Fastcamaro87

ok Recently i installed a new oil pump because my old one went bad(pressure releif valve was sticking), and was blowing oil out the oil filter seal, luckily i noticed it before anything bad happened, so as the story goes..
I replaced the oil pump with a DM-55HV with a new pickup and driveshaft. Then i filled the motor with valvoline 10w40 conventional, the car seems to run fine but my oil pressure readings are really strange, for example the other night it went down to zero, and stayed there while the car was running, i drove it home (about 5 minutes away) and it stayed at zero the whole time, i shut the car off and let it sit 4 30 mins and i started it up, now it was reading 30 psi, that is what it is at on average, only the pressure does not increase with rpm, and after driving for a while it drops to about 25.

ok here is some more info:
I checked everything and no leaks
The pump came with a notice that said it is a high volume high pressure pump, and it came with a different (non colored)spring, to use if a lower pressure was desired, and said to replace the (colored spring).when i talked to a few people, and they said that i should use the non colored spring because it was the stock one.oh and the oil pressure sending unit is new

Is it possible that the pump is leaking internally? any way to check this?

What else could it be?

Anyone know what the psi is for the colored and non colored spring?

I really got to get this problem figured out..




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87 IROC-z 305 TPI
Borg Warner T-5 fresh rebuild
10-bolt 3.73 Richmond gears rebuilt GM posi,
formerly BW 9-bolt w/3.45 gears(broke it)
Ported Plenum and Runners Homemade AFPR
ACCEL 8.8 wires, High output coil,and cap & rotor
Bosch platinum + 4 plugs
Ram Air w/ K&N filters,
MAF sensor screens removed, TB coolant bypass
Polyurethane tranny and torque arm mounts
No Cat, Dynomax Headers & catback w/custom tips
K&N oil filter,Mobil 1 synth,Factory Oil Cooler, Futura GLS Super Sport tires 265/50/15 rear and 235/60/15 front mounted on 86 monte carlo SS rims.

406 siamesed TPI in progress

'87FAKE-IROC-Z

sounds like the sending unit malfunctioning. I can't imagine driving 5 minutes on zero pressure wouldn't do any damage. Check all the connections. I used the high pressure spring with my new pump with no problems. It will cruise around 50 psi, and peak at 60.
Sounds like an electrical thing.
Good hunting.

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'88 RS (originally 2.8)
-350, .040 over, vette alum. L98s, stock tpi.
-305 injectors & chip
-TES headers & edelbrock cat back
-3.73 gears, 700r4.
Best with 2.8-17.4@77mph
Best with 305-15.0@93mph
Best with 356-13.7@101mph
on a 2.050 60 ft.
(Damn the 2.8!)