engine problem

[Blackwizard22]

I put my new engine in:

Its a ZZ4 shortblock:
4 bolt one piece rear
Cast steel crank
Powder rods 5.7" (ZZ4)
LT1 hyper 4 valve pistons (ZZ4) (10.25:1 compression)
Plasma moly rings
Steel billet hyd roller cam: Bullet racing cams 530/530 lift 242/242 @ .050 on a 108
Ls1 Roller lifters
Stock spider/dog-bone combo with retaining plate
Cloyes single roller
Speedpro std volume high pressure pump with steel pinned intermediate shaft (Arp studded)
Gm stainless .028 compressed head gaskets
GMPP Vortec Bowtie heads: 25534351C
180cc intake runners (flow benched 253 intake/ 205 ex. @ .525)
2.00 intake/ 1.55 stainless backcut valves
65cc chambers
Ported exhaust runners and bowl work
Manley springs, retainers, and crane 10 degree machined locks
7/16 Rocker studs
Stainless 1.5 fuller roller rockers
5/16 Hardened Manley pushrods
Edlebrock rpm airgap intake
Blueprinted HEI
SFI flexplate
PP Bonded 8" balancer
Centerbolt tall ball milled valve covers
Aluminum water pump

Trans:
Th350 trans with BM shift kit
TCI 3000 stall 10" street fighter converter

Rear:
3.73 posi with 27" tall tires


Im running a holley red pump and a 670 street avenger with vac secondaries.

The engine will pop once in a while until it warms up and then itll idle perfectly at 6-7psi fo fuel pressure.

Cracking the throttle in the driveway it will rev fine as well, but as soon as you put it under load and drive it, it keeps popping. It has no power and when you floor it, it pulls a bit then i guess once the secondaries open it sputters out. Also when it changes gear under full throttle it will break up. When i bring the car home from a very short test drive im running 3.5 psi fuel pressure and have to shut it off.

Is the holley red not enough pump? Is something wrong with my carb? Should i switch to a 650 double pumper with mech secondaries?

 

[81Elky]

Are you running a fuel pump regulator? A 670 street avenger is definitely not too much. What is the fuel pressure when it is popping while warming up?

 

[Blackwizard22]

Are you running a fuel pump regulator? A 670 street avenger is definitely not too much. What is the fuel pressure when it is popping while warming up?

The red pump has internal regulator.

While warming the pressure is 6.5

 

[Blackwizard22]

I have a 90 degree fitting leading into the pump, i wonder if this is causing my gradual drop in psi. But it still doesnt explain my carb problems.

 

[CutlassRacer]

Is your fuel pressure gauge liquid filled and located in the engine compartment?

 

[MY FYN 79]

Is your fuel pressure gauge liquid filled and located in the engine compartment?

I'm with Kevin!

 

[Blackwizard22]

Is your fuel pressure gauge liquid filled and located in the engine compartment?

yes it is why?

 

[MY FYN 79]

Liquid filled gauges are notorious for reading low once warmed up. I fought a low fuel pressure problem for a long time, and with the advice of another member here I "burped" the gauge when it was reading low. Just like magic the fuel pressure jumped back up to normal.

There should be a little plug on the gauge where the liquid was filled into it. When the gauge is reading low, pull that plug loose enough to let it breath... see what happens.

 

[Blackwizard22]

Ill have to try that. Still trying to figure out this popping off idle problem

 

[Redline396]

you could have a intake leak(vac) around the intake ports . that will cause the motor
pop on acceleration, or check your distributor and timing.