LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

96 Z28 idle and oil pressure

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Old 03-11-2011 | 12:21 AM
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Z28allmine77's Avatar
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96 Z28 idle and oil pressure

i have a 1996 chevrolet camaro z28 when engine warms up and you put the car in rev. or drive the rpm drops almost botoms out then levels off at 800 rpm and oil pressure drops to about 5 or 6 psi until i accelerate is this normal or should i wory and the trans wont shift out of 2nd or third gear rpm spikes at 5000 and 55 mph i just baught the car and now this.
Old 03-11-2011 | 03:45 AM
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Re: 96 Z28 idle and oil pressure

welcome 2 the site. this is off subject but what part of tn r u from. i just moved up here a few years ago from alabama. good luck w/your car problem
Old 03-11-2011 | 03:55 AM
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Re: 96 Z28 idle and oil pressure

Generally, normal idle pressure is around 20psi@800rpm. To have it at 5 or 6psi@800rpm is not good. You could try changing your oil pressure sending unit to see it that is bad. What is the pressure on cold startup?
Old 03-11-2011 | 07:50 AM
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Re: 96 Z28 idle and oil pressure

Actually, the rule of thumb for Chevy small block engines is 10 psi per 1000 rpm. Most run higher but not all. I'd say nothing at all is wrong with an oil pressure of 5-6 psi at 800 rpm.
Old 03-11-2011 | 04:21 PM
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Re: 96 Z28 idle and oil pressure

thanks for the info bw hunter that make me feel a little more at ease and i will try the sending unit come payday and let you know the out come . and im lokated just north of jackson, tn town called milan
Old 03-11-2011 | 04:29 PM
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Re: 96 Z28 idle and oil pressure

5 - 6psi at idle isnt good, yeah try to replace the oil pressure sending unit. or hookup an manual oil pressure guage, if it still reads 5psi. something is wrong. It should be about ~20psi at idle.
Old 03-11-2011 | 04:47 PM
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Re: 96 Z28 idle and oil pressure

Take a look at the oil. It might be way overdue for a change. Run synthetic 10w 30. I've heard of plenty of LT1's with low oil pressure. It is a somewhat common problem, and it is not easy to fix. I would drive an LT1 with low oil pressure but I would never mod one with lots of go-fast parts.
Old 03-11-2011 | 05:32 PM
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Re: 96 Z28 idle and oil pressure

i plan on keeping it mostly stock. i just went out to warm it up and double check the gauge . cold engine idle 1200 psi at 40 in park when in gear cold 800rpm and about 35 psi as it warms up about 15 to 20 psi at 1200 or 1300 rpm in park then in gear 800rpm and about 10 psi as i let it run in park 1300 rpm and about 10 psi in gear 800rpm and just barley above the red line. and when i put it in gear the car lunges and the rpm and psi almost bottom out some times it dies and sometimes hops back up to 800rpm and just barley above the red line for psi but psi does go up slightly when i accelerate
Old 03-11-2011 | 05:34 PM
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Re: 96 Z28 idle and oil pressure

i dont know if it might be caused by tps or iac or maybe the map sensor
Old 03-11-2011 | 07:40 PM
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Re: 96 Z28 idle and oil pressure

Originally Posted by bw_hunter
Actually, the rule of thumb for Chevy small block engines is 10 psi per 1000 rpm. Most run higher but not all. I'd say nothing at all is wrong with an oil pressure of 5-6 psi at 800 rpm.
I understand what your are saying, but normal LT1 oil pressure across the board is ~20psi@800rpm. Somewhere, there is a problem with that engine. Mark my words, if it's not the oil pressure sending unit.....it's worn bearings. There is the possibility that the wrong oil viscosity is in the thing...but that is a long shot....I don't think there is a good chance that anything thinner than 5w30 would be in it.

From my understanding, engines that do not have a good pressure at a hot idle, have worn bearings(or loose clearances).

Last edited by ACE1252; 03-11-2011 at 07:53 PM.
Old 03-11-2011 | 07:40 PM
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Re: 96 Z28 idle and oil pressure

Just started having the same problem, my buddy says I should replace my pump with a high volume...any thoughts?
Old 03-11-2011 | 07:46 PM
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Re: 96 Z28 idle and oil pressure

Originally Posted by ScottyZ28
Just started having the same problem, my buddy says I should replace my pump with a high volume...any thoughts?
If it's stock with the stock pan. No. If you go to a high capacity pan....maybe...but you are still covering up the problem. Worn bearings(or loose clearances).

You could move to 10w40. That increased my pressure 5psi across the board, but I have good bearings in mine as well. The pressure increase could be lower for worn bearings. You just need to be careful that it does not get too cold where you live for a cold startup. The 10w is too thick at certain temps than the 5w(could increase cold startup bearing wear).

The reason I went to 10w40 is that my engine with this CC503 runs 15 degrees hotter than my stock setup. I almost feel that the thing may be too lean, but I will have to get a wide band to see.

Last edited by ACE1252; 03-11-2011 at 07:52 PM.
Old 03-11-2011 | 08:13 PM
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Re: 96 Z28 idle and oil pressure

Well according too alldata... Minimum, 6 psi @ 1000 RPM; 18 psi @ 2000 RPM; 24 psi @ 4000 RPM
Old 03-12-2011 | 06:48 AM
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Re: 96 Z28 idle and oil pressure

Originally Posted by ACE1252
I understand what your are saying, but normal LT1 oil pressure across the board is ~20psi@800rpm. Somewhere, there is a problem with that engine. Mark my words, if it's not the oil pressure sending unit.....it's worn bearings. There is the possibility that the wrong oil viscosity is in the thing...but that is a long shot....I don't think there is a good chance that anything thinner than 5w30 would be in it.

From my understanding, engines that do not have a good pressure at a hot idle, have worn bearings(or loose clearances).
I think we'll just have to disagree here. I don't think most stock LT1s have 20 psi at idle and 6 psi at idle has been fine for about 40 years of small blocks.....
Old 03-12-2011 | 08:04 AM
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Re: 96 Z28 idle and oil pressure

10psi per 1k rpm..... I agree with bw_hunter that is just fine for a sbc, the LT series does not have uber high tolorences unless it was a rebuild with this in mind. Remember you are getting your reading from the back of the block and not directly from the pump. Id change the oil and filter since you just got her and probably dont know when it was last changed.
And def stick away from hi volume pumps, you not only run the risk of running a dry pan but also the gears on the pump wear out faster.


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