is there an easy way to R&R the oil pressure sensor?

[flubyux2]

so, im having problems w/ my oil pressure readings and its the exact same symptoms as another friend in the area. his problem turned out to be a faulty sending unit as well.

see, on cold start, my oil pressure gets up to about 35psi at idle... but within a few minutes of running, my oil pressure reading drops to about 5-7psi... even before the oil would normally have warmed up. my oil pressure does fluctuate a few psi between idle and driving operating RPM's... its just reading too low to make sense. i have a complete oil sytem though;
new oil pump
releif valve shimmed 12mm
NA oil filter stud
oil filter relocation
-6an lines
fc3s oil cooler with thermostatic bypass valve

but, between my power steering pump brace, radiator hose, Ic hose and power steering line, i cant get a got-damn wrench on there. i cant get it from Under the car either cuz the subframe runs underneath it... i cant even get pliers on the shell of it to twist it off.

will a crow's foot wrench work? am i boned? what do i do... ive never had to do this in the car. i usually do it while the motor is out.

 

[dbsupra90]

you are boned!

nah, a crow's foot is the only way to roll. i have a brand new in the package from toyota sensor if you are interested. id let it go for pretty cheap if you end up needing one

 

[flubyux2]

dave, thanks a bunch... youre a great guy, i dont care what the other kids say!

i guess im gonna go pick up some crow feets and get this one out. if it turns out that the crow foots make it easy to R&R and this spare sensor i have turns out to be crap, ill PM you for that one you have!

 

[Justin727]

you have crows feet near your eyes right?

 

[flubyux2]

no, im not old. im still a young buck. bastard....

it seems as though the crow foots are gonna be sears-only. home depot, lowes and Advance had nothing. im sure AutoZone will be just as luck-free in that department. ill find out tomo i guess.

 

[dbsupra90]

dave, thanks a bunch... youre a great guy, i dont care what the other kids say!

i guess im gonna go pick up some crow feets and get this one out. if it turns out that the crow foots make it easy to R&R and this spare sensor i have turns out to be crap, ill PM you for that one you have!

its a good thing! people talk some mad shit about me and my way of doing things.

http://www.sears.com/shc/s/p_10153_12605_00904363000P?vName=Tools&keyword=crows+foot

thats the set i have. i also added a 22 and 24mm, those are handy.

id take a look at the wiring too, it often gets crunchy from the heat over the years.

 

[thedave925]

Oil Pressure Sensor isn't a hard removal. Easier than the turbo oil pressure/return lines.

pull the accordian hose/ intake setup, remove the 12mm nuts and bolt from the PS reservior, pull it aside as much as the return hose will allow.

Reach down there and pull the boot off the sensor, then the plug slides down towards the wire of the plug, do not pry it outward!
Take a 4" crescent or a short 10mm spanner wrench and have at it. It takes patience as you need some play in the wrench grip to accomodate the tight space to work with.
I've done this twice with a 10" crescent wrench, takes about 45 minutes for removal.

Use a teflon paste thread seal and screw the new one in by hand, and cinche it up 1/8th turn past hand tight.
Slide the sensor wire plug back in place, and then slide and fit the boot over the new sensor.
Slide the PS reservior and brace back into place taking care not to squash any lines or wires.
Use blue 242 medium strength thread-lock on the 12mm nuts and bolt,and cinche well.
Install accordian hose/intake back onto the turbo.

Whole process should take around 1.5-2 hours. You don't need to drain the oil either.
-Dave

 

[flubyux2]

well, turns out, the craftsman crowfoot wrench set doesnt work with the oil pressure sender. the bell on the sender is too large of a diameter to allow the crowfoot to engage the hex. soo, i spent $39.99+tax for nothing. im gonna take them back tomo.

what i ended up doing was removing the PS belt, unclip my NA ps resivoir for some play in the lines. i took the bolt out of the pump and loosened the pivot bolt. i slid the pump outward as far as possible. then i removed the alt/water pump belt for more room. i then removed the PS pump upper bracket. with this out of the way, and the intake pipe, i was able to get the 14mm wrench on the hex of the sender. i had to flip the wrench over each time because i couldnt get much of a rotation out of it. the wire connector wasnt broken or frayed, it was in good shape, as it should be for having 74k miles on it.

i ended up switching out my stock sender for another sender out of an 87, no difference. then i swapped in a sender from my 90 RX7, that seemed to read lower than the 7M units. so i put the 87 unit back in. amongst other repairs, like my thermoswitch connector, replacing the lost nut on the oil drain/feed flange, degreasing and cleaning the motor, i buttoned it up and drove it.

so, before the car warmed up, i was getting about 20psi shifting at 3000rpm. shifting at 4500ish, i was getting about 25psi.

im starting to think its my FC oil cooler. i have good oil pressure before the motor warms up. after its warm is the problem... gonna check for info on the FC oil cooler retrofit...

 

[dbsupra90]

i know mine works, odd. i think did use a wobble extension, not sure. you should see some of my creations to get at bolts haha.

good luck finding your issue.

 

[flubyux2]

i went to my hydraulic guy and bought a -8 to -8 male union to tie my oil lines together and bypass the cooler. if that works, ill use the -8 hose splice i also bought to modify the lines so i can reverse them.

the "toes" on my crowfoots werent long enough to reach under the bell, so idk. i got my $42.51 back though.

 

[jetjock]

Ugh. You went through a lot of work. The sender comes out pretty easily the way dave925 says if you have a stubby or decent crowfoot. Sorry I missed this as I could have told you Crapsman wouldn't do it. I know because I had to help a guy remove his sender and those were all he had. A little grinding took care of it.

I dunno what the deal is with RX 7 senders but I'd be surprised if they worked on the Supra because it's a weird system. You also threw away an oppurtunity to calibrate your stock sender. They can be made to be accurate with a little work. Mine is pretty much dead on at all pressures. Due to how they operate they'll always be a tad slow though.

 

[IJ.]

Chris: Got a pic of the one that works?

 

[shaeff]

JJ, care to explain how to calibrate the sensor? i never knew they could be calibrated.

don't feel obligated, but it'd certainly make a great writeup if you had some spare time you wanted to kill!

i'd sure read it, and attempt it.

 

[flubyux2]

i couldnt find a crow foot anywhere. Auto Zone had a set, but i forewent it since it was missing the 12mm and i thought thast the size i needed. so i went to sears but those werent long enough. i didnt know where else i could find thse things.

i can get to it fairly easily now that i know what to do. my engine bay is quite simplified.

i guess technically, both the one from my 89 (from a 90 originally) and the 87 (whats on there now) were physically identical. the RX7 one just had a longer hex. it sits further away from the block, about 1" more. JJ, i figured id try the rx7 one since i KNOW it works and was the same thread and connector.

the readings are definitly laggy too, just as it was before. i removed my oil cooler (since it was plumbed backwards). i didnt know it was directional but i learned it is. so i have the lines connected and i have a steady 20psi at cruise, 2250rpms. idle is about 7psi too. or so it reads on the guage. w/o the sender hooked up, my guage needle sits Way below the 0psi mark. i dunno if thats normal or its just not calibrated correctly?

im really curious on how to calibrate it. does it require disassembling the unit itself? i imagine it should have a specific resistance between the terminal to the shell/body at 0psig? i can hear, what seems to be, the windings of a spring rattling when i tap the sensor... is it just a pot in relation to a diaphragm with a spring for tension?