Another Oil Pressure Issue
 

Folks, I'm to this website and have owned five second gen's in the past 5 years. I'm mechanically inclinded but don't know much about rotaries because none of the ones I've ever owned have ever given me any maintenance problems.

Here is my issue I need help with:

1991 normally aspirated 13B with 23,000 miles on it<--original miles never rebuilt
Compression is 115 psi all around
Engine runs like new (after all it has only 23k on it) No smoke on start, runs normal temps and well taken care of.

Problem:
35 PSI oil pressure at idle but at highway speeds it never hits 60 psi either cold or warmed up.
When warm:
In 5th gear between 2,000-3000 rpm oil pressure is 55 psi
In 5th gear over 3,000 rpm oil pressure drops betwee 45-50 psi

Has anybody had their oil pressure sender or dash guage go bad?
I'm going to get an adaptor from Mazdatrix and plug a manual guage to check readings and was wondering if the external guage matches the dash guage, what should I troubleshoot next?

Could it be that thermal pellet and can it be easily replaced without removing the engine?

Thanks, I've got a lot of learning to do about rotaries. I'm a quick study and not afraid to tackle a project.

Thanks,
Drew

well, i've had my oil pressure and and temp gauge go out.. and drove me crazy trying to find out what it was.. it's usually the simple things you over look, start with the gauges, then move on through the list.

The stock oil pressure sender unit is known to not be so accurate or easily crap out, confirm these numbers with a mechanical gauge put in its place and reving the car in neutral with the engine warm. Or install an electrical or manual gauge somewhere inside and test it out while driving.

Idle pressure sounds great, so it's odd that higher rpms would be low. Usually when there are oil pressure problems idle especially shows low.

probably not the e-shaft thermo valve/pellet as the idle pressure would be low (usually down 15 psi) as well.

I would look at a bad calibration of the factory unit

In my opinion, that's all just typical variation in both the stock oil pressure gauge and in the stock oil pressure. I wouldn't be worryng about it. But if I did, I would be focusing on electrical grounding issues. Otherwise, drive it like you stole it and watch your oil levels.

Mine reads 30- idle and 60 cruise also, But i notices when i slightly add some more gas at cruise it drops a hair.