Hi everyone, I just have a simple question. the oil pressure in my 93 FD has been normal until recently that it started showing something strange.
While driving, the pressure is correct and varies between 30 and 90 PSI according to the speed but in Idle where it used to be at around 10 to 20 PSI, now sometimes it fluctuates and goes to 0 and up to 20 very rapidly.
The car has oil and I checked many time to make sure.
Can it be that the oil pump has to be primed like in some other cars? Maybe the car ran very low on oil sometime and it caused that? This car is consuming like 1 quart of oil every 900 miles or so since I bought it 3 months ago.
Any suggestions would be appreciated.
Thanks...

 

The oil pressure sender is notoriously flaky. Either it needs to be replaced or cleaned, or the electrical connection to it is not making good contact. Search for oil pressure sender - there are lots of posts.

Dave

 

The stock oil pressure sensor has been known to be faulty thats why I opted to to go with aftermarket pressure and temp gauges. You can sometimes remedy the problem by pulling the sensor and cleaning it up and reinstalling it. But you will notice your oil pressure to drop -slightly- between oil changes as your oil gets diluted which is normal. Only thing that I'm concerned with is your oil consumption. Every motor is different, but on a stock port/turbo motor the norm is about 1 qt for approx 2500-3k miles. It all depends on the condition of your motor, turbos, as well as the weight of oil. How many miles are on your current motor/turbos?

 

For your oil consumption issue i go through about a quart every 1000 miles.

How much do you sit at IDLE, how much are you WOT and how much are you CRUISING? At idle they said it uses the most oil.

When Pettit did my rebuild they made the oil injector ports larger and bored out the injectors themselves.

 

computer just spontaneously shut down. axed everything i just wrote. kinda mad.

as long as your oil pressure increases with throttle (and especially boost) you should be fine. my oil pressure is usually about 20psi at idle, 40psi at about 3k cruising and about 60-70psi during WOT.

I use more oil than that (royal purple synthetic). I'll be doing a full oil change this weekend if i find anything interesting i'll come back to report.

 

Either ignore it or remidy it by replacing the Oil pressure sensor with a rather exspensive mazda replacment, you could always look for a second hand MX5 one as these are the same and interchangable.

If the problem persists after easter i could possibly dig one up from work www.mx5city.com for about £20+postage, they are nearly £90 from mazda.

 

Mine too is faulty but like everyone else said...it's common. Replace the sender instead of getting aftermarket gauge. If you want a good write-up on how to replace sender...check out Dale's walkthrough...pictures and all:

http://www.clubrx.org/default.asp?id...ntent=50&mnu=5

P.S. ^...may want to browse around other of his how-to's...tons of cool little tricks and install info.

 

Thank you very much everybody, you have been very helpful.
Veger, I would interested in the oil pressure sensor if you are able to get one. Just let me know how much it would be with delivery. I live in Seattle, Washington.
As for the engine by the way, it has 80,000 miles and I drive it medium fast most of the time and not much time idling with a few WOT a day.
Take care and thanks again...
Leo

 

so would i be fine at 10psi idle and 55psi at 3k? Using a defi gauge and using 20w50 oil

 

Im thinking that the oil is diluted, everyone else seems to be getting 20-30psi at idle. my 55 psi at 3k is within oem specs

 

IMO yes.
Fuel dilution is pretty common on these cars. One reason for the shorter intervals that most recommend.
My indicated idle pressure will vary a little, depending on operating temp, oil viscosity rating I'm using, how long since the last oil change and whether or not the wire contact at the sender is dirty...again.

 

today my defi gauge is reading 0 psi at idle, (it was 20psi at idle before) 40psi at 3k and 55psi at 4k, cruising at 2krpm sits around 20psi. Not sure whats going on, im going to look at the oil in the morning. Vacuum reading is at 18inhg and water temp stays between 85-89degC

 

What weight oil is in the car and how long since the oil was changed?

 

it was 20w50. Changed the oil this morning and had 4qts come out. No sign of coolant in the oil. No sign of oil in the coolant fill neck. It does not smoke at idle. When the car is started cold i get the basic condensation/smoke for like 30sec. Still runs strong and idles great. My vacuum is like 18-20inhg and water temps are great. Do you think the electrical oil sensor on the defi gauge is taking a crap like the oem oil sensors do? Anything else i can check out?

 

If your idle isn't tractor-low, I'd can't think of anything else. I'd double check connections, make sure everything is clean. What is the factory gauge reading? Are the readings generally higher on cold start-up when compared to operating temp?

 

stock gauge is crap like everyone elses, anyways the stock and defi both show 0psi at operating temps...Cold start its around 40-50psi..

 

Then yes, I would suspect something going on with the DEFI guage.

 

^thanks for your all your input and responses, I hope that the deif gauge took a crap like the oem sending units do.........anyone else want to chime in??

 

happen to glance at my stock oil pressure gauge at idle reading 20 or so psi, took a glance at my defi gauge and it read 0psi. I think both of my sensors are crap

 

ive also got oil pressure which sound similar to the above.
Im using a aftermarket gauge which works fine (tested it on another car)

When oil temp is low I i get 30psi up to 3000rpm.

When the car warm to 45/50 degrees the oil pressure increases to around 50psi at 2200rpm. However after this point the oil pressure drops all the way up to 7000rpm where the oil pressure is around 30psi. Any ideas?

 

Just bumping an old thread back up to update my issue so that whoever has the same problem can see the resolution.

Finally decided to purchase a new OEM oil sensor from Malloy and now it reads like it should at all temps. I wonder how much DEFI wants just for the oil sensor unit? The Defi sensor lasted three years.