|
|
Register To Post |
| j3studio | Why Would An Oil Pressure Sending Unit Fail In Less Than A Year? | ||
|
Elite Guru
 
|
[1985, 68k miles, very stock]
Why would an oil pressure sending unit fail in less than a year? The sending unit was replaced last March. When it was replaced, it read these (good) values: 50 lbs. cold idle 30 lbs. warm idle 50 lbs. warm 1,200 r.p.m. The new sending unit has now failed (I noticed it in November) and mostly reads 80 lbs. (the upper limit of the LCD read-out). This is exactly the same failure pattern of the previous sending unit. Does anybody have any idea what could be going on besides simple bad luck? |
||
Posted on: 2011/2/20 16:34
|
|||
|
_________________
Grace, 2003 50th Anniversary Convertible |
|||
 Transfer
|
 
|
||
| Matatk | Re: Why Would An Oil Pressure Sending Unit Fail In Less Than A Year? | ||
|
Webmaster
 
|
Was it a GM/Ac Delco unit? I try to use oem parts for anything sensor/electrical.
I will have to check my fsm, there is a troubleshooting procedure for the oil pressure sender to narrow down if it's the sender, wiring, or dash. Did you do this, yet? Matthew |
||
Posted on: 2011/2/20 16:37
|
|||
|
_________________
2002 EBM convertible, Magnusson supercharger, cam, headers, etc. 1989 Corvette...RIP |
|||
|
Transfer
|
|
||
| j3studio | Re: Why Would An Oil Pressure Sending Unit Fail In Less Than A Year? | ||
|
Elite Guru
|
Quote:
Matthew, It was a GM unit. It did work (well) for six months. I'll take look at my FSM - I guess it could be the wiring. This is one of the three things that have to be fixed before I attempt a Performance Verification in May. |
||
Posted on: 2011/2/20 16:41
|
|||
|
_________________
Grace, 2003 50th Anniversary Convertible |
|||
|
Transfer
|
|
||
| bogus | Re: Why Would An Oil Pressure Sending Unit Fail In Less Than A Year? | ||
|
Grand Imperial Pooh-Bah
 
|
I will put it this way... REPLACEMENT PARTS ARE JUNK!!!!!
and it doesn't matter who makes'm... I had a run on bad coolant temp sensors, some NAPA, some GM... It happens. Now, with an 85, some of the bets are off. But I would make sure the connectors are clean. To be honest, I think a dead sensor sets it to 80lbs, a dead harness sets it to 0. Check the book, I don't remember for sure. |
||
Posted on: 2011/2/20 19:11
|
|||
|
_________________
The single biggest problem with communication is the illusion that it has taken place. - George Bernard Shaw Education is the best tool to overcome irrational fear. - me |
|||
|
Transfer
|
|
||
| JDSWHITE93 | Re: Why Would An Oil Pressure Sending Unit Fail In Less Than A Year? | ||
|
Senior Guru
 
|
REPLACEMENT PARTS ARE JUNK!!!!!
absoFNlutely.... It's all made in China and it's all garbage no matter what name is on the box. |
||
Posted on: 2011/2/20 22:43
|
|||
|
_________________
The few, the proud, the crazy, the LT1 owners association :thumbright: |
|||
|
Transfer
|
|
||
| rayquayle | Re: Why Would An Oil Pressure Sending Unit Fail In Less Than A Year? | ||
|
Senior Guru
|
Quote:
Depends on what you mean by "dead". Open circuit as in disconnected or sensor open internally, reads 80; shorted as in wire to ground or sensor internally shorted, reads 0. |
||
Posted on: 2011/2/22 16:15
|
|||
|
_________________
Ray Quayle in England '86 Indy PaceCar, 4+3 NCM Founder #2896 NCM Lifetime #672 Graduate of Gordon's School |
|||
|
Transfer
|
|
||
| bogus | Re: Why Would An Oil Pressure Sending Unit Fail In Less Than A Year? | ||
|
Grand Imperial Pooh-Bah
|
I am digging deep here, Ray, so bear with me.
IIRC, the oil pressure switch is normally open. So when it fails, it fails open, and that is why it reads 80 psi when failure occurs. If the wiring dies, meaning a shorted circuit, then you get a 0 reading. When the wiring just breaks and there is no short, then you get 80. Does that sound about right? I have never heard of the OPS failing and doing anything other than reading 80 psi. |
||
Posted on: 2011/2/22 19:09
|
|||
|
_________________
The single biggest problem with communication is the illusion that it has taken place. - George Bernard Shaw Education is the best tool to overcome irrational fear. - me |
|||
|
Transfer
|
|
||
| rayquayle | Re: Why Would An Oil Pressure Sending Unit Fail In Less Than A Year? | ||
|
Senior Guru
|
Quote:
You've got it right Andy, but they can and do fail open, shorted and anything in between. I have one in my toolbox that is stuck at about 50 Ohms that yields a pressure reading of around 45 psi at all times as a result. Don't ask why it is still rolling around my toolbox! |
||
Posted on: 2011/2/22 21:27
|
|||
|
_________________
Ray Quayle in England '86 Indy PaceCar, 4+3 NCM Founder #2896 NCM Lifetime #672 Graduate of Gordon's School |
|||
|
Transfer
|
|
||
| BillH | Re: Why Would An Oil Pressure Sending Unit Fail In Less Than A Year? | ||
|
The Stig Moderator
 
|
Quote:
You guys are dead on. I do think it's important for J3 to inspect the harness to see if it's grounding anywhere. |
||
Posted on: 2011/2/22 21:41
|
|||
|
_________________
Every man dies but not every man lives. |
|||
|
Transfer
|
|
||
| bogus | Re: Why Would An Oil Pressure Sending Unit Fail In Less Than A Year? | ||
|
Grand Imperial Pooh-Bah
|
That test is rather straight forward... pull the DIC, pull the OPS, jump accordingly.
If it comes back without tone, you have found the problem. |
||
Posted on: 2011/2/22 22:11
|
|||
|
_________________
The single biggest problem with communication is the illusion that it has taken place. - George Bernard Shaw Education is the best tool to overcome irrational fear. - me |
|||
|
Transfer
|
|
||
You can view topic.
You cannot start a new topic.
You cannot reply to posts.
You cannot edit your posts.
You cannot delete your posts.
You cannot add new polls.
You cannot vote in polls.
You cannot attach files to posts.
You cannot post without approval.
|
|