Oil psi drops to 5 psi under hard braking - help

[12secondv6]

This weekend I drove about 200-250 miles completely problem free.

Last night I hit the brakes hard and noticed the oil psi guage drop very suddenly down to about 5 psi and the "check guages" light came on. I let off the brake and tapped the gas and the guage went back up to just under 40 psi.

This has never occured before. Car ran completely fine.

I drove a bit more, hit the brakes to test it again and oil psi guae dropped again. This time I hit the gas pedal before it had a chance to go so low. At idle oil psi sits at around 40 psi.

I drove to work and home problem free. While the engine was cold I was seeing about 45 psi - once warm just a bit under 40.

When I give it gas it goes up to 50-55 psi

I went out to test it again and same thing, hard braking and the psi drops.

Hard acceleration - psi does not drop.
Hard left turn - psi does not drop.
Hard right turn - psi does not drop.
Hard braking - psi drops????



I have a 96 Trans Am A4 w/ 113XXX miles
Basic mods - full exhaust, intake, a tune, ignition, mildly ported heads, 1.6 roller rockers, etc.

It's my daily driver. I don't beat the hell out of the car - just a nice daily driver to cruise in. It rarely sees over 4,000 rpm's. It has seen the track maybe 3-4 times for maybe a max of 12 runs?? I've had it for 1.5 years and oil psi has always been fine.

The original owner always ran royal purple oil - I have continued that.



Any idea what is going on? I find it really odd that oil psi would suddenly drop to 5 psi under hard braking?!?!!

Thank you for any help!

[chrisfrom nj]

oil pressure sencor

[bubba428]

did you check your oil level????

[12secondv6]

First thing I did was check oil level.

Sensor?? Hmmm. Any idea where it is on an LT1 engine?

[ar0ck]

Their is a fitting for the sensor on the drivers side of the oil pan, its easily accessible once the car is lifted on jacks around the oil filter. Its certainly worth a look.

[12secondv6]

You guys rock.

I can order a new one for about $17 from rock auto. I'll give that a shot.

Thanks!

[BonzoHansen]

Don't stop. Problem solved.

LOL

OPS is at the top LH side fo the block on SBCs. Not sure if they moved them on LT1s. Although I'm not sure a faulty OPS will do that.

[bubba428]

well.....the sensor isn't going to effect the reading only when braking...it would be wacky all the time. maybe you have some build up in there? I would try giving it a flush

[BonzoHansen]

NO FLUSH. FLUSH IS BAD.

No, if it does not fix the problem, you get a teast gauge and verify the dash gauge.

[bubba428]

Originally Posted by BonzoHansen

Don't stop. Problem solved.

LOL

OPS is at the top LH side fo the block on SBCs. Not sure if they moved them on LT1s. Although I'm not sure a faulty OPS will do that.

...the OPS is on the feed side, as long as the oil pump is pumping it should be getting constant pressure....I think the pump screen might be buggered up

[12secondv6]

So, if I remove the oil pressure switch I can see if there is crap in the screen?

When I remove the oil pressure switch.... will oil pour out like crazy or dribble out?

[12secondv6]

Posted on ls1tech:
http://www.ls1tech.com/forums/showth...1#post10071515

Some people think the oil pick up might be an issue - maybe fell off???

[bubba428]

thats what I keep saying the screen...pick up tube is the same thing...it has to do with swish in the pan...you need to take off the pan

[12secondv6]

Ugh, so bare minimum.... I gotta remove the oil pan?

Then I can see if crap is stuck in the screen.... or if the pick up tube fell off? I just find it crazy that it only occurs under hard braking..... and everything else is fine?!?!?!

What causes the pick up tube to fall off?

Any idea how long it takes to remove/ reinstall oil pan etc?

I am still recovering from surgery and am not allowed to do anything physical for the next 6 weeks - grrrrrrrrr

[bubba428]

well are you still living in the north pole of jersey?

[BigAls87Z28]

James, its gunna be a fair bit of work to get all that done in your current shape.

Either your oil level is too low, but either way the oil pick up is not being submerged when taking hard turns or braking. That is not good. It should drop down, but not as far as you are saying.

[LTb1ow]

The LT1 oil pressure sensor is behind the intake, and on the driver side of the block right around the mount there is a plug that you can tap a mechanical gauge to if your feeling up for it. The thing on the side of the pan is the low oil level light, and thats not tied into the computer,just a light on the dash.

[BonzoHansen]

That is what I thought (basically like SBCs), but I am not familiar enough with lt1s.

Where is sliderule on this?

[LTb1ow]

I would def check out your gauge and sender before anything else. LT1 gauges are always a bit off anyways.

[01blackz28]

how many miles on the car ???

[JW]

Originally Posted by 01blackz28

how many miles on the car ???

This was covered in the first post.

Originally Posted by 12secondv6

I have a 96 Trans Am A4 w/ 113XXX miles

Reading is good

JW

[SuperSweet]

Originally Posted by 12secondv6

any idea how long it takes to remove/ reinstall oil pan etc?

about 3-4 hours with everything going smooth and a lift.

[LTb1ow]

Originally Posted by SuperSweet

about 3-4 hours with everything going smooth and a lift.

[BonzoHansen]

Originally Posted by 12secondv6

Any idea how long it takes to remove/ reinstall oil pan etc?

I am still recovering from surgery and am not allowed to do anything physical for the next 6 weeks - grrrrrrrrr

Given your current condition, you may want to call Josh & get a price to R&R the pan and fix the screen (actual diagnose and then fix - pickup is the just the likely culprit here).