87-88 4runner 22re oil sender ?'s

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cody c

cody c

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hey all, does anyone have pics or info of where the pressure gauge and cut off switches for oil pressure are located, Im just at a friends who has an 87 runner that isnt getting a reading for oil pressure, the block was rebuilt before we bought it and appears to have the oil cut off but cant locate the pressure sender. dont know wtf is going on, im curious if during the rebuild they got things mixed up, cause the wiring seems strange.
Thanks in advance!
 
Sender is right under the oil filter, screwed into the side of the block. One wire coming off it. If it's a small sender, then it is only a simple switch the turns the dash light on and off. But it it's bigger (about 2" diamater), then it is for a gauge.
 
there is the smaller sender under the filter, but from my understanding there is this switch which will turn on the engine light, and a oil pressure sender which will tell the oil gauge which he has, how much pressure. Is there another location for the pressure sender?

The electrical schematic shows a switch and pressure sender, but we cant find the larger pressure diaphram.
 
There is only one sender on that motor and it is under the filter big one is for the gauge or the small round one is for the light there is nothing too tell the computer that the motor does not have oil pressure. pull the sending unit out and install a mechanical gauge and see if you have oil pressure about 2-10 at idle and 40-70 above 1500rpm.
 
87toycrawler said:
There is only one sender on that motor and it is under the filter big one is for the gauge or the small round one is for the light there is nothing too tell the computer that the motor does not have oil pressure. pull the sending unit out and install a mechanical gauge and see if you have oil pressure about 2-10 at idle and 40-70 above 1500rpm.
Click to expand...

Exactly.

The engine ECU takes no input from the oil pressure. It will keep running, even if you lose oil pressure. At least until it seizes.
 
perfect, thanks for the replies, i was confused because the manual showed 2 switches in the electrical schematic, but i guess there is only 1. Ill swap it in later today.
THANKS MUD!!
 
swapped the senders, the wierd thing is the wire that goes on the sender has a notch in it that matches the pressure sender, but also has a rubber boot that matches the smaller sensor.

We screwed in the new larger pressure sender, and the wire to it has power when the vehicle is running, but the gauge isnt moving.
Anyone have ideas, it seems there shouldnt be power there if the gauge was burnt.
 
Did you swap in an SR5 gauge without changing the sender? If so, you may have fried the dash gauge...... Hate to bear bad news.... The idiot light sender is just an on off switch, the gauge sender is a variable thing, I don't think it ever lets full voltage through....
 
cody c said:
swapped the senders, the wierd thing is the wire that goes on the sender has a notch in it that matches the pressure sender, but also has a rubber boot that matches the smaller sensor.

We screwed in the new larger pressure sender, and the wire to it has power when the vehicle is running, but the gauge isnt moving.
Anyone have ideas, it seems there shouldnt be power there if the gauge was burnt.
Click to expand...

your right if you have power to the wire it isnt the guage,it must be the sender.the sender is a variable resistor type thing,it varies the ground.try a different sender.
 
ill post some pics tommorrow as they will be worth a thousand words. But in the mean time the new pressure sender is brand new out of the box. And the wire shows power to the sender, the oil gauge isnt working, and there is a check engine light on. The motor was rebuilt around 20,000 miles ago, but my friend hasnt had it very long.
 
pictures to explain dilema, as you can see there is a notch on the wire connector to match the pressure type sender, but the rubber boot is for the smaller switch.
IMG_5340.webp
IMG_5341.webp
IMG_5344.webp
 
more pics to help, pics of oil gauge and old sender. The old sender shouldnt need the wire connecter with the notch in it, only the pressure sender because it has a round button shaped doo amihickey. The rubber boot seems the right size for the smaller sender.

Strange huh?
IMG_5346.webp
IMG_5347.webp
 
It's not strange at all. This truck obviously originally didn't have a gauge, just the light on the dash. That's all that small sender does, it's a simple on/off switch. Yes, there will be voltage going thru the gauge wire, the sender sends this signal to ground to control either the light or the gauge.

In the case of the small sender, when there is little or no pressure, the switch is closed and the oilcan light on the dash turns on to warn you. But with the bigger sender, it changes resistance as the oil pressure fluctuates, and the gauge fluctuates accordingly to match it.

The problem is, if you swap the dash cluster to the SR5 gauges and hook the gauge up to the small sender, when you start the engine and the switch closes, too much current goes thru the gauge and it goes POOF. No more gauge.

Sounds like that's what happened here, you get to replace the gauge in the cluster now.

It's likely that the CEL light is on because the knock sensor is disconnected, that's what that green connector is for. Have you jumpered the diagnostic connector to pull the error out of the ECU?

BTW... get the crappy POS Fram filter off your engine NOW. Do not use them, they suck. Get OEM filters or something better, the NAPA Gold is also a decent filter if you don't have a dealershp nearby.
 
they also had two versions of senders for the pressure gauge.try hooking sender wire to ground it should read full then.if not then it is gauge,but if you have power to that wire i doubt it is the gauge.
 
KLF said:
It's not strange at all. This truck obviously originally didn't have a gauge, just the light on the dash. That's all that small sender does, it's a simple on/off switch. Yes, there will be voltage going thru the gauge wire, the sender sends this signal to ground to control either the light or the gauge.

In the case of the small sender, when there is little or no pressure, the switch is closed and the oilcan light on the dash turns on to warn you. But with the bigger sender, it changes resistance as the oil pressure fluctuates, and the gauge fluctuates accordingly to match it.

The problem is, if you swap the dash cluster to the SR5 gauges and hook the gauge up to the small sender, when you start the engine and the switch closes, too much current goes thru the gauge and it goes POOF. No more gauge.

Sounds like that's what happened here, you get to replace the gauge in the cluster now.

It's likely that the CEL light is on because the knock sensor is disconnected, that's what that green connector is for. Have you jumpered the diagnostic connector to pull the error out of the ECU?

BTW... get the ****py POS Fram filter off your engine NOW. Do not use them, they suck. Get OEM filters or something better, the NAPA Gold is also a decent filter if you don't have a dealershp nearby.
Click to expand...

if there is current going to the wire then it is going through the gauge,gauge cant be shorted,if it was then there wouldnt be any current.power goes through gauge and then through the sender.
 
i believe it came with the smaller sender, so the gauge would have already been gone. what about the notch on the wire connector, and the smaller boot, which sensor would this have been made for?
I havent really done anything to this vehicle as it is a friends who I am visiting in hawaii, i will tell him to go to a different filter. This is a $2700 vehicle in kauai, and he doesnt seem to want to keep it for more than a year, just to get to work and bring the surf boards to the beach. Although not hving an oil light on and zero pressure on the oil gauge would help resale value. I think it would be easier to add an aftermarket one in the dash for wwhat its worth.

I dont know much about checking the diagnostic codes, where can i find more info on this?

Thanks for your help! (mahola! )
 
my fsm says to check for 4.5 volts at the sender wire,then check for 44ohms resistance at terminals a&b on back of gauge cluster to verify gauge is working.
 
jhnLennon said:
if there is current going to the wire then it is going through the gauge,gauge cant be shorted,if it was then there wouldnt be any current.power goes through gauge and then through the sender.
Click to expand...

Exactly. Current goes thru the gauge, to the sender, which sends it to ground (via the engine block). If you have the smaller switch sender, when the engine starts it closes and sends full current to the ground, which is too much for the fragile coil in the gauge, and it goes POOF. With the larger sender, it has a variable resistor in it, which never goes down to 0 ohms, so the gauge is protected.

The connector on the wiring harness is the same for both senders, I believe. If you have the small boot on the harness, then it originally had the small sender "switch" on the truck, which fried the gauge on the dash.
 
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