svrider76

Ive seen a few threads about the oil pressure sensor but wanted to address a few concerns i had while i was changing mine out today.

My gauge has been pegged at 60psi since i got the car (just a few weeks ago) So i decided to change the sensor. Took out the old one, not too hard. The new one i had (POS BWD part) was only a one prong while the sensor i removed (original i presume) was three prong. The BWD part would not clear the carburetor cables bracket because the body diameter was too large. So i went to another local autoparts store (), and got a Duralast single prong sensor with a smaller body. Still 60psi and same threads, this unit actually had red thread sealer on it which was nice.

My concern is the connection with the single blade sensor vs. the original 3 blade sensor. After reinstallation the gauge was reading right around 40psi (which seems normal based on some other posts). Is the conncection okay with just the single blade connected or should i get an original AC Delco part?? The connection seemed secure but the boot didnt seem to completely cover the "neck" like the original style.??? Thoughts??

edit: car is an '83 LG4 Firebird

vetteoz

iTrader: (13)

Don't know about your particular car but the 3 wire unit has a switch for the fuel pump that keeps the pump running if
the pump relay fails.
Allows you to start and run car instead of being stranded on side of road.

Apeiron

You car originally should have had a single wire sender.

InfernalVortex

iTrader: (4)

Sounds like you got the wrong sender?

The larger 3 wire one is supposed to go above the oil filter, it's for I think 89-92 cars.

svrider76

The car is a 1983 LG4, The original sensor is/was a 3 prong/blade plug. The new one (which is working now) is only a single blade. Thats' what came up in the auto-parts stores database as an OE replacement. AC Delco no longer available which was three blade style like factor.

KnightmareCS

iTrader: (7)

I'd like to add my 2 pennies to this.
My 83 T/A LG4 has the 3 prong/blade OPS stock. My 82 T/A LG4 has a 1 blade switch stock. Both 60 PSI gages.
The 3 prongs are still available through RockAuto and Amazon.

lexpaintitblack

iTrader: (2)

so I am attempting the same switch debating which part to order from rockauto. The 1 blade is dirt cheap and still AC Delco whom I trust; the 3 blade is not so cheap. I don't want to put the wrong thing in here and pay for it later, but did anyone figure out if the 3 blade was for the filter adjacent unit and the one blade for the unit near the distributor? (I know there are actually two on the older models like mine and possibly OP's).

svrider76

I will say this. Its over a year later and my gauge/sensor/car is fine. This includes an 800mile/15 hour trip i took in 1 day in the Fall of 2012.

But. If i had to do it over, i would get what was in there originally. (3 prong for me)

lexpaintitblack

iTrader: (2)

Thanks svrider76. Was this sender located near the distro? I only had a minute to check it before work but I saw something similar over there. Also found an egr hose someone clipped leading to nowhere >_< but yeah I guess I'll go for the one blade and order again if it doesn't work! Thanks again for the update

svrider76

Yes behind the distributor and below the windshield wiper motor...Like i said in the first post, i would avoid the BWD Auto zone or Advanced (cant remember which) the diameter was too large.

svrider76

If you have aftermarket headers, it could be for the AIR injection system leading to the headers. My car had that gone when i bought it but the tubes were still there on the headers.

Damon

I believe on some cabrueted 3rd gens the other 2 wires on the OPSU complete the circuit path to the electrical choke heater on the factory QJet carb. Older cars they would just bake the choke heater in the key-on position even if the engine wasn't running. So in some 3rd gens they would "qualify" voltage going to the choke by referencing against oil pressure. If there wasn't any, the choke heater circuit path would not be completed and the choke wouldn't start to warm up until the engine actually fired up (oil pressure is present).

My guess is that they used a quick-opening choke as emissions got tighter and tighter. So even modest delays between key-on and actual engine start could have thrown things off, made for difficult starts or blown cold-start emissions beyond the limits of OEM testing. That's just a guess, though.

If you have a FACTORY 3-wire OPSU plug, I would certainly advise getting a proper replacement OPSU for it. No reason not to unless a suitable replacement can't be found.

Also- a question. If you just unplug the OPSU connector, does the oil pressure gague read zero? It should. Otherwise the problem isn NOT the OPSU, but rather the wiring or gague itself.

KnightmareCS

iTrader: (7)

^What he said.
If you have factory 3wire, go with 3 wire.

I had an extra 3wire OPSU from my 83 around when I put the motor in for my 82. It's the large diameter 3wire unit, which I think is BYD. Don't remember, but I think it was a yellow/black box. Anyways, I used some Watts pipe/90*elbow from Home Depot to make it work. Plugged the stock 1 wire connector into the center blade and it works. Both cars have 60PSI gages. The 82 reads 60 when cold or running, warm idle is at 30. I believe that should be ok. This is with only PCV on the pass side VC.

tom1985

Hi-I have an 85 camaro with 1 prong and pressure gauge sometimes is around 30 for a few minutes and then jumps to 60 and stays there-

Is this a common problem and can I believe the 30 psi before it jumps to 60?

Just cleaned and clear coated the drum like sensor and really don't want to buy a new one-no money

vetteoz

iTrader: (13)

I doubt it.
The oil pressure usually goes lower as the engine gets hotter

tom1985

sorry I was adding to the original post of "his gaige was pegged at 60psi and was wondering if this was the symptom of a bad sending unit and if it would read correctly until it went to 60

Tibo

iTrader: (15)

If you have a stock never rebuilt engine, who knows how much gunk is in your oil system or if all the oil passages line up or if your relief valve in the filter function properly.

tom1985

so tibo, I guess a new sending unit is also not the answer, I should immediately pull the engine and send it out for a complete tear down and flushing of all oil related passages and components??

the question was " is what I originally described a common symtom of a sending unit going bad

Tibo

iTrader: (15)

Wow. I was commenting on what could be a problem with your oil circulatory system, why did you feel the need to snap back like a spoiled little girl?

tom1985

sorry Tibo i"m nt trying to offend ayone but I've recently been attacked and am kinda fed up with this car, and my lack of knowledge. However, my question was " is what I originally described a common symtom of a sending unit going bad, in the context of the original post where his gauge was at 60 all the time, and it was later "fixed" with a new sending unit. So I am still looking for a reply to that question I posted before. Sorry for any ill will-I really respect you guys for helping us less fortunate in skill.

p.s: I do think that some repliers are more interested in not answering the question posed, but in ranting about what the "right" way of doing things is. I suggest that these repliers 1. concentrate and make sure the question is understood, 2. reply to the answer to the answer if you know it, 3. then do the "toot" on why you think it's not "correct" to do it. - I have a recent post on ECU emissions wires, hope you can help me-no offense
tom1985

tom1985

Oh
I do like young girls though