ngc1068

Hi, i

I have a 2016 Chevy SS, M6 car, with the original LS3. I have installed a Whipple and Headers, I had a TSP Stage 3 Pos Disp Cam installed by a reputable shop in Houston about 1800miles ago, including trunion upgrade, push rods, retainers, and springs. Also installed ID1050x's and its been FF tuned by an expert. Car has been running perfectly until today.... when I hopped in to go to the store, looking over my shoulder out the rear window, started backing out of the garage, and heard a chime turned around and saw "no oil pressure, stop engine!" so that's what I did... I honestly don't remember the engine running funny. I connected HP tuners and put the car in service mode and read the ECU, no diagnostic codes were set?! Hmmm. checked the oil, level is fine no puddle in front of me where the car was parked for last 5 days.. I had a short log from HP Tuners I took Monday, just coincidentally, i was checking %ethanol before I filled up, i like to keep it around 50%, it was 46% ish... So i looked at that log and the oil was 44.5psi with the engine cold and warming up Monday before the log ended.. I looked at a log from a year ago and it was about the same at that time....so whatever is going on with low oil pressure wasn't showing up last time I drove the car 5 days ago...

I drained the oil into a pan and there's no metal that I can see obviously. I passed a strong refrigerator magnet all over the large surface of my drain pan and zero metal was picked up...

Anyone ever seen a anything like this? Advice?

Thank you!

RonSSNova

iTrader: (3)

Sending unit failure?
It isn’t terribly hard to replace.
if truly 0, lifters will clatter very quickly

ngc1068

If the sensor was failing. Would it not throw
a code?

DualQuadDave

iTrader: (6)

My LS2 did this to me. Was the sensor. Like was said, if the lifters are not making noise, probably ok. Check the plug on the sensor and make sure the wiring is ok going to it.

SLP IROC-Z

iTrader: (14)

Replace the oil pressure sensor as previously mentioned. Another thing that can cause zero oil pressure out of nowhere is a stuck pressure relief valve in the oil pump. If it comes down to the sensor not fixing it i would replace the oil pump and related gaskets and o ring

ngc1068

Thanks for the advice. I took the sensor off, looked up the pinout and applied 12vdc across power (ref terminal 2) to ground (ref terminal 3). Sensor is putting out about 6.071vdc measured from output (ref terminal 1) to ground (ref terminal 3). I applied as high as 60psi to the sensor port...voltage does not change.... seems like bad sensor for sure.

Going to order a GM replacement and see how it responds to pressure.

RonSSNova

iTrader: (3)

Nice. Good job.
since the oil pressure sensor will read 0 at start up, I don’t think there is a sensor DTC.

Let us know

ngc1068

Terrible news... 8(

I believe the correct supply voltage to the sensor must be 5VDC, not 12VDC.

At 0psi applied and 5VDC power, sensor output is right at 0.50 VDC...with about 45psi applied, I get about 2.45VDC out.

The sad news...that is how the one I pulled off the engine behaves, and that is how the new one I just purchased behaves.

SLP IROC-Z

iTrader: (14)

Yes that sensor only uses 5v

Old Geezer

iTrader: (3)

Mechanical gauge test time.....

ngc1068

Well, thinking I would only be risking more damage to run a mechanical gauge test...since both original sensor and new sensor are functioning the same (correctly)...I might as well accept this is a true low pressure problem...yes?

Anyone know the correct Melling p/n for the LS3? I see Oreilly has two Melling pumps listed and in stock their p/n M295 and another p/n M295HV which is described as having higher volume by 18%.

When I filter by 2016 Chevy SS, TSP site shows a MEL10295 and a MEL10296 which is 18% higher..

Melling site says 10295 and 10296 are for Gen III LS.

Melling site shows 10355 and 10355HV are for Gen IV LS. 10355 is 33% higher flow than 10295 and 10355HV is 20% more than that.

I would assume the 10296, higher volume I see on TSP site is the right choice...but I’m confused because the LS3 is GenIV, which would lead me to the 10355 or 10355HV based on the description at Melling site?

Confused...

Thanks!

tblentrprz

A few things:
Not sure what the factory sender output voltage is per 10psi of pressure is. You could measure your sender output voltage as a reference to see if it's in the mid range (OK) low range (problem) .
Check for restricted filter screen under the oil pressure sender.
One way to really know what the oil pressure is, install a mechanical gauge or install known pressure sensor and voltage output scale. Oil galley port - use 16mm x 1.5mm threaded male plug
You can measure oil pressure (before oil filter) at oil galley plug on driver side front
Measure after oil filter - driver side rear oil plug just rear of filter. You may be surprised how much pressure drops across filter.
Measure at oil pressure sender port - after filter screen (significant drop when screen restricted)

For reference - I dealt with a 2003 6.0 231K miles that was run low on oil, pressure dropping to 0 and metal flakes in filter and pan. With fresh 10W40 oil and filter, oil pressure would drop from 25psi at 2K to 0psi at idle when hot. Lifters never made noise when idling. Oil pressure drop across new oil filter (Carquest long R85522) at hot idle was 17psi. Oil pick up tube seal was sealing well (not hard or cracked). I suspect metal got into the oil pump relief valve keeping in cracked open. Due to miles and shedded metal, motor will be swapped out. I may pull front cover to inspect oil pump relief valve for grins.

ngc1068

I guess it comes down to 10295 or 10296. The others are for VVT/DOD applications.

Should I go with the higher volume 10296 or stick with the 10295? Which pressure relief spring to select?

G Atsma

Go with 10295. You don't need higher volume, but extra pressure but extra pressure is a good thing. Use the stiffer spring. I believe the other one is the stock spec one.

joyridin'

iTrader: (1)

Just a suggestion, but you may want to drop the pan and see if the pick-up is plugged. In a previous post, I found out the piston skirt coating came off my new pistons and plugged up the pick-up. Not saying that is your issue, but an oil pump going bad to the point of having no pressure seems a bit odd.

MixedE36

I had a small burr that got hung up in my oil pump relief valve causing 0 oil pressure. Seems like a common issue when have 0 oil pressure.

ngc1068

Just got my pump out, I took the pump apart and sure enough the pump relief was stuck open, pic 1 shows the valve open a little if u zoom in closely, second pic shows daylight thru the valve between pump
discharge and suction... i tapped on the valve piston a couple of times with a screwdriver and it snapped shut..

fingers grossed the motor isn’t hurt.



Blue arrow, relief piston valve plug. Yellow valve piston open, not against seat

Daylight passing through the opening between pump discharge and suction, bypassing the engine.

rkupon1

iTrader: (3)

Damn. Good find. That lil bit of daylight caused 0 pressure? If you didnt hear 0 oil pressure audibly, your prolly fine.

MixedE36

Your motor should be fine. Do an oil change and see if you see anything in the old oil.

ngc1068

Thank you, yes I did that oil drain and examination as mentioned near end of my long winded first post. I am waiting on new Melling 10295 pump to arrive. I can see into the oil pan pretty far, and not only was the oil metal free, but the pan looks clean and shiny with no particulate or sediments visible.

*fingers crossed*