Engine manual and confirmation on Oil Pressure

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Tim@TBDevelopments

Tim@TBDevelopments

Lifer
I have a customers car in the workshop at the moment that is suffering from a flickering oil pressure light on idle.

I have run some tests on the pressure and checked the numbers against my workshop manual I purchased specially for working on starlets.

http://www.jpnz.co.nz/afawcs0131171/CATID=26/SUBID=358/ID=565/SID=63076686/productdetails.html

But I'm starting to doubt some of the translations.

According to the manual warm idle should be 7psi and 5000rpm should be 58psi.

Now these are the numbers I'm getting from this engine, although the oil light continues to flicker. I'm also starting to doubt the manual because searching the forum people are saying there getting around 2bar on idle. Plus 2-2.5bar is the typical idle oil pressure on other Toyota engines from the same era.

Can anyone share any light on this? Once I know if the pressures are correct I can start to diagnose the issue if there is one.

its very awkward not being able to have Toyota specifications for these cars

Many thanks

Tim
TB Developments
 
weeJohn

weeJohn

Lifer
This may be more confusion than help but it may prove useful in a way. My Toyota 4EFE manual lists oil pressure on a warm engine as...

at idle = 5.9 psi (or more)
at 3000 rpm = 38 - 52 psi.

Considering most of the oil system is the same, I cant see there being a big difference in a 4EFTE.

I have never seen 2 bar on my Apexi gauge at idle, measured from a tee piece at the oil pressure switch location. My Haynes manual for a 4EFE Corolla lists it as 4.3 psi at warm idle, 36 - 71 psi at 3k.
 
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Tim@TBDevelopments

Tim@TBDevelopments

Lifer
see that's in the same sort of regions atleast, few psi etc.

but on another source for replacement oil pressure switches its showing activation between 2-7psi, this makes it even more confusing as why have an oil light activation that is higher than recommend oil pressure.

Going to connect up my test gauge to my glanza tomorrow and see what that's making on idle for if nothing else some kind of comparison. I've also ordered a replacement oil pressure switch for this customers car as it wasn't alot to rule out issues with the sensor itself. The light isn't even constant its flickering so will also have to test for wiring shorts.

Engine sounds fine on idle no bearing rattle or anything suggesting a clearance issue was just looking for confirmation that what I'm seeing is correct.

Driving is fine, even with the idle raised to 1000rpm it sits nicely at 20psi and then 56psi at 5000rpm so thats about right as well going from my manual.

Tim
TB Developments
 
R

Rev

Member +
From the 5e point of view idle in the 1996 Tercel service manual shows -

@ Idle speed: 29kPa _______( 0.3 kgf/cm2, 4.3 psi ) or more
@ 3,000 rpm: 245 - 490 kPa ( 2.5 - 5.0 kgf/cm2, 36 - 71 psi )

Also the manual oil test ( page 616 ) shows these pressures are as measured at the oil pressure switch directly.
 
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Tim@TBDevelopments

Tim@TBDevelopments

Lifer
seems the manuals correct then on these smaller capacity engines.

Guess i'll start diagnosing the issues then with the oil pressure switch or shorts in the wire as it sits stable around 0.5bar on the gauge at idle of 800rpm.

Thanks

Tim
TB Developments
 
A

AdamB

Member +
It will be the oil pressure switch mate on the front of the block. I got the same problem on my N/A at the moment. No noise from the engine at all.
 
dac69er

dac69er

Super Moderator
AdamB said:
It will be the oil pressure switch mate on the front of the block. I got the same problem on my N/A at the moment. No noise from the engine at all.
Click to expand...

I had a similar problem when I first got my runabout GT. it hadn't been looked after very well. oil light didn't go off at all. after an oil change and a good run it started flickering and then was ok. had a few blips with it, but for the most part it was working fine.

when I rebuilt the engine I replaced the switch and that has been ok. if it hasn't been done already, for the sake of a few £££ I would just change the switch
 
S

Skalabala

Member +
It greatly depends on the oil being used and the actual temp of the oil.
But if the pressure on my 4E goes less than 15psi on worm idle I will not drive it and will do something to up the pressure.
Make it easy for yourself Tim and diagnose with a manual pressure setup :)
 
G

GP82

Member +
I see 2.5 bar, approx. 35 psi of oil pressure at warm idle 800/900rpm. I take the reading from the feed to the oil filter via a filter relocate kit. I would have thought that anything below 2bar on a warm idle would not be healthy at all.
 
Tim@TBDevelopments

Tim@TBDevelopments

Lifer
oh im capable of diagnosing the issues and fixing if needed.

i just needed to know exact numbers that were allowable on this engine and without an easily viewable manual just to get the specs its a little difficult.

But the manual is showing 7psi on idle and this is what were getting. new oil pressure switch was already ordered so will try that first

Tim
TB Developments
 
dark_knight

dark_knight

Member +
anyway, given a man of your motoring background, i'm sure you will figure it out. just come back here and share for those who may run into the same predicament.. :)
 
G

GP82

Member +
The oil pressure low warning light fail safe is rubbish. It activates when there is hardly any pressure. 7 psi of oil pressure is way too low, sure the journals will be riding on the bearings at such a low pressure and this is hard to listen out for.
 
A

AdamB

Member +
GP82 said:
The oil pressure low warning light fail safe is rubbish. It activates when there is hardly any pressure. 7 psi of oil pressure is way too low, sure the journals will be riding on the bearings at such a low pressure and this is hard to listen out for.
Click to expand...

Agree with this, the stock light is virtually useless, although that said it's in the manuals for a reason so it is very confusing.
 
G

gorganl2000

Lifer
http://www.ebay.com/itm/Longacre-Un...arts_Vehicles_CarParts_SM&hash=item565aafe645

its for the exact reasons listed above that for the longest time i was considering changing the stock unit to maybe 15 - 30 psi oil pressure switch

just replacing the oem unit with one that fits the stock location/connection----like in the link above
a unit that would be maybe more useful to help prevent engine damage


sorry Tim, i'm not trying to do a tread hijack,,,,it just seems like a natural flow to this one
any thoughts on the best pressure to use? -15psi, 18psi, 20 psi, 25psi, 30 psi???
 
Tim@TBDevelopments

Tim@TBDevelopments

Lifer
well i was only going on the toyota manual to see what was acceptable, but tested 3 other starlets today and most sit at 15-20psi at idle so i'm going to say that this customers 7psi, plus the fact the car has heavy breathing issues, but only when you get the engine hot with boost and about 30 seconds afterwards is suggesting to me there might be something seriously wrong inside the engine. The breathers are funny one. Leakdown tests and compression tests show the engine is fine, Driving normally its fine. But you get on boost so cylinder temps get upto the 800degree mark, and the breathers smoke like a champ, Then as you can imagine the cylinders cooling back down to there normal 300degree cruise/idle temps the smokes gets less and less until its back to normal.

Think it might be a case if the customer agrees to get this apart and see whats happening inside the block. especially seeing its a rebuild engine (stock spec) and done just over 10k miles, but was the 3rd engine from the builder as the others failed doesn't fill me full of confidence :(

Such a shame and i really feel for the owner :(
 
T

toyotacelica73

Fresh Recruit
OR maybe advise the customer to seek advice from somebody who understands the intimate workings of this engine type before incurring cost of stripping it down and rebuild?
 
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Tim@TBDevelopments

Tim@TBDevelopments

Lifer
toyotacelica73 said:
OR maybe advise the customer to seek advice from somebody who understands the intimate workings of this engine type before incurring cost of stripping it down and rebuild?
Click to expand...

was that aimed at me? I've over 15 years experience building toyota race engines. But none of my engines have ever had low oil pressure so was just looking for confirmation as my toyota BGB manual just seemed a bit low for my liking

Tim
TB Developments
 
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