1uz, reasons for no initial oil pressure?

[George]

1uz-fe, vvti. Upon start-up, oil warning light stays on for as long as 20 seconds after the engine has been off for ~4 hours or more. At the same time the pressure is there for 5 seconds or more after the engine has been turned off. When doing timing belt and water pump replacement noticed almost mint condition, which surprises me a bit... I suppose worn oil pump or some blocking in oil pan, however both options are very unlikely to my thoughts...maybe I missed something else?

p/s the engine is off some 1998ish celsior. Never started it prior to putting in my car.

[dumbass]

Run a flush thru engine then drain and give engine oil change
These japs don't like to get services done on their cars because they get rid of them every few years

[George]

That sounds weird as there's completely no signs of gunk under cam covers...how could it build up only in sump?

[George]

here's how it looks from inside


of course the pic has nothing to do with oil system but it does give a feel of overall condition

p/s after 100km on it, new oil remains yellow which also contradicts gunk buildup version

[ta22fan]

I'm not familiar with this motor, but worth checking whether you need an ail filter with integrated backflow valve(s). Some of the after-market ones don't, and this can result in low oil pressure on startup in particular for 20-30 seconds. The correct Toyota filter or one from Ryco will be correct in this regard.

[George]

ta22fan, I'll try another oil filter and I'm familiar with toyota's needing backflow valve in a filter, but that version sounds weird for me as well. I got one 1uz-fe non-vvti, and a couple of vvti engines handy, all of them run the same filter and even oil type, and all of them don't have such a problem. However there's always place for bad part etc etc so I'll give it a try

[dnegative]

Have you confirmed the pressure issues with a gauge?
Sounds like the sensor could be dodgy, you shouldnt have oil pressure with the motor off.

[George]

dnegative that's what I plan to do this Sunday, replace the sensor with some used one and if that doesn't help, check the pressure with analog gauge, only have to source thread adapter for that. (if the new sensor is ok, I'll use old one to manufacture the adapter)

[woggin]

wat about something blocking the strainer...the motor might be perfect, but if rocker covers/sump been removed and re-installed using FIPG (form in place gasket, i.e. liquid gasket maker) it can fall into the engine and make its way to the sump, and its way to the strainer, blocking it....my mates 7m, yes i know, was a clean as motor, ripped the sump off and there was FIPG blocking the strainer....which caused the rod knock....had nothing to do with the hg being blown in 7 places...

good idea to take the sump off and have a look....pressure after shutdown isnt uncommon.

[allencr]

The filter is almost vertical & below the pump, if it's on the crank snout, so no drainback problem there.
So I'd suggest a lazy sensor or pickup smegma.

[dnegative]

My money is on a sensor sticking

[George]

I don't actually know what's been done to the engine previously, but I didn't remove cam covers, only took a look thru oil cap hole. I don't see apparent traces of liquid gasket maker anywhere though. That's my bad I didn't take the sump off when the engine was on floor, hope to run through everything suggested above this weekend.

p/s regarding backflow valve. It's popular to put 1uz filter to JZ engines which suffer badly from lack of such a valve. That's why I assume there's one in factory 1UZ filter, and that it's important.

[lexsmaz]

As has been said could hopefully be a dodgy switch, but also what is the sump pan like as in is there a upwards dish to it which could be restricting the oil getting to the pick up screen ??

[4th surf]

Not to sound old but "back in the day" where you would get "import engines" and cars which had suffered due to the lack of servicing, yes fine the top end might look clean as some rotten sod had pulled the rocker cover(s) off and cleaned everything to make it appear clean and "low mileage" but when oil pressure problems occurred this was usually accompanied by a weird noise which once we took sumps off turned out to be the oil pumps cavitating due to a blocked pick up screen. Now on some UZ engine packages and half cuts particularly front cuts I find that the sump bowl is slightly pushed up due to wrong placement of a forklift at some point in time. Now as the oil pick up screen sits fairly close to the bottom of the sump bowl this in turn gets pushed up and cracks the welds on the pickup allowing an air leak and thus longer to pick up on oil pressure. This doing the conversions that I've done doesn't really affect me as the sump bowl and in turn oil pick up get modified (or even changed completely) as to clear the steering on an IFS Hilux 4wd but I do have one sitting at my house that without mods will suffer this problem and I even know who bent it due to his wifes nagging (me). This would be worth looking at and also throw a master gauge on it just to be sure.

On the funny side after I bent mine (note to self do not operate forklift with wife nagging and a hangover) the wife carried on even more about placement of said half cut "I don't want it there" "Well it's a bit late now woman, I've already taken the forks and the tilt tray back to work"

[George]

4th surf - brilliant response, that's exactly what I have. Unfortunately I have very little time for my own car so I've not been posting anything here for a while

The terrible sound disappears after a while and don't come back unless the car's been left for some 4 hours or more. I was inclined to think it's vane pump cavitating due to some problem in low pressure side of power steering system (so I thought it could pick up some air when left sitting for a while), but surprisingly I removed acc belt and still could hear the same sound.

The sump is really bent, it's been bent upon transportation, and we added some strikes here and there to fit it over front suspension crossmember. We do it on every conversion and all of them have been fine until now. My first thought was that the excessive amount of bend made oil pick up 'stick' to the sump, or somehow damaged the pick up pipe (introduces cracks or something), but opening the sump of another 1UZ shown heaps of free space (up to 20mm) betweel pick up pipe end and the sump itself. However I'll recheck everything, I'll have to remove the sump anyway as it leaks a tad...say couple of drops per week.

I have a rooted 1uz handy so even if it's not blocked screen I'll replace the whole pump assembly. Overall, looks like the genie is outta bottle but all the shit didn't hit the fan yet...at least the engine has no sort of clicking noise that would indicate any bottom end issues

funny enough that 'rotten sod' translates literally without losing its meaning