Fuel Delivery Not working

RussianMax · Aug 14, 2014

Fuel pump will not pump fuel at all.
I check fuel pump by hooking up to the battery - Works
Checked MPI and Fuel Pump Relay - Works
Checked to make sure voltage runs to MPI and Fuel pump relay - Works
Checked that voltage is running to Fuel pump connector (main fuel level sending unit) - Works
Checked resistance on main fuel level sending unit - Good ohms
I depressurized the gas couple months ago and the car has been sitting till now. Now it won't creat any pressure
I also checked the "run fuel pump" box on my ECMlink v3 and no sound.
I have a walbro 255
Any ideas what is causeing the fuel pump to not kick on when I try starting the car.

c2ypt1c · Aug 14, 2014

At this point, there's not much more you can do...I would try a different pump.

ThunderChild · Aug 15, 2014

its possible that you are getting a voltage drop from an old or damaged wire, or the fuel pump will free spin but not create pressure.

i would start monitoring wires when you turn the key, check voltage and if you can amperage. also, what about your fuel pump ground?

NHerron · Aug 15, 2014

If your test results are performed correctly then the problem is that the computer is not allowing the fuel pump relay to turn on. Whether that is a computer internal issue, output issue or the computers' input signals (cam/crank signal)

Does the check engine indicator light when you turn the key to on?

mercaholik · Aug 15, 2014

Did you also check the ground circuit wire? That has to be in good working order had well. If the ecu is sending it enough volts thru the relay, then it must be ground side. Check the pumps pressure and volume with the power jumped to the pump. The sending unit is different then the fuel pump power wires, well it is on a 1g. It could be an ecu issue, but seeing you have link was it sent to them for check/install? Also like nherron said check for codes and cam and crank sensor signals.

athlete3344 · Aug 15, 2014

To rule out the pump, can you jump or bypass the relay with a direct source of power to hear if it turns on or not?

c2ypt1c · Aug 15, 2014

athlete3344 said:
To rule out the pump, can you jump or bypass the relay with a direct source of power to hear if it turns on or not?

I didn't realize this earlier but he has confirmed the pump is working:

RussianMax said:
I check fuel pump by hooking up to the battery - Works

Zufelt · Aug 15, 2014

NHerron said:
If your test results are performed correctly then the problem is that the computer is not allowing the fuel pump relay to turn on. Whether that is a computer internal issue, output issue or the computers' input signals (cam/crank signal)

Does the check engine indicator light when you turn the key to on?

If I remember correctly, the fuel pump will still turn on in DSMlink when the box is checked to turn on the fuel pump, regardless of what is going on with the cam/crank signal. Figured that out when I was trying to find out why my car didn't wanna start (threw a CAS sensor malfunction code).

- Zufelt

RussianMax · Aug 15, 2014

tametalon92 said:
its possible that you are getting a voltage drop from an old or damaged wire, or the fuel pump will free spin but not create pressure.

i would start monitoring wires when you turn the key, check voltage and if you can amperage. also, what about your fuel pump ground?

I'm not sure if things were rewired or not from previous owner. All wire look fine. Ill check the voltage while I crank then[DOUBLEPOST=1408125712][/DOUBLEPOST]

NHerron said:
If your test results are performed correctly then the problem is that the computer is not allowing the fuel pump relay to turn on. Whether that is a computer internal issue, output issue or the computers' input signals (cam/crank signal)

Does the check engine indicator light when you turn the key to on?

I did just buy a ecu that has the ecmlink v3 chip sauldered in, but it it was computer, wouldnt there be no voltage?[DOUBLEPOST=1408125922][/DOUBLEPOST]

mercaholik said:
Did you also check the ground circuit wire? That has to be in good working order had well. If the ecu is sending it enough volts thru the relay, then it must be ground side. Check the pumps pressure and volume with the power jumped to the pump. The sending unit is different then the fuel pump power wires, well it is on a 1g. It could be an ecu issue, but seeing you have link was it sent to them for check/install? Also like nherron said check for codes and cam and crank sensor signals.

The the ecmlink was installed at home by previous owner. So it could be the ecu like you guys are saying, I thought it wouldnt be ecu because it reads voltage to the relay by grounding it in the connector and not a piece of metal. I have a 1g CAS too[DOUBLEPOST=1408125974][/DOUBLEPOST]

Zufelt said:
If I remember correctly, the fuel pump will still turn on in DSMlink when the box is checked to turn on the fuel pump, regardless of what is going on with the cam/crank signal. Figured that out when I was trying to find out why my car didn't wanna start (threw a CAS sensor malfunction code).

- Zufelt

OKay, thank you for that rule out

mercaholik · Aug 15, 2014

Ok you have 12+ to your fuel pump relay and also 12v at the power wire of the fuel pump? But it only works when you directly jump power from the battery? Kinda doesn't makes sense to me but you can check the relay with a 9v battery and paperclip using a dmm to check resistance of the coil with no voltage, then power it you should hear and feel it click then check the out put terminals. Search for how to test the relay and it will give you some specs, let me know if you have any trouble. The ecu won't ground the relay if it doesn't see all the correct sensor inputs it's looking for. Process of elimination, only way to know is to test.

RussianMax · Aug 15, 2014

mercaholik said:
Ok you have 12+ to your fuel pump relay and also 12v at the power wire of the fuel pump? But it only works when you directly jump power from the battery? Kinda doesn't makes sense to me but you can check the relay with a 9v battery and paperclip using a dmm to check resistance of the coil with no voltage, then power it you should hear and feel it click then check the out put terminals. Search for how to test the relay and it will give you some specs, let me know if you have any trouble. The ecu won't ground the relay if it doesn't see all the correct sensor inputs it's looking for. Process of elimination, only way to know is to test.

I tested both the relays with the light bulb trick. I know relays are good and that there is voltage going to it. The fuel pump works when connected to a battery. Im at the conclusion of that it has to be something with the connection to main fuel sender unit where the fuel pump is connected to. But it doesn't make sense.

ThunderChild · Aug 16, 2014

when you are jumping the fuel pump to the battery, are you just using a piece of wire to jump all the way or are you removing the pump and jumping it?

it sounds like either your 12v feed isnt sufficient or your fuel pump ground is no good.

monitor voltage when you try to activate the fuel pump too see if its dropping off, had that issue today with a deck at work, pissed me off for a good 30 min.

plus, check your fuel pump ground to make sure its not corroded and causing a lower voltage impass.

mercaholik · Aug 16, 2014

I was saying check ground circuit too, but unless it's finding ground thru the body(I don't see how) then it seems like ground is somewhat functioning. When you jump power to it, it always needs to return to battery for voltage to flow. Like tame said you should pull the pump out and check all connections at and inside the unit. Hope you get this figured out.

BlackDSMthingy · Aug 16, 2014

As tametalon92 asked, did you have the pump installed in the tank when you jumped it or out in your hand? I had a whineboro that junked because the impeller came unbonded from the shaft of the pump. Spun like crazy when it was in my hand, but with the added resistance of the fuel, the shaft spun, but the impeller stayed put (or at least turned slow enough to not do anything). If you're confident it's not this, then I would say the connection on the top of the sending unit is the culprit...

NHerron · Aug 17, 2014

RussianMax said:
I did just buy a ecu that has the ecmlink v3 chip sauldered in, but it it was computer, wouldnt there be no voltage?

I have no idea what you mean here and I have no idea if your engine indicator bulb is lighting up on the dash with the key 'ON' so I can't help you thus far.

Pardon my casual impression but, I suck at overcomplicating electrical issues and sounding like a wizard with a quick diagnosis. Really though, we aren't needing to be technical yet.

ThunderChild · Aug 17, 2014

electrical is a pain in the rear nherron, and admittedly its probably my worst area, but having to do it for work and having great mentors in my former instructor and former co-worker has helped alot.

quick checks should reveal this problem as either an electrical unsufficiency or a mechanical failure in the pump, as blackdsmthingy referred too.

mattmro444 · Aug 17, 2014

Hi there,

You bypass the relay with a direct source of power

mrosupply

ThunderChild · Aug 17, 2014

if you are checking the pump, then yes you could do this, but it is not advised for a permanent solution. high resistance could cause a fire possibility.

RussianMax · Aug 17, 2014

Thank you all. Update - the part of the ecu that grounds to fuel pump relay is messed up. I grounded the red and white wire off fuel pump relay. So now fuel pump works as soon as key is on

NHerron · Aug 17, 2014

Why in the world did you do that. The fuel pump relay pins 3&4 (black/white wires) have power with key on, ECU can be missing from the car and you'll have power. The relay turns on when the ECU gives the relay a ground (pin2 white/red wire) when the CORRECT CONDITIONS are met. The pump only runs when the computer sees the CAS outputting a signal, it shouldnt run with just key on. SO you bypassed the computer guessing.

Well, does the car start?

RussianMax · Aug 19, 2014

NHerron said:
Why in the world did you do that. The fuel pump relay pins 3&4 (black/white wires) have power with key on, ECU can be missing from the car and you'll have power. The relay turns on when the ECU gives the relay a ground (pin2 white/red wire) when the CORRECT CONDITIONS are met. The pump only runs when the computer sees the CAS outputting a signal, it shouldnt run with just key on. SO you bypassed the computer guessing.

Well, does the car start?

Yes i bypassed until I fix ECU! By car starts now. But runs awful :/

NHerron · Aug 20, 2014

Have you opened up your ECU to check for any obvious board damage? I'm assuming nothing would be wrong since it's been ECMlinkd' but I guess you never know.

bryanwheat · Aug 20, 2014

Sounds exactly like what happens when the caps leak on the board. I would inspect that area of the board closely. It might of been fixed but failed.

bmxfelon420 · Aug 20, 2014

Or link could have been installed by an individual. Dont they also just sell the chip and cable itself?

bryanwheat · Aug 20, 2014

bmxfelon420 said:
Or link could have been installed by an individual. Dont they also just sell the chip and cable itself?

The main package is just the memory module/chip, cable, disc and clutch wire. You have to pay extra for to install a socket or install it on a non eprom ecu.

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