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The 14 pin is the front engine harness to the fender well near the jump start post the harness that has the oil sending unit wires inside.....SO WHERE WERE YOU TAPPING ???
OH , got it. .DUH!! i was thinking you were all referring to the 10 pin connectors (thought they were 14) at the fuse panel.. Now i see why you thought this was bad, that something changed by tapping there.
I just went out and did more looking around.... the wires on the pressure sensor look good and the spade is tight, and so is the smaller wire with the nut on it. a little oily though around the larger post.
turn the key on, the oil pressure sensor seems to prime..... red warning light on...........then , start the car, it flys up to max over 5bar and stays there.. electrically, obviously, not pressure. and turn off the ignition, and the needle falls.. (before it was sticking , so when i tapped the "K" 10pin connector on the fuse panel , the needle fell) now, it doesnt do that.
maybe i can short the two wires on the sensor together, or remove the connections while running and see things change. sure looks like connections are good, but the sensor is bad.. but that's a guess.
Generally speaking parts that move are more likely to fail than parts which do not.....the oil pressure sender has moving parts inside Think of it as a mechanical relay
There are two wires on the sender. One offers a current sinking capability to ground proportional with oil pressure. The other wire offers a switched path to ground unless oil pressure exceeds some minimum number. Do Not Short The Two Wires Together. Do Not Mix The Two Wires.
The connectors at the sender are, as Jake says, tied to two conductors in the front-of-engine harness that terminates at the 14-pin connector on the right-side fenderwall by the jump post. The harness enjoys heat and mechanical flex in normal service. The connectors, conductors and insulation all suffer. Failure modes for the wires themselves include melting insulation internal to the outer sleeve, mechanical failure from repeated flexing, and melt-through from increased resistance in a primary power or "50" starter solenoid trigger wire.
You can disconnect the wiring at the sender/switch, and use a jumper between the sender pins and the associated pins in the bottom of the 14-pin connector. Just pull the 14-pin apart so you can connect to the female sockets in the stationary part of the connector. The needle should stay low and the light should come on with key in "run" position. If the gauge still pegs and the oil light doesn't come on, swap the wires.
The sender itself is the little gold-colored barrel with the terminals. It screws into a spring-loaded pressure/temperature relief device, a two-piece shell with spring and piston inside, whole thing screws into the block by the oil filter. Removing the sender means unscrewing the small barrel piece from the piece above it. Plan on counter-holding the pressure relief can above as you loosen the sender, else risk having a bunch of oil and spring-loaded pieces drop down on you. If you can't get a wrench on the hext at the top, use a strap wrench on the pressure-bypass canister. Remove Just The Sender. Drop the oil filter for easier wrench access. With the undertrays off and the car supported maybe with LF wheel removed, swapping the sender is less than 10 mins including cleaning the tools and replacing the wheel. You'll get a small oil dribble when there's no sender installed. Perhaps add a couple wraps of Teflon thread tape on the threads of the new sender. I like the TFE paste better. On the wiring with two possible options, you have a 50% chance of getting it right the first time, and a 100% chance of getting it wrong.
Thanks for all the information guys! i just ordered a sensor and also drove it around today. sure enough, the gauge just reads full scale when running as it has. it goes to 0 when the ignition is turned off. it stays at 0 until the car is started then it pegs to 5+ bar. turn off the car, and the gauge reads 0. the warning light stays on until the car is started, so thats a good thing. im wondering , if i should disconnect the existing oil pressure sensor, connect it to the newer sensor, and then start the car. that way, the warning light should be on and the gauge should read 0 while its running. seems logical as a test.
that way, im not risking breaking the block trying to remove this oil pressure sensor. im not sure, but this could be an original holbert part too.
lil'l help here? i cant imagine how connecting the new oil pressure sensor, wouldnt rule out the issue. plug the new one in to the wires and start the car.. i would suspect both the light and the gauge reading 0 would be the case if the old one is bad.. then, unscrew it and put the new one in the block.. any issues? grounding?
Im going to tackle the oil sensor today. this piece of jewlery just showed up from 928Intl. so shinny! first ill try and just connect the spades and ground it to see if the readings on the guage change. (full scale issue when ign on) not a lot of room up there for the 24mm wrench. but i guess i might be able to make a shorty and remove the oil filter to get at it. maybe grab the body and twist with a vice grip. (cave man technique) i forgot the torque level, but it looks pretty beefy? do you really need to counter hold? (27mm)?
there is another thread going on where someone said you couldnt remove the sensor without draining the oil.. I think we all know that is not true.. you can even change a filter without draining the oil... the sensor and filter are well above the oil level in the pan.
You need to counterhold the relief assembly and to do this you need the oil filter out of the way otherwise it is a 30 second job. For other reasons I also had the alternator out and the power steering pump console out of the way - whether or not that helped matters as well I cannot recall but it was an easy task.
Thanks for the tip regarding the grounding of the body of the sensor.... i hooked it up, grounded the sensor with some thick wire and clamps and started it up. YEP!!!! its the sensor, the new one just read "0" and the pressure light was blinking! so, went on to get the old one out. Yep, removed the filter , but had no way to counter hold the engine part.... so, i was going to cut off a 24mm wrrench, but thought , "how tight can it be, maybe a small vice grip can start the pressure snesor loosening" and low and behold, it started to move .. however, not the sensor, the part that goes into the engine. AHHH.. and why didn you guys tell me there is all sorts of stuff that comes out??? "BOINGGGGG" LONG SPRING, SOME pressure sensing looking plunger,/diverter, etc. anyway, i remembered how it went together and the only question was what direction the spring went in. it was a long spring, with a wider end. i put the wider end back in the engine and the smaller side pointing down.
i was able to free the bad sensor on the bench with my vice grip, 24mm and my foot.... tightened it up with the vice grip and a lot of force (but its small, so maybe 30lb-ft, got it all back in the engine , wired it all up and yes, IT WORKS!!
BTW, its not 8 oz of oil that you lose, its 10 oz. (filter and oil pressure sensor are removed)
thanks for all the help on this little job!
Originally Posted by FredR
Mr Kilbort,
You need to counterhold the relief assembly and to do this you need the oil filter out of the way otherwise it is a 30 second job. For other reasons I also had the alternator out and the power steering pump console out of the way - whether or not that helped matters as well I cannot recall but it was an easy task.
I think Dr Bob advised you about the spring going ker plunk if you removed the underlying assembly or maybe it was in the Kilbort thread!
No- it was definitly Dr Bob
yes it was. i didnt heed his warning. he said it could be done in 10 mins with a "strap wrench" on the "barrel piece" that screws into the block. didnt know what that was. and it was doable with just the filter removed.... well, now i know what to do next time. any pics of a "strap wrench" that could secure that barrel for counter hold? ill tell ya, it was not easy to get them separated on the bench. that sensor was ON there.
so, by the way.. what direction DOES that spring go in?? wide side in the block? makes sense, other wise, it seems the spring can block the ports in the T-stat (i think its a tstat)
Last edited by mark kibort; 03-31-2018 at 05:56 PM.
01-26-2018, 08:56 PM
Think of it as a mechanical relay
