Thread: Oil Pressure SPIKE THRU THE ROOF

03 GTP 128K.

P.O. installed Autometer 5727, short sweep electric Oil Pressure guage, 0-100 PSI. Had car for 1 yr and guage always worked good, typ reads 50-75 psi.

I just finished differential install. In order to reach the parts, I drained oil and removed oil filter and oil pressure sending unit.

On first test drive I noticed oil pressure guage was burried past 100psi. Then in a minute, it dropped and jerked back up, repeated. I thought I would let it warm up, pump new oil thru engine. & guage did return to normal in few minutes--big relief. No problems on test drive.

Then this morning, coming to work, guage spiked again, burried past 100psi and stayed there, even at idle... Engine seems to run fine, but this can't be good.

Few monthes ago, piece of plastic from my dipstick broke, lost in the tube, presumbly in pan. I changed oil couple of time since, have not had any problems like this before. Is it possible to thread sending unit in too far, or too tight?

Can anyone shed some light on this? Could really use help to get this solved...

its electric.

could be a short.

inspect wiring.

Plastic piece would get stuck on strainer, won't go anywhere.

Hey thanks Matt! I was freaked out by palstic at first, but info on this forum helped put my mind to ease. But w/ this issue, I thought I should mention it...

I'll pull wheel and get my multimeter...

ok, so thinking about it a little. Is this a electrical issue w/ guage, or w/ oil pressure sending unit itself (I don't know how unit works)?

If that sending unit is the same size as the one for my Sport-Comp gauge then it's possible that the wire got ripped or frayed by something under there. IIRC its a tight fit with all the other stuff back there.

update, and more problems.

I checked wire @ sending unit & tightened nut. guage worked for 1 day. then spiked past 100psi & stayed there. I took another look, & found wire insulation was cracked & bare wire was touching 1 of the steel lines. So I tried to remove nut, to tape wire insulation, except this time the nut would not come free and entire thing spins when I turn wrench. Finally got it off, & taped wire.

In the process, I loosened entire outer bolt from cylinder/body portion of sending unit. Now guage does not move, reads 0 all the time. I think I broke the sending unit..... first things first, then I'll get to fixing it.

Can I safely drive my car?

Thanks, could really use input, have not been able find info on how the sending works/how it affects engine.

Just an update. & to say, THANKS AGAIN.

Breaking my oil pressure sending unit, ~$40, spurned me into replacing PO's guages to something closer to my personal pref. PFYC.com Z series autometer. The font does not match, but IMHO the colors work much better. I'll probably spring $25 for the amber LEDs before I'm thru. & I'm glad to NOT to have the LED flashing light show in my face anymore. All in all, I'm real happy I finally got this off my to do list.

New b/v guage was bouncing and sticking. I found a tip on "proper" place to T into b/v line for guage, moved T from under snout to end of line on the back side and ran the new nylon tubing that came with new guage. Works great now!

A few pics, before and after.













My ABS & TCS OFF lights are like old friends now.

Lol at the ABS/Trac Off. Mine's been on for almost 4 months now. Just got around to messing with it and found the pass. front hub has some nice play in it. Time for a Timkin.