well i had to change my intake manifold gasket this weekend and now the oil pressure is at about 30 when i start it, Before it was about the same and never went below 15, now when it gets hot the and the car is at idle it drops to zero and if i let idle to long it die. but on the highway it the pressure stays at between 15 and 20. what can i do ?

 

Not yet!

First thing to do is verify that the gauge is actually accurate. Try installing an aftermarket mechanical oil pressure gauge and compare the readings between the 2 gauges. It's not uncommon for the stock gauge and/or oil pressure sender to be faulty in these cars and give wacky readings.

Now, to answer your next question (probably), when you go to install the aftermarket gauge, you have 2 choices on where to install it. you can either install it next to the distributor on the rear "china wall" where a 1/8" NPT (if I remember correctly) plug is located, you probably saw it during your intake swap. The other place to install is to get a T fitting (from a hardware store) and install it where the oil pressure sender is located, which is right above the oil filter. That way you have a place for the factory sender as well as the connector for your aftermarket gauge.

 

so if the gauge is off , could the reason the car dies at idle be from the time being off? What if the gauge is right what should i do then?

 

There is an oil pressure kill switch that shuts off fuel if it doesn't see oil pressure. If both the oil pressure guage and the kill switch think there is no oil pressure, then there probably isn't any. I'd go ahead and double check with a mechanical guage to be sure.

 

It could be possible. Did you check the timing after you replaced the intake manifold gaskets? If not, you should. Even if you marked the rotor before you pulled it out, or set the #1 to TDC, you should still make sure that the timing is correct after removing the distributor.

But, having the car die at idle could be a number of things, really. How recently has the car had a full tune-up (plugs, wires, cap, rotor, O2 sensor, fuel filter, etc.). Have you checked fuel pressure? Does the engine seem to run fine the rest of time?

If the stock gauge is right, then it will be time to get a new motor or tear the old one down and find the problem. Might be a simple problem, might not.

 

well i am pretty sure we had the timing right, but when i get home this weekend i'll check it. I donno the car acts normal when it first starts but after while it will die at idle.
o yeah also checked plugs still good and new wires, ingnition coil, distriburtor rotor, and cap

 

Sounds like your timing is off or you have a vacuum leak.

As far as the oil pressure, you changed your oil and filter after the gasket install right???? No matter how careful you are on a SBC you will still get coolant into the engine and therefore into the oil. Coolant will dilute the oil and lower the pressure as well as damage bearings and other parts.

 

yea i changed it, hmm i will check timing we were having a hard time figuring out which line to get it on

 

In the stock tbi cars, the only purpose served by the switch was to act as a backup source of power for the fuel pump if the ecms hardware where to fail. Sort of stupid if you ask me but I guess gm had to stick something in that hole in the block. IIRC, the switch used to control the CHOKE light.

 

It is a safety item. If you get into a wreck that rips open a fuel line, the engine will stall and fuel will not be pumped out of the tank anymore (in theory).

 

Both the ecm and the switch will cut power to the relay when the engine stops running. As long as the ecm sees reference pulses, though, the pump will remain on. Both the switch and the ecm are in parallel.

 

They are wired in parallel but after the engine is running the relay should de-energize. Unplug the oil pressure switch and all of my TBI engines quit running. I believe atleast on trucks the fuel pump relay is only used to prime the system and during cranking. The relay should be open when the engine is running. That also serves as a low oil pressure shut-down.

 

Its probably different with the trucks. With my car, at least, its not needed. I never bothered to intstall the pressure switch.

 

well if i have to replace it i mine as well get a 350tbi...I get one those out of a carprice or chevy pick-up right? which would be the best?

 

Caprice or some vans as they have roller cam setups to begin with. A 350 tbi with a LT1 cam makes a good combo.

 

yea thats what i was thinkin to a cam and head swap would be a good idea for some more power.

 

Do you think my car can last a few months with low oil pressure(if that is my problem) or is something i need to fix immediately? Because i am hoping it can make until is out which is about 4 more weeks then i will be going to florida for a week and i want to got to Thirdgen fest on May 28....