is this normal

[justlearning]

ok after my car reaches operating temp. when i pull up to a stop light my oil pressure falls what seems to be very low, around 20 or the mark right before the red lines. when i go to accelerate or when im moving everything is just fine pressure right at 60. is this normal or do i probably need a new oil pump and pickup. oh yeah and when my pressure drops it seems like my idle is a lil rough nothin drastic but it kinda feels like its sputterin a lil. and i have a 91 305 tbi. my idle might be rough though because i think i might need a new fuel filter and possibly a o2 sensor but any help would be great. and how hard would it be to change the pump by myself???

[-Josh-]

Quite possibly you could just need the O2 Sensor, but it might also be as simple as replacing the guage, you never know sometimes. The guage on my Buick goes up to 80 upon acceleration, and back down to 40 while cruising, i'm just to lazy to get it replaced. Fix the O2 sensor and i'm sure it will fix your idle problem though.

[92rs25th]

HA ! Ssssshit same thing happens to my 92. really pisses me off and freaks me out. Thing is..I bought my baby about 10 months ago and I took it in and had a lube flush about 3 months ago. Same day the problem started..I really don't like seeing the orange down in the red.

Like stated above , starts about 60 - 70 , drops to 40 , Hits 195 , goes down to about 10-20 oil psi area.

I'd imagine cleaning out the gunk would free up some flow and there would be less restriction MAYBE causing a small drop in pressure but I don't think it's suppose to be that way. It's quite scary seeing your oil pressure in the red when you're haulin 75mph+ and it should be about 45-50 ish.

I'm going to pull my oil pan off this weekend and tinker around inside probably do a new oil pump , new seals , Obviously new oil.

Ps - My engine only has about 40K on it.

PS-S - Would eliminating the PVC air valve that runs into the TBI Unit cause any sort of oil pressure drop and sticking a plug off or a breather on ? Let me know.

[poormillionaire2]

I have a 94 Z28 and my oil gauge does that too. I think its normal, I think the oil increases as your engine needs it, so when you rev, it will go up, and at idle, it may sit low.

[92rs25th]

It shouldn't be in red unless there is a problem.

[Hypsi87]

you should snap a gauge on it. Stock gauges are known to read wrong because they are eletrical.

As long as you have the correct ammount of pressure when you are in the RPM's you should be fine. Really at idle, you would only need like 10 PSI min at idle. The reason that you need pressure at RPM is to keep the oil from being airrated.

[GTStang]

Originally Posted by Hypsi87

you should snap a gauge on it. Stock gauges are known to read wrong because they are eletrical.

Stock guages are junk except for letting you know when there is a serious problem(except speedo). 90% of the time when people switch all the guages to a company like autometer they think something is wrong cause they get all new readings. The truth is quality guages are giving you an accurate reading unlike the stockers. So like Hypsi said if your really worried about something I'd go get an aftermarket guage for your readings.

[92rs25th]

I was thinking of getting the 3 pod set up , temp , oil , electric and cutting ecaxt fit holes in the face of my dash just above the console ( Stereo , a/c heater controls. ) You guys think that would fit ?

[justlearning]

okay well then who sells a 3 guage pod i can mount somewhere in my car or do u guys have instructions for making one??? because i will probably get one for oil pressure water temp, and fuel pressure since i will be buyin an adjustable fuel pressure regulator

[92rs25th]

auto zone, checker and napa

[Waterman1963]

Originally Posted by 92rs25th

HA ! PS-S - Would eliminating the PVC air valve that runs into the TBI Unit cause any sort of oil pressure drop and sticking a plug off or a breather on ? Let me know.

Edgar, the PVC valve is there for the reason of minimizing sludge buildup in your engine. The lifters "push" oil up through the rods (that's why they are hollow) to lubricate the rocker arms and springs. The action of all these moving parts under the valve cover plus the high engine (oil) temperature creates an oily mist or spray that would stick to all of these components. Therefore, in short order, creating sludge buildup. The PCV valve is connected to a vacuum port on the TBI or Carb to "pull" this mist to the intake, mixing it with fresh air and fuel, burning it in the combustion process. So, not only should the PCV valve stay put, it has an important function that does need to be checked and replaced when needed. To check while the engine is running , simply pull the PCV valve from the valve cover (leave the hose on the PCV valve) and place your finger over the bottom of the PCV valve. You SHOULD feel a vacuum. If you do not, replace it immediately. With the engine off, do the same but instead of checking for a vacuum, shake the PCV valve and you should feel and hear it "rattle" inside. A PCV valve is cheap and runs from $3-$7.00 at part stores.
A faulty PCV valve will also cause stalling, bucking and a rough idle as well.

[92rs25th]

O.o Well , I don't have any of that and I eliminated my PVC valves.

[89IROC&RS]

well, while i wont say ignore the oil guage, a good "shade tree mechanic" trick is that if you dont hear the engine makin alot of metalic tapping sounds, your oil pressure is probly fine.

[nvrenough]

It's typical for the oil pressure to drop while you are at idle. Your oil pump is drivin by your cam and the faster you buzz the engine the more pressure you'll build up. As long as it's not in the red while you are cruising down the road you will be fine.

[Waterman1963]

First of all John, a few basic questions to help all of us:
1) Did this just start all of a sudden or after something was altered or repaired? If you just bought the car was it already doing this?
2) Does the SES(service engine soon) light come on at all? If you are having a rough idle it could come on. With the OBD I(On Board Diagnosis) equipped cars the ECM (Electronic Control Module) could be having to compensate for an incorrect fuel/air mixture. The SES light would be a clue.
3) How is the oil pressure at idle when the engine is cold? And when accelerating while the engine is not yet hot?
4) How old and what viscosity is the oil? If you don't know because you just bought the car or it has been too long then a $20 oil change is cheap investment for a piece of mind.
Everyone that answers your question could be correct but any more details would help narrow it down. However, sometimes previous owners do some dirty deeds to sell a car. The SES light could be disconnected to hide a problem. Go to an Auto Parts store that has a FREE "Tool Loan Program". Tell them your car is outside and ask them to hook an OBD Scanner to the pod under the dash. If there is a code you will then be wiser. If you want to keep such a scanner around, then that's another $20-$40 investment. A shop will charge you more and...what will their diagnosis be?
So, take all of our advise with caution but the best thing to do BEFORE you begin troubleshooting with your wallet, let the Auto Parts store scan just to be safe. That doesn't cost a dime. Good luck and post any more details you can think of.