FAST LS1

First let me say this is in a Firebird, but it's still an LS1 so I'm trying to get as much info from every source I can.

So the oil pressure guage is at zero.
When I'd take the key out of the ignition, the guage would rise to about 20-25psi, then as soon as I turn the key to run, it would drop to zero. I started it a 3-4 times and on the last try I heard ticking and turned it off and left it set
Full of oil, I checked that the first time I cranked it, and it started and still read zero.

The fact the guage moved off of zero while setting makes me think it's not the guage, and the slight ticking on the last attempt is sickening. I probably should have said **** it and left it set the first time it read zero, but I was stubborn.
Leaving work the check guages light came on. I saw zero oil pressure, cut the engine instantly in the middle of the road. Stopped, checked, and started it back up and it read 40-45psi, so I thought the guage was just going out. Damnit.

So know to diagnose the problem, because from previous posts on the subject I know it could be any number of things.
1) Sending unit is bad. I haven't done an intake swap though to hurt this sensor.
2) Oil pump is bad
3) Spun bearing

I've posted this on a few boards, just trying to get some input by anyone who's been down this road, and knows first hand.
Any help is appriciated.

*Update*
Installed a new oil pump and sending unit.

mvvette97

I would try the sending unit first thing. If it was a spun bearing you would hear more than a tick.

Dan_the_C5_Man

Always try the easiest solutions first. Try replacing the sending unit, they have a history of going Tango Uniform.

Next on the list would be the oil pump itself. I have a 2000 MY, and when I do my cam swap, I'm going to replace my perfectly good pump with an LS6 / updated model.

V8_Club

Did you check the pressure yourself ? i.e. with an external pressure gauge ? I would recommed that first. I had this problem before and we handled it systematically. Sadly in my case it was the cam bearing that were at fault. Pressure wouldbe high then drop constantly. We replaced the bearings & voila .

FAST LS1

Updated first post.

Flintstone

What year?

GM replaced the engine in my '99 because of a faulty pressure relief valve in the pump body.

Let me rephrase that. Dealer insisted there was nothing wrong with the pump and drove it 80 miles with very little oil pressure and damaged the engine, and THEN replaced it for me.

Symptoms were zero pressure on startup, and it would eventually come up to around 6 psi at idle once you brought the revs up a couple times.

F

FAST LS1

It's a 2000 with 76k miles on it.

candlewood

I had this happen to my 2001 vette. First the oil sensor was replaced, which is underneath the intake manifold. There was still no oil pressure and the oil pump had to be replaced which required the removal of the engine. LS1 engines would pick up some aluminum casting imperfections from the oil pan and be sucked through the oil pump thus cracking the pump. In my case, the repair was covered under the warranty. The engine was fine and no harm was done, so good luck.

schpenxel

wrong...oil pump is easily replaced with the engine still in, but since it was under warranty its ok

kloller

Sending unit first.