mdpalmer

iTrader: (24)

EDIT: Yes, I searched on this. Many of the threads found a crappy OE oil pressure sender/connector to be the culprit. I have an aftermarket gauge/sender, so that does not apply to me

Hey guys, need your input on this one. I missed a Steve Kan tune thanks to this weirdness.

A few weeks back I resealed my oil pan to stop some annoying leaking. After doing the job and firing up the motor again (with fresh 20W50 oil/filter), I noticed that the oil pressure was a bit lower than it used to be, especially when the motor warms up and revs go up.

Recent Symptoms:
1. Engine completely cold @ 800 RPM (~50 degF ambient) --> ~60 psi
2. Engine warm @ 1000 RPM (water temp = 87 degC = 189 degF) --> ~15 psi
3. Engine warm, revs > 3000 RPM --> 35-40 psi (will not go higher!) (Mazda standard [1993 FSM pg. D-3] calls for at least 50 psi @ 3000 RPM)

Previously, I noticed that oil pressure was totally normal (I'd get around 50-60 psi @ 3000 RPM and around 90-100 @ higher revs on a warm motor... I'd get 90 psi @ cold startup). One thing to note: I dented the **** out of my oil pan at one point when trying to wrestle the motor back onto the subframe and thought that I may have bent the pan around the oil pickup (possibly restricitng flow to the pickup screen).

So I checked the FSM and consulted with a local rotary mechanic. Decided to leave the car with a him and he resealed the pan and removed the dents = same results as before. He checked with an analog/external pressure gauge (before and after re-sealing the pan) and confirmed that the reading is consistent with the one we're seeing on my cockpit electonic oil pressure gauge (aftermarket sender/gauge). He is going to check the oil control & regulator valves first, and if they aren't the culprit, check the oil pump/etc. (remove the front cover, etc.... DON'T WANT TO DO THAT!). If that's not the problem then I hope that it's not something more serious (like a bearing/clearance issue, etc.).

This motor has been running VERY strong and problem free since I had it rebuilt ~5000 miles ago. What do you guys think could be the problem? And can you explain to me the function (and if you've seen a failure) of the the oil control & regulator valves?

Thanks in advance and hope you all enjoyed the extra hour of sleep last night

FC3S Murray

iTrader: (7)

this might help: https://www.rx7club.com/showthread.p...essure+problem

mdpalmer

iTrader: (24)

Thank you very much. I skimmed the whole thread... I need time to digest some of it. Best of luck to you too. Sounds like a strong motor you've got otherwise

FC3S Murray

iTrader: (7)

No problem man. God forbid anyone has to go through what I did with my oil pressure problem so if this helps you, mission accomplished.

Keep me posted or if you have any questions shoot me a private message. Good luck bro.

mdpalmer

iTrader: (24)

Anyone else have input?

mdpalmer

iTrader: (24)

UP!

Anybody have this problem and figure it out? Why would my pressure be so different after taking the oil pan off? I didn't do anything else to the car. Except use an STP filter... The rotary mechanic used an OE Mazda filter with the same results. The motor is leak free, dents removed from the pan, pickup tube sealed to the motor and regulator valves in place... ANY IDEAS? There's no way my bearings could have **** on me all of a sudden...

mdpalmer

iTrader: (24)

^^

Gadd

Only two things I can think of. The pickup tube was bent by the dented oil pan and that bent the pickup tube flange. Or when you resealed the pan the first time you used too much sealant and some pieces of sealant got lose in the oil and is clogging something. I'd ask your mechanic if he had to clean off the pickup tube screen. And cut open the old filter, and if there are bits of sealant inside.

rexhvn

I have a similar problem lol. I started my FD today and noticed that my oil pressure gauge is not working at all!!! It just sits there on 0!! I did some searching and only got a thread on the sender and should clean it. But i'm thinking it could just be a fuss of something.

mdpalmer

iTrader: (24)

Old filter was trashed and pickup tube didn't have any stuff on it. Pickuptube was not bent, sealed just fine to the motor. Another mechanic at the facility said it's possible that one (or both) of the bearings may have "rotated", although that is very unlikely. They said that kind of problem would be accompanied by lots of mechanical noise...

I was reading in the manual that the oil cooler has a bypass valve... do you think it's possible that the valve is opening prematurely? I'm running out of ideas! Rotary mechanic checked the thermal pellet in the e-shaft and said it's fine.

I read another post where someone forgot to put an o-ring back in during assembly and he got very similar symptoms to what I have now:

weird oil pressure due to blown gasket for white o-ring that is between the front housing and the front cover

Thanks anyway

GoRacer

iTrader: (2)

Go to Signal Auto or XS Engineering if you have the funds but mechanics guessing will cost more then an expesive shop that can fix it. I know yours is aftermarket but I was told my sender was bad but it just had oil on the connector and cleared up in a few days. I am at 30psi on idle, 60psi on cruise and 90psi on full floor throttle. I thought that was normal reading the FSM. I used to use Mobil-1 filters but found pep boys has Pure-1 just as good for 1/2 price. You may have crap in the lines, switch back to 10-30 since 20-50 may be too thick to flush it out. The oil should be bypassing the oil cooler when cold starting. You state the pressure gets worse when warm? Do you have a way to check if the oil cooler is clogged? ...bypassing it when engine is warmed up.

mdpalmer

iTrader: (24)

Hmm. Good idea. Another person I talked to said the same thing (the lines may be clogged). He also said to use thinner weight oil and to try using the "engine flush" type of chemical to try and remove it. I'll try to get this guy to bypass the cooler lines... thanks

Gadd

Oh.. You left out the part about removing the front cover. Yes leaving out the oil crossover o ring will result in the low oil pressure you've discribed. Also if it was installed incorrectly it can blow out. But if it was replaced by a "rotary mechanic" then he most likely did it properly. The pressure regulator and relief valve do not fail very offen and there is no reason for them to fail because you removed the oil pan. If if you had good pressure before you pulled the pan and low pressure after you need to concentrate your efforts on what you did there. Did you pull the front cover? Did you take precautions to make sure the thrust washer spacer didn't fall? Does the front main pulley woble when runnig? Don't waste your money on engine flush. Even if the oil cooler were cloged (very unlikely ) the pressure would be high at cold start up.

mdpalmer

iTrader: (24)

I did not remove or atttempt to remove the front cover. I decided that it was too risky and given that the motor was put together by some folks that are a LOT more experienced than I, I decided to leave the issue to them.

To answer your other questions about whether or not the front pulley wobbles, etc... the rotary mechanic informed me that there is no evidence from the outside of the engine that anything is amiss.