LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Sudden, complete loss in oil pressure?!?!

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Old 08-20-2009, 05:51 PM
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Default Sudden, complete loss in oil pressure?!?!

What would cause this?

I was driving my SS down the road. I stopped at a stoplight and some chick was talking on the phone. My SS is cammed with open headers so its loud as ****...

We start driving and she yells at me because I was too loud so I stepped on it a little bit, not WOT, but slightly more than 1/2 throttle to annoy her more.

Immediately after I lose ALL oil pressure. It went straight to 0...do not pass go, do not collect $200.

No knocking, no pinging, nothing...It did not stutter, idle did not change, no unusual noises, no pops or anything when it lost pressure...

I shut it down for 2 days, and didnt touch it. When I restarted it today to pull it up on the curb to get under it and look around, oil pressure was perfect. WTF

It has an oil leak coming from behind the distributor. I thought it was the crank, but it is dripping onto the crank and getting slung around...The leak is no worse than it was before and I still have oil...

WTF?
Old 08-20-2009, 05:53 PM
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You using the stock gauge? Put a mechanical on it and run it and see what it does.
Old 08-20-2009, 05:59 PM
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When you "lost" oil pressure, how was the car running? If it suddenly got rough running, then you actually lost oil pressure, as the lifters aren't pumped up anymore, the valve lash goes wacky, etc. etc....

IF, however, the car still was running reasonably well, then it's possible that you didn't actually lose oil pressure, but your o/p gauge or sending unit "hiccupped"......
Old 08-20-2009, 06:05 PM
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Have you checked you oil pressure sensor to make sure the plug isnt coming loose? The same thing happen to me but mine was cracked and it actually just broke in half.
Old 08-20-2009, 06:08 PM
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Definitely look at the OPSU first, especially if you don't have any drivability issues.
Old 08-20-2009, 06:16 PM
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Is there oil in the engine? did it make any weird sounds? how did the engine run when it lost pressure?
Old 08-20-2009, 06:23 PM
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well if you guys actually READ the original post I covered that lol...

No knocking, no pinging, nothing...It did not stutter, idle did not change, no unusual noises, no pops or anything when it lost pressure...
I got under it and played with the OPS and it was on nice and tight, didnt seem anything was wrong with it.
Old 08-20-2009, 06:28 PM
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there is a possibility that the OPSU is going bad. Like stated before if it happens again install a mechanical sensor and check to make sure there is actual pressure.
Old 08-20-2009, 07:21 PM
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Originally Posted by Z28Camaro30Ann
well if you guys actually READ the original post I covered that lol...
I was thinking the same thing LMAO!
Old 08-20-2009, 08:07 PM
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lol yeah.

Well I took it for a drive to see what it did and it did it again. I gunned it and the pressure dropped...HOWEVER...when I stopped at a stop light I started to drive again and didnt hit the gas enough and I bogged it a slight bit on accident...When I did that, the oil pressure came right back.

Same as the first time...no knocks, no change in the way it ran, no difference in idle whatsoever. I think I may have a wire hitting a header or something and grounding out or the OPS is going bad.
Old 08-20-2009, 08:19 PM
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that would be my guess. Good luck finding the problem. But it doesnt sound like anything major. It could just be like you said under the torque of the engine it causes the wire to hit the header.
Old 08-20-2009, 10:17 PM
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Or the pickup for the oil pump fell off.
Old 08-20-2009, 10:27 PM
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Originally Posted by RamAir95TA
Or the pickup for the oil pump fell off.

If that was the case he would lose pressure while braking, not while accelerating. Since the oil would be forced towards the front of the pan when stopping. it doesnt sound like the pickup is the issue at all.


i bet he put the cam in backwards. i would tear down the engine and get it rebuilt
Old 08-21-2009, 12:02 AM
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har har har lol
Old 08-21-2009, 04:14 AM
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Originally Posted by Z28Camaro30Ann
What would cause this?

We start driving and she yells at me because I was too loud so I stepped on it a little bit, not WOT, but slightly more than 1/2 throttle to annoy her more.

Karma?
Old 08-21-2009, 05:45 AM
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Originally Posted by RamAir95TA
Or the pickup for the oil pump fell off.
That is what I was thinking. It happened to me.

Originally Posted by Badazz 97 TA
If that was the case he would lose pressure while braking, not while accelerating. Since the oil would be forced towards the front of the pan when stopping. it doesnt sound like the pickup is the issue at all.
I wouldn't say that. When mine fell off, it didn't make much pressure at idle or slow engine speeds. I don't know what pressure it made when it was at WOT as I didn't look. Once I knew it spun a bearing, I beat the crap out of it Luckily the extended warranty took care of it
Old 08-21-2009, 12:48 PM
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Originally Posted by litch2004
there is a possibility that the OPSU is going bad. Like stated before if it happens again install a mechanical sensor and check to make sure there is actual pressure.
I agree. when my trans was rebuilt a couple years ago they started the car up and it had ZERO op. they found that the OSU had been broken during the trans swap (but yet they wouldn't pay to replace it ) the silver part on mine split from the black plastic part but it's possible the OP's did the same thing with an internal break since he said his is still tight. I don't know what brand they used to replace it but ever since i've had the typical low oil pressure at hot idle reading that most lt1's have. i didn't have it before they broke the unit.

and i'm pretty sure my oil pickup is in the right spot because i was having the oil pressure issue BEFORE changing the oil pan gasket last summer and the pickup tube was in the proper place at that time. under normal driving and when my car is cold the oil pressure is fine but at idle warm it will read around 10psi or just about halfway between the red zone and 1/4 white mark.

this video is from last summer about 2500 miles ago right after i changed to 10w30. i recently went back to 5w30 because the place i went to get the oil changed at didn't have 10w30. i don't think it made much of a difference anyway

http://www.youtube.com/watch?v=Myfc5...e=channel_page
Old 08-21-2009, 01:14 PM
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I could've sworn if you unplug the OPSU that the oil pressure gauge will sky rocket because it has no resistance? Whereas if it's going to "0" it would be the wire shorting/grounding out?
Old 08-21-2009, 01:55 PM
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Originally Posted by meissenation
I could've sworn if you unplug the OPSU that the oil pressure gauge will sky rocket because it has no resistance? Whereas if it's going to "0" it would be the wire shorting/grounding out?
come to think of it, you're right. i tried that on mine once. unplugged it and it went all the way to Max.
Old 08-21-2009, 02:27 PM
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Seems to me like it'd be the wire is grounding/shorting out or there was debris that got sucked into the oil screen and blocked oil flow. Now in your post you say it goes to 0 but did it come back up at all for the rest of the drive home or did it stay at 0 the entire way home?

I would carefully go over the sending unit wire with a magnifying glass (figuratively speaking) and see if it's shorting out somewhere that would cause it to dip to 0. If not, if it truly went to 0 oil pressure, need to figure out what it was fast cause it won't take long for bearings to start going if there's no lubrication.


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