No power to fuel injectors

[norman2013]

Ok guys, I picked up a boat from the auction that was said to be flooded. Boat has a 2012 mercury 90 four stroke efi serial# 1b943661.
Once I got the boat home I drained the oil (had some water), pulled plugs, sprayed fogging oil in cylinders, cleaned filters, cleaned tank where fuel pumps are located, cleaned manifold where fuel injectors are located, new oil and fuel.
Motor fired right up for about 1 minute and shut down. Now I cannot get to fire but if a spray a little starter fluid through the throttle body it will fire for a second. (Only did that once). Tried checking to see if there was voltage to the injectors and it appears there is not. Lastly I plugged my smart craft monitor onto it and it says low voltage. Iv tried 2 batteries, voltage at motor reads 13.6 with charger hooked up. I’m at a cross roads. Any help would be much appreciated!

 

[Faztbullet]

Can you hear electric fuel pump run???

 

[norman2013]

Yes, electric fuel pump will run for about 15-20 seconds then a click sound over by the solenoid/relay area. Fuel pressure at the shredder valve is 48-52 psi.

 

[havoc_squad]

What was the low voltage error specifically?

Need to be more specific than that. I'm not familiar with the exact type of injector for your model but it usually follows the same or at least similiar setup as automotive fuel injection systems.

If it is the dual wire injector setup (one to supply power to actuate the injector that is high amp, one wire low amps that triggers the injector to fire), you need to find out how they get power.

If I know I have 12 volts on the injector actuator wire but the trigger wire never gets any voltage, its a wire issue or engine computer issue that needs diagnosing.

If you don't get 12 volts on the injector actuator wire then work up the wire diagram to find out where that gets enabled/powered.

 

[Faztbullet]

ECU fires the injectors. Start with a new battery, clean all connections and grounds...

 

[norman2013]

Ok I will hook up a new battery, clean all of the leads/grounds.
I checked the injectors themselves and each one read 16.7 ohms.
I also checked the plugs coming into the injectors with a volt meter and get nothing. Is there a better method? From my understanding there should be a constant ground on one side is that correct?

 

[Chris1956]

How many wires on those injectors? Automobiles usually have 3. They are power, ground and signal from the ECU. The power and ground should be constant when the ign is active.

 

[norman2013]

They are two wire injectors.

 

[norman2013]

I am getting a couple warnings from my smart craft monitor app. I will post pictures.

 

[norman2013]

Guys any advice would be much appreciated!
Here are some things if tried. I was able to get my hands on a used ecu with all matching numbers, Iv also replaced the main relay with a new one that Iv had in the shop. Also tried a new battery and switched out the main power cables coming in.
If I hook a connection light up to a ground and touch one side of the injector plug it does light up when key is on.
We have spark on all cylinders
I’m getting warnings on my smart craft mobile
“ critical low voltage” and “ecu has detected a problem when trying to output a signal to this device”
The only other thing I can think to replace would be the starter solenoid? Any other suggestions? This motor was flooded at one point but have had it running for a few min sense.

 

[QBhoy]

Have you tried it with no smart craft connected and the weather cap back on the plug ?
Likely not the issue perhaps…but if there is any suspicion around water ingress or exposure…I’d be un plugging all electrical plugs and drying them out, with some electrical cleaner too. Especially around the ecu loom.

 

[norman2013]

Yes, I just purchased the smart craft so it was not on the motor when submerged.
Have good spark on all plugs. The thing that stumps me is it ran for a few minutes after I got all the water out.

 

[QBhoy]

Yes, I just purchased the smart craft so it was not on the motor when submerged.
Have good spark on all plugs. The thing that stumps me is it ran for a few minutes after I got all the water out.

I think id be unplugging everything I could to dry out. There are many sensors and ancillaries in like that require a feed to operate properly. Take one delicate component out the system and it all goes wrong

 

[norman2013]

I’m in the process of disconnecting everything, cleaning and drying out and I noticed some sand and crud coming out of alternator. Could a faulty alternator cause any of the symptoms listed above? I will disconnect it and get it checked at a local parts store

 

[alldodge]

I’m in the process of disconnecting everything, cleaning and drying out and I noticed some sand and crud coming out of alternator. Could a faulty alternator cause any of the symptoms listed above? I will disconnect it and get it checked at a local parts store

Yes

Harness was submerged, It needs to be thoroughly cleaned. I would remove the harness and fill a container with white vinegar and let it soak. Then pull out and soak in clean water. Then spray down with WD40 and then air hose and blow dry