Fuel pump won't stop priming?
#43
The relay is just a switch that gets flipped by an electromagnet. The electromagnet is a just a coil of wire. When the coil has electricity flowing through it you get a magnetic field that physically moves an electrical contact mounted on an arm.
Wht/blu in the diagram is the 12+ feed for the coil and for the actual power feed to the fuel pump. We have power on this wire only when the key is on.
The LT GRN wire is the ground for the coil supplied by the ECU. So the pump will only run when there is power on wht/blu and ground on lt grn.
We know wht/blu is doing it's job. Since the pump is running when it's shouldn't it means LT GRN is being grounded when it shouldn't. Either the MS3 is grounding the wire when we don't want it to or that wire is making contact with ground somewhere along the wiring run.
The same LT GRN wire is also split and runs to the diagnostic connector underhood. This means we have easy access to the wire underhood for troubleshooting.
The original testing I told you to do would rule out a bad relay. Since we now know it's not the relay we need to figure out if it's a megasquirt issue or a vehicle wiring issue. Easiest way to do that would be to unplug the ecu with the key on engine off when the pump seems to be continuously running.
Wht/blu in the diagram is the 12+ feed for the coil and for the actual power feed to the fuel pump. We have power on this wire only when the key is on.
The LT GRN wire is the ground for the coil supplied by the ECU. So the pump will only run when there is power on wht/blu and ground on lt grn.
We know wht/blu is doing it's job. Since the pump is running when it's shouldn't it means LT GRN is being grounded when it shouldn't. Either the MS3 is grounding the wire when we don't want it to or that wire is making contact with ground somewhere along the wiring run.
The same LT GRN wire is also split and runs to the diagnostic connector underhood. This means we have easy access to the wire underhood for troubleshooting.
The original testing I told you to do would rule out a bad relay. Since we now know it's not the relay we need to figure out if it's a megasquirt issue or a vehicle wiring issue. Easiest way to do that would be to unplug the ecu with the key on engine off when the pump seems to be continuously running.
#47
its time based. so either the relay or the ecu.
by that logic, he shouldn't be having this problem, at all, but here we are, so......
in typical fashion, this is being over-theorized and will go on for many pages lol
if you pull relay and it dies then problem is either relay or ecu. or you can pull relay and check if trigger voltage is being supplied continuously.
or just not care and hardwire it bypassing all of this
in typical fashion, this is being over-theorized and will go on for many pages lol
if you pull relay and it dies then problem is either relay or ecu. or you can pull relay and check if trigger voltage is being supplied continuously.
or just not care and hardwire it bypassing all of this
#54
Which is connected to the LT GRN fuel pump output off the ecu. Which is triggered for a set time to prime the system.
Highlighted is your regulator. When pressure reaches the point the regulator is set for the extra fuel is dumped back in to the tank while the pump continues to run.
Highlighted is your regulator. When pressure reaches the point the regulator is set for the extra fuel is dumped back in to the tank while the pump continues to run.
#56
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Pump does absolutely nothing when the ECU is unplugged. No priming, period.
Plugged everything back in and it decided to act normal... for now. I'm sure it'll start sticking again the next time I turn it on.
Plugged everything back in and it decided to act normal... for now. I'm sure it'll start sticking again the next time I turn it on.
Last edited by ridethecliche; 09-27-2018 at 03:16 AM.
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