Hey guys, I don't normally post on this forum but I am a avid browser. I have a question that maybe you guys can help me solve. I apologize if this is the wrong section, if so let me know and please move it for me! I know about search feature, used it many times, but found nothing that helped me.

UPDATE: CHANGE SENDING UNIT BACK TO STOCK, OIL LIGHT CUT OFF, PRESSURE IS RESTORED!! BLOWN SENDING UNIT!

Here is my issue:

I have a 400+ HP GSR motor that had been running on 17psi for 3 years. After 3 years of running, and after a mis-shift, it spun a rod bearing and started knocking 60 miles later. My good and trusting friend and engine builder Chris helped me to rebuild. We re-built the motor with the existing CP pistons and Eagle rods. I had the one rod with the spun bearing resurfaced. I bought a NEW GSR crank, due to scarring. So in a nutshell, CP Pistons, Eagle rods, ARP Headstuds, ACL race rod bearings. All NEW parts other then the pistons and rods that were in there. I broke in the motor perfectly for about 1000 miles and one oil change, and installed an autometer Oil Pressure gauge to prevent future failure. I took my girlfriend out to dinner one night last week and was merging on the interstate, and got on it a bit. Didn't take it past 6k in third gear and threw it back from 2-3-2. Novice mistake which I have never made, but wasn't used to throwing gears or weighted **** in a while. saw the tack clock past 8 and way into red and hit the clutch. My Gauge lost all pressure right after the shift. Went straight to 0 PSI. I blipped the gas and there was NO MOVEMENT at all. I shut the car off, towed home, and let it sit a week. Started it back up today cold and the gauge didn't move one bit, nor with any gas. No knocking, good connections, and the motor sounds perfect as it always is while running...it was running about 20-25 PSI at idle, and was at at 90ish PSI by 5k RPM, before the miss...now 0PSI across the board

---Could I have blown the sending unit due to too much pressure at over rev? Wouldn't there be SOME pressure especially at a cold start and a little throttle if it were a bearing? my pressure is below 0. (on an electronic AUTOMETER gauge)

--Could I have cracked the oil pump and caused a leak in pressure?

--Or could I have spun another bearing and it just hasn't started knocking? I feel like I would still have a bit of pressure even with a spun bearing, but i have NONE NONE NONE....the needle didn't move a bit.

Please give me some ideas before I begin stripping it down. I was going to put the dummy light back on and see what happened, but i don't want to keep starting the motor. Thanks in advance.

 

just to get this out of the way....the motor will rattle like hell if you have no actual oil pressure.

if it doesn't sound like a bucket of bolts when you start it i would consider testing what's already on your mind. you should be able to crank the engine over by hand...or by impact gun with the VC off and see oil moving if you actually have a flowing oil system

 

Test another gauge prefurable a mechanical....hell pick up a sunpro from vatozone for $25

Are you currently running a mechanical or electric gauge?

And quit mis-shifting your car

 

What do you mean by "pegged"?

I'm assuming it's an electrical unit. Electrical units, will be far below the line when no power is present, rise to the line when there is power but no pressure, and then read pressure as it sees it.

If you are BELOW the 0 mark, there is something wrong with the gauge.

 

That is what I mean by pegged. I apologize for it not being clear. Yes it IS an electronic gauge. The mechanical suggestion is a good one, I need to try that, and the valve cover removal. Thank you for the good help. I checked the power wire to the gauge and it was still intact, but it did in fact never rise to the 0 mark.

And the first mis-shift was not me, that was my buddy who re-built the motor for me. The PO never changed the oil and we were testing out some changes.

BUT, what could have caused the gauge to loose sending unit power from a mis shift? Maybe the shock?

 

Deff. Invest in a manual Gauge i have had a few Electronic units Fail on me. Also like stated before removed the valve cover or start the car and remove the oil cap and look in the VC with a Flashligh to see if you have oil pressure or not. Off topic a little but you have 100psi of oil at 5k? what pump? has it been shimmed?

 

Just the sending unit going bad will not send a signal back to "raise the gauge" so to speak. Mine did the same thing.

Let me put it this way, if you really lose all oil pressure at high RPMs, you will probably lose the engine before you can even react.

 

Sorry, went and looked at the gauge and didn't realize it only goes to 100PSI so I was probably a decent amount below that. Either way nothing unusual when under load. Its just the stock GSR pump from a 2001 motor with 60k on it.

 

nothing like having hot oil coming to your gauge . . .....

 

The motor has literally been ran for a cumulative minute an a half since it was over revved. Could the mis shift cause the sending unit to fail and read incorrectly is what I am trying to figure now. Tomorrow if time permits I will put the dummy light back in and see what happens, then hit you guys back up..Thank you for all the good help!!! keep it coming!