Fuel pressure problem

[megaladon6]

is it a TBI, batch fire, or bank fire EFI?
usually EFI requires the ecm to know where #1TDC is, or better yet, where each cyl's TDC is. a tach signal won't cover that. (TBI is the exception IIRC.) what inputs does the ecm have to monitor the engine?
sorry for the annoying questions, i'm trying to get a picture in my head of how the system is set up. also, what are the symptoms of the start-up issue?

 

[FE3X CLONE]

is it a TBI, batch fire, or bank fire EFI?

It's a multiport bank fire. I have it setup for two squirts alternating which just means that each injector bank injects fuel once, alternating back and forth from one bank to the other.

usually EFI requires the ecm to know where #1TDC is, or better yet, where each cyl's TDC is. a tach signal won't cover that. (TBI is the exception IIRC.)

That's true of an SEFI system (squential port fuel injection) but bank fire systems are the same as TBI. They aren't dumping the fuel based on when each cylinder needs it but rather just dumping the fuel into the intake ports of the heads whether the valves are open or not.

what inputs does the ecm have to monitor the engine?

Coolant temp
Intake Air Temp
Idle Air Control
Wideband O2
Tach
Throttle Position
Manifold Absolute Pressure

Beyond that I will still need to add a bit more wiring that will tie into the CCC distributor's 4 way connector when I'm ready to hook up the ignition capabilites of the system.

also, what are the symptoms of the start-up issue?

It just cranks over and doesn't start at the moment. My tach inside the car is showing a reading while its cranking but when I review my datalogs, my RPM is 0 the entire time I'm cranking.

It ran pretty consistantly last fall but I had to pull the intake back off to seal a coolant leak and so most of my wiring had to come back out. The only thing I changed this time around is that I taped my tach wire to the rest of my wiring harness. I'm thinking maybe my tach wire is picking up too much interfernce from the other wires. Not entirely sure yet.

 

[megaladon6]

well, you've already though of my first thought (interference)
are the tach and ecu off of the same wire?
just because it can cause weird issues, is the ecu well grounded?

 

[FE3X CLONE]

well, you've already though of my first thought (interference)
are the tach and ecu off of the same wire?

Yeah. That's the only way I know to hook it up.

just because it can cause weird issues, is the ecu well grounded?

Yeah. The ECU is actually grounded through the relay board in the engine bay. What I have is this:

It has all the relays and fuses needed for the system. My engine wiring harness runs to this board and then I have a cable I made up that runs from the board into the car to the ECU.
I have the relay board grounded to the engine block with a 10ga wire.

 

[anakputa]

The pump is in the Tank? I've seen the hose split between the pump and the tank bung..Also check the pump too, it could be bad and bleed down. Remove the injectors and leave them on the fuel rail to see if any of them are dripping. Check to see if your getting a full 12V at the pump and relay. then check the grounds..

 

[FE3X CLONE]

The pump is in the Tank? I've seen the hose split between the pump and the tank bung..Also check the pump too, it could be bad and bleed down. Remove the injectors and leave them on the fuel rail to see if any of them are dripping. Check to see if your getting a full 12V at the pump and relay. then check the grounds..

I'll double check everything but the pump is working fine. I get a steady 42psi at the fuel rails when the pump is running. It just bleeds down really quick after the pump shuts off.
And yes, the pump is in the tank.

 

[anakputa]

if it build pressure but bleeds down its most like the check ball/valve in the pump.

 

[FE3X CLONE]

Well, I can't explain it but it seems to be working just fine now. Managed to get the car started today and noticed the pressure was fine. Even after shutting it off it will still hold pressure.

The only thing I can think of is that maybe it was so low on fuel that it took it a while to suck the new fuel I put into the tank through the entire system?

 

[megaladon6]

that can definitely happen. is the tank sumped?