IDriveChevy

iTrader: (5)

Hey everyone, I just bought a 2000 Trans Am so I'm fairly new to the LS1, so bear with me. I searched around for a bit and that kind of helped but nobody seemed to have the same symptoms as me, so here we go.

I just got tags for the car yesterday and went to take it on the maiden voyage. The car is lower miles (92k) and all stock. Previous owner did an oil change before I bought it and it held 60 psi at idle and between 40-60 driving. When I got on it a hair yesterday (maybe 4k rpm, just a first gear short pull) my oil pressure gauge dropped from 60 to 0. So I think to myself oh *#@(! I pull over and check my oil and its at the normal spot on the dipstick so I putt her home on the back roads. The oil pressure gauge seemed to be stuck at 20 and flickered around there sometimes dropping to 0. I was thinking to myself that the pressure sensor could have gone bad.

I get back to my garage and I hear a faint ticking noise so now I'm thinking the lifters weren't getting enough oil so I drain the oil and check it out. It didn't look too abnormal but I saw a small amount of silver ish look in the oil, but it wasn't a lot of material and my magnet didnt pick it up. So I cut the filter open and it was clean, no metal shavings or chunks in there. So could have something happened to the oil pump or pickup to cause the problem?

The oil filter looked like it was a cheap quick lube shops filter so who knows what kind of oil was put in. What should I check right off the bat? Maybe do an oil change with a good filter and synthetic and go from there? Thankfully this isn't my daily driver so it can be down for a little while

Thanks ahead of time for the help.

hardbones

Change the oil and filter and try again, cheapo filter could have been the problem. If you did have 0 oil psi you would have heard a lot more than a slight tick from the lifters and these motors are notorious for lifter tick anyways.

good luck!

IDriveChevy

iTrader: (5)

Yeah at 0 psi a little man with a hammer would be trying to knock his way out of the bottom end I'll grab a napa gold (wix) filter and 6 quarts of oil and give it a shot. I guess I should move onto the pressure sending unit if that doesn't help? What part # napa gold should I pick up for it?

1 Slow WS6

iTrader: (1)

If the lifters got considerably louder than normal , they definitely are not getting oil. You need to verify if you have good pressure or not obviously. you can replace the sensor and fire it up real quick to see if you get pressure or hook a mechanical gauge up to it if you have one. That same thing happened to me and it landed up being the relief valve in the oil pump got stuck in the open position.

IDriveChevy

iTrader: (5)

Well I put a mechanical gauge tapped in above the filter and changed the oil+filter and that appears to have fixed my issue. the mechanical read around 45# cold and 35 or so hot at idle. It stayed right around there according to the dash gauge when I took it out for a quick cruise, and the ticking from the lifters went away I hope a junk filter was the cause of it.

IDriveChevy

iTrader: (5)

Update: Took it out for a ride and the oil pressure fell to about 10 pounds or so after it got warmed up Started it back up cold this morning and it had 60 pounds again?? What would cause good pressure at idle and poor pressure after it warmed up

hrcslam

Put it in 2nd at about 35mph and hold 2nd, give it the go go pedal (roll into it semi-aggressively) if the oil pressure drops then it's likely rod bearing clearance. You could try thicker oil (I'm running SAE 50), but you may not need that.

But of course, go by what your mechanical gauge says over your electric one if they are reading differently. My dash gauge drops (from 50-60psi to about 35-45psi) with heavy throttle in all gears at high rpms (over 4500) and with moderate throttle (between 2500-4500 rpms) in 2nd, 3rd, and 4th gears, only when the engine is at operating temps. But my mechanical gauge stays steady at about 35-45psi at moderate throttle and 50-60psi at high rpms.

IIRC, GM states 6 psi min at idle and 6 psi for every 1000 rpms min. These are the worst allowable limits.

On a side note, many prefer to shoot for higher PSI like 60-70psi at redline. Which is fine, but not necessary.

Darth_V8r

iTrader: (4)

Mine did that three days ago. Except it was a 5500 rpm shift point. Driver side, rear of intake manifold just toward the center from the base of the cylinder head, there is a vertical electrical connector to your oil pressure sending unit. Mine is still attached to the sensor, but the sensor broke at the base

If you have three elbows on your right arm you might be able to reach back there and feel it. Worth a shot and if it is broken you'll know for sure that's all it is

garygnu

consider swapping in a new oil pump and a new ls2 timing chain .you will need a cam swap kit ,and a new oil pump .check out a couple of vendors for prices on these parts .check out ls1howto.com for instructions .

1 Slow WS6

iTrader: (1)

This, sounds like the pump.

IDriveChevy

iTrader: (5)

Well since many are saying its the pump, I guess I better buy one and do a new timing chain while I'm in there. I plan to eventually cam the car so I might as well do the supporting mods early! Which pump/chain does everyone recommend? Tick? Katech? I can get a tick ported ls6 from a guy local for a decent price thats new. Im guessing everyone runs the LS2 chain?

1 Slow WS6

iTrader: (1)

I run a C5R chain and a melling 10296 pump

1_MEANZ28

iTrader: (4)

I used to own a 98 ls1 z28.car had great pressure under normal driving.the day I decided to take it to the track after the 1/4 mile oil pressure went to 0 and developed a small knock ..i turned of the car and checked everything ,2-3 mins passed I turned her on and pressure came back ,knock went away.after further inspection discovered car had a lot of sludge..this might be your case.pull open valve cover to check .I had to clean everything and replace oil pump for a tsp ls6 ported and had oil pan cleaned and replaced pick up tube ,,took the time to do cam heads and all internal mods .after that oil pressure was amazing 65 cold 40 hot. never had the problem again...if you haven't done it start replacing oil pressure sending unit. and take if from there

IDriveChevy

iTrader: (5)

Well I went ahead and ordered the melling 10295 and an ls2 chain along with arp cam bolts and a balancer bolt. I hope this fixes my issue!

1 Slow WS6

iTrader: (1)

Good luck , hope it solve the problem! post your results, I'm curious myself

srs bzns

iTrader: (3)

Could he possibly have "gotten on it" hard enough to slosh the oil in the pan and starve the pick up for a second if the previous owner did not put enough oil in the car at the oil change?

IDriveChevy

iTrader: (5)

Well i got it done and it looks like my problem hasnt gone away. I started it up and had great pressure with the new melling and after it got hot from driving around the pressure fell back between 0 and 20 bouncing around a bit on and off between the two and my lifters started making noise again. So I guess I've got bearing clearance problems unless there could be something else.

hrcslam

Did you put a mechanical gauge on it to verify the dash reading?

IDriveChevy

iTrader: (5)

The lifters made noise after a test drive which means they werent getting oil. So a mechanical gauge would just tell me my pressure no good. I can hook it back up again but it will only tell me something I already know. I guess a bearing or something is messed up in my motor

1 Slow WS6

iTrader: (1)

If the mains are that bad , sad to say it's time for a rebuild