No oil pressure, help
09-10-2005, 01:56 PM
#1
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No oil pressure, help The car is a 2000 Trans Am WS6 with headers, exhaust, cam, intake, the usual bolt-ons. Previous to today, I hadn't started the car in approximately two weeks since I've been away at school. I went outside today and started it up, and immediately see the "CHECK GAGES" light and notice the oil pressure gauge is reading 0(completely to the left side). All in all, the car probably ran about 15 seconds without any problems as far as I could tell. I turned it off immediately, looked over the engine a bit, and started it again. Once again saw no oil pressure, so shut it off immediately(2 seconds total). I'm not going to try to start it again because I'm not sure what's wrong.
From reading on the boards, I've seen this coming from people having problems with either the oil pressure sending unit or the oil pump. I checked the oil pressure sending unit briefly and it seemed fine. Not much I can check with the oil pump. I don't see how the oil pump could go bad from the car sitting for 10 days.
Does anyone have any ideas or suggestions?
From reading on the boards, I've seen this coming from people having problems with either the oil pressure sending unit or the oil pump. I checked the oil pressure sending unit briefly and it seemed fine. Not much I can check with the oil pump. I don't see how the oil pump could go bad from the car sitting for 10 days.
Does anyone have any ideas or suggestions?
09-10-2005, 02:14 PM
#2
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They do take a long time to prime the pump. When you put in a new motor, you have to prime the system with pressure. If yours was running good two weeks ago, it should start up fine, maybe a short delay. Since a LS1 oil pump is up on the crank, it has to suck oil up from the pan. Make sure that the oil level is full, or add one extra quart. You could take out the spark plugs and crank it over.
09-10-2005, 02:16 PM
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The motor isn't new nor has it ever been rebuilt. The cam was put in over a year ago.
A couple other things I forgot in the first post:
1) There is no oil leaking anywhere
2) When I have the key out of the ignition, the oil pressure gauge will slowly go up from 0psi to around 20psi before settling down. It takes about 30 seconds for it to do this(it moves up slowly). But, once I put the key in the ignition and turn it to accessory, the pressure goes right back down to 0.
A couple other things I forgot in the first post:
1) There is no oil leaking anywhere
2) When I have the key out of the ignition, the oil pressure gauge will slowly go up from 0psi to around 20psi before settling down. It takes about 30 seconds for it to do this(it moves up slowly). But, once I put the key in the ignition and turn it to accessory, the pressure goes right back down to 0.
09-11-2005, 09:23 PM
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I changed the oil today, Mobil 1 5W30 Synthetic, what I usually use. The old oil wasn't clean looking but didn't look too bad..it's only been 500 miles since the last oil change. After changing the oil, the pressure gauge read around 30psi while the key was not in the ignition, and of course read 0 once the key was in the ignition. I started the car for about 5 seconds and still had no oil pressure, and shut it off before it caused any damage.
I ordered a new oil pressure sending unit. I took the intake off and checked out the original one..it looks fine from the outside and the wire was fine as far as I could trace it.
If it's not this, am I safe to assume it's the oil pump? Also, is there any way of checking to see if the oil pressure will go back to normal without starting the car up? I've started it up 3 times now with no oil pressure, and it's starting to feel pretty risky.
I ordered a new oil pressure sending unit. I took the intake off and checked out the original one..it looks fine from the outside and the wire was fine as far as I could trace it.
If it's not this, am I safe to assume it's the oil pump? Also, is there any way of checking to see if the oil pressure will go back to normal without starting the car up? I've started it up 3 times now with no oil pressure, and it's starting to feel pretty risky.
09-12-2005, 01:41 AM
#7
Originally Posted by Grimes
once you get the new sending unit in, you could take out the fuel pump fuse, and crank it over a while to build some pressure up.
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09-12-2005, 08:27 AM
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I'll do that Thursday when the oil pressure sending unit comes in. Is there any way to tell if I'm building pressure when cranking it? Or should I just crank for 10 seconds, wait a minute, and crank it for 10 seconds again, then give it a try? I'm really worried about starting the car too many times with no pressure.
09-12-2005, 08:37 AM
#9
You could probably take the oil pressure sending unit out. Put a rag back there and try cranking it over with the fuel pump fuse out and then see if the rag is wet with oil. If it is then you have a bad oil pressure sensor. Only problem is it is basically impossible to get to the sensor without taking the intake off. But then agian if it's a bad sensor you will have to take it off anyways.
09-12-2005, 08:48 AM
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I would start it up with the oil refill tube cap off. Have someone stand over it with a flashlight. If there is zero oil presssure you will not see any oil comming through the pushrods...
Since the oil pressure sending unit is only about 15 bucks.... you probably should have replaced it while you had the intake off...
Obvoulsly, don't run the motor for more than 45 seconds or so...
Oil pumps in Gen 3 engines go bad often ....mine did the same thing twice while under warranty.....the GM dealer said, "next time to run the engine without oil and Gm would replace it"......That is when I said BS and I pulled the bad pump and replaced it myself...
Since the oil pressure sending unit is only about 15 bucks.... you probably should have replaced it while you had the intake off...
Obvoulsly, don't run the motor for more than 45 seconds or so...
Oil pumps in Gen 3 engines go bad often ....mine did the same thing twice while under warranty.....the GM dealer said, "next time to run the engine without oil and Gm would replace it"......That is when I said BS and I pulled the bad pump and replaced it myself...
09-12-2005, 09:59 PM
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I took the intake off already and I'm waiting for the sending unit to arrive Thursday so I can swap it. Regardless if the original sending unit is bad or not I decided to replace it. After that, I'll put the intake all back together and try to figure out how to test for oil pressure. With the intake on, I can't get to the sending unit to see if oil is going through that, so right now it looks like I'll try what Robert said with the oil refill cap. Does anyone else know any other ways of seeing if I have oil pressure before I try running the engine and risking the bearings?
09-30-2005, 10:37 PM
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Here's a delayed update on this situation:
I ordered the oil pressure sending unit from Pep Boys. They're retarded and it took them 19 days to get it, when they told me it would be three days at the most. Anyway, I got it today. I put it in and put everything back together. I started the car up..no oil pressure..no oil pressure..no oil pressure..then after about 5 seconds the oil pressure gauge shot up to around 65psi! I was like great, this is the best my oil pressure has ever been. I let it run for about three minutes, revving it a little bit occasionally and watching the oil pressure fluctuate.
I shut the car off because I still needed to put my swaybar back on. I jacked the car up and put the swaybar on. Lowered it, went to start it to go get gas, started it up...0 oil pressure. I waited..waited..waited..still no oil pressure. From the second I started it, I noticed this loud tapping noise coming from the engine bay. I got out and popped the hood to check on the noise..it seemed to be coming from around the intake or (most likely) below that. I shut the car off and got my dad to come check it out. I started it back up, 0 oil pressure still, tapping noise still(although it seemed to get quieter the more the engine ran). I sat there and let it run about 2 minutes straight. No SES code or anything bad. It idled and revved fine. Just sat there, reading 0 oil pressure with the CHECK GAGES light.
I have no idea if I've spun any bearings or not. I figured it would have sounded worse and idled worse with ruined bearings. It ran exactly as it always has, except with that tapping noise. The noise got quieter after a couple minutes and I could only notice it when leaning near the intake. Does anyone have any idea? It can't be the oil pump, in my opinion, because the car has now run 3-4 minutes with this problem and hasn't even thrown a SES code for it.
I ordered the oil pressure sending unit from Pep Boys. They're retarded and it took them 19 days to get it, when they told me it would be three days at the most. Anyway, I got it today. I put it in and put everything back together. I started the car up..no oil pressure..no oil pressure..no oil pressure..then after about 5 seconds the oil pressure gauge shot up to around 65psi! I was like great, this is the best my oil pressure has ever been. I let it run for about three minutes, revving it a little bit occasionally and watching the oil pressure fluctuate.
I shut the car off because I still needed to put my swaybar back on. I jacked the car up and put the swaybar on. Lowered it, went to start it to go get gas, started it up...0 oil pressure. I waited..waited..waited..still no oil pressure. From the second I started it, I noticed this loud tapping noise coming from the engine bay. I got out and popped the hood to check on the noise..it seemed to be coming from around the intake or (most likely) below that. I shut the car off and got my dad to come check it out. I started it back up, 0 oil pressure still, tapping noise still(although it seemed to get quieter the more the engine ran). I sat there and let it run about 2 minutes straight. No SES code or anything bad. It idled and revved fine. Just sat there, reading 0 oil pressure with the CHECK GAGES light.
I have no idea if I've spun any bearings or not. I figured it would have sounded worse and idled worse with ruined bearings. It ran exactly as it always has, except with that tapping noise. The noise got quieter after a couple minutes and I could only notice it when leaning near the intake. Does anyone have any idea? It can't be the oil pump, in my opinion, because the car has now run 3-4 minutes with this problem and hasn't even thrown a SES code for it.
09-30-2005, 11:29 PM
#15
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That tapping noise is probably the lifters. They are the first thing to make noise when you are low on oil pressure. When you get oil pressure they will quiet down with no harm. If the sound is from the bearings, it will not quiet down. I would not run it for more than 10 seconds without pressure.
09-30-2005, 11:31 PM
#16
Originally Posted by Jaspirr
It can't be the oil pump, in my opinion, because the car has now run 3-4 minutes with this problem and hasn't even thrown a SES code for it.
-Mike
10-01-2005, 12:33 AM
#17
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Originally Posted by MM98
The oil pump is mechanical not electrical, so of course it's not gonna throw a ses light... Nor can the pcm detect a spun bearing after running the car for 3 minutes with no oil psi.
-Mike
-Mike
Does anyone have any suggestions what might still be wrong, or what to do next?
10-01-2005, 02:59 AM
#18
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i have a 2000 also, your story scares me!! either way, time for a new oil pump, if you replaced the sensor, i dont see it being anything else, i think the 98-00 have the crappy oil pump if im not mistaken.
10-01-2005, 07:29 AM
#19
I recently changed my oil pump. The old oil pump Seal had a small cut in it when took it out and was almost all the way threw it might of failed if i left it. Our maybe somthing wrong with the gauge?
Last edited by LS1FIRE; 10-01-2005 at 07:39 AM.