Quote:
Originally Posted by FRSowner
Hi,
I've followed this thread with great interest and here's my take on what *possibly* may be happening.
Most of the occurances of this issue seem to be happening when the engine is fully warmed up and at idle. The CEL comes on and the car goes into 'limp mode'. Some have had a successful fix with an ECU reflash or new ECU. Some have had cam gears replaced or engine failure.
There have been some thoughts posted that the problem may be low oil pressure to the cams, a sensor reads this low pressure, trips a CEL, and as a safety measure, the engine goes into limp mode. This hypothesis is mine also.
However, could the core cause of this problem be the 0W oil that that Scion/Subaru recomemends for this engine? If you have changed your own oil and used this weight, it has the consistency of water.
As the engine warms, the oil will thin out. At idle, the oil pressure will be at it's lowest. If it gets too low, the sensors detect it and set off the CEL.
In the 'old days', cars had an 'oil pressure' idiot light (some had oil pressure gauges) that might flicker on hot days when you were sitting in traffic - the oil pressure was too low (the lights would usually come on at about 2 - 5psi) due to low viscosity or low oil level. As soon as you revved the engine slightly, the pressure would increase and the light would go out. But on an electronically monitored engine like these, it would trip a CEL and limp mode.
When the ECU is reflashed or replaced, maybe the new parameters allow for lower oil pressure to be present at idle speeds for X amount of time before tripping the CEL. Maybe they change the reprograming of the ECU to not trip at the previously low oil pressure levels (i.e. before, CEL was tripped at 7psi but after reflash, would only be tripped at 3 psi).
What if users just started using a slightly heavier weight oil such as 5W or even the old standard, 10W? What if Toyota/Subaru did a recall and replaced the oil pumps with a higher volume/pressue model? The heavier weight oil and higher oil pressure would affect gas mileage slightly but I personally would accept that as a trade off for engine longevity.
Any thoughts?
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Hi!
Just my 2 cents reg oil pressure
I got my DEFI oil press\temp gauge installed recently
On a warmed engine (90С\190F oil) engine runs 1-0,9 bar \ 13-14 psi oil pressure
On the road the oil pressure seems to follow the tacho pretty fast and pretty straightforward in most cases - 2K rpm for 2bar \ 30psi , 3 for 3bar and so on till the bypass at 6 bar \ 87 psi sharp , no matter how you redline the engine
of course, when it's cold, the oil press could be higher
I wonder how safe is running 13 psi idling on this waterish 0-20W
I got used to see 30+psi idling on my EJ20's and EJ25's , but the oil viscosity I used was never lower than 10-40, mostly 5-50 and 15-50
FYI - no CEL by now on my car, but it's too early to be sure it's safe (<2K miles yet)