What Powers the Fuel Pumps? Bad ECU?

[012017]

2000 Challenger with the a 2000 240 EFI.
2nd year owned. Have had an intermittent cold start problem. Sometimes when the key is turned to the "on" position, the lift pump with clack and the the motor would fire and run great. Other times, no lift pump noise, boat would crank but no start. This year, cranks fine, no start at all.
Replaced lift pump and port side temp sensor, no change. I have 12+ volts to all power wires for lift and high pressure fuel pumps but they wont run. Following a Manual, it appears the ECU "grounds" out both electric pumps to make them work, that doesn't appear to be happening in my case. If I ground the negative terminal on the high pressure pump to the battery, both pumps will run and the motor will start, so this eliminates a number of other issues as far as spark, compression and the "mechanical" side of the fuel delivery.
My question is.....is there anything else that tells the ECU to "ground out" the pumps? At this point I'm at a bad ECU, I've checked continuity of the harness to the ECU and its good. I took the ECU out and it looks pretty grungy, I'd not be surprised if its been under water judging by the scum line. Anybody know a decent service near Michigan that checks/repairs marine ECU's? or is there something simple I've missed?

 

[poppie]

If the wires have continuity then all that's left is the ecu unfortunately. I've seen some threads on here regarding ecu rebuilds. Try searching them up.

 

[012017]

If the wires have continuity then all that's left is the ecu unfortunately. I've seen some threads on here regarding ecu rebuilds. Try searching them up.

Thanks.
I wasn’t sure if there was some other obscure function/sensor on this motor/boat just to allow the pumps to function, since you have to pretty much stand on your head to work on it. Lol.

 

[Tim75]

The good news is that the ECUs seldom fail. They are potted in rubber inside. Not saying they never fail. Try Brocatto (sp). The have their own design or can repair yours.
You will need to BOAT.
Break
Out
Another
Thousand.

Or find the problem. Start with all the ground wires and connectors. Just because a wire does not wiggle is no guarantee of a good connection.

Your lift pump will stop when it reaches its pressure (about 6psi) or when the ECU times out (about 20 seconds). The vst pump runs as long as the key is at RUN. IF the vst pump wires ever got reversed, the pump will run, but will not build pressure. BTW.what is your vst pressure? Have you checked the tps? Many threads here about it.

 

[012017]

I was hoping for something as simple as a bad ground, especially since at first the problem was intermittent and the motor will run when I run a ground from the vst pump to the battery, but haven’t found one that makes a difference yet, and apparently the ECU “makes” the ground for the pumps. The fact that it will run with a direct ground to the high pressure pump eliminates a lot of potential problems. Thanks.