Oil pressure sensor 305 / 350

[AuroraGirl]

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19244500 but a GM tsb says 10201489
but THIS IS AA a square body.. it should have a old styyle sender not a sensor

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OIL PRESSURE GAUGE OPERATION​

ALL MODELS​

Oil pressure gauge measures electrical current from variable resistance unit (oil pressure sending unit). Sending unit has low resistance when oil pressure is low and has about 90 ohms resistance when oil pressure is high. A change in resistance changes current flow through gauge electromagnetic coils, causing pointer to move from low to high. Sending unit locations are as follows.

• 2.5L - In right side of block, under intake manifold.
• 2.8L - At bottom left of engine block, on oil filter housing.
• 4.3L (Astro, Safari, S and T Series) - At top rear of engine block.
• 4.3L (All Others) - At lower left rear of engine block.
• 5.0L & 5.7L - At lower left rear of engine block.
• 6.2L - At top left rear of engine block.
• 7.4L - At lower left front of engine block.

OIL PRESSURE GAUGE INACCURATE​

1. Check for shorts or opens in wiring between oil pressure sending unit and cluster or for inoperative oil pressure sending unit. Disconnect oil pressure sending unit at engine. Connect one lead of Instrument Panel Tester (J-33431) to Tan wire and other lead to ground.
2. Turn ignition on. Set tester resistance dial to zero ohms. Oil pressure should read low. Now set resistance dial to 35 ohms. Oil pressure gauge should read half or have 7-8 segments illuminated. Set resistance dial to 90 ohms. Oil pressure gauge should read high.
3. If fuel gauge responds correctly, replace oil pressure gauge sending unit. If gauge does not respond as indicated, check Tan wire between fuel gauge sending unit and cluster connector. If wire is okay, replace inoperative cluster.

 

[mibars]

Interesting... So what did I replace?

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At around 3:10 mark you can see what have I replaced, it looks slightly different...

I don't have an old style metal can sending unit attached to the oil filter base.

 

[AuroraGirl]

Interesting... So what did I replace?

xc_hide_links_from_guests_guests_error_hide_media

At around 3:10 mark you can see what have I replaced, it looks slightly different...

I don't have an old style metal can sending unit attached to the oil filter base.

Old style my guess

 

[HotRodPC]

Rcotner, you need the pressure sensor it looks like a bell of sorts. The sensors job is to send a signal to oil pressure gauge.

The oil pressure (switch) has a couple jobs which I can’t remember at the moment. It’s located behind the distributor near the firewall.

Hope this helped

If it hasn't been said yet, IIRC, it has something to do with the Auto Choke and high idle too. If the OP doesn't come up, it won't allow the choke to set or high idle or something like that, and why some trucks have a CHOKE light on the dash to let you know when the CHOKE is engaged.

 

[mibars]

An update: It sits at 15 PSI high or low rpm, cold or hot. Only when hot and idling it drops a little bit to like 12 or so.
If I understand operation of oil pump correctly it shouldn't behave like that, higher RPM even on worn out engine should have some effect on pressure. It's like either the sensor is never going above 15 PSI or the actual pressure is capped at 15 PSI for some reason.

Engine runs fine, doesn't make any worrying sounds and even does not burn much oil for 185k miles or so it has on a clock. I'd prefer to double check the reading with some aftermarket oil pressure gauge. What are the good spots to put the oil gauge and what threads would I need? Is my memory correct that ther is one plug with 1/4 NPT on an oil fiter base?

 

[AuroraGirl]

An update: It sits at 15 PSI high or low rpm, cold or hot. Only when hot and idling it drops a little bit to like 12 or so.
If I understand operation of oil pump correctly it shouldn't behave like that, higher RPM even on worn out engine should have some effect on pressure. It's like either the sensor is never going above 15 PSI or the actual pressure is capped at 15 PSI for some reason.

Engine runs fine, doesn't make any worrying sounds and even does not burn much oil for 185k miles or so it has on a clock. I'd prefer to double check the reading with some aftermarket oil pressure gauge. What are the good spots to put the oil gauge and what threads would I need? Is my memory correct that ther is one plug with 1/4 NPT on an oil fiter base?

i would think your oil pressure sensor is not good anymore, it sounds like the small drop is proper but the sensor should read higher. Get a oil pressure gauger from autozone and plug it in where the sensor is. If you get normnal readings, then ground out the gauge and leave it open, does it peg and sink?


THat will tell you what needs replacement