3FE fuel issue

[hawaiicruz]

pump looks aftermarket? and no fuel sock.

 

[jonheld]

You are so patient and helpful.

I believe my wife and kids would dispute that. Thanks for the kind words anyway.

 

[hawaiicruz]

Here's a pic of the old pump, it spins but doesn't pump. I wonder if there is any way to tell if it is the check valve failure caused by a faulty FPR that I have read about in other threads?

 

[jonheld]

Not without pulling the pump apart. The check valve would be in the output section of the pump. I have never seen one but I am told its a simple ball bearing/spring design.
I suppose you could try whacking the pump body and see if that frees up the valve.

The fact that there's no pre-filter on the pump leads me to believe that there's a high possibility of crap/poop in the system. Perhaps this was replaced due to low voltage in the first place. Perhaps it's the OEM pump. Hard to say.

You did change the inline fuel filter as well, correct?

 

[hawaiicruz]

Not yet. I just got an aftermarket pump and sock but haven't installed yet

 

[hawaiicruz]

Spot on analysis of the old pump, I was able to free up the check valve and get it working again ( at least temporarily ) I am hesitant to install the new pump until I figure out the voltage problem, so more tests coming. thanks again

 

[hawaiicruz]

hmm... now zero at the check connector

 

[hawaiicruz]

The fuel pump is fired from the circuit opening relay (COR) in the driver's kick panel. The COR is fired both from the starter signal (runs the fuel pump during starter cranking) and the flap in the AFM. This ensures that in the event of an accident, the fuel pump is shut down if the motor stalls.

I strongly suggest fixing the problem correctly.
Pin 14 of connector ID2 (the one in the driver's kick) is the FP hot lead. It changes color from red/green stripe on the FP side to red/black stripe on the COR side.

You should also verify that you're seeing a strong +12 at the check connector pin 8.

1.5v at pin 14 of the ID2 connector

 

[jonheld]

You need to verify you're on the pin labeled as B+ on the check connector. It should be pin 8, however I've been starring at the FSM and can't make heads or tails on the numbering system that they use. Under the cap of the check connector ther should be a high contrast label for the pins. I can't get to mine as my ARB compressor is in the way and I can't flip up the cover all the way.

You should do a contunuity check from B+ on the check connector back to the EFI relay terminal 4. This should be a direct connection (through a series of connectors).

It sounds like you're looking at the wrong pin and being led down the primrose path with me at your heels.

I will reach out to the 3FE mail list and see if anyone can snap a picture of the inside cover of the check connector.

 

[hawaiicruz]

yes I'm on pin B+ 0v key on

 

[jonheld]

If you're getting 0VDC on B+ then the EFI relay is open/faulty or there's a real bad connection somewhere.

Have you verified that pin 2 of the EFI relay is getting a strong +12?
Have you checked continuity from pin 4 of the EFI relay to B+ on the check connector (pin 8)?

 

[hawaiicruz]

Will do that now, thanks

 

[hawaiicruz]

If you're getting 0VDC on B+ then the EFI relay is open/faulty or there's a real bad connection somewhere.

Have you verified that pin 2 of the EFI relay is getting a strong +12?
Have you checked continuity from pin 4 of the EFI relay to B+ on the check connector (pin 8)?

Pin 2 12.4v...no continuity from pin4 to B+

 

[hawaiicruz]

hold on...retesting

 

[hawaiicruz]

Holy s***! After looking closer at your pic of the fsm, I was on the wrong plug on the test connector, the hinge on my lid is broken and the lid was on backwards...soooo back to the original test you asked me to perform, jump FP to B+ fuel pump works. Sorry for wasing your time, maybe someone can learn from my mistake

 

[hawaiicruz]

That and the fact that I was looking at my 94 fsm and they are on the opposite side

 

[jonheld]

I've been starring at the FSM and EWD for a while now and I got pictures sent to me from Robert on the 3FE list. I drew out the connector in Excel, inverted and relabeled all the pins.
What you see below is how it appears to you on the firewall, not inverted as it is shown on the label.
It's easy to understand how you can make an error.

 

[hawaiicruz]

Problem solved! It was the fuel pump check valve all along. If you ever make to the Big Island I owe you a beer...And I obviously need that FSM. Thanks

 

[DesertCruiser80]

Hey @hawaiicruz , I'm gonna resurrect your thread. I'm having starting issues related to fuel pressure not being maintained after shutdown. Sounds very similar to what you had. I have refreshed the entire fuel system with new parts,. Made sure to get a denso fuel pump.

How did you 1. free the check valve on the fuel pump, and 2. verify that the fuel pump check valve was the issue?