Does anyone know what this is

[Burban1990]

I replaced this oil pressure sensor as well as cleaned and reinstalled the two other fittings. I use to use teflon tape but decided to go with permatex 56521 thread sealant instead. It mentions that it cures in 24hrs at 72 degrees. It's 40 degrees here where I live today and was curious if anyone had any idea how long it'll take at that temp to cure. Doesn't mention it on any site or product packaging and I've never used it before. Had great reviews so I thought I'd give it a try.

 

[seniorbear69]

i have an 88 firebird with tbi oil sender is behind dizzy the one in the side is a pressure switch so fule pump wont run with no oil pressure

 

[Swearbody]

Does anyone know what this is and do they have a tendency to leak oil? It's a Chevy 350 TBI engine. Never had a Chevy engine that didn't leak oil, this one's pretty tight but it seems to have a slight drip from this part.

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Mine leaked like hell once it got installed on my new engine. Started a damn fire during break-in leaking on the header. It was plenty tight but leaked through the body of the sensor. My truck ran both oil sensor/sender from the factory. Im now using just the one on the back of the block.

 

[Swearbody]

I replaced this oil pressure sensor as well as cleaned and reinstalled the two other fittings. I use to use teflon tape but decided to go with permatex 56521 thread sealant instead. It mentions that it cures in 24hrs at 72 degrees. It's 40 degrees here where I live today and was curious if anyone had any idea how long it'll take at that temp to cure. Doesn't mention it on any site or product packaging and I've never used it before. Had great reviews so I thought I'd give it a try.

I use the white permatex on everything. I usually wait no more than an hour and fire it up if I wait at all. Never used it to try and seal a bad seal before but on new threads I just go for it. I used that stuff on the exact spot your sensor is with a plug and fired it right up.

 

[Snoots]

I replaced this oil pressure sensor as well as cleaned and reinstalled the two other fittings. I use to use teflon tape but decided to go with permatex 56521 thread sealant instead. It mentions that it cures in 24hrs at 72 degrees. It's 40 degrees here where I live today and was curious if anyone had any idea how long it'll take at that temp to cure. Doesn't mention it on any site or product packaging and I've never used it before. Had great reviews so I thought I'd give it a try.

As long as the case of the sensor is grounded to the block you're ok. Teflon tape on electrical sensors is a BAD idea.

 

[fast68chevy]

ok well this is factory,, both of these parts.

most motors '80s up motors were this way, by the time that the electric choke years models came out. the E4ME carb models for example.

however one is actually a sensor for dash and the other is a switch, for choke or for fuel pump depending on if is a tbi motor truck or carb motor truck, etc.


one is for fuel pump or for the electric choke models. and other is for dash.. like Rick has stated. he knows..

why ppl have to post incorrect info is beyond me,.
just because someone has never seen something does not mean thats how all of them were..
ppl should not just blindly assume things. and that all motors and models ran the exact same oil switch and sensor systems.. when that is totally not the case..

here is a pic of many random different OP switches that i have stashed around here, the ones with black plastiic plug wire terminals kind of oval-shaped end with the three terminals/pins are from stock oil pressure switches 1987-up GM TBI or other '80s and up GM fuel injected motors. for the fuel pump, typically.

and the one with the red writing on it is not from a V8 it is from a MPFI V-6 or possibly a 2.5L or 2.2L GM as late as early 2000s years. like an N or J body car,
or possibly an S-series truck,
and then there is another one of these sensors right below this one, next to the two-spade OP sensor or switch.

there is also a heated O2 sensor and also an air temp sensor in the pic too lol.
and heated means that it is not a single-wire sensor, and that it has two wires for the heating circuit "coil" that is built into the sensor, to heat it. for when its cold. etc.
so that it will begin to talk to the PCM, and send or communicate voltages/values much quicker, for when its cold, etc.,
because a non-heated single-terminall O2 sensor is essentially "asleep" until it hits a certain temp,
and the short length three-spade sensor or switch may possibly be a transmission temp sensor.

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[Ricko1966]

factory,, one is for fuel pump and other is for dash.. why ppl have to post incorrect info is beyond me,.

Not always, mechanical pump cars used 2 also, 1 for the gauge or light
And 1 for the choke

 

[fast68chevy]

How would they use both? Or are you saying it could be found in either/or one of the 2 locations in a model? This is an honest question, please take it that way.

two totally different parts. and they do/are for two totally different things.......

 

[fast68chevy]

I don't believe your TBI will have one behind the dist, mine don't?

do you have an oil pressure guage sender unit? if so then you dont have a switch for your fuel pump. someone has possibly removed it.

 

[Ricko1966]

because these ar etwo totally different parts. and they do two totally different things....... open your mind.

Some trucks do use 2, fast knows this, I know this.to explain it as simple as I can 2 switches 2 functions both are oil pressure switches or senders though.Somectrucks trucks will use 1 behind the distributor as far as I know that one always works the dash (gauge/light) to make it more confusing gm also made a sender that did light/gauge and fuel pump 2 circuits in the same sender some applications 1 for light/ gauge behind the dizzy on everyone I ever saw and a second one for the fuel pump or choke on the side of the block.Purpose of controlling pump/choke with oil pressure switch is no fuel if the engines not running(especially helpful if you crashed) or no power or to the choke so the choke doesn't open premature and cause a no start or cold drivability problem.

 

[fast68chevy]

Not always, mechanical pump cars used 2 also, 1 for the gauge or light
And 1 for the choke

thats what i was saying.. one for dash and other for choke or FP

choke = mech fuel pump cars..

switch = choke or FP

sender/sensor = dash for oil lamp or guage



i said the exact same thing already. up there.

 

[fast68chevy]

As long as the case of the sensor is grounded to the block you're ok. Teflon tape on electrical sensors is a BAD idea.

just to clarify, this really only matters if it is an engine block or head or intake maniifold casting "ground-through" type sensor.. which would be a single/terminal/pin/wire type sensor.

this type design of sensor will simply allow engine block ground through itself and into the terminal/wire on/in it.
and so with these sensors they DO indeed need to be grounded through the threads- clean with no sealant at all- to the engine block or part casting that it installs/threads into,. yep.

a good example of this are the single-wire CTS sensors. you defiitely never should thread seal a single-wire CTS. but the two terminal TBI ones yes thats fine, can thread seal those no problem.

 

[Ricko1966]

Damnit I missed where you put in choke,I only saw fuel pump my bad. Anyway hit me back on that harness

 

[Dave M]

Side question here, could someone please explain the sequence of operation of the electric choke. Am l to understand this element is constantly powered with the engine running and this holds the choke open ?

 

[Ricko1966]

Side question here, could someone please explain the sequence of operation of the electric choke. Am l to understand this element is constantly powered with the engine running and this holds the choke open ?

The choke has a spring,heat changes the spring tension.Some cars use an electric element to heat the spring which opens the choke,as the spring cools it pulls the choke shut.When the choke is shut the engine can't draw as much air so consequently it draws more fuel so you have a rich mixture for cold starts.There' s also a cam on the choke rod that holds the throttle open a little when the choke is on so the truck will idle cold.