Oil Pressure

[randy ransome]

I just want to say thanks to the forum for all the info that is published on here to help people out. I bought my 95 Z about 2 years ago with 38,000 miles and it's always had a low oil pressure reading. Not bad low, but low.

Recently it started reading real low, but no low oil light. After checking on here I went out to the car to check the switch by the oil filter, when I tried to unplug it the top part of the switch almost fell off in my hand.

One order from Jerry's Gaskets and today I now have great oil pressure. What I thought might be a big problem turns out to be a piece of cake all because of the forum brotherhood.

Looking forward to the gathering in May at Bowling Green.
:flag2:
Thanks Again folks.

[We Gone]

Great news, don't you like it when its just the little stuff.

[scottfab]

After replacing mine a few times I investigated the failure mechanism and came up with a fix. No failure since.

http://zr1netregistry.com/Information/TechNet/%5BAllArticles%5D/tabid/262/articleType/ArticleView/articleId/216/Oil-Pressure-Sender-Reconditioning.aspx

[randy ransome]

Yea, I'm glad it was a simple fix.

The complete black top of mine disconnected from the metal base, no fixing.

[Racinfan83]

Mine freaked out on me one day last year and was reading near 0psi when hot at idle. No light though. Which FREAKED ME OUT for sure!
Got on here - asked the question, got the answer, ordered new one from Jerry, Problem Fixed!
I love this place as well! :handshak::cheers:

[TheBlackPearl]

I'm having the opposite problem, I start mine up and it is at max 80 psi at idle, after a good amount of time it only starts to drop to 70 psi and then 60 when fully warmed up. I put in Amsoil 10w-40 back in November but never really took notice of what it was before the change. Should I be concerned?

[scottfab]

I'm having the opposite problem, I start mine up and it is at max 80 psi at idle, after a good amount of time it only starts to drop to 70 psi and then 60 when fully warmed up. I put in Amsoil 10w-40 back in November but never really took notice of what it was before the change. Should I be concerned?

The senders can fail both reading low or high.
My first one (in 97) always read as yours, high.

[Mystic ZR-1]

Not only the screwy readings,
but they usually leak too...

[csavaglio]

I went through about 3 or 4 different senders a few months ago trying to find ones that matched up with the actual pressures I was getting in the car that I verified with a mechanical gauge tapped in at the sender location.

I have a new Delco one that I didn't check, but all of the parts house ones either read way low or way high. The one NAPA carried is calibrated correct and that's what's in the car now. I have the Delco one as a spare.

Chris

[TheBlackPearl]

Are the rest of you running AC Delco sensors?

[TheBlackPearl]

I replaced the sensor yesterday and found that the old one did not leak or any visible problems with it. When I started up my Z the oil pressure was exactly the same if not higher. So the sensor was not broken, now what? Is it fine or should I go further?

[csavaglio]

I had several sensors that read the same but much too high compared to the actual pressure on the ZR-1. The parts store one in my LT4 reads on the low side. I would go down to Harbor Freight and pick up a mechanical oil pressure gauge kit. It wasn't expensive and will give you some peace of mind knowing what the actual pressure really is. I want to say it was around 20 bucks for the kit was all the different fittings. The LT5 sensor's in an easy spot to get to to hook up the mech gauge to.

Just because the sensor doesn't look bad and is working, doesn't mean it's calibrated correctly. I tried 3 or 4 different brand sensors before I found one that was calibrated properly for the car and matched the mechanical gauge.

[scottfab]

I replaced the sensor yesterday and found that the old one did not leak or any visible problems with it. When I started up my Z the oil pressure was exactly the same if not higher. So the sensor was not broken, now what? Is it fine or should I go further?

For grins why not disconnect the electrical connection on what you think is the pressure sensor then see what it says on the gauge.
Does it read zero?

[We Gone]

Just replace my sending unit on the 93 was getting a bit jumpy with one from NAPA, warmed up sits at the first tick mark idle as soon as you touch the gas goes to the 2nd mark or just a bit past and about midway to the last at WOT.

[TheBlackPearl]

I had several sensors that read the same but much too high compared to the actual pressure on the ZR-1. The parts store one in my LT4 reads on the low side. I would go down to Harbor Freight and pick up a mechanical oil pressure gauge kit. It wasn't expensive and will give you some peace of mind knowing what the actual pressure really is. I want to say it was around 20 bucks for the kit was all the different fittings. The LT5 sensor's in an easy spot to get to to hook up the mech gauge to.

Just because the sensor doesn't look bad and is working, doesn't mean it's calibrated correctly. I tried 3 or 4 different brand sensors before I found one that was calibrated properly for the car and matched the mechanical gauge.

Is this the one?
http://www.harborfreight.com/engine-oil-pressure-test-kit-98949.html

I'll disconnect the plug tomorrow and see what it says.

[csavaglio]

Yep, that's the one. It's not hard to figure out which fitting to use.

My NAPA sending unit reads the same as WeGone's.....which matched up pretty close to what the mechanical gauge said. As I said, I have a Delco one but I've never tried it. I figured if the Napa one gets weird, I'll swap it in.

[TheBlackPearl]

Do you know the NAPA part #? I picked up the oil pressure gauge, so i'll check it tomorrow.

[csavaglio]

It was Echlin 6677. When I went down there, I took the car, brought a wrench and swapped the sensor out in the parking lot to make sure it worked right on the spot. Funny, but I had them call the manufacturer to give the calibration curve....i.e. X PSI gives Y ohms and it was the same as the junk Autozone and Oreillys senders made by Wells, but what I found when I broke out the multimeter was that the Wells units gave much higher resistance values than correct...65 psi was giving over 110 ohms and the gauge feeds off of 0-110 ohms, meaning that at just 65 psi, it was pegging the gauge full high.

The Echlin/Napa sender gave readings consistent with what the FSM called for and has been working fine since November when I put it in. Since I have the Delco spare on hand, it's pretty safe to say it'll never go bad.

Here's the link to the thread I had going about this issue a little while back....

http://zr1.net/forum/showthread.php?t=21648&page=2

It's worth reading from the beginning.


Chris

[We Gone]

Do you know the NAPA part #? I picked up the oil pressure gauge, so i'll check it tomorrow.


OP6677

[scottfab]

It was Echlin 6677. When I went down there, I took the car, brought a wrench and swapped the sensor out in the parking lot to make sure it worked right on the spot. Funny, but I had them call the manufacturer to give the calibration curve....i.e. X PSI gives Y ohms and it was the same as the junk Autozone and Oreillys senders made by Wells, but what I found when I broke out the multimeter was that the Wells units gave much higher resistance values than correct...65 psi was giving over 110 ohms and the gauge feeds off of 0-110 ohms, meaning that at just 65 psi, it was pegging the gauge full high.

The Echlin/Napa sender gave readings consistent with what the FSM called for and has been working fine since November when I put it in. Since I have the Delco spare on hand, it's pretty safe to say it'll never go bad.

Here's the link to the thread I had going about this issue a little while back....

http://zr1.net/forum/showthread.php?t=21648&page=2

It's worth reading from the beginning.


Chris

The one I took apart and then re-crimped together had an adjustment in it.
Link-to-Oil-Sensor (http://www.zr1netregistry.com/Information/TechNet/%5BAllArticles%5D/tabid/262/articleType/ArticleView/articleId/216/Oil-Pressure-Sender-Reconditioning.aspx)

[TheBlackPearl]

I did the test today, right on start up i got 65 psi, within 2 minutes it started to drop to 62 psi before i turned it off. It's about 46 out right now. Are these roughly the same numbers you were getting csavaglio?

[csavaglio]

Looks like you're dead on for what I saw and what's expected if it's working right. My cold idle was 65psi and fully warmed up was in the low 20s.

I think you found that you have the same issue I have....the car's working properly but the sending unit isn't. Try the Echlin one and see what you come up with on the gauge. If not, pick up the more expensive Delco one.

http://jerrysgaskets.com/store2/root/index.php?main_page=product_info&cPath=26&products_id=106


Chris

[TheBlackPearl]

Bought the Echlin one, i'll see how it goes when it gets here, most likely early next week.