150 Mercury XRI no power and hard start

**Nuckolsn** · 08-27-2022, 11:56 AM

I’m still questioning why that check valve needs to be on the feed line to the electric pump.
Does anyone know if the electric pump is a diaphragm style pump?
That would explain the need for a check valve or “one way valve”

**David - WI** · 08-27-2022, 12:48 PM

Dremel that orange piece out and see how it runs. I would think the check valve is there to hold fuel pressure when you shut the engine off, so it re-starts right away rather than stumbling until the fuel pump builds the pressure back up.

**Nuckolsn** · 08-27-2022, 01:00 PM

That is an idea
Im going to check around Monday and see if I can find a good used check valve

**Nuckolsn** · 09-22-2022, 11:20 PM

Ok another update
Replaced the check valve and no change
In an earlier post I had stated that I had replaced the engine head temp sensor

The hard start issue I was having could be alleviated by unplugging the sensor
And I believe I now know why

The FSM states that the ECU receives signal from this temp sensor until the motor reaches 90 degrees
But it also states that unplugging (opening the circuit) this sensor fuel is increased by 40%
So today while on the water I unplugged that sensor and the boat would plane out and run

I am now convinced that my injector driver in the ECU is failing and by unplugging that sensor the ECU is compensating somewhat by throwing more fuel to the injectors.
Does this make sense to anyone else? I plan to ship my ECU to Brucato to have it tested
Any thoughts?

**OnPad** · 09-22-2022, 11:48 PM

Have you checked out your flow from fuel pressure regulator yet?
I see in a previous post you tried a different ecu, with not much change?
How's your power supply to ecu? Grounds?

Your going to be expert on laser injection, and answering my questions, when you get it sorted!!!

**Nuckolsn** · 09-23-2022, 12:06 AM

I have flow tested out of the regulator
I also double checked my fuel pressure today while trying to plane out and it’s good

Additionally I checked the high pressure pump capacity by squeezing the fuel line before the regulator while the pump was running and was able to easily reach 50psi

I also ruled out the fuel pump driver by completely grounding the fuel pump while trying to plane out and that had no effect either

It is my understanding that the increase or decrease of fueling is accomplished by the ECU changing pulse width on the injectors and I believe that is where my problem lies

If the driver(s) for the injectors are failing and not pulsing enough to satisfy the fuel needed to make the boat plane out, then you unplug the engine head sensor and it increases the fuel by 40 percent and after that it is able to plane out and run, this is what I’m thinking the scenario is

I guess I’ll know for certain when I get the diagnosis from Brucato

**Nuckolsn** · 09-23-2022, 12:07 AM

The other ECU I tried was for a 200
The guy said it should be the same but I’m not convinced that this was a conclusive enough test

**OnPad** · 09-23-2022, 12:14 AM

Give Brucato a shot.

I would think bad drivers would have showed up in your test with the dva, but I'm no expert.

**PanRonnie** · 09-23-2022, 09:51 AM

You did not mention getting your injectors checked
You might wanna buy some of ebay and get a matching set togehter
With an adjustable regulator you can fine tune your mixture

**OnPad** · 09-23-2022, 12:59 PM

I'll second PanRonnie's post. Send your injectors to Brucato while your getting your ecm tested.

**Nuckolsn** · 09-27-2022, 03:51 PM

I heard back from Brucato and my MAP sensor is not functioning
The FSM states that the information sent by the MAP sensor helps the ECM determine fuel delivery
During the last test I stated that I could get the boat to plane by disconnecting the engine head temp sensor (which increases fuel flow 40%)
Does this sound reasonable? Would unplugging that sensor “ override “ so to speak, the ECM and just throw 40 percent more fuel and mask the problem of the MAP sensor not functioning?
Ill probably get the Brucato ACU regardless since the MAP sensor functioning sounds pretty critical lol
I just hope that fixes my issues
Any thoughts?

**Nuckolsn** · 09-27-2022, 03:52 PM

Also as mentioned above
the next step will be having the injectors professionally tested and serviced

**David - WI** · 09-27-2022, 05:49 PM

Originally Posted by Nuckolsn

I heard back from Brucato and my MAP sensor is not functioning
The FSM states that the information sent by the MAP sensor helps the ECM determine fuel delivery
During the last test I stated that I could get the boat to plane by disconnecting the engine head temp sensor (which increases fuel flow 40%)
Does this sound reasonable? Would unplugging that sensor “ override “ so to speak, the ECM and just throw 40 percent more fuel and mask the problem of the MAP sensor not functioning?
Ill probably get the Brucato ACU regardless since the MAP sensor functioning sounds pretty critical lol
I just hope that fixes my issues
Any thoughts?

Yes, the extra 40% would probably cover up the bad MAP a little bit.

You can have your ECU repaired... especially if it just needs the MAP sensor replaced.

https://www.cdielectronics.com/

**David - WI** · 09-27-2022, 06:50 PM

Actually Brucato can probably fix that, and it's there already?

**Nuckolsn** · 09-27-2022, 08:02 PM

Yes they have my ECU
It was recommended by them to just replace
They are worried that since the MAP went out the other drivers and such probably aren’t far behind