FRC Carmichael

I've replaced my oil pressure sensor but am still getting no pressure reading on the cluster. We confirmed that the cluster works--it looks like the sensor doesn't have power. I've have the wiring diagram and tried to follow the wire as it leads away from the sensor but loose it in the close quarters under the hood. I'm thinking it may be a broken wire that is the problem.
Where does the wire physically head from the sensor?
Any help is appreciated.

madmatt9471

I don't have the schematic -

But have you checked "all" the fuses?

It's a starting place!

Thanks,Matt

FRC Carmichael

Yes--checked all the fuses and they look OK

junkman123

the LS engines are bad about the oil pump pick up o-ring failing and causing lose of oil pressure.the best way to test for that is to pull the fuel pump relay so the car wont start,remove the oil filter and with a catch pan under it have someone spin the engine over for a few seconds.if you get oil then then the o-ring is good,if not the o-ring is bad.its like trying to drink a milk shake with a hole in the straw,the pump gets nothing but air. I just replaced one in an 07 suburban with an LS1 in it that had zero oil pressure.

FRC Carmichael

but this should not effect the power/voltage to the sensor--I don't think it's getting power

madmatt9471

PM Bill Curlee here on the Forum - he should be able to post the wiring diagram for the sensor - I can look in my book too!

He can post it up for you to see as well and it will be much easier!

He is the wiring guru here

Thanks,Matt

SteveDoten

I would get a "known good" OPS and plug it it

GOOD, gauge sweep returns to zero

BAD, gauge sweep pegs out max (typical)

this can be done prior to engine start (KOEO)

the engine harness run along the block and RHS cyl head then feeds under the battery

Quicksilver Vert 01

Is the +5V reference voltage present, when measured from Pin B of the sensor connector plug to a chassis ground?

Bill Curlee

Here is the schematic that you need. The 5 VDC comes from the PCM.
The GREY wire has to have 5 VDC. Have you connected or disconnected any sensors lately?? Could have damaged a pin.

I installed a MAP Sensor extension harness and Murphy's law says that the harness can be plugged in 180 out I had no oil pressure reading also until I flipped the connector over.

NOTE. If you have a problem with any other sensor, it can affect the other sensors. See if you have 5 VDC on the other sensors.

FRC Carmichael

Thanks for the help guys--I've gotten tied up with a few other projects and haven't made it back to the problem yet. I'm putting the car away this weekend and luckily have a space that I can do some work on it over the winter.
I'll keep you posted on how it goes.

Keep up the great forum--I'm learning tons from the postings.

Thanks again for the help

Canadian FRC Eh!

FRC Carmichael

Hi Bill
I sent you a PM

Bill Curlee

Look at the schematic Where each wire goes into the PCM you will see a pin number and a dotted line. At the end of the line its labled C1 or C2

SO,,,, the Grey wire is in PCM Connector C1 at pin #7

The black wire is in PCM Connector C2 at pin #63

ultraspeed

I am having the same problem on my 07. Gauge sweeps but stays at zero. Replaced sensor with no luck same issue. Held the acc switch for 5 seconds to turn every thing on and I am not getting the 5v on the reference wire when I put a volt meter on it. I really don't think the oil pump is bad its only a year and a half old

FRC Carmichael

OK--I think I follow it now.

I'll test the wire and let you know
Thanks again for the help

ultraspeed

I know we got different year cars but maybe we can help each other through this since we have the same problem. I am 100% sure mine is now electrical. I removed c2 from the ECM and read out wire 41(that's my 5v wire) had .02 resistance so I no the wire is good. I read the actual pin out on the ECM in acc mode and I got 5.7 volts so I know the ECM is good. As soon as I connect c2 back to the ECM and go read wire 41(5v power to pressure switch) it says I have .15v going to sensor. I am going to check my crank position sensor and see if it is shorting out to ground next and is messing up that. But my point to you is if power is good check the other sensors for shorts

FRC Carmichael

Ok--thanks for the additional info

cptinjak

After about 4 sensor failures, I ended up having to tweak the contacts in the connector, to bend them slightly outward. They had loosened up and were no longer making good connection with the pins on the sensor. Might be worth a try. Just take a small 90* pick and bend the contacts outward slightly.

Jack

FRC Carmichael

OK--Thanks Jack