low oil pressure

[cedalice]

my 90 ZR1 has only 8900 miles
the car is arrived in europe with 8000 miles in 91 but since 91 only 800 miles.
In 2006 the motor has been rebuilt because there was a lot of water is the tank and when the owner has started the motor there was some damages.
Now the problem is with the oil pressure gauge or may be the oil pressure.
I had a leak from the oil pressure sensor. I have replaced the sensor yesterday.
When the car is cold pressure is around 80 but after 40-50 miles the pressure is low around 0 !!!!!!! but there is no leak under the motor, from the sensor. The oil level is good.
when the oil pressure gauge is around 0 I have no "check gauges" .Before I change the sensor I had this "check gauges" when the car was cold or hot.
All the others gauges are OK oil temp or water temp.
So can you help me ?
and sorry for my english

[BOB HDZ]

http://w39syg.bay.livefilestore.com/y1pAH9_PzloiRALFlq042KuPjCb1twKzC12nwk7LNb1svnueTj RdaRJcnN-GRGpZNDzD2edv4ineAYpheQuE-l59kLzQ6J84mY6/IMG_0607.JPG HOPE THIS HELPS

[cedalice]

thanks but it's not the oil temperature but the oil pressure

[Jeffvette]

There are two sensors. One for the ECM which triggers the low oil pressure and will kill the motor. Then a second sensor that sends the data to the gauge.

Check the actual pressure with a mechanical gauge.

[Pete]

Change/replace oil sending unit (the one next to the oil filter) cost $10.

Common LT5 issue/problem.

Pete

[A26B]

As you may know, there are two(2) oil pressure sensors. The sensor that provides the signal to the instrument panel gauge is the large one, on the top near the oil filter.

The other sensor is just for the low oil pressure warning light. It is located below the oil filter, on the oil filter housing, just below the forward, right corner of the cam cover.

If you are not seeing a warning light and do not hear any engine noise (cam chains or lifters), then you probably have oil pressure even though the gauge indicates near zero(0).

I would suggest installing a mechanical, oil pressure gauge (no electronic sender). A "tee" can be installed below the oil pressure sender you replaced. The gauge can be installed permanently or temporarily until you confirm the indicated "drop to zero."

I don't trust the electronic gauge and installed the manual oil pressure guage on the pillar.
http://i190.photobucket.com/albums/z224/A26B/GaugePod.jpg

[cedalice]

I have replaced the low oil pressure sensor warnig light not the other one.
I have installed a temporarly mecanical gauge. When the motor is hot the pressure is 26 PSI (in the shop manual they say mini 12 psi), not 0 but the electronic gauge says the same thing now...
I wait 1 or 2 hours and I will retry.
thanks for your help

[A26B]

I have replaced the low oil pressure sensor warnig light not the other one.
I have installed a temporarly mecanical gauge. When the motor is hot the pressure is 26 PSI (in the shop manual they say mini 12 psi), not 0 but the electronic gauge says the same thing now...
I wait 1 or 2 hours and I will retry.
thanks for your help

Don't worry about the "other sensor." It does not affect the gauge readout and if you are not getting a warning and have oil pressure, then it is working OK. Since you do not have a warning and do not hear engine noise, you probably have oil pressure.

[salvatore1]

As you may know, there are two(2) oil pressure sensors. The sensor that provides the signal to the instrument panel gauge is the large one, on the top near the oil filter.

The other sensor is just for the low oil pressure warning light. It is located below the oil filter, on the oil filter housing, just below the forward, right corner of the cam cover.

If you are not seeing a warning light and do not hear any engine noise (cam chains or lifters), then you probably have oil pressure even though the gauge indicates near zero(0).

I would suggest installing a mechanical, oil pressure gauge (no electronic sender). A "tee" can be installed below the oil pressure sender you replaced. The gauge can be installed permanently or temporarily until you confirm the indicated "drop to zero."

I don't trust the electronic gauge and installed the manual oil pressure guage on the pillar.
http://i190.photobucket.com/albums/z224/A26B/GaugePod.jpg


This sensor is the one thats leaking on me. It seems impossible to remove so I cannot even get to it to grab a part number. By any chance do you know the part number for this guy, and do you have any advice on how to get at it?

Thanks,
Sal

[Jeffvette]

This sensor is the one thats leaking on me. It seems impossible to remove so I cannot even get to it to grab a part number. By any chance do you know the part number for this guy, and do you have any advice on how to get at it?

Thanks,
Sal


25036935

[salvatore1]

25036935

Thanks - now to get my hammer.

[cedalice]

hi
I have changed the sensor and now the gauge is OK
thanks
now I can look for the others problems ...

[secondchance]

hi
I have changed the sensor and now the gauge is OK
thanks
now I can look for the others problems ...

Sometimes it takes a while to sort it all out if the previous owner had been neglecting but, trust me, it's worth it!:hello:

[scottfab]

I have replaced this pressure transducer twice. I finally took one
of the old ones and rebuilt it so it would not leak. I also found an
adjustment screw..... the pics are at
http://www.zr1netregistry.com/ZR1_oilpressure.htm
But the write-up is missing up there so here it is:
<H2 align=left>Oil Pressure Sender Failure</H2><H2 align=left>February 10, 2002</H2>

The oil pressure sender failed again. This is the second time in five years. These devices should not be failing so often. An investigation was necessary. The symptom is when the pressure indicated on the dash fluctuates from 80lbs to 0lbs the back to 80lbs.
Upon dissecting the sender unit I found that it could be rebuilt. Actually reconditioned is the proper term. I did not set out to do this because the part only cost $22. It just turned out that way.
The part is a Neihoff DR4010. I went to four different auto parts stores and they all had the same one. As you will see in the pictures this device has three pins one of which is used for the actual output. The other two are not connected to anything. There is also an adjusting screw that is accessible down through the top of the connector. The access in initially blocked with a rubbery substance which is easily remove to access the screw. This can come in handy later if you want to set the calibration yourself.
As the pictures will show, I first pulled the plastic over up about 1/2 in. The tapped out the center pin. The center pin is the only one that you need to tap out. Then pull off the cover and drain any oil out. You will note that the assembly is a wire wound coil over a rectangular substraight with a center wiper which is moved across the coil to a position depending on the pressure pushing up on the spring.
The sensor it self started to leak when it failed. The leak is small but is enough interfere with the center wiper causing an intermittent loss of signal.
The pictures tell the story. Use the down arrow to select a thumbnail view. If you want to see the thumbnail larger then click on it, but of course you knew that already.

[secondchance]

I have replaced this pressure transducer twice. I finally took one
of the old ones and rebuilt it so it would not leak. I also found an
adjustment screw..... the pics are at
http://www.zr1netregistry.com/ZR1_oilpressure.htm
But the write-up is missing up there so here it is:
<H2 align=left>Oil Pressure Sender Failure</H2><H2 align=left>February 10, 2002</H2>

The oil pressure sender failed again. This is the second time in five years. These devices should not be failing so often. An investigation was necessary. The symptom is when the pressure indicated on the dash fluctuates from 80lbs to 0lbs the back to 80lbs.
Upon dissecting the sender unit I found that it could be rebuilt. Actually reconditioned is the proper term. I did not set out to do this because the part only cost $22. It just turned out that way.
The part is a Neihoff DR4010. I went to four different auto parts stores and they all had the same one. As you will see in the pictures this device has three pins one of which is used for the actual output. The other two are not connected to anything. There is also an adjusting screw that is accessible down through the top of the connector. The access in initially blocked with a rubbery substance which is easily remove to access the screw. This can come in handy later if you want to set the calibration yourself.
As the pictures will show, I first pulled the plastic over up about 1/2 in. The tapped out the center pin. The center pin is the only one that you need to tap out. Then pull off the cover and drain any oil out. You will note that the assembly is a wire wound coil over a rectangular substraight with a center wiper which is moved across the coil to a position depending on the pressure pushing up on the spring.
The sensor it self started to leak when it failed. The leak is small but is enough interfere with the center wiper causing an intermittent loss of signal.
The pictures tell the story. Use the down arrow to select a thumbnail view. If you want to see the thumbnail larger then click on it, but of course you knew that already.


A terrific info! I saved the page just in case.

Thank you.

[Norsky4360]

A GM Master Tech friend of mine told me that the oil pressure gauge sending unit failure was a common problem across the whole GM line back in the late 1980s and early 1990s. Had it happen to us on the 1st day of a 15 day road trip a couple of years ago. He said as long as the oil and water temps were normal and there were no unusal noises coming from the engine we were ok. Replaced the sending unit and haven't had a problem since.

[secondchance]

He said as long as the oil and water temps were normal and there were no unusal noises coming from the engine we were ok. Replaced the sending unit and haven't had a problem since.

Wouldn't it be too late by then?

[Norsky4360]

If the water temp spiked and the engine started making noises, yes it would be to late because there was no oil being circulated. But as long as oil was getting circulated the temps remained normal.

When we got to the end of the drive that day I popped the wiring connector off of the sending unit and there was oil in there. My friend told me it is supposed to be dry. I wiped it clean, reconnected it, and fired up the engine. The gauge worked until for a couple of minutes before the connector got wet again and quit working.

The next day (Sunday) we drove for about four hours before finding a parts store that was open. Replaced the sending unit and all has been well since.