oil pressure 1993 1800

johngalt · Post by **johngalt** » Sun Oct 11, 2009 4:48 pm

Whats the normal reading when car is hot at idle and 2500 rpm? cheers

Mark · Post by **Mark** » Tue Oct 13, 2009 10:48 am

People seem to report around 1-2 at hot idle, 3-4 at 3000 rpm. IIRC that's about what Na's that I've driven read.
But that's going to depend on several things - how warm the motor is, oil viscosity grade and how old the oil is, as well as how accurate the gauge is.

Factory spec for the NB8 is 3-4 (43-56 psi) at 3000rpm at normal operating temperature. The NA8 is probably the same spec.

If the gauge reading is way out, but no other symptoms (rattles, smoke, burning oil, big loss of oil etc) then it's probably an electrical problem, the connection on the sender, the sender itself or something else in the wiring or the gauge in the dash. I'd suggest to check and clean the contact on the sender first.

After that, if it's still out, you could put your mind at rest by getting oil pressure checked with an accurate external gauge, but the sender is in a nasty difficult place to get at, behind / above the filter. I've never done it on an MX5, but expect that some contortionist skills and patience would be needed.

Euen · Post by **Euen** » Tue Oct 13, 2009 2:16 pm

There is one thing to be careful of with the NA. For a few years, Mazda only fitted a pressure switch to drive the oil pressure guage. This meant that you only got an on-off reading on the guage. I can't remember what years or models were affected though.

Mark · Post by **Mark** » Tue Oct 13, 2009 4:32 pm

I think that's Na from about 1996 on, and Nb models. The OP's 1993 should have a proper gauge and sender.

Timmo · Post by **Timmo** » Tue Oct 13, 2009 4:41 pm

Yep my 97 NA has an un marked gauge which only indicates oil pressure (i.e. no actual pressure markings)

My car takes perhaps 5-10 seconds for that gauge to move up to its 'usual' position....im not sure if that is normal.

Post by **jif** » Tue Oct 13, 2009 5:56 pm

yep - the '93 and earlier ones had a real oil pressure gauge - you can tell as it has numbers on the gauge and actually moves around when you drive, unlike the later "idiot" (on/off) gauges!