Oil pressure sender in hilux

[ftruckn]

Hey guys need some help, have 1uz in early 90s hilux (had 22r) and now 1uz

anyway sorting on the oil pressure gauge (using stock gauge) so I put the 22r sender on the 1uz as the original 1uz sender was just a switch I presume? As didn't have any resistance.

The gauge works but reads dead on low on startup and just under a quater on around 3000rpm, so just wondering would the oil pressure still be ok in the 1uz but just reading different on the hilux gauge because of different psi pressure in both motors? Oil weight difference etc?

Any help would be great guys just want to make sure oil pressure is all good

 

[ftruckn]

Anyone? I'll take guesses lol

 

[duza]

From memory, I think I had a similar problem. I got about a 500 ohm pot and put it between earth and the sender wire (sender not connected), then wound it until the guage was at 3/4 full scale. I recorded that resistance. I then measured the resistance of the sender (wire not connected) with motor revving at about 3000RPM. It was then just an easy calculation to get a resistor soldered in parallel with the sender to get the desired resistance so that max oil pressure was at 3/4 full scale of the meter. Sorry I can't remember what that resistance was.
Ric

 

[ftruckn]

Cheers mate that helps, I'll just wondering what's a ohm pot?

Cheers

 

[Zuffen]

Interesting approach to assume max oil pressure at 3,000rpm.

What if the motor is knackered?

The gauge should read exactly as it did in the Lux so if it's low find out why.

Much cheaper to invest some money in finding out what is really happening than to blow and engine and then find out.

An aftermarket oil pressure gauge is pretty cheap compared to a new engine and the effort of swapping it in. Don't even mention the cost of swapping engine numbers with the RTA.

 

[sideshow]

toyotas have the wowrst gauegs of any cars out there
there is a fix someone has posted on fixing the piss poor temp gauges
so maybe some one can come up with a fix for the oil gauge
even with a 22r the oil press gauge on my hilux was up the arseeee

anyway if yr driving around racing yr car and u suddenly see no oil press then
yr enigne is stuffed
same with if u have a light and it comes on at hi revs then yr stuffed to
in reality oil lights or gauges are only good for chekcing when start up
to see if u go oil press in the morning
most of the other time if u have oil press probs by the time u see it its usually too late

on the race cars we used to fit oil press switches that came on at bit higher oil press
i thinnk std is like 15psi we would fit 25 psi switches
this is good when driving but not good at idle as it came on
so u reallly need 2 swithces if u were anal
anyway id either fit a light or jut leave it
my 1uz never had oil probs in 7 years and hasnt had any probs since i sold it

also id prob use a 15w30 ro 40 oil not a 10w something
mine felt quieter on 15w

 

[ftruckn]

I didn't assume max oil pressure was at 3000rpm I gave it some squirts up quite high and no change, and I don't agree with you on " if oil sender from lux is in the 1uz gauge will read right" as I'm sure both the motors have different oil psi, oil weights etc.

I was just wondering if anyone had a similar problem before I pull anything apart.

Cheers, zuffen and sideshow

 

[duza]

Interesting approach to assume max oil pressure at 3,000rpm.

What if the motor is knackered?

The gauge should read exactly as it did in the Lux so if it's low find out why.

Much cheaper to invest some money in finding out what is really happening than to blow and engine and then find out.

An aftermarket oil pressure gauge is pretty cheap compared to a new engine and the effort of swapping it in. Don't even mention the cost of swapping engine numbers with the RTA.

Well, My guage didn't read the same. Initially I fitted a manual pressure guage to make sure the engine oil pressure was within FSM specs. It was. I determined that at about 3000RPM the oil pressure was approximately at the maximum that guage read. Knowing that analogue meters are at their most accurate between 1/4 and 3/4 full scale, I set about calibrating the Lux meter so that the guage would give me the best reading in that 1/4 to 3/4 range. The Lux meter has no pressure readings on it, only marks, so the actual pressure reading does not matter. My Lux is a 94, others may be different. I just saw no point in fitting an aftermarket guage on the dash when it had a perfectly good looking one in the dash.

Ftruckin, Go to Dick Smiths and buy a 500 ohm potentiometer. It is a variable resistor just like a volume control on your stereo. It will cost under $10. It has 3 solder lugs. Connect the centre to earth and either one of the others to the pressure sender wire. Turn the ignition on and slowly wind the knob until you get to around 2/3 to 3/4 full scale of the meter. Remove the pot. Measure the resistance with a reasonable quality multimeter. Lets say it comes in at 100 ohms. Do the thing with the sender unit as I suggested in my last post. Lets say the sender comes in at 300 ohms. You need to get it down to the 100 ohms. The formula for resistors in parallel is 1/R1 +1/R2= 1/R3. That is: 1/300+1/R2=1/100. Or R2= 50 ohms. Go back to Tricky Dicky and buy a one or two watt 50 ohm resistor, solder it between earth and the sender wire. It will work. You will end up with a meter which reads at or near max oil pressure above 1/2 full scale and around 1/4 full scale when the motor is warm and idling.
Ric

 

[ftruckn]

Thanx mate legend

 

[Zuffen]

ftruckn,

Think about it.

If the same sender is sending information to the gauge as it always has the figures will be the same.

Oil weight and any other variables won't change the way the gauge reads the same information it has always seen.

I'm a dummy but even I know that!

 

[ftruckn]

ftruckn,

Think about it.

If the same sender is sending information to the gauge as it always has the figures will be the same.

Oil weight and any other variables won't change the way the gauge reads the same information it has always seen.

I'm a dummy but even I know that!

yes but say 22r oil pressure 40psi max, 1uz 80psi = gauge reading wrong as pressure is different on the sender, that's my understanding anyway

 

[Zuffen]

Your question is a little academic as the 1UZ doesn't run an oil pressure gauge.

It has an oil pressure switch only.

If you use the UZ item the gauge will show either zero oil pressure (when running correctly) or max when the oil pressure drops below around 10psi.

I'd run the Lux sender so at least you're getting an indication which is all it is at best.

 

[ftruckn]

Yeh mate already running the lux sender, says in first post, cheers anyway guys all fixed now

 

[litldv8]

just done one in a ln111 - just used the lux sender that was in the 3l to work the guage and the guage seems to work just fine.
neil