. I have installed a new gauge and sender and yet I still have the same problem. The gauge pegs high as soon as I turn the key (before engine fires). Does anyone have any additional ideas. I know some of the previous threads mentioned checking the earth wires. Without wanting to sound like a complete DA - Which ones ?

Just got turned on to this forum by a friend and do not know how I have managed this long without it. (had my car for over 2 years). Love it !!

delisedesign

I have same exact issue.....two trying to solve the problem means diagnosis in half the time?
my concern is if consistently high oil pressure can cause a problems down the line? since in both of our cases its been pegged for awhile, it doesn't seem to affect performance in the short term. i have read up on what oil pressure actually pertains to, and all i got out of it is that was all technical jargon that doesnt really help solve anything, other than the 'how it works'....my car's PO was a certified mechanic, so im thinking it may be that the work he did on it just overcorrected low oil pressure, which would obviously be a much more significant issue....anyway, lets keep each other posted on progress of this issue.

joejoe

I had this issue with the water temp. For me it was a new sender needed. To replace the guage you must have removed cluster. What condition was the flexible circuit board for the guages? Did you clean the connector ends on the 3 plugs (a pencil eraser works great) the sender has 2 connectors (at least on my 86.5) and I think if they are connected wrong what you are experiencing may happen. Not positive, but may be something to try.

Not sure where all grounds are, but there is a cluster behind fuse panel on top. Perhaps another will post where others are. If you have time tomorrow give 928intl a call and ask Mark or Tom, 1 714 632 9288. Lastly welcome to the tank, and now that we know where you are we expect you to come to sharktoberfest in October.

Ducman82

check your engine ground strap.

Mrmerlin

try swapping the connectors to the oil pressure sender

AO

+1

giddyupp

I have tried swapping the connectors. Also checked the color of the wires to the manuals and all seem to be correct. I replaced the entire cluster from a 10,000 mile car. All the connections and the flexible circuit board were in like new condition. I also tried removing one of the wires and when I turn the key the gauge still pegs high.

-

Mako 928

The next thing to look at is the 14 pin connector in the engine bay, passenger side.
Also come on out to the funrun this Saturday 7/17 and pick some brains. www.norcal928.org for directions/ times.

Gary Knox

Giddyupp,

I've had this issue with 2 S4 cars. Oil pressure gauge pegged to 5 bar when the switch was turned on, and never changed. I replaced the oil sending unit by the oil filter, and wunderbar - everything worked fine - for both cars.

Gary Knox

tveltman

I had this problem. Swapped the sender, she worked like a charm. You can probably check the gauge by bridging a doulbe A battery across the terminals. If the needle jumps and then falls back down when you remove the battery, the gauge is good. You could also try the same test with the leads coming from the sender to check the wiring. I think the pressure sender is a 0-5V gauge, although I am not positive. This would at least give you a quick way to test it out.

Toms928

I have an 88 also that had the same problem. In fact, I changed out the oil pressure sender today and when I first started it up, I noticed it pegged out. But after driving it about 15 miles when i got home and let it idle, I noticed it came down. First time i've seen it lower since buying the car. I also changed the oil while I had it up too. But you've already done this. When you do find out what it is, let us know.

giddyupp

I guess at this point, I am going to try another new sender. Just don't know what else to do. I will let you know what happens.

Mrmerlin

did you ever figure this out?

Mrmerlin

Finally got to swapping out my original oil sender on my 88 5 speed,
the gauge was pegged when the key was turned on.
Dropped the alternator ,
used my 12 inch nipix flat jaws to hold the thermostat housing mount,
used the 24MM wrench to loosen the sender out it came,
lost about 2 oz of oil.

Tightened the thermostat mount then screwed in the sensor.

Hooked up the alternator and sensor wires,
Fired it up, gauge works perfectly

FredR

Stan,

Was the gauge pegged when the motor was running or was it indicating normally?