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Discussion Starter · #1 ·
Hi mates...would really appreciate if anyone can pls guide me on what could be wrong with the engine of my 2001 JDM Celica.

Engine: Stock 2ZZGE 6MT
Engine sounds good, performs really good. Very Good acceleration.
Oil used: Castrol Edge 5W-40 (summer temp. in my country is appx 35 deg celsius, and winter appx 15 celsius; now it is winter)
Oil pressure at startup: 90 psi (as shown on Racetech stepper series oil pressure gauge)
Oil pressure at idle: 15-20 psi (using Royal Purple extended life oil filter)
Oil pressure at 3K RPM : Appx 60 psi
Oil pressure plays around 20-70 psi in line with rpm up to lift engagement point.

I've been observing this for the last couple of days: As soon as it hits lift, oil pressure seems to drop drastically to 30 psi or less on a straight road (so rules out the possibility of oil starvation due to banked track or high g force).
Oil level at early morning check before start: Between upper and lower marks of the dipstick (not sure if oil level is too low).


Can anyone kindly guide on what to check? Thanks!! Worried :/:
 

· Electromagnetic Wave :-h
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Given my history with Edge (albeit 5W-30), I am suspicious of a worn main bearing (possibly #4). Try a heavier oil and see if the pressure significantly improves? Its only a guess.
 

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Given my history with Edge (albeit 5W-30), I am suspicious of a worn main bearing (possibly #4). Try a heavier oil and see if the pressure significantly improves? Its only a guess.

How would a worn bearing contribute to such a pressure drop? Can u pls explain in bit more detail?
What could be other possibilities?
 

· fuck the police
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How would a worn bearing contribute to such a pressure drop? Can u pls explain in bit more detail?
What could be other possibilities?
oil pressure is the pressure of the oil as it moves through an oil passage in the block. if you have a worn part that makes that passage bigger the pressure will drop. main bearings have a hole where the oil is applied to them. however lots of things can cause low oil pressure such as a bad oil filter.

http://www.2carpros.com/articles/high-or-low-engine-oil-pressure - a little info

http://www.aa1car.com/library/us1097.htm - alot of info
 

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Given my history with Edge (albeit 5W-30), I am suspicious of a worn main bearing (possibly #4). Try a heavier oil and see if the pressure significantly improves? Its only a guess.
yeah thats not possible, if that was the case, the bearing would be shot and spin. and how can you place blame on #4? what did #4 do to you?
 

· Daddy Daycare
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It did a lot to him actually. I saw the pics, not pretty. I'm talking about the kind of damage you'd expect to see on a rod bearing, not a main.
 

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Perhaps the oil pressure relief valve in the pump is getting weak or stuck. I haven't torn one apart, but other Toyota ones have spring loaded poppet valves in them that will stick open or closed sometimes when the spring gets weak.
Perhaps something similar is happening within one of the oil control valves. SMAAY?
Dentman
 

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Discussion Starter · #8 ·
Thanks for the guidance guys.... It is also to be mentioned that my dashboard oil warning light does not light when the oil pressure gauge shows the drop.

Here's what i plan to do in sequence:
1. Drain oil
2. Open sump and check for clogs on the oil suction net and pressure sensor
3. Check for debris on the magnetic sump nut
4. If all seems ok, put in fresh oil and filter. Oil level as per factory recommended level
5. Test drive.
6. If problem persists, check oil pump and replace if needed.

I hope the issue gets resolved by step 5. Will update once done. Thanks.
 

· Electromagnetic Wave :-h
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that is a sign of contamination in the oil.
Perhaps the oil pressure relief valve in the pump is getting weak or stuck. I haven't torn one apart, but other Toyota ones have spring loaded poppet valves in them that will stick open or closed sometimes when the spring gets weak.
Perhaps something similar is happening within one of the oil control valves. SMAAY?
Dentman
show me where that has ever happened before
 

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It has happened a couple of times on old 18R, 20R and 22R series motors with high miles. The oil pump relief valve is spring loaded and gets weak. If they sit for a long time or the oil is never changed, the valve sticks and that part of the pump has to be cleaned. I have lots and lots of experience with a variety of old Toyotas. My first one was a 79 Corolla back in 1982.
So moving into the new models, can there be similar symptoms with a new oil pump or oil control valve? As stated I have not taken one apart. SMAAY?
Dentman
 

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Discussion Starter · #14 ·
Opened the sump and vvti ocv today. Not a bit of sludge or any sort of dirt in the sump....nor in the OCV strainer or oil suction screen. Here are pics just after opening.







Btw, this sump was never opened before..still had the original factory fitting.
From what I see above, I don't think there any possibility of finding sludge anywhere in the engine. Moreover, oil pump pressure seems to play across the dial very nicely. Stays at 95 psi at cold start up, and gradually comes down to 15-20 psi when oil temp reaches 80*C. 75-80 psi at 3k rpm. That's why my mechanic suggested not to open up the oil pump.

However, lift activation still shows a drastic drop in pressure which seems more like the gauge's oil pressure sensor is giving away when pressure reaches a certain level. Would it be safe to assume the gauge pressure sensor is bad?

My next plans:
- Observe for few days
- Have the oil pressure checked by a mechanical gauge
- If pressure found ok, get rid of the Taiwan made Racetech gauge and get an Autometer gauge
 

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Could there be something in the high cam engagement system in the head that would bleed off oil pressure when lift is engaged?
 

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Do the cam oil sprayers spray oil all the time or only in lift? If they only spray in lift and if that tube isn't seated correctly, could it dumping oil affect overall engine pressure?
 

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