2000 Firehawk. Newly rebuilt LS1 motor. New Texas speed cam. New Melling (high output) oil pump, new oil sending unit, new fuel pump, 10/30 Lucas break in oil.
Less then 10 miles on the motor.

Cold start 40psi, warm 20psi, and motor will shut down.

Before motor was dropped back into car it was brought to a shop to have a once over to make sure everything was ok. Which it was.

No clunking sound. Runs smooth and strong when driving.

I'm probably forgetting some info, and I apologize for that in advance.
If there is something that is missing with my description, I will have to ask my husband tomorrow. He is sleeping now.

Any suggestions?

 

If you're just measuring the PSI at idle I'm almost certain those numbers are fine. What are the readings while the car is in motion and at speed? You're saying the car also shuts off on its own?

 

This will do better here in internal engine.

But do come back to the Firebird section to tell us more about this car!

 

I will Paul. I wasn't too sure where to put this post.

Myk, When my husband drove it for the first time to the exhaust shop to get the custom made Y pipe:
1) it would not come out of 2nd gear
2) when he came to a stop, it stalled.
3) Gauge is saying 20psi when I believe it is at idle.

New shift cable is being put in right now at shop, because that broke.

We are hoping that the shop is going to do a pressure check to see why the pressure is dropping.

The reason that I am posting this is because well, the mechanics around here, um let's put it this way, I DO NOT trust them at all.
Three shops around here messed up my '78 Trans Am and did botched up jobs like using zip ties to hold wires together. smh

Some claim that they are "knowledgeable" with LS1 motors, but most do not know anything about them. So we are in sort of a pickle right now.

 

Hmm 40psi at start up with 10/30 seems a little on the low side for a high volume oil pump.. But by GM standards you are still in the normal operating range

6 psi @ 1k rpm
18 psi @ 2k rpm
24 psi @ 4k rpm

But a lot of people start to panic if hot idle drops below 20 psi

They need to hook up a mechanical oil pressure gauge to see what it's reading

You mentioned you have a new oil pressure sending unit (switch)

Did you use a cheapy one? Or possibly crack it on install, they are know to give false readings

 

Burken, this is what we got

 

That looks good

If they hook up a mechanical gauge and it reads the same oil pressure then you can rule out the oil sender switch.

If it reads higher then replace the oil pressure sender switch..

Last resort would be to check and make sure the oil pump O-ring was not pinched on install

You mentioned they are not experienced with ls1 motors, a lot of people install the oil pumps and pinch the ring which causes low oil pressure and in some cases close to 0 PSI

 

As mentioned, 20psi at idle is fine. Drive it and the psi should go up with rpm. I have a ported pump and I don't get as high psi as others claim either. Being just gone over, no psi is what would worry me.

Don't bank in the gauge dead on accurate either

 

Ok, thanks for the info.
We should be picking up the car in a few, from getting the new pipes on and shift cable. We will drive it home and will take note of the psi while driving.
Before we dropped off the car, no O2 sensors were on it or the catalytic converters were on the car , and it was just straight headers.
And yes, we have emission here in NC. =(
The car would stall at every red light.

Hmmmm, anyone think that the sensor may have something to do with it?

 

If it had long tube headers with no cats then the rear O2 sensors need to be tuned out so they don't throw a code..

Also if the original owner did not get a tune after the header install then that might contribute to some drivability issues but shouldn't mess with oil pressure unless you have an extremely low idle

 

Yes, I've leaned when it comes to sensors, it's best to use GM original equipment or GM/ACDelco professional grade. Especially when it comes to the OPSU.

On the motor I build, I used this one: http://stores.precisionoilpumps.com/...ume-race-pump/

And I did a spin test basically to make sure I had no leaks. No spark plugs. Keep in mind this is a new never fired engine so after it's run a bit, the pressure should be lower. Pressure at cranking speed:

 

Well, car is STILL at the shop. They are going to put a mechanical oil pressure gauge to it,.........................whenever. Maybe today, maybe not. UGH.
No check engine light is on either.

 

I would avoid a mechanical guage. A plastic tube filled with oil routing where ever the guage is no Bueno for me...a quality electric guage is preferred.

 

You don't read threads? Nobody said to replace the electric gauge with a mechanical

But just to use a mechanical to rule out the OPSU

 

The PCM needs the front O2 sensors. Without them, the engine will at best stay in open loop mode. Without them, it's no surprise it shut down.

 

Ahhhhh, maybe? Well, the O2 sensors are now on the car with the Y pipe and cats.
They did not finish the car yesterday (checking the psi), nor did they call us to let us know how the psi is.
So, now it is a waiting game.

But I do appreciate everyone's input!

 

Main bearing clearances could be on the loose side and bleading off pressure.
Aluminum blocks expand considerably when up to operating temperature, which is why the room temp clearances need to be around .001"-.0014" and not .0025"-.003" like an iron block app.

 

Update:

Called the shop and they said to me that the car needs a "tune up and Dyno test".

I was kind of confused on that, because why would it need a tune up if everything is new?

They said they took it on a test drive and the car did not stall at stops like it did before, and shifted perfectly, which is a good thing now, and they don't remember what the psi was while driving, because they forgot to look. smh

The shops around here are so incompetent

Question..........
IS it possible that the computer in the car is adjusting to the new motor? The car has less then 10 miles on it.

 

Are you driving the car with an aftermarket cam and stock programming?

If so then you are more incompetent and a greater threat to the car than the shops.

Betting they told you it needs a dyno tune, not a tune up. I don't care what cam sellers say, the stock cam benefits from a retune, running an aftermarket one with stock programming is stupid at best.

Reprogramming for a larger aftermarket cam often includes raising idle which would raise idle pressure.

I know I didn't give you any warm fuzzies there but searching the thread I didn't see any mention of a tune for the mods and that is wildly ignorant and ANY amount of research before hand would tell you that.
If you did say it was tuned I apologize and will change the recommendation to checking the tune.
The stalling situation improving could be the pcm learning but is NOT a real solution.

pcmperformance is good and I believe one of the owners lives on Long Island.