I read around for the last week, couldn't come to a conclusion. My problem seems a little different then the ones that ive been seeing here.

Just some background..
LS1 with mods in sig, haven't tuned after LT's were put on. No cats, so multiple SES codes for O2 sensors.
Codes: P0157, P0160, P0420, P1153.

So at cold start, she'll idle at around 40psi give or take, and at warm start, maybe 30. When accelerating it will drop significantly, 10-20 some days, 0 others. When 0, Check gauges comes on.

Last night, for the first time I heard tapping from the lifters around 2,500 rpms, and the gauge would drop to 0 if i gave it some juice.


Took it to my mechanic, he ran an analogue gauge to check and see if the one on my dash was the problem, since it ran fine. analogue gauge showed same thing, low psi all around, 40ish at idle.

He says that the oil is pretty black and should get changed (last change <1600k). I asked him to Seafoam it and we'll change it after the foam does some work.

So aside from possible sludge, think there's something else going on?

 

Most of the memebers helped me out with low oil issues they told me the gauge is sometimes off and to check it with a mechanical gauge. My car was dripping small spots of oil now then and it was due to a clogged and broken pcv hose, after I replaced that my oil gauge started working better as well.

 

Lifters tapping and low oil pressure on 2 different gauges... I would be replacing the oil pump. Less than 10psi of oil pressure can start to wreck bearings, so I wouldn't run it much until you get it figured out.

 

get the gen 3 oil mechanical gauge adapter for where the oil filter goes then take your oil psi reading, hopefully you dont have a locked up oil ring on the piston

 

Bad oil rings will not cause oil pressure issues.

 

Check crankshaft end play. Thrust bearing may be toast. Only thing that can cause oil pressure problems is oil pump or bearings.

 

Yea I would replace pump and check pickup oring, but disassemble the old pump because that will most likely show if that was your problem. A lot easier to replace oil pump then bearings, cheaper too.

 

And, what did you find in the oil filter, when you cut it open??

 

do a leak down test,you mite have some blow by.

 

LMAO! Low oil pressure caused by blow-by? Explain that one to me.

 

Blow by = fuel contaminated oil = ruined bearings = low oil pressure.

 

lol so much fail in that sentence...

 

Did this problem just start happening out of the blue...?

 

Or a cam bearing that walked.

 

I would check the oil pump first easiest and cheapest then pull a bearing however it does sounds like a cam bearing...

 

Prove me wrong. Fuel will deteriorate your oil and can lead to bad bearings. Where is the fail?

 

fuel will thin the oil thus causing pre mature bearing failure

 

How? He's completely right. Ask people who lost motors to leaking injectors :/

 

Guys, I don't think he meant to say you were all wrong. I interpreted that as he agrees with you.

 

I just tore my motor down because of blow-by. It didn't effect my oil pressure. If you were getting enough contamination in the crankcase to break the oil down surely you would see blue smoke out of the exhaust as well. Once the oil thins out it's going to go right past the rings and you'll have oil consumption problems. I never saw any mention of oil consumption. Isn't blow-by because of bad rings!